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200 Cards in this Set
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A 6 year old female spayed golden retriever is presented for acute onset of flaccid jaw paralysis. The dog is unable to close her mouth, has difficulty eating and is drooling. There is no history of trauma. What is the most likely diagnosis?
A. Meningoencephalitis B - Myasthenia gravis C - Facial nerve paralysis D - Trigeminal neuritis E - Masticatory myositis |
D - Trigeminal neuritis
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What are the clinical signs associated with cauda equina?
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PAIN in the lumbosacral area (elicited by tail raise, hindlimb extension), LMN hindlimbs, especially Sciatic nerve damage at L7-S1 (lack withdrawal), +/- urinary/fecal incontinence, +/- SELF-MUTILATION of tail, perineum, pelvic limb.
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Is Cauda equina syndrome acquired or congenital?
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Lesion due to compression of cauda equina at L7-S1 (lumbosacral stenosis). Can be congenital (abn development dorsal arch L7-S1, small dogs, Border Collies) or acquired (degenerative changes, big dogs, especially German Shepard, Rottweiler, Boxer).
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Where are the most common lesion localization sites for Wobbler's syndrome?
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Wobbler syndrome is a cervical spinal cord disease (also called cervical vertebral instability/ caudal cervical spondylomyelopathy). In adult form it is an intervertebral disc disease, usually seen at C5-C6 or C6-C7 in Dobies> 5 yrs, Great Danes> 2 years.
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What are common clinical signs associated with diskospondylitis?
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Typically a large middle aged dog presenting with lumbosacral pain. Due to bacterial/fungal infection of intervertebral disk and adjacent vertebral bodies. Look for systemic signs like fever (1/3 of patients), weight loss, anorexia.
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What is the lesion location and common age of onset per breed for Wobbler's Syndrome?
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Wobbler syndrome (also called cervical vertebral instability/ caudal cervical spondylomyelopathy). In the adult form it is an intervertebral disc disease, usually seen between C5-C6 or C6-C7 in Dobermans more than 5 yrs old and Great Danes more than 2 years old.
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In dogs, all reported cases of IAC have been in the _________ fossa.
a. rostral b. middle c. caudal d. none of the above |
c. caudal
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Formation of IACs in dogs is believed to be due to
a. a split in the arachnoid meningeal layer during embryogenesis. b. failure of the neuroectoderm and nonneural ectoderm to separate during embryogenesis. c. compensatory fluid accumulation following an in utero brain infarction (stroke). d. failure of the cerebellar vermis to form correctly during embryogenesis. |
a. a split in the arachnoid meningeal layer during embryogenesis.
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Proposed theories to explain progressive expansion of IACs in dogs include
a. active secretion by the arachnoid cells lining the cyst cavity. b. movement of fluid into the cyst cavity along an osmotic pressure gradient. c. movement of fluid into the cyst from the neighboring subarachnoid space via slit-like openings (one-way valves) into the cyst lumen. d. all of the above |
d. all of the above
active secretion by the arachnoid cells lining the cyst cavity. movement of fluid into the cyst cavity along an osmotic pressure gradient. movement of fluid into the cyst from the neighboring subarachnoid space via slit-like openings (one-way valves) into the cyst lumen. |
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Which is most characteristic of the typical signalment for dog with an IAC?
a. 10-year-old female spayed German shepherd b. 4-year-old male castrated shih tzu c. 2-year-old female greyhound d. There is no typical signalment. |
b. 4-year-old male castrated shih tzu
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Clinical signs associated with IAC in dogs include
a. abnormal mentation. b. generalized seizures. c. cerebellar dysfunction. d. all of the above |
d. all of the above
abnormal mentation. generalized seizures. cerebellar dysfunction. |
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The preferred imaging modality for diagnosis of IAC in dogs is
a. ultrasound. b. scintigraphy. c. magnetic resonance d.imaging. computed tomography. |
c. MRI
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The characteristic MRI appearance of an IAC in a dog is a large, well-demarcated, cyst-like structure that is
a. hypointense on T1-weighted images. b. hyperintense on T2-weighted images. c. contrast-enhancing and hyperintense on FLAIR images. d. a and b |
d. a and b
hypointense on T1-weighted images. hyperintense on T2-weighted images. |
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In a study of IAC cases in which brain compression by the cyst was measured, dogs were found to be most likely to exhibit clinical dysfunction if
a. the cyst compressed more than 14% of the occipital lobe of the cerebrum. b. both the occipital lobe of the cerebrum and the cerebellum were compressed by the cyst. c. a and b d. none of the above |
c. a and b
the cyst compressed more than 14% of the occipital lobe of the cerebrum. both the occipital lobe of the cerebrum and the cerebellum were compressed by the cyst. |
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Medical therapy for IAC in dogs is directed at
a. decreasing brain edema associated with the cyst. b. controlling seizure activity if present. c. minimizing increases in intracranial pressure. d. all of the above |
d. all of the above
decreasing brain edema associated with the cyst. controlling seizure activity if present. minimizing increases in intracranial pressure. |
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Which statement regarding surgical management of IAC is false?
a. Both cyst fenestration and cystoperitoneal shunting procedures have been described in dogs. b. Cystoperitoneal shunt (CPS) placement has been shown to be superior to fenestration in dogs and humans with IAC. c. The success rate for surgical management of IAC appears to be high in people and dogs. d. a and b |
b. Cystoperitoneal shunt (CPS) placement has been shown to be superior to fenestration in dogs and humans with IAC.
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Which of the following is imperative for patients with a suspected unstable acute spinal cord injuries (SCI)?
a. immobilization on a firm, flat surface b. evaluation of gait c. evaluation of posture d. administration of high doses of corticosteroids |
a. immobilization on a firm, flat surface
dexamethasone has very little ability to inhibit oxygen radical damage in central nervous system tissue |
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Primary injury consists of
a. direct damage to the spinal cord parenchyma via compression, contusion, shearing, laceration, or stretching. b. depletion of the neuronal ATP level. c. intracellular accumulation of calcium and sodium. d. oxygen free radical formation and increased cytokine production. |
a. direct damage to the spinal cord parenchyma via compression, contusion, shearing, laceration, or stretching.
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Management of an SCI should include
a. appropriate diagnostics and surgical stabilization or decompression if needed. b. high doses of MPSS. c. dexamethasone. d. PEG. |
a. appropriate diagnostics and surgical stabilization or decompression if needed.
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The preferred imaging modality for evaluation of patients with a suspected FCE is
a. plain film radiography. b. MRI. c. myelography. d. CT. |
b. MRI.
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The antibiotic _________ has potential for use in the treatment of SCI
a. penicillin b. enrofloxacin c. minocycline d. amoxicillin-clavulanic acid |
c. minocycline
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If surgery is cost prohibitive, recommendations for managing patients with SCIs include
a. high doses of MPSS. b. dexamethasone. c. leash walking for at least 15 minutes three times/day. d. strict cage rest, pain management, and physical therapy. |
d. strict cage rest, pain management, and physical therapy.
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Which carries a grave prognosis?
a. absent superficial pain perception with a suspected disk extrusion b. absent DPP within 24 to 48 hours with a suspected disk extrusion c. superficial pain and absent voluntary motor function with a suspected FCE d. absent DPP after trauma causing a fracture/luxation of the vertebral column |
d. absent DPP after trauma causing a fracture/luxation of the vertebral column
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__________ do(es) not have potential as a future therapy for SCI.
a. Olfactory ensheathing cells b. Oscillating field units c. PEG d. Naloxone |
d. Naloxone
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Management of a nonambulatory animal consists of
a. regular turning. b. appropriate bedding to prevent decubital ulcers. c. appropriate bladder management. d. all of the above |
d. all of the above
regular turning. appropriate bedding to prevent decubital ulcers. appropriate bladder management. |
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In patients with SCI secondary to trauma, the initial assessment should focus on
a. a thorough neurologic examination. b. obtaining lateral radiographs. c. airway, breathing, and cardiovascular assessment. d. obtaining MRI images. |
c. airway, breathing, and cardiovascular assessment.
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Which of the following is NOT considered a component of the lower motor neuron?
A. Cerebellum B. Neuron cell body in ventral gray matter C. Axon of the neuron cell body D. Neuromuscular junction E. Peripheral nerve |
A. Cerebellum
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Which one of the following is not a component of the reflex arc ?
A. Dorsal root ganglion B. Upper motor neuron C. Sensory Nerve D. Sensory Nerve endings/receptors E. Neuromuscular junction F. Lower motor neuron |
B. Upper motor neuron
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What reflex will provide more precise localization of a lesion between T3-L3
A. Babinski reflex B. Schiff Sherrington response C. Panniculus(Cutaneous trunci) reflex D. Thomas extraordinarily accurate reflex E. It is not possible to localize the lesion more accurately. |
C. Panniculus(Cutaneous trunci) reflex
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All of the following are signs of forebrain disease EXCEPT:
A. Abnormal behavior B. Seizures C. Turning or circling to one side D. Weakness with decreased proprioception on one side E. Visual deficits on one side F. Head tilt |
F. Head tilt
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A 7-year-old cat presents with head tilt and ataxia. The neurologic examination shows an alert cat with generalized ataxia and a head tilt to the left. Postural reactions are decreased in the left thoracic and pelvic limbs and normal in the right limbs. Spinal reflexes are normal. There is a positional rotary nystagmus. Proprioception is normal in all limbs.
A. Left inner ear B. Right inner ear C. Left brainstem D. Right brainstem E. Left forebrain |
C. Left brainstem
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An 11-year-old dog presents with slowly progressive abnormal behavior, characterized by loss of normal interaction with the family. Exam shows a quiet dog with a tendency to turn to the left when walking. Postural reactions and proprioception are slightly slow in the right thoracic and pelvic limbs and normal in the left. The remainder of the exam is normal.
A. Left brainstem B. Right brainstem C. Right forebrain D. Left forebrain E. Left inner ear |
D. Left forebrain
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A 7 year old, spayed female, chow is presented with a right forelimb paralysis following being hit by a car. The left forelimb and both rear limbs are normal. There is no withdrawal reflex in the right forelimb. There is no response to deep pain elicitation in any of the toes. There is a Horner's syndrome on the right side. Which one of the following statements is true:
A. The clinical signs are indicative of an injury to the nerves at the level of the brachial plexus. B. The injury is in the spinal cord between C1-C4. C. The injury is in the spinal cord between C5-C7 D. The injury involves the nerve roots between C5-T3 |
D. The injury involves the nerve roots between C5-T3
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A patient's CSF shows 20-50 WBCs/microliter and 20-50 RBCs/microliter. Are the WBCs due to CNS inflammation or blood contamination from the procedure?
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Inflammation. If the WBCs wre from contamination by circulating blood, there would be 1000x more RBCs than WBCs (i.e. as shown on a CBC where WBCs are reported in thousands/RBCs in millions)
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What is the main excitatory neurotransmitter in the brain and spinal cord?
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Glutamate
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Necrosis in the CNS is typically of which pathological type?
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Liquefactive necrosis
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The Cushing reflex/Cushing response is activated with severe increases in intracranial pressure. What is the expected change in arterial blood pressure that occurs as a result of the cushing reflex?
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Systemic arterial hypertension. When intracranial pressure rises markedly (e.g. injury, inflammation), this reflex helps ensure that arterial perfusion of the brain is maintained.
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UMN signs in both the thoracic and pelvic limbs localize a neurological lesion to which segments of the spinal cord?
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C1-C5
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If nystagmus changes direction with head position, is the vestibular lesion most likely central or peripheral?
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Central - i.e. due to a brain lesion.Mystagums due to peripheral (middle/inner ear) lesions does not change directions with changes in head position.
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The cervical intumescence, which is the origin of the LMNs for the thoracic limbs, contains which spinal cord segments?
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C6-T2
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Except in a standing animal, the crossed extensor reflex is considered abnormal. Is it a sign of UMN or LMN disease?
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UMN
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In Horner's Syndrome, how can a lesion be localized pharmacologically to determine if it is preganglionic or postganglionic (of the LMN portion of the pathway)?
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Application of a dilute direct acting sympathomimetic to both eyes reveals minimal pupillary dilatin if the lesion is preganglionic, and rapid marked dilation of the lesion is postganglionic.
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What is the anticlinal space and where is it found in the cat and dog?
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It is the narrowest thoracic intervertebral disk space. It is found between the 10th and 11th thoracic vertebrae (the 11th thoracic vertebra is the anticlinal vertebra).
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Which nerve and associated spinal cord segments does the patellar reflex test?
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Femoral nerve (spinal segments L4-6)
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The trapezius muscle is innervated by which nerve?
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Accessory nerve (cranial nerve XI) - dorsal branch
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Which disorder of globe (eyeball) movement is seen with central but not peripheral vestibular dysfunction?
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Vertical nystagmus (horizontal and rotary nystagmus can occur in both). Also acceptable: nystagmus that changes in direction with change in head position.
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What are the 2 components of the intervertebral disk?
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Nucleus pulposus and annulus fibrosus
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Does an animal with paresis, hyperreflexia, and disuse atrophy that is mild and slow to develop have UMN or LMN disease of the affected area?
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UMN
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When observing for symmetry of facial expression in the dog, you are mainly assessing the status of which cranial nerve?
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Facial nerve (CN VII)
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Which nerve provides somatic innervation to the external urethral spincter?
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Pudendal nerve
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In neurology, what is meant by the term "root signature"?
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Lameness and pain resulting from reduced sensation in nerve root or sensory nerve of the cervical or lumbosacral intumescence. It usually is a result of nerve compression.
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The menace response test assesses which cranial nerve?
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CN II and VII (optic and facial nerves)
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List 4 nerves or neuroanatomical structures involved in the menace response?
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Retina, optic nerve (CN II), medulla, cerebral cortex, cerebellum, facial nerve (CN VII)
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A lesion affecting the ascending reticular activating system in the brainstem would result in which characteristic clinical manifestation?
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Depressed mentation, coma
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Which branch of the trigeminal nerve (CN V) innervates the muscles of mastication?
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Mandibular
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What is the name of the interneurons of the spinal cord that are affected by tetanus toxin?
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Renshaw cells
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Which part of the brain is responsible for the modification and coordination of body movements so that they are fluid in nature?
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The cerebellum
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Observing the PLR tests which cranial nerves?
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CN II and III (optic and oculomotor)
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Observing symmetry of eye position and pupils tests which cranial nerves?
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CN III, IV, and VI (oculomotor, trochlear, and abducens)
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In addition to causing paralysis of the limb and loss of sensation distal to the elbow, a complete brachial plexus avulsion typically causes 2 other neurological deficits. What are they?
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Ipsilateral Horner's syndrome (T1-3; sympathetic nerve) and loss of cutaneous tunci reflex (C8, T1; lateral thoracic nerve)
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Which ligaments in the thoracic spinal column keep the thoracic intervertebral discs in situ?
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The intercapital ligaments (present at T1-2 to T9-10)
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Cranial nerve IV, the trochlear nerve, is the motor pathway to a single muscle only. Which one is it?
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Dorsal oblique muscle of the eye
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The nuchal ligament is absent in this domestic animal species.
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The cat
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What is the main physical examination finding in dogs with trigeminal neuritis?
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Bilateral paralysis of the masticatory muscles (dropped jaw; inability to close jaw).
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During a neuro exam, what does a normal panniculus reflex indicate?
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Integrity of the spinal cord between the site of stimulation and the C8-T1 spinal cord segment
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What is the most common cause of cervical ventroflexion in the cat?
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Hypokalemia. OP toxicity, thiamine-responsive disease, and hyperthyroidism are other moderately common causes of the syndrome.
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A 7 month-old beagle has acute-onset guarding of the neck suggesting cervical pain; generalized hyperesthesia; and anorexia, which resolve within 24 hours of treatment with corticosteroids. What is the most likely diagnosis?
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Juvenile polyarteritis ("Beagle pain syndrome")
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A dog with a head tilt to the left, vertical nytagmus, ataxia, absent facial sensation ipsilaterally, and poor proprioception of the left fore- and hindlimbs has a neuro lesion of which specific anatomical location?
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Left-sided central vestibular system (medulla, cerebellar peduncles, cerebellum, or combination)
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What is the typical signalment of dogs affected by fibrocartilagenous embolism (FCE)?
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Adult, large and giant breed, non-chondrodystrophic breeds
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A dog presents BAR, seemingly not painful, but unable to close the mouth or prehend food. Jaw tone is lax; the mouth is easily closed manually. This is most likely a case of:
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Trigeminal neuritis - resolves spontaneously in 2-3 weeks
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Although not pathognomonic, myoclonus is a movement disorder most commonly associated with which specific CNS infection in dogs?
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Canine distemper virus infection
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During a neurological examination, where is a spinal lesion likely to be if there is pathologically increased resistance to bladder outflow?
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UMN lesion cranial to the sacral spinal cord segments (L7 or cranial to it), causing increased urethral sphincter tone
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What is the primary differential for a 1-month-old puppy with a dome shaped head and bilateral ventrolateral strabismus?
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Congenital hydrocephalus
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A 4 year-old Dachshund is acutely unable to voluntarily move her hindlimbs. A firm pinch of a toe on the affected limb reveals withdrawal of the limb (flexion). What information does this response provide you regarding pain sensation?
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None. Withdrawal of the limb is only part of the flexor reflex arc, and is independent of conscious proprioception.
the withdrawal (flexor) reflex only requires the peripheral nerves and the L6-S1 spinal segments. The cord could be totally transected cranial to L6 and you will still see withdrawal of the limb when you pinch the toe |
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A 1-year-old Great Dane has gradual, progressive hindlimb ataxia and mild hindlimb proprioceptive deficits. The remainder of the exam is unremarkable. What is the most likely diagnosis?
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Cervical vertebral malformation/malarticulation (Wobbler's syndrome)
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In a dog or cat, in which directin should the hindlimb be manipulated to minimize the risk of sciatic nerve damage when placing an intraosseous needle in the proximal femur?
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The hindlimb is rotated internally and adducted, to widen access to the trochanteric fossa and reduce the risk of sciatic nerve damage.
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What is the most effective treatment for resolving idiopathic vestibular disease affecting older dogs?
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Nothing - as most cases spontaneously resolve in 1-2 weeks. +/- antiemetics, anxiolytics or sedatives - but usually not needed
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A dog HBC has bilateral HL paralysis and FL extensor hypertonia, iwth preserved voluntary movement and CPs in the FLs - what is the term and location for the lesion?
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Schiff-Sherrington posture; thoracic or cranial lumbar spinal cord.
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A 4 year old, MN, dachshund is presented with an acute onset of paraplegia after jumping off a couch. She's BAR, and can walk on the FLs w/out difficult, FL reflexes are intact. Patellar reflexes are absent in the right PL and decreased in the left PL. Flexor reflexes are normal in both PLs. Anal tone and the perineal reflex are intact. CNs are intact. Based on HL reflexes is this UMN or LMN?
Which spinal cord segment is affected? a. C1-C5 b. C5-T3 c. T3-L3 d. L3-L4 e. L5-L7 |
d. L3-L4
Paraplegia with decreased or absent patella reflexes would indicate the lesion is in the spinal cord at L3/4 where the cell bodies of the femoral nerve which mediates this reflex are located - the normal flexor reflex in the HLs would indicate that the spinal cord segments between L5 and L7 are intact |
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Why should deep pain be assessed in all toes?
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~Deep pain should be assessed in all toes because of differences in innervation:
-first digit in the TLs if present is supplied by a branch of the radial n. - other 4 digits are supplied by anastomoses between branches of the median and ulnar nerves |
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7 yr old, FS mixed breed dog is presented w/acute onset of tetraparesis. The patient is BAR, not painful, and has voluntary motion in all limbs but cannot stand without support. CP deficits are present in the right TL and both PLS - CP is normal in left
TL - Rear leg reflexes are hyperactive. The TL flexor reflex is normal on the left side but significantly decreased on the right. Anal tone and the perineal reflexes are normal. Superficial and deep pain are present in all limbs. Cranial reflexes are normal however there is a Horners syndrome present in the right eye. Q) Based on the TL reflexes is this an UMN lesion or a LMN lesion? A. LMN B. UMN Q) Where is the lesion? A. C1-C5 B. C5-T3 C. T3-L3 D. L3-L7 E. S1-S3 |
A. LMN
B. C5-T3 ~Tetraparesis with UMN reflexes in the rear legs and LMN reflexes in the right FL indicate a spinal cord lesion involving the cervical intumescence on the right side ~Horners syndrome on the right side may be due to a spinal lesion at T1-T3 where the sympathetic cell bodies are located |
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A 10 year old, M/N, DSH cat is presented with a flaccid tail and urinary and fecal incontinence after having been hit by a car.
The cat is mentally alert and ambulatory but quite painful. Proprioception and postural reactions are normal. Peripheral reflexes are normal. Cranial nerves are within normal limits. The tail is limp, the anus is widely dilated and there is no perineal reflex. The bladder is very large and can be easily expressed Q) Where is the lesion? A. C1-C5 B. C5-T3 C. T3-L3 D. L3-L7 E. S1-S3 |
E. S1-S3
Rads revealed a sacro-coccygeal fracture - this type of traumatic injury commonly results in avulsion of the nerves of the sacral and coccygeal spinal cord resulting in irreversible urinary and fecal incontinence. ~It is important to note that due to differential growth of the spinal cord and vertebral column, spinal cord segments tend to lie somewhat cranial to the intervertebral foramen from which their nerves exit ~This is especially true of spinal cord segments L5-Cy as the cord in the dog ends at about vertebral level L6 ~The cord in the cat terminates slightly more distally ~When we refer to an S1-3 lesion we are referring to the spinal cord segment not the vertebral level |
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What is the name of the antigen-presenting cells in the CNS?
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Astrocytes are antigen-presenting cells in the CNS
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What is located in gray matter, and white matter?
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Central gray matter, peripheral white matter
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What is the difference between Hansen type I and type II intervertebral disk disease?
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Hansen type I - acute extrusin of nucleus pulposus int vertebral canal
Hansen type II: slow chronic protrusion of annulus fibrosus into vertebral canal |
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What is the half-life of metronidazole and where does it have a high affinity?
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T1/2 is 3-13 hours
It has excellent bioavailabilty and a high affinity for bone and CNS. |
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What are the most common signs associated with metronidazole toxicity in dogs?
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Adverse effects: seizure, tremors, and rigidity.
Neuro signs most common: central vestibular or other disturbances of balance - head tilt, falling, paresis, ataxia and vertical nystagmus. |
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What are the most common signs associated with metronidazole toxicity in cats?
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In cats: disorientation, seizures, and central blindness - i.e. signs related to cerebral dysfunction
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Which rad view is best for detecting polyps?
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an open mouth view under general anesthesia with the endotracheal tube removed.
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When you are not sure if the nystagmus is vertical or horizontal, what else may indicate central?
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Decrease in postural reactions with central disease that usuallyaffect both front and hind limbs
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3-yr F Sheltie presents for udden onset of apparent blindness 3 days ago - PE: alert, disoriented dog that bumps into things. Gait, postural reactions, and spinal reflexes are normal. The menace response and visual following are absent bilaterally. Both pupils are dilated in room light and there is no pupillary light reflex (PLR). Lesion localization:
A. Retina, optic nerves/chiasm/tracts B. Forebrain (cerebrum, thalamus) C. Cerebellum D. Brainstem |
A. Retina, optic nerves/chiasm/tracts
The absent pupillary light reflexes indicate a lesion in the PLR pathway: Retina --> optic nerve --> optic chiasm --> optic tract --> midbrain (pre-tectal nucleus, parasympathetic nucleus CN III) --> cranial nerve III --> pupils |
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How do you further localize the lesion in an acutely blind patient?
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with a blind patient, the first thing to do is assess the pupillary light reflexes (PLRs):
1. If PLRs are absent, then the lesion is in the retina, optic nerve, chiasm or tract. 2. If PLRs are normal, then the lesion is in the forebrain (thalamus, cerebrum). |
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Important differentials for blindness with dilated, unresponsive pupils and a normal fundus are:
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1. Sudden Acquired Retinal 1.Degeneration Syndrome (SARDS)
2. Optic neuritis 3. Neoplasia affecting the optic nerves. |
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When suspecting SARDS, what is the confirmatory diagnostic test?
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electroretinogram (ERG) to check retinal function:
1. If the ERG is flat, then there is no retina function, which means the diagnosis is SARDS. 2. If the ERG is normal, then the retina is fine, so it's probably optic neuritis or neoplasia. At that point, a spinal tap is indicated in an attempt to identify the cause of the optic neuritis and a CT or MRI to identify a tumo |
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What is the TOC for optic neuritis?
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Prednisone. With optic neuritis, the chance of recovering vision is best with early treatment. So acute blindness an urgent condition.
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Case: 9 yr GRD presents with sudden onset of difficulty walking 48hr duration - client does not believe it has progressed.
PE: disoriented dogs with a head tilt to the left (the left ear is lower than the right). When walking, she has generalized ataxia and tends to lean and fall to the left. Her proprioceptive positioning and hopping are weak on the right, normal on the left. Spinal reflexes are normal. When you extend her head up, there is a vertical nystagmus, fast phase down. The rest of the exam is normal. Lesion localization: A. Peripheral vestibular (inner ear) B. Central vestibular (brainstem/cerebellum) C. Forebrain D. Cervical spinal segments |
B. Central vestibular (brainstem/cerebellum)
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Which side is the GRD's brainstem lesion?
a. left b. right |
b. right
The lesion is on the right, the side of the weakness. With peripheral vestibular lesions, the head will tilt toward the side of the lesion. However, with central vestibular lesions the head can tilt to either side. But with brainstem lesions like this, the weakness is always on the same side as the lesion. These pathways dont cross to the other side until you get to the forebrain. A head tilt to the opposite side of the lesion even has a special name, paradoxical vestibular syndrome. This is usually caused by a lesion in or near the caudal cerebellar peduncle, a structure that connects the cerebellum with the brainstem. |
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What is the most likely etiology for the GRD?
A. brain tumor B. encephalitis C. stroke D. toxin E. middle ear infection |
C. stroke
The primary considerations for an acute, nonprogressive brainstem lesion would be a stroke (infarct). Tumor and inflammatory lesions (GME, fungal, protozoan, etc.) are also possible but less likely with the sudden, nonprogressive course. |
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What are the Ddx for underlying etiologies causing stroke?
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hypothyroidism, hypertension, Cushings, renal disease, or coagulopathy, and in cats hyperthyroidism
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If a stroke is caused by an infarct to the right cerebellar hemishere, what is the prognosis? And what usually causes it?
a. grave b. poor return to function c. good |
The signs gradually resolved with 10 days of supportive care.
Generally an embolus (blood clot) but we often don't find a specific cause, esepecially in older dogs. |
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True or false. Strokes are rare in cats and dogs.
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False - with CT and MRI we recognize that stroke is not rare in dogs and cats and is an important consideration in patients with a sudden onset of a focal brain lesion that does not worsen with time.
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How does hypothyroidism cause a stroke?
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It can cause atherosclerosis, high choleterol and high triglycerides. This damages the blood vessels and promotes clots.
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What are the generalized signs associated with cerebellum dz?
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Generalized ataxia with hypermetria and no weakness or proprioceptive deficits indicates a lesion of the cerebellum. Proprioceptive positioning tests conscious proprioception and the cerebellum is concerned with unconscious proprioception. The cerebellum coordinates movement, but does not initiate movement, so there is no paresis (weakness). Intention tremors.
Cerebellar lesions will sometimes cause an absent menace response with otherwise normal vision. |
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Non-progressive cerebellar signs present since several weeks of age suggest _____
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cerebellar hypoplasia
Kittens - ususally in utero infection w/ panleukopenia Puppies - in utero parvo or hereditary |
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With progressive signs of cerebellar dz in a puppy what would be the Ddx?
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If the signs progress, differentials would include metabolic storage diseases, abiotrophies, or encephalitis. Metabolic storage diseases and abiotrophies are rare hereditary disorders caused by a lack of an enzyme in a metabolic pathway. They are most common in pure bred dogs because they are most often recessive traits, meaning both parents must carry the gene. They usually have an onset at a young age and cause multifocal or diffuse signs, such as ataxia, hypermetia, paresis, blindness, and abnormal mentation. They progressively worsen over time. In some cases, MRI or genetic testing is diagnostic. There is usually no treatment but diagnosis can be important for the breeder.
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What is one of the most common ortho conditions referred to neuro for IVDD?
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bilateral CCLs
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How does infarct differ from a tumor on MRI?
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he keys are minimal mass effect, which you would see with tumor, gray and white matter invovlement equally, and wedge-shape corresponding to a vascular territory
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What is the typical CSF tap with optic neuritis?
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usually have some CSf abnormalaties ... but not all
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6 yr F mix presents w/ 2-week duration of abnormal behavior - no longer interacts normally with the family, has recently started to walk in a circle. 2 days ago she had a seizure.
Examination shows an alert dog that tends to turn and circle to the right. Postural reactions are slow on the left, normal on the right. Spinal reflexes are normal. Menace response is absent on the left with normal pupils. The remainder of the exam is normal. Where is the lesion? A. Right forebrain (cerebrum or thalamus) B. Left forebrain (cerebrum or thalamus) C. Right sided brainstem D. Left sided brainstem E. Cerebellum |
A. Right forebrain (cerebrum or thalamus)
Abnormal behavior suggests a forebrain lesion. Seizures also arise from the forebrain. Animals with an asymmetric forebrain lesion may turn and circle to the side of the lesion, suggesting Bobbie's lesion is on the right. A right-sided forebrain lesion would also account for left hemiparesis due to damage to the upper motor neurons (in the forebrain, motor and sensory function crosses over to the other side). An absent menace with normal pupils also indicates a forebrain lesion. Again, at the level of the forebrain, deficits are contralateral -- on the opposite side of the body. |
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The term forebrain refers to the structures derived from the ____
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prosencephalon:
1. the cerebral cortex 2. cerebral white matter, 3. basal nuclei, and 4. thalamus. |
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True or False. Clinically, you usually can't distinguish between lesions involving the forebrain.
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True. For example, a lesion in the left cerebral cortex will cause the same signs as a lesion in the left cerebral white matter - thus forebrain dz is used
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Describe why circling can occur with forebrain dz.
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Certain forebrain lesions can disrupt the part of the brain that serves to direct attention to stimuli. This can cause a hemi-neglect (also called hemi-inattention) syndrome. There are two components:
1. Unawareness of the contralateral environment. This refers to both the external environment (sight, sound, etc.) and the internal environment (touch, etc.). 2. Compulsive orientation to the ipsilateral environment. This is manifested as a tendency to always turn and circle toward the side of the lesion. |
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All of the following are signs of forebrain disease EXCEPT:
A. Abnormal behavior B. Seizures C. Turning or circling to one side D. Weakness with decreased proprioception on one side E. Visual deficits on one side F. Head tilt |
F. Head tilt
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In general, signs of forebrain disease include:
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1. Abnormal behavior
2. Seizures 3. Turning/circling to the side of the lesion 4. Contralateral hemiparesis 5. Decreased touch and proprioception on the contralateral side 6. Deficits in the contralateral visual field with normal pupils Note: it is RARE to have all of these signs, and signs can be very subtle |
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In the case above presenting with forebrain dz, what is the Ddx?
A. Toxic and metabolic disorders B. Stroke and trauma C. Brain tumor and encephalitis D. Idiopathic epilepsy E. Otitis interna |
The primary differentials would be: 1. Neoplasia: primary, or less likely metastatic brain tumor
2. Infectious/inflammatory disorders, including: a) necrotizing encephalitis, b) granulomatous meningoencephalitis (GME), c) fungi, d) protozoa, and e) Rickettsia. The likelihood of each of these will depend on what you see in your region. Stroke and trauma are less likely because these are usually very acute and not progressive. Metabolic and toxic disorders are unlikely because those usually cause diffuse signs. For example, why would a toxin or hypoglycemia affect one side of the brain but not the other? Idiopathic epilepsy does not cause focal neurological deficits and otitis media does not fit w/ forebrain dz. |
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How can Rickettsia disease cause encephalitis?
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Rickettsial infections can cause a vasculitis that affects the brain and causes an encephalitis.
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What is the most common inflammatory brain dz in dogs?
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granulomatous meningoencephalitis (GME)
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What is the treatment for GME?
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Treatment consists of immune modulating drugs - i.e. prednsione and cytosine
Alternate use of azathioprine or cyclosporine |
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What is the most common signalment for GME?
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Middle-aged, female poodles, terriers and other small breeds are at increased risk
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What is the prognosis for GME?
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Most dogs improve with therapy, although some dogs eventually relapse and become refractory to medical therapy, usually about 2-3 years after diagnosis. However, some affected dogs can live relatively disese free for much longer.
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How long does treatment for GME last?
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t's usually life-long - attempts have been made to wean off after a year but most relapse and harder to achieve a 2nd remission. Wean to LED (usually q48h)
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What are the most common CSF findings with GME?
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lymphocytic, monocytic pleocytosis with large lacy looking macrophages
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3-year-old female cat is presented with a sudden onset of difficulty walking - client reports that P was sleeping on the couch when she suddenly fell off and seemed to suffer some type of "seizure". PE: stressed cat that stays crouched to the floor. When encouraged to walk, she has severe ataxia of the head, trunk, and limbs. She leans and falls to the left and her head tilts to the left. There is spontaneous, horizontal jerk nystagmus, fast phase to the right. Jerk nystagmus means nystagmus with a fast and slow phase. The remainder of the exam, including proprioceptive positioning, is normal. Lesion localization:
A. Forebrain B. Inner ear C. Brainstem D. Cervical spinal segments |
B. Inner ear
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Where do vestibular lesions occur?
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1. Peripheral (inner ear), or
2. Central (brainstem/cerebellum). |
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What clinical signs are consistent with central lesions causing vestibular disease?
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1. Vertical nystagmus or nystagmus that changes direction with different head positions.
2. Cranial nerve deficits. Other cranial nerve deficits indicate a central lesion, with the exception of facial paralysis (CN VII) and Horner's syndrome, because these nerves are located very close to the inner ear 3. Decreased levels of consciousness suggest a central lesion Note: there can be a head tilt with central vestibular |
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With peripheral vestibular disease is the fast phase in the direction of the lesion or away from the lesion?
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The fast phase is usually towards the opposite direction of the lesion.
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Differentials for peripheral vestibular lesions include:
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1. Otitis media/interna
2. Idiopathic vestibular disease (any age cat, old dogs) 3. Nasopharyngeal polyp (cat, rarely dogs) 4. Ototoxins (chlorhexidine, aminoglycosides) 5. Neoplasia 6. Hypothyroidism (dogs) |
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Workup for peripheral vestibular disorders involves:
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1. otoscopic and pharyngeal exam (usually under sedation/anesthesia),
2. thyroid testing in dogs, 3. and possibly skull/bullae radiographs. |
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Describe UMN lesions.
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The white matter of the spinal cord is made up of myelinated and unmyelinated axons. Some of these axons arise from neurons which are located within the brain. We refer to these neurons and their axons as Upper Motor Neurons (UMN). UMNs connect the brain with the LMNs and allow the animal to initiate movements and to refine them.
No UMN = no voluntary movement. ~Interruption of the UMN anywhere between the brain and the LMN results in proprioceptive deficits, ataxia, paresis and/or paralysis depending upon the degree of injury. ~Because the spinal cord segment containing the reflex arc is left uninjured, the reflex remains intact and is often hyperactive due to the lack of a modulating affect by the UMN. This phenomenon is referred to as an UMN reflex. |
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Describe the crossed extensor reflex.
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Refers to simultaneous extension of the opposite limb in response to elicitation of a flexor reflex in the stimulated
limb. The reflex occurs as a result of lack of UMN modulation of interneurons which connect the reflexes arcs on either side of the body. -Crossed extensor reflexes in the HLs indicate a spinal cord lesion above the level of L6 -Crossed extensor reflexes in the FLs indicate spinal cord lesion above the level of C6 |
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What is the rad finding for atlanto-axial luxation? And what is commonly also observed with this condition?
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lateral radiograph reveals an increased distance between the dorsum of C1 and C2 compatible with a diagnosis of atlanto-axial subluxation
May also note the lack of an apparent dens. Some with atlanto-axial luxations have agenesis of the dens |
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What is the most common clinical manifestation of atlanto-axial luxation?
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Young, small breed (yorkies) that are painful, holds head down, with an acute and progressive history.
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A 12 year old F/S mixed breed dog is presented with a history of chronic progressive paraparesis and severe back pain of several months duration - based on PE are the signs UMN or LMN?
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An UMN lesion. The LMN is intact and is released from modulation by the brain secondary to an injury to the UMN spinal tracts above the level of the reflex
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What are decreased or absent reflexes referred to as?
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LMN reflexes. It is important to realize that the reflex is an entirely local phenomenon. The UMN is not part of the reflex arc.
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Paraplegia with decreased or absent patella reflexes would indicate the lesion is in the spinal cord at:
A. C1-C5 B. C5-T3 C. T3-L3 D. L3-L4 E. L5-L7 F. S1-S3 |
D. L3-L4 - where the cell bodies of the femoral nerve which mediates this reflex are located.
The normal flexor reflex in the rear legs would indicate that the spinal cord segments between L5 and L7 are intact Retention of normal anal tone and perineal reflexes indicate that spinal cord segments S1-S3 are intact. |
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A spinal cord injury above the level of S1-3 can cause urinary and fecal incontinence because ____
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control of urination and bowel movements is mediated by the brain
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What is the innervation of the PLR?
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PLR is a reflex. Light is sensed by CN II; parasympathetic fibers of CN III cause contraction of the
iris muscle with direct and indirect simulation. The pupil is also innervated by sympathetic fibres responsible for dilation, which have their origin in the thalamus and send fibers down the cervical spinal cord to the T1-T3 spinal nerve roots, before they ascend up the neck and through the middle ear. |
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With anioscoria how do you determine which pupil is abnormal?
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the animal should be evaluated in the light and dark.
In the dark, a sympathetic lesion will mean the affected pupil will not be able to fully dilate. In the light, a parasympathetic lesion will mean the affected pupil will not be able to fully constrict |
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Spinal cord consists of grey matter and white matter. What neurons run within the grey matter?
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Neurons within the grey matter with axons that run within peripheral nerves are called Lower Motor Neurons (LMN)
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Which one of the following is not a component of the reflex arc?
A. Dorsal root ganglion B. Upper motor neuron C. Sensory Nerve D. Sensory Nerve endings/receptors E. Neuromuscular junction F. Lower motor neuron |
B. Upper motor neuron
We refer to decreased or absent reflexes as LMN reflexes. It is important to realize that the reflex is an entirely local phenomenon. The UMN is not part of the reflex arc. |
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f the spinal cord is injured above or below the level of the reflex arc, will the reflex be intact?
a. Yes b. No |
a. Yes, because the reflex arc is still intact
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A 4 year old, MN, dachshund presents with an acute onset of paraplegia after jumping off a couch.
The patient is BAR and can walk on the FLs without difficulty. FL reflexes are normal. Patellar reflexes are absent in the right rear leg and decreased in the left rear leg. Flexor reflexes are normal in both rear legs. Anal tone and the perineal reflex are intact. Cranial nerve reflexes are normal. Which spinal cord segments are involved? a. C1-C5 b. C5-T3 c. T3-L3 d. L3-L4 e. L5-L7 |
d. L3-L4
Paraplegia with decreased or absent patella reflexes would indicate the lesion is in the spinal cord at L3/4 where the cell bodies of the femoral nerve which mediates this reflex (patellar) are located. The normal flexor reflex in the rear legs would indicate that the spinal cord segments between L5 and L7 are intact. Retention of normal anal tone and perineal reflexes indicate that spinal cord segments S1-S3 are intact. A spinal cord injuryabove the level of S1-3 can cause urinary and fecal incontinence because control of urination and bowel movements is mediated by the brain. The bladder of such a patient will be difficult to express because the LMN s which control the internal and external sphincters to the bladder are intact and are released from control by the UMN. |
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What is the overall Px for this patient with L3-L4 intervertebral disk herniation?
a. Excellent b. Fair c. Guarded d. Grave |
c. Guarded - due to the location of the lesion at the lumbar intumescence, the loss of deep pain in one leg and decreased deep pain in the other leg.
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Why wouldnt it be a T3-L3 for this patient?
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T3-L3 would affect the UMNs. This would spare the patelar reflex. And in this patient the patellar reflexes were weak.
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What is more susceptible to permanent injury, thus overall Px - grey or white matter?
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Cell bodies in the grey matter are more susceptible to permanent injury than are the myelinated axons of UMN that run in the white matter.
Prognosis for recovery is more guarded if injury to the spinal cord involves the cervical or lumbar intumescence where the cell bodies whose axons supply the front and rear limbs are located or to the cell bodies at S1-3 whose axons supply the bladder and anus. |
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A 7 year old, FS, mixed breed dog is presented with an acute onset of tetraparesis. The patient is BAR, not painful, and has voluntary motion in all limbs but cannot stand without support. CP deficits are present in the right FL and both HLs. CP is normal in the left front leg. HL reflexes are hyperactive. The FL flexor reflex is normal on the left side but significantly decreased on the right. Anal tone and the perineal reflexes are normal. Superficial and deep pain are present in all limbs. Cranial reflexes are normal however there is a Horner's syndrome present in the right eye. Lesion localization:
a. C1-C5 b. C5-T3 c. T3-L3 d. L3-L7 e. S1-S3 |
b. C5-T3
Tetraparesis with UMN reflexes in the rear legs and LMN reflexes in the right front limb indicate a spinal cord lesion involving the cervical intumescence on the right side. Horners syndrome on the right side may be due to a spinal lesion at T1-T3 where the sympathetic cell bodies are located. |
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Which diagnosis would be most likely in this patient?
A. Degenerative spinal cord disease B. Anomalous spinal cord disease 7 (13%): C. Neoplastic spinal cord disease D. Infectious/Inflammatory E. Traumatic spinal cord injury F. Vascular spinal cord injury |
E. Traumatic spinal cord injury
or F. Vascular spinal cord injury Vascular (Fibrocartilagenous embolism) Traumatic (Intervertebral disk herniation) The acute onset, assymetry in clinical signs and non-painful presentation would make FCE the most likely diagnosis. |
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What is the treatment and Px for FCE?
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Nothing in terms of medical Tx helps. it's nursing care, physical therapy , and time - usually takes 2 to 4 weeks for full recovery
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A 10 year old, M/N, DSH cat is presented with a flaccid tail and urinary and fecal incontinence after having been hit by a car.
The cat is mentally alert and ambulatory but quite painful. Proprioception and postural reactions are normal. Peripheral reflexes are normal. Cranial nerves are within normal limits. The tail is limp, the anus is widely dilated and there is no perineal reflex. The bladder is very large and can be easily expressed. Where is the lesion? |
S1-S3 - rads revealed a sacro-coccygeal fracture. This type of traumatic injury commonly results in avulsion of the nerves of the sacral and coccygeal spinal cord resulting in irreversible urinary and fecal incontinence. Tail avulsion injuries can be similar.
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It is important to note that due to differential growth of the spinal cord and vertebral column, spinal cord segments tend to lie somewhat cranial to the intervertebral foramen from which their nerves exit. This holds especially true for which spinal cord segments?
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This is especially true of spinal cord segments L5-Cy as the cord in the dog ends at about vertebral level L6. The cord in the cat terminates slightly more distally. When we refer to an S1-3 lesion we are referring to the spinal cord segment not the vertebral level.
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Explain UMN.
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The white matter of the spinal cord is made up of myelinated and unmyelinated axons. Some of these axons arise from neurons which are located within the brain. We refer to these neurons and their axons as Upper Motor Neurons (UMN). Upper motor neurons connect the brain with the lower motor neurons and allow the animal to initiate movements and to refine them. No UMN, no voluntary movement.
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Interruption of the UMN anywhere between the brain and the LMN results in:
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proprioceptive deficits, ataxia, paresis and/or paralysis depending upon the degree of injury
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Can interruption of the UMN between the brain and the LMN effect reflexes?
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Because the spinal cord segment containing the reflex arc is left uninjured, the reflex remains intact and is often hyperactive due to the lack of a modulating affect by the UMN. This phenomenon is referred to as an UMN reflex.
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A 7 month old, male, Yorkshire Terrier was presented with a history of acute, progressive tetraparesis and severe pain of 4 weeks duration.
Physical examination was normal except for a small 1cm open fontanel. The dog was ambulatory but had a scrabbling ataxic gait and kept his head down and turned to the left. Placing responses and proprioception were absent in all limbs. Postural reactions were performed normally. There was resistance to manipulation of the head and neck. Withdrawal reflexes were present and normal in all limbs. Patellar reflexes were normal. Other peripheral reflexes were normal. Mentation was normal except for screaming in pain whenever touched or picked up. Lesion localizes to: a. C1-C5 b. C5-T3 c. T3-L3 d. L3-L7 |
C1-C5
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Which set of Ddx seems most likely in this case?
A. Degenerative, Neoplasia, Vascular B. Metabolic, Toxic, Nutritional C. Anomalous, Traumatic, Inflammatory D. None of the above E. All of the above |
Anomalous, Traumatic and Inflammatory diseases should be at the top of the differential diagnosis list because this is a young dog, he is painful and the condition is acute and progressive.
Yorkies have a breed predisposition for atlanto-axial subluxation and for necrotizing encephalomyelitis. |
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What is the typical sign of Chiari malformation?
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Chiari malforamtion can cause spinal cord lesion (syringomyelia). But the more typical sign of a Chiari malformation is progressive neck pain, and paresthesia, usually characterized by scratcing at the neck or skull base.
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What is the diagnostic TOC for atlanto-axial subluxation?
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The lateral radiograph reveals an increased distance between the dorsum of C1 and C2 compatible with a diagnosis of atlanto-axial subluxation.
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What is the treatment and Px for atlanto-axial subluxation?
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Two small screws placed to stabilize the atlanto- axial joint.
Recovery is usually uneventful and usually within a few weeks of strict rest at home. |
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A 12 year old F/S mixed breed dog is presented with a history of chronic progressive paraparesis and severe back pain of several months duration.
Neurological examination reveals an alert but severely painful, paraparetic dog. Front limbs and cranial nerves are within normal limits. The dog can wheelbarrow normally on the front limbs. She can bear weight on the rear legs when assisted to stand but is extremely painful and assumes a sitting position with the rear legs extended forward when unassisted. Proprioception is absent in both rear limbs and rear limb postural reactions are markedly impaired. Front limb reflexes are normal. Patellar reflexes are hyperreflexic with clonus bilaterally. Other rear leg reflexes are normal. The perineal reflex and anal tone are normal. Superficial and deep pain are present in all limbs. 1. is the lesion UMN or LMN? 2. Lesion localizatin is: a. C1-C5 b. C5-T1 c. T3-L3 d. L3-L7 e. S1-Cy |
An UMN lesion. The LMN is intact and is released from modulation by the brain secondary to an injury to the UMN spinal tracts above the level of the reflex.
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What reflex will provide more precise localization of a lesion between T3-L3?
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Panniculus(Cutaneous trunci) reflex
Because spinal cord segments lie slightly cranial to the relevant dermatomes, the spinal cord lesion is usually located 1or 2 spinal cord segments ahead of the level of skin twitch loss. If there is a LMN injury to the lateral thoracic nerve the cutaneous trunci reflex may be lost unilaterally caudal to the lesion. |
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Spinal radiographs suggested lysis of the vertebral endplates of T13-L1 compatible with a diagnosis of diskospondylitis. MRI confirmed diskospondylitis at T13-L1.
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Brucella titer
Brucella canis would be important to rule in/out because it is known to be a cause of diskospondylitis and has zoonotic potential. A Brucella titer was negative. Staphylococcus was cultured from the urine. The patient was treated with Cephalosporins and made a full recovery. |
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Describe crossed extensor reflex.
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A crossed extensor reflex refers to simultaneous extension of the opposite limb in response to elicitation of a flexor reflex in the stimulated limb. The reflex occurs as a result of lack of MN modulation of interneurons which connect the reflexes arcs on either side of the body.
Crossed extensor reflexes in the rear limbs indicate a spinal cord lesion above the level of L6. Crossed extensor reflexes in the front limbs indicate spinal cord lesion above the level of C6. |
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Describe Shiff Sherrington posture.
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Shiff Sherrington posture occurs with spinal cord lesions between T3 and L3. When lying in lateral recumbancy the front limbs are stiffly extended and the rear limbs are paralyzed. The patient is able to walk with the front limbs but the gait is often very stilted.
Shiff Sherrington posture occurs due to the interruption of inhibitory influences of interneurons below the level of the lesion on LMNs which innervate the extensor muscles of the front legs. |
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Are crossed extensors and Schiff Sherrington poor prognostic signs?
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They are not. They only localize the problem to an area of the cord. In the case of shiff Sherrington to T3-L3. In the case of crossed extensors to the region above the level of the flexor reflex
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Give an example of a degenerative spinal cord disease.
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Degenerative diseases are usually diffuse, affecting large parts of the spinal cord.
Degenerative spinal cord diseases associated with enzymatic abnormalities occur in very young animals, often involve the brain as well and are rapidly progressive. Degenerative myelopathy in the German Shepherd is an example of a degenerative disease of the spinal cord with a slower progression which affects middle age to older animals. |
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Degenerative myelopathy in the German Shepherd is an example of a degenerative disease of the spinal cord with a slower progression which affects middle age to older animals. What is the mutation involved and tested for?
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mutation in the SOD-1 gene
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What are the clinical signs of spinal neoplasia and how is it classified?
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Spinal neoplasia is usually focal in nature, can be seen at any age and is more often slowly progressive although owners will often miss early signs and therefore provide histories of a more acute onset. Spinal tumors are classified as extradural, intradural-extramedullary or intramedullary depending upon their location in relation to the meninges and the spinal cord.
Spinal neoplasia can be primary or metastatic. The most common primary spinal tumors in the dog are the meningioma and nerve sheath tumor. The most common spinal tumor in the cat is Lymphoma. |
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What are the clinical signs of fibrocartilagenous embolism?
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Vascular lesions are non-progressive and non-painful. Fibrocartilagenous embolism is an example of a very common vascular disease of the spinal cord
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What clinical signs are consistent with diseases fo the peripheral nervous system?
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Flaccid paresis or paralysis, exercise intolerance, hyporeflexia or areflexia, muscular atrophy and in some cases decreased sensation are characteristic of diseases of the peripheral nervous system.
Occasionally cranial nerves are affected. Examples of cranial neuropathies include: idiopathic facial paralysis, trigeminal neuritis, laryngeal paralysis and optic neuritis. We refer to these diseases as lower motor neuron diseases. Lower motor neuron diseases may affect one nerve (mononeuropathy) or multiple nerves (polyneuropathy). Some lower motor neuron diseases are very gradual in onset and progression. Other diseases such as polyradiculoneuritis (Coonhound paralysis), and tick paralysis begin acutely and progress rapidly. |
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Why do we see muscle atrophy with neurogenic disease?
A. Because the patient is unable to use the limb B. Because the nerves have a trophic affect on the muscles. |
B. Because the nerves have a trophic affect on the muscles.
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What protozoal infections are most likely to cause neuromuscular disease?
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Toxoplasma and Neospora are very similar protozoal diseases which can result in neuromuscular disease. Neospora infection in young puppies often results in a typical clinical presentation of acute paraplegia with the hind limbs fixed in rigid extension. Hind limb muscles are firm on palpation but patellar and withdrawal reflexes are absent.
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A 10 week old, intact male, Australian Shepherd was presented with a history of acute progressive tetraplegia of one week duration. Clinical signs began with rear leg ataxia and progressed to tetraplegia within 24-48 hours. The owners also noted an inability to bark. The puppy had been obtained from a breeder at 7 weeks of age and had received a DHLPP vaccination at 9 weeks of age.
PE was WNL except for slight proximal muscle atrophy in all limbs. Flexor reflexes were absent in all limbs. Sensory perception was normal in all limbs (vocalized on pinching to test for the absent flexor reflexes). The lesion can be localized to which area? A. Peripheral nerve or neuromuscular junction B. C1 - C5 C. C5 - T3 D. Brain |
A. Peripheral nerve or neuromuscular junction
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What types of disease should be included on the Ddx for the puppy's clinical signs of peripheral nerve or neuromuscular junction?
A. Degenerative diseases B. Inflammatory/Infectious diseases C. Toxicities D. B and C |
Inflammatory/infectious diseases are more likely to cause multifocal lower motor neuron disease however tick paralysis is the result of a neuromuscular toxin.
Most degenerative diseases are not so acute in onset. |
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List 2 toxins that could be causing the puppy's clinical signs of peripheral nerve or neuromuscular junction?
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tick paralysis, and botulism
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List 2 infectious diseases that could be causing the puppy's clinical signs of peripheral nerve or neuromuscular junction?
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While atypical Toxoplasma and Neosporum may affect both peripheral nerves and muscles. Neither typically causes a flaccid paralysis. Titers for Toxoplasma and Neosporum Caninum were negative.
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List an inflammatory non infectious disease which could cause the puppy's clinical signs of peripheral nerve or neuromuscular junction?
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Polyradiculoneuritis is one of the most common inflammatory non-infectious diseases which causes acute flaccid paralysis. The owners declined EMG/NCV testing. Supportive care was provided and the puppy returned to normal 4 weeks following initial examination.
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Is coon hound paralysis same as polyradiculoneuritis? mechanism?
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Coonhound paralysis is a type of polyradiculoneritis. The mcahnism is an immune-mediated response to an antigen in raccoon saliva that affects peripheral nerve and nerve roots.
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What is the treatment for polyradiculoneuritis? What is the cause?
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No medical treatment. Time and nursing care are all that make a difference.
The idiopathic form is thought to be immune-mediated. |
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How would you confirm a tentative diagnosis of myasthenia gravis?
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Identify the presence of serum acetylcholine receptor antibodies.
Edrophonium (Tensilon) testing is considered obsolete |
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What is the most common mistake when assessing for deep pain?
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Not pinching the bone. Hard. If you just pinch the skin, you are testing superficial pain, which is that sharp, well-localized pain originating in the skin
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When would phenobarb therapy warrant alteration?
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1. Clinical signs of hepatoxicity
2. ALT >> SAP 3. SBA increases 4. Inc serum phenobarb levels despite no increase in dose |
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How do you distinguish btwn bilateral cruciate tears and neuro dz?
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Spinal cord dz - CP deficits, ataxia,
Ortho dz - reluctance to bear wt, with support normal CP, walk is usually short-strided gait and often sit down after a few steps d/t pain (polyarthritis w/b same). |
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What spinal lesions can present w/ lameness and no other deficits, thus look very similar to ortho dz?
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The most common are cadual cervical disc extrusions and nerve sheath tumors in the brachial plexus causing thoracic limb lameness and lumbosacral lesions causing pelvic limb lameness. What's happening is there is nerve root or peripheral nerve attenuation, which is very painful. And the pain is referrable to the nerve distribution in the limb
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What is the most common clinically manifestation of hypothyroid neuropathy?
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diffuse, symmetrical polyneuropathy characterized by tetraparesis and ataxia with decreased reflexes. But cranial neuropathy has also been documented, including vestibular dysfunction, facial paralysis, and laryngeal paresis
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Do clinical signs resolve with regulation for both DM and hypothyroid neuropathy?
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For cats with diabetic neuropathy, the signs will often improve with good control of blood glucose but not always.
For hypothryoid neuropathy, they generally improve within 4-6 weeks of thyroid supplementation. |
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The peripheral components of the vestibular system
a. are not closely associated with the sympathetic trunk. b. include the vestibular nuclei in the medulla. c. are contained within the inner ear (the petrosal portion of the temporal bone). d. none of the above |
c. are contained within the inner ear (the petrosal portion of the temporal bone)
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In a dog with vestibular disease, the characteristic head tilt results from
a. loss of tone to the antigravity muscles of the neck. b. fluid in the tympanic bulla. c. increased intracranial pressure. d. none of the above |
a. loss of tone to the antigravity muscles of the neck.
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In a dog with vestibular disease, which statement describes the characteristic head tilt?
a. The ventrally deviated ear is usually on the opposite side from the lesion. b. The ventrally deviated ear is usually on the same side as the lesion. c. It is difficult to differentiate from torticollis in a dog with a central vestibular lesion. d. none of the above |
b. The ventrally deviated ear is usually on the same side as the lesion.
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Which statement is true regarding pathologic jerk nystagmus in a dog with vestibular disease?
a. Vertical nystagmus can indicate a central vestibular lesion. b. The slow phase is usually toward the side of the lesion. c. The nystagmus may resolve if the head is held in normal position. d. all of the above |
d. all of the above
- Vertical nystagmus can indicate a central vestibular lesion. - The slow phase is usually toward the side of the lesion. - The nystagmus may resolve if the head is held in normal position. |
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Which statement is true regarding physiologic jerk nystagmus?
a. It can be induced in a normal animal by rotating the head to simulate a head tilt. b. If the head is turned from side to side, a slow drift of the eye is seen toward the direction of travel followed by a fast compensatory phase in the opposite direction of movement of the head. c. A reduction or loss of physiologic jerk nystagmus is abnormal and can indicate pathology. d. all of the above |
c. A reduction or loss of physiologic jerk nystagmus is abnormal and can indicate pathology.
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Which statement is true regarding Horner syndrome?
a. It is characterized by ptosis, miosis, enophthalmos, and nystagmus. b. It is usually not seen with central vestibular disease. c. It is associated with a poor prognosis if it occurs with vestibular disease. d. all of the above |
a. It is characterized by ptosis, miosis, enophthalmos, and nystagmus.
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Which clinical finding(s) is/are normally associated with central vestibular disease?
a. abnormal mentation b. hemiparesis and postural deficits c. deficits involving two or more cranial nerves (in addition to cranial nerve VIII) d. all of the above |
d. all of the above
- abnormal mentation - hemiparesis and postural deficits - deficits involving two or more cranial nerves (in addition to cranial nerve VIII) |
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Which clinical finding(s) might characterize a dog with vestibular signs associated with ear disease?
a. normal mentation b. facial paralysis c. Horner syndrome d. all of the above |
d. all of the above
- normal mentation - facial paralysis - Horner syndrome |
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Deficits of cranial nerve(s) ________ are more likely to occur in a dog with central vestibular disease.
a. III b. IV and VI c. V, VII, and VIII d. VIII |
c. V, VII, and VIII
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Which statement is false regarding bilateral vestibular disease?
a. It is most commonly associated with central vestibular disease. b. Ataxia may be observed. c. A head tilt is uncommonly observed. d. Pathologic nystagmus is unlikely to be observed. |
a. It is most commonly associated with central vestibular disease.
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Which one of the following choices includes the cardinal sign of trigeminal neuritis?
A - Dysphagia, dysphonia and stridor B - Inability to close the mouth C - Circling and head tilt toward side of lesion, no other signs D - Masseter muscle pain associated with chewing E - Paralyzed eyelid, ear or lip on one or both sides of the face |
B - Inability to close the mouth
Idiopathic trigeminal neuritis, cranial nerve 5, (CN 5) is characterized by acute onset of flaccid jaw paralysis. Affected animals cannot close their mouth and have difficulty eating and drinking. Seen occasionally in dogs, rare in cats. Cause is unknown. Idiopathic facial nerve paralysis, cranial nerve 7, (CN 7) results in the inability to move the eyelid, lip, or ear and dryness of the eyes and mouth. Masticatory myositis is characterized by pain on opening the mouth and swelling of the muscles of mastication (acute) or atrophy of the temporalis and masseter muscles with the inability to open the mouth due to fibrosis (chronic). Dysphagia, dyphonia, and stridor are most often associated with dysfunction of the vagus nerve, cranial nerve 10 (CN 10). Circling and head tilt toward the side of the lesion with no other signs is a common presentation of vestibulocochlear nerve, cranial nerve 8 (CN 8) lesions. Concurrent CN 7 paralysis and Horner's syndrome (ptosis, miosis, enophthalmis) may be present with middle- and inner-ear infections. |
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An HBC dog presents w/ hyptonic FLS and spastic paralysis in the HLs. All 4 limbs have CP deficits and sensation loss signs are worse in the FLs. Where is the lesion?
a. cervicothoracic C6-T2 b. lumbosacral L4-S3 c. cranial cervical C1-C5 d. cannot say w/out cutaneous trunci/panniculus results e. thoracolumbar T3-L3 |
a. cervicothroacic C6-T2
Weak, hypotonic (LMN) FLs and spastic paresis (UMN) HLs are signs of cervicothoracic (C6-L2) lesion. May see signs worse in the FLs than in the HLs. Note: This is the OPPOSITE presentation of Schiff-Sherrington syndrome - i.e. spinal cord trauma to T3-L3, with thoracic limb extensor rigidity (UMN) and HL flaccid paralysis (LMN). Lesion is caudal to T2, typically seen in animals soon (w/in hrs) after a bad trauma, i.e. HBC |
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With C1-C5 what clinical signs would be expected?
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UMN (spastic paralysis) in all 4 limbs, usually worse in HLs
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A 2 year-old Bernese Mountain Dog is presented for acute pelvic limb paralysis while outside chasing a cat.
In the exam room, the dog is dragging the right pelvic limb and barely walking on the left pelvic limb. Exam reveals decreased conscious proprioception in the left pelvic limb and absent conscious proprioception in the right pelvic limb. Patellar reflexes are absent on the right and intact on the left. No back pain can be elicited. The rest of the neurologic exam is normal. You strongly suspect a fibrocartilaginous embolism. Which of the following tests can show concrete evidence of a fibrocartilaginous embolism? A - Magnetic resonance imaging B - Acetylcholine receptor antibody test C - Myelography D - Computerized tomography E - Cerebrospinal fluid analysis |
A 2 year-old Bernese Mountain Dog is presented for acute pelvic limb paralysis while outside chasing a cat.
In the exam room, the dog is dragging the right pelvic limb and barely walking on the left pelvic limb. Exam reveals decreased conscious proprioception in the left pelvic limb and absent conscious proprioception in the right pelvic limb. Patellar reflexes are absent on the right and intact on the left. No back pain can be elicited. The rest of the neurologic exam is normal. You strongly suspect a fibrocartilaginous embolism. Which of the following tests can show concrete evidence of a fibrocartilaginous embolism? A - Magnetic resonance imaging |
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A 7 year-old cat is presented with miosis, ptosis, enophthalmos, and protruded nictitating membrane involving the right eye.
These symptoms are caused by damage to which one of the following innervation pathways? A - Left oculomotor innervation to the eye B - Right parasympathetic innervation to the eye C - Right sympathetic innervation to the eye D - Left vagal innervation to the eye E - Right trigeminal innervation to the eye |
C - Right sympathetic innervation to the eye
Right sympathetic innervation to the eye. Horner's syndrome(miosis, ptosis, and enophthalmos) is caused by defective ipsilateral sympathetic innervation to the affected eye. |
