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183 Cards in this Set
- Front
- Back
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Problem in neural tube defects:
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Neural tube fails to close
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What structures are involved in neural tube defects?
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Vertebrae +/- skull +/- meninges, spinal cord, or brain
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HALLMARK of neural tube defects:
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Elevated aFP in maternal amniotic fluid OR serum
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Probable cause in many cases of neural tube defects:
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Folate deficiency
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Failure of posterior vertebral arches to close:
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Spina bifida
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Spina bifida with no clinically apparent abnormalities:
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Spina bifida occulta
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What's is the defect limited to primarily in Spina bifida occulta?
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only 1 or 2 vertebral arches
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Spina bifida + herniation of MENINGES thru a defect:
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Spina bifida cystica
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Herniated membranes consisting of meninges only:
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Meningocele
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A portion of spinal cord included in herniated tissue:
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Meningomyelocele
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Markedly diminuted or absent fetal brain tissue with absence of overlying skull:
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Anencephaly
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Group of infections transmitted from mother->fetus with similar clinical manifestations:
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TORCH
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Torch is:
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Toxoplasma
Rubella CMV HSV |
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3 features usually seen in Torch infections:
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-Chorioretinitis
-Microcephaly -Focal cerebral CALCIFICATIONS |
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Increased vol of CSF in the cranial cavity is:
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Hydrocephalus
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Hydrocephalus in infants is usually accompanied by:
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Increased skull size
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3 common causes of hydrocephalus in infants:
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-Congenital malformations
-Tumors -Inflammation All block CSF flow |
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Rare cause of hydrocephalus:
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overproduction of CSF by choroid plexus papilloma
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Hydrocephalus due to decreased brain vol:
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Hydrocephalus ex vacuo
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2 conditions that cause hydrocephalus ex vacuo:
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Cerebral atrophy due to infarct
Alzheimer disease |
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Internal hydrocephalus:
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increased vol of CSF is entirely within the ventricles
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External hydrocephalus:
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Increased vol of CSF is entirely within the subarachnoid space
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Communicating hydrocephalus:
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Free flow of CSF between the ventricles and subarachnoid space
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Noncommunicating hydrocephalus:
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Obstruction of CSF flow from ventricles to subarachnoid space
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Arnold Chiari malformation:
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Downward displacement of cerebellar tonsils and medulla thru the foramen magnum
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What does Arnold Chiari result in doing to brain tissue?
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Pressure atrophy of the displaced tissue
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2 common findings in almost all cases of Arnold Chiari malformation:
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-Hydrocephalus
-Meningomyelocele in thoracolumbar region |
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Fetal congenital CNS malformation that may be asymptomatic and often in assoc with other abnormalities:
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corpus callosum agenesis
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Excessive maternal alcohol intake during pregnancy:
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Fetal alcohol syndrome
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Common findings in FAS:
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Abnormal facies
Microcephaly Growth/mental retardation Atrial septal defects |
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Inheritance of Tuberous sclerosis:
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Autosomal dominant
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3 hallmark findings in Tuberous sclerosis:
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-Nodular tubers-proliferations of abnormal astrocytes in brain
-Sebaceous adenomas on face -Angiomyolipoma of the kidney |
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What are the 2 presenting symptoms often in Tuberous sclerosis and when is onset?
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-Mental retardation
-Seizures Beginning in infancy |
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Most COMMON group of CNS disorders is:
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Cerebrovascular disease!
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Most common cerebrovasc disease:
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Infarction
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Cerebral infarction is more common than:
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hemorrhage
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Cerebral infarction leads to what changes in brain tissue?
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-Liquefactive necrosis
-Cyst formation |
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2 ways that cerebral infarction can occur:
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-Thrombosis
-Embolism |
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What is more common?
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Thrombosis
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Thrombosis in a cerebral vessel is usually due to:
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Atherosclerosis
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Embolism in a cerebral vessel can be caused by:
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-Cardiac MURAL thrombi
-Endocardial infectious VEGETATIONS -Amniotic fluid emboli -TUMOR emboli -Air |
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2 most common sites of THROMBOTIC occlusions:
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-Carotic bifurcation
-Middle cerebral artery |
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Most common site of EMBOLIC occlusion:
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MCA
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Clinical manifestations of cerebral infarctions of carotid and MCA are:
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-CONTRALATERAL paralysis
-Motor defects -Sensory deficits -Aphasias |
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Clinical manifestations of cerebral infarctions in the POSTERIOR circle of willis:
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Cranial nerve deficits - vertigo, visual deficits
Coma Cerebellar problems - ataxia |
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Lesions that result from an infarct of a SMALLER vessel:
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Lacunar
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What do lacunar infarcts look like after healing?
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Small pits
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How do Lacunar infarct clinical manifestations compare to those of large vessels like ICA/ECA and MCA?
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PURELY motor or sensory; more focal
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Where will a lacunar infarct cause a PURE motor deficit?
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Internal capsule
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Where will a lacunar infarct cause a PURE sensory deficit?
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Thalamus
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2 forms of cerebral HEMORRHAGE:
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-Intracerebral
-Subarachnoid |
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What is Intracerebral hemorrhage?
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Bleeding into the brain parenchyma
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Most common cause of intracerebral hemorrhage:
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Hypertension
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How does hypertension cause intracranial HEMORRHAGES?
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Small dilations form at small artery bifurcations
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What are these small dilations at small artery bifurcations called?
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Charcot-Bouchard aneurysms
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And what happens to Charcot-Bouchard aneurysms?
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They rupture and cause intracerebral hemorrhage!
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Where do Charcot-Bouchard hemorrhages most often form and hemorrhage?
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Basal ganglia and Thalamus!
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Subarachnoid hemorrhage is:
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Bleeding into the subarachnoid space
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What is subarachnoid hemorrhage usually caused by?
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BERRY ANEURYSMS
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What is the most common site for Berry aneurysms to form?
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Bifurcation of ACA
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In general Berry aneurysms form at:
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Bifurcations of the circle of Willis
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What are 3 syndromes in which you often see berry aneurysms?
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-Adult polycystic kidney disease
-Marfan's syndrome -Ehlers danlos |
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What compounds the likelihood of a berry aneurysm rupture?
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Hypertension, smoking, aging, and black race
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What are TIA's?
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Transient ischemic attacks - brief episodes of impaired neurologic function
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What are TIA's caused by?
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Temporary disturbances of cerebral circulation
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What does NOT result from TIA's?
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Permanent damage
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Why are TIA's bad though?
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They are precursors to more serious occlusive events
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What type of head injuries predispose to brain infection?
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Penetrating wounds
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Brain injury AT the site of impact is a:
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Coup injury
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Brain injury on the opposite side of the brain from the site of impact is:
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Contrecoup injury
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What type of injury do contusions cause?
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Both coup and contrecoup
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What are Epidural hematomas almost always caused by?
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Skull fractures of the Temporal bone
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What vessel is damaged by a Temporal bone skull fracture?
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Middle meningeal artery
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What are the hallmark clinical manifestations following an Epidural hematoma?
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-Lucid interval
-Then rapidly developing signs of cerebral compression |
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Why do the signs of Epidural hematoma develop so rapidly?
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Because this is arterial bleeding which is high pressure
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What does a CT scan show in an epidural hematoma?
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BiconVEX lens - the blood does is limited by suture lines and does not cross them
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How are Epidural hematomas treated? Why?
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Surgically - they are amenable because the bleeding does not enter the brain matter at all
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What are Subdural hematomas caused by?
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Rupture of bridging veins between the brain and dural venous sinuses
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What is the onset of symptoms in a Subdural hematoma like? Why?
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Insidious and slow - because the bleeding is venous which is under much lower pressure
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How long can the onset of signs of cerebral compression take in a subdural hematoma?
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Days to even weeks!
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What causes the cerebral compression in a subdural hematoma?
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After the bleeding spontaneously stops, the area has higher osmotic pressure which imbibes water and causes a slow-growing tumor like mass
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What does a subdural hematoma look like on CT?
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Crescent shaped and crosses suture lines
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What are 3 main risk factors for subdural hematomas?
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-Brain atrophy
-Shaking -Whiplash |
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So in what individuals are subdural hematomas typically seen?
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-Elderly
-Alcoholics -Shaken baby syndrome -Trauma/whiplash |
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What type of brain hemorrhage is associated with "worst headache of my life"?
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Berry aneurysm ruptures and SubARACHNOID hemorrhage
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What is a common lab finding associated with subarachnoid hemorrhages?
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Xanthrochromic CSF on spinal tap
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What is NOT a portal of entry for infection into the CNS?
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Lymphatics - there are no lymphatics in the CNS!
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What is the most COMMON portal of entry for infection into the CNS?
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Hematogenous
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What are 3 three other portals for infection to enter the CNS?
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-Penetrating trauma
-Local spread from the paranasal sinuses or dental infections -Peripheral nerve spread |
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What are Fever, Headache, Prostration, and Nuchal rigidity hallmark signs of?
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Pyogenic meningitis!
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What are the top 3 bacteria that cause NEONATAL meningitis?
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-Strep group B - agalactiae
-E. coli -Listeria monocytogenes |
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What are the top 2 populations of patients that GET pyogenic meningitis?
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-Children - 75%
-Elderly |
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What are the 3 complications that cause cerebral damage in pyogenic meningitis?
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-Reactive fibroblast arachnoiditis
-Obliteration of the arachnoid space -Hydrocephalus (communicating) |
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What is another vascular complication of pyogenic meningitis?
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Leptomeningeal venulitis
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What does Leptomeningeal venulitis lead to?
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Venous occlusion and hemorrhagic INFARCTS + Brain Abscesses
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What are the hallmark lab findings in Purulent meningitis?
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-Purulent exudate in subarachnoid space
-Increased protein/PMNs/pressure in CSF; decreased glucose |
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What are the top 3 bacteria to cause neonatal meningitis?
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-Strep group B
-E coli -Listeria monocytogenes |
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What are the top bacterial causes of meningitis in older infants to young adults?
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Strep pneumoniae and Neisseria meningitidis
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What are the top bacterial causes in older adults?
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Strep pneumo and GNB
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What is the worst complication of Pneumococcal meningitis?
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Waterhouse Friderichsen syndrome
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What are the 3 hallmark findings in Waterhouse Friderichsen syndrome?
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1. Hemorrhagic destruction of the adrenal cortex
2. Acute hypocortisolism results in cardiovascular collapse 3. DIC |
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Acronym for Waterhouse Friderichson:
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HAD it - the adrenals are DONE with meningitis and so the Hemorrhage, Acute hypocortisol, DIC
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What is the skin manifestation often seen in fulminant meningococcemia?
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Purpuric skin lesions
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2 ways that cerebral abscesses from infections can arise:
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-Penetrating skull injuries
-Spread from infection elsewhere |
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What are the 2 most common sites for cerebral abscess infections to spread FROM?
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-Middle ear
-Paranasal sinuses |
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What are 2 other less common sites from which infections can spread to the brain and cause abscesses?
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-Bronchopulmonary
-Infective endocarditis |
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2 types of CNS infections that Mycobacterium tuberculosis can cause:
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-Tuberculosis of BRAIN SUBSTANCE
-Tuberculous meningitis |
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How does TB of the CNS develop?
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Secondary to TB elsewhere
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What other organisms can infect the brain substance or meninges?
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Fungal
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What are most Fungal infections of the CNS associated with?
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Impaired resistance - immunocompromised state
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How are lab findings different in Fungal or Tuberculous CNS infections compared to Pyogenic meningitis?
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The cells will be lymphocytes instead of PMNs
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What parasite can infect the brain?
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Toxoplasma gondii
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How does Toxoplasma infect neonates?
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Transplacental transmission from the mother
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How is Toxoplasmosis transmitted between adults?
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By ingestion of food contaminated with animal urine or feces
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How does Toxo get into animal urine/feces?
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Cats are reservoirs
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What are 3 clinical manifestations of Fetal toxoplasmosis in newborns?
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-Mental retardation
-Hydrocephalus -Neurologic abnormalities |
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Hallmark CT findings in Toxoplasmosis?
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PERIVENTRICULAR CALCIFICATIONS
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What are the main CNS sites of involvement in Toxoplasmosis?
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-Cerebral cortex
-Basal ganglia -Retinae |
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What other organs are commonly involved in Toxoplasmosis?
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-Lungs
-Liver -Heart |
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What is the usual manifestation of toxoplasmosis in NORMAL adults?
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Just lymphadenitis
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When does Toxo cause CNS disease in adults?
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HIV - immunocompromised
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What components of the CNS can VIRUSES infect?
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-Just the meninges
and/or -Brain matter -Spinal cord |
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How do we label Viral meningitis in contrast to Pyogenic meningitis?
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Aseptic/lymphocytic meningitis
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Clinical signs of viral meningitis?
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Same as bacterial - Fever/HA, nuchal rigidity
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How are lab findings on CSF different in VIRAL meningitis?
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-Pressure is N or only sl higher
-Protein is normal -Glucose is normal -Cells are lymphos |
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What do we call viral infection of the brain and/or meninges?
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Meningoencephalitis or Encephalitis
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What are the 3 hallmark morphologic changes in Meningoencephalitis/encephalitis?
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PIG
-Perivascular cuffing -Inclusion bodies -Glial nodules |
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What is Perivascular cuffing?
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Mononuclear cell infiltration of Virchow-Robin spaces
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Where are Inclusion bodies typically found?
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In neurons and glial cells
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What are Glial nodules the result of?
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Nonspecific proliferation of microglia
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What viruses that cause encephalitis are housed by horse and bird reservoirs?
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ARBORVIRUSES
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What are the 3 arbovirus encephalitides?
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1. St. Louis encephalitis
2. Eastern equine encephalitis 3. Western equine encephalitis |
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What is the vector for spread of St. Louis encephalitis?
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Mosquito
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Which arbovirus encephalitis is associated with the highest mortality rate?
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Eastern equine
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How does Western equine encephalitis compare to Eastern?
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Less severe
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What are the most common viral causes of encephalitis in:
-Younger children -Older teens/YA |
Young = Enteroviruses
Teens/YA = Herpes Simplex HSV |
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What virus has the hallmark characteristic of causing degeneration and necrosis of ANTERIOR HORN CELLS of the SC?
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Poliovirus - Poliomyelitis
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How is Polio transmitted?
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Fecal-oral
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What are the steps in Polio infection before it enters the CNS?
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-Proliferation in the oropharynx and small intestine
-Bloodstream spread to CNS |
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What are the signs of LMN lesions caused by Polio?
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-Muscle weakness/atrophy
-FASCICULATIONS -Fibrillations -LOWER deep tendon reflexes - hyporeflexia |
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What type of CNS infection does RABIES cause?
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Severe Encephalitis
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What does Rabies encephalitis do to the CNS?
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INCREASES excitability - so very small stimulations produce Convulsions and Violent muscle contractions!
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How can Rabies be treated?
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Only BEFORE onset of symptoms with ACTIVE immunization
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What is the hallmark histologic finding in Rabies?
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Negri bodies - eosinophilic inclusions in cytoplasm of neurons
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Where are the neurons that contain Negri bodies located?
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-Hippocampus
-Purkinje cells of the cerebellum |
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How does Rabies enter the CNS?
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By retrograde migration from peripheral nerve axons
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How long can the incubation period of Rabies take before CNS symptoms even develop?
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LONG time - 3 months!
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What are 2 common clinical manifestations of Rabies encephalitis?
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-Seizures
-Hydrophobia - foam at mouth and can't swallow |
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When does CMV typically cause CNS infections?
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Immunocompromised - HIV
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What type of CNS infection does CMV cause?
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Encephalomyelitis
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What are the characteristic histologic findings in CMV myeloencephalitis?
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Eosinophilic inclusions in both the cytoplasm and nucleus of Giant cells!
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What are the main clinical findings in CMV infections of INFANTS (Torch)?
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-Mental retardation
-Microcephaly -Chorioretinitis -Hepatosplenomegaly -Periventricular calcifications! |
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What are infectious agents that do not contain RNA or DNA?
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PRIONS
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What DO Prions have?
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Only PROTEIN
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What are Prions capable of?
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-Transmission
-Resist heat denaturation |
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What are the infectious particles of Prions called?
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PrP - Prion Protein
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What are Prion diseases called based on their anatomical pathologic manifestations?
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Spongiform Encephalopathies
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What does Spongiform encephalopathy consist of histologically?
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-Clusters of CYSTS in CNS gray matter
-Marked INFLAMMATORY response |
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What did Spongiform Encephalopathies USED to be called and why?
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Slow virus diseases - because they have a super LONG incubation period.
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So what is the onset/progression of Prion disease in humans like?
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Slow and Progressive
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What are the 4 human prion diseases?
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-Kuru
-Creutzfeld Jakob (CJD) -Gerstmann-Straussler-Scheinker -Fatal familial insomnia |
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What are the animal prion diseases?
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Mad cow disease and Scrapie
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How are Prion diseases transmitted?
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By eating or being exposed to Prion-containing tissue
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Where has Kuru most notably been seen? How was it transmitted?
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In Cannibals of new guinea - ate brains of humans
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What are the main histologic findings in Kuru?
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-Neuron loss
-Gliosis -Spongiosis of the Cerebrum, cerebellum, and spinal cord -Cerebellar ATROPHY |
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So what are the main symptoms of Kuru?
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-Cerebellar ataxia
-Marked intention tremor -Slurred speech -Progressive mental deterioration, death in few months |
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What are the morphologic changes in Creutzfeld jakob?
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Similar to those in Kuru
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What is the main thing associated with CJD transmission?
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Corneal transplantation
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Symptoms of CJD?
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Same as Kuru
-ataxia -progressive dementia -early death |
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What are the 2 SLOW VIRUS infections?
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1. Subacute Sclerosing Panencephalitis (SSPE)
2. Progressive Multifocal leukoencephalopathy (PML) |
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What is SSPE caused by?
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MEASLES virus - a persistant infection caused by an ALTERED virus structure!
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When is the measles virus typically acquired in SSPE? When do the neurologic manifestations of SSPE develop?
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Acquire In infancy
Neurologic sx in late childhood or early teens |
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How is the Measles virus altered in SSPE? What does this result in?
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It lacks the M protein - necessary for Extracellular viral spread; makes the onset of SSPE very slow
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What does SSPE usually result in for patients?
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Death
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What can be found in the CSF of patients with Measles SSPE?
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-Anti Measles immunoglobulins
but -NO Anti-M protein |
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What virus causes PML?
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the JC Polyoma virus - Papovavirus
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What type of structure do the Papovaviruses have? What is the other major one to know of?
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Naked unenveloped dsDNA circular
-Include the JC virus and HPV |
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What cells does the JC virus preferentially infect and what is the result of this?
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Oligodendrocytes - demyelinates axons in the CNS!
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What are 3 conditions that predispose patients to getting PML and the JC virus?
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-Leukemia
-Lymphoma -HIV |
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What other way can HIV patients get CNS infection?
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The HIV virus itself can cause CNS infection!
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What is the vehicle for entry of HIV into the CNS?
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Monocyte-Macrophage cells
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What is the downhill course of progressive dementia in patients with HIV called?
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AIDS dementia complex
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What are the hallmark histologic findings in Aids dementia?
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Microglial nodules with multinucleated giant cells.
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