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25 Cards in this Set
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a diagnostic term for a group of congenital abnormalities that occur either in utero, during the birthing process, or during the first 2 years of life. Characteristically these abnormalities are non-progressing in nature and can have multiple different etiologies. The most prominent presentation of cerebral palsy involves motor abnormalities, but sensory and cognitive defects can also be present.
Synonyms: CP Brain paralysis Static encephalopathy Natural History: Most common form of severe chronic motor disability in children Incidence is estimated at 1.5-2.5 per 1000 births; prevalence is approximately 1 million Defining feature is that the causative insult occurs prior to complete development of the cerebrum Major risk factors include preterm birth and maternal or fetal infections, two processes that are often related Other risk factors include: multiple births chorioamnionitis antepartum vaginal bleeding second stage of labor lasting longer than 4 hours untreated hyperbilirubinemia fetal anoxic events low birth weight intrauterine growth retardation Cerebral palsy can be acquired postnatally from traumatic injury (abuse) or infection CENTRAL NERVOUS SYSTEM Congenital diseases Cerebral Palsy Presentation: Symptoms typically involve motor disorders but can include sensory and cognitive defects as well Clinical signs can be absent at birth and develop slowly as infant matures Milestone delays can be the initial presenting clinical symptom, especially those milestones involving motor behavior Major motor abnormalities include: Spasticity (80% of cases) Spastic hemiplegia Spastic diplegia Spastic quadriplegia Dyskinesias (20% of cases) Athetosis (choreoathetosis) Rigidity Other presenting features can include: Seizures (1/2 of cases) Intellectual impairment (2/3s of cases) Sensory impairment Diagnostic Testing: History and physical are important to rule out progressive disorders Clinical assessment instruments are available US of fetus during pregnancy MRI scan is most useful CT and ultrasound has also been used |
Cerebral Palsy
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A dysraphism is a defect in the formation of the midline in an embryo. The Chiari malformations are dysraphisms in which defects, possibly skeletal in origin, in the closure of the midline structures related to the metencephalon result in a range of neurological abnormalities involving the posterior cranial fossa. The fundamental abnormality involves the displacement of the tonsils of the cerebellum often along with the medulla into the foramen magnum. Three types of Chiari malformations are described in the literature, two of which, Types I and II, will be considered in this section.
Natural History: Epidemiology Chiari Type I Appears to be much more prevalent than originally thought Using MRI data, it is estimated at 0.6% in the adult population and 0.9% in the pediatric population Chiari Type II Estimated at 1 case per 1000 in the US population The most common serious malformation of the posterior cranial fossa. Etiology Chiari type I Low-lying cerebellar tonsils extending through the foramen magnum Possible obstruction of CSF and medullary compression Not associated with hydrocephalus in the young, can cause adult-onset hydrocephalus Strongly associated with syringomyelia Chiari type II Bony and dural abnormalities are present Small posterior cranial fossa Misshapened midline cerebellum Brainstem abnormalities Vermis which extends downward through the foramen magnum Almost always accompanied with hydrocephalus and myelomeningocele CENTRAL NERVOUS SYSTEM Congenital diseases Chiari Malformation Presentation: Chiari type I Signs and symptoms may develop at puberty or early adolesence Headache Neck pain Urinary frequency Progressive cerebrallar ataxia and lower extremity spasticity Apneic episodes can occur in infants Older children can present with scoliosis, weakness and syringomyelia Up to 14% of the patients in one pediatric series had a documented syrinx Usually not associated with hydrocephalus Chiari type II Signs and syptoms often develop early in life Progressive hydrocephalus and myelomeningocele Respiratory distress, stridor, episodic apnea, weak cry, facial weakness and aspiration in infants bilateral abducens palsies can be present Syncopal episode, nystagmus and spasticity in older children Syrinx can be present in the cervical or thracic spinal cord on imaging |
Chiari Malformation
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a dysraphism of the metencephalon. Its features include agenesis of the cerebellar vermis, cystic dilation of the fourth ventricle and enlargement of the posterior cranial fossa. This constellation of defects can also be associated with dysplasia of the brainstem.
Natural History: Epidemiology Incidence is approximately 1 case per 25,000-35,000 live births Accounts for approximately 1-4% of hydrocephalus cases Pathology and pathogenesis Features an enlarged posterior cranial fossa, loss of the cerebellar vermis with an enlarged midline fluid-filled, ependymal-lined cyst representing an expanded fourth ventricle Diagnostic Testing: CT or MRI |
Dandy-Walker Formation
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a failure of closure or a reopening of the previously closed caudal portions of the neural tube, thus it is classified as a neural tube defect. Neural tube defects are the most common congenital abnormalities in the central nervous system. Three types are described:
Spina bifida occulta midline defect in the vertebral posterior arch structures with no involvement of the neural components Meningocele midline defect of the vertebral posterior arch structures with herniation of the meninges but not of the neural structures Myelomeningocele midline defect of the vertebral posterior arch structures with herniation of the meninges and neural structures Synonyms: Spinal dysraphism Natural History: Incidence of neural tube defects is decreasing, currently in New England it is estimated to be 0.77 per 1000 births Spina bifida occulta is the most common of the neural tube anomalies 75% of the myelomeningoceles occur in the lumbar region CENTRAL NERVOUS SYSTEM Congenital diseases Spina Bifida Presentation: Spina bifida occulta General asymptomatic Minor changes in skin can be present over the dysraphism Meningocele Fluid-filled, cyst-like sac can extend off the back over the region of the dysraphism No untoward neurologic signs or symptoms Myelomeningocele Numerous organ dysfunctions, specific dysfunctions depend on the locale of the dysraphism Cyst-like structure covered by a thin layer of epithelialized material Lumbar myelomeningoceles result in lower extremity paralysis and loss of bladder and bowel control |
Spina Bifida
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an abundance of fluid in the ventricular/subarachnoid compartments of the cranium. It is not a specific diseases but a finding or complaint; the clinical features of hydrocephalus are the same regardless of the etiology.
Natural History Pathophysiology: Overproduction of CSF Impaired drainage of CSF Etiology: Obstruction of the cerebral aqueduct secondary to masses or viral infections Structural abnormalities such as the Chiari malformation or the Dandy-Walker syndrome in infants Clinical manifestiations: Infant Abnormal enlargement of the head or accelerated rate of head enlargement Young Child Brisk tendon reflexes, spasticity, clonus Older child (closed cranium) Irritability, lethargy, poor appitite, vomiting, headache |
Hydrocephalus
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a rare neurocutaneous disorder. These disorders are also termed the phakomatoses.
Natural History Vascular abnormality that develops as the primordial vascular suply to the head, brain and face is organizing Overlying leptomeninges is over vasculated while the brain is under vasculated and suffers calcifications and atrophy Presentation: Facial nevus (port-wine stain) about the eye extending in the ophthalmic division of the trigeminal nerve Glucoma may be present in the ipsilateral eye Seizures develop in the first year Metal retardation and severe learning disabilites follow in about 50% of the cases |
Sturge-Weber Disease
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a degenerative processes of the cerebral cortex that results in senile dementia.
Synonyms: AD Presenile dementia (old) Alzheimer's dementia Alzheimer's sclerosis Senile dementia of the Alzheimer's type Natural History: Epidemiology It is estimated that 5 million Americans have Alzheimer’s disease giving it a prevalence of 17 per 1000 people Alzheimer’s disease is the most common cause of dementia in the elderly and is considered a leading cause of death in the U.S. Etiology Strongly age-related disease Family pattern Pathogenesis Located on the long arm of chromosome 21; close to the gene for Down’s syndrome Presenilin genes located on chromosomes 1 and 14; early-onset disease Currently 4 different susceptibility genes are recognized CENTRAL NERVOUS SYSTEM Degenerative diseases Alzheimer's Disease Pathology Key pathology features include diffuse atrophy of the cerebral cortex with ventriculomegaly, sulcal enlargement and hippocampal atrophy Of the cortical atrophy, it is most marked in the parietal cortex, can involve extensive frontal lobe loss as well Neuritic plaques or senile plaques containing A beta amyloid Neurofibrillary tangles contain hyperphosphorylated tau proteins Accumulation of Ab amyloid around arterial walls intracerebrally The b-amyloid gene encodes a large protein termed the amyloid precursor protein (APP) Neuronal loss seen in the hippocampus, entorhinal cortex and association areas of the neocortex Severe pathology also presents in the hippocampus and the basal nucleus of Meynert (cholinergic system) Presentation: Usually begins in the 7th to 9th decade of life; an early-onset form is also recognized Slowly progressive decline in memory and orientation Normal laboratory values Memory impairment spreading to language and visuospatial deficits can be present Daily activities of living are affected Delusions characterize the later stages Typical duration is 8 to 10 years |
Alzeimher's Disease
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An unrelentingly progressive degenerative disease of neurons in the peripheral and central motor systems.
Natural History: Epidemiology The incidence of ALS is approximately 0.01 per 1000 persons but the prevalence is low due to the rapid lethality of the disease. The most common form of progressive motor neuron disease Pathogenesis Pathogenesis may involve failure of astrocytes to adequately remove glutamate from the synaptic cleft resulting in continual motor neuron activity leading to excitotoxicity, oxidative stress, failure of superoxide dismutase enzymes and eventual cell death Pathology Hallmark of the disease involves the death of peripheral motor neurons from the ventral horn and brainstem nuclei as well as the bulbospinal and corticospinal neurons in the brainstem and cerebral cortex respectively Denervation of skeletal muscle results in weakness and muscle atrophy Peripheral and central sensory systems remain unaffected in this process Autonomic nervous system function remains intact Death usually involves respiratory failure, average length of survival from diagnosis is 3 to 5 years Presentation: Initial presentation can be asymmetric, typically involving one hand, then progressing to a symmetric involvement Cramping of muscles, typically early in morning such as while stretching in bed Involvement of spinal motor neurons presents with flaccid weakness, atrophy and fasciculations Involvement of corticospinal motor neurons presents with spastic weakness Brainstem bulbar motor neuron involvement presents with dysphagia, dysarthria and dyspnea eventually leading to aspiration Dementia is not a normal component of the progression, but can be present in combined illnesses |
Amyotrophic Lateral Sclerosis
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the classic form of progressive, hereditary spinocerebellar ataxia. It involves significant loss of myelinated fibers in the posterior columns, spinocerebellar tracts and the corticospinal tracts of the spinal cord.
Natural History: Epidemiology The most prevalent form of unhereditary ataxia Incidence of 1 in 50,000 people in the U.S. Etiology Autosomal recessive mutation Pathogenesis Mapped to chromosome 9q13-q21.1 The gene is termed frataxin, and contains expanded GAA triplet repeats in most patients Pathology Progressive myelin and axon loss from the spinocerebellar tracts > posterior columns > corticospinal tracts in the spinal cord Fibrous gliosis present in these tracts Reduction of neurons in the nucleus of Clarke's column and in the dorsal root ganglia - lumbosacral > cervical Cell loss is also seen in the dentate nucleus of the cerebellum and in the inferior olivary nucleus of the medulla; loss of Purkinje cells occurs in the cerebellar cortex as well CENTRAL NERVOUS SYSTEM Degenerative diseases Friedreich Ataxia Presentation: Initial complaint is typically difficulty walking Ataxic signs in the legs bilaterally; both sensory and cerebellar ataxia are present in gait Wide spread unstable stance, with constantly shifting position; foot slapping when walking Rhomberg sign is present; check and rebound signs are present Arms ataxia presents following legs months or years later Speech is slow and progressively softer; may have choking due to uncoordinated respiratory muscles Tendon reflexes are abolished, plantar reflexes are extensor with flexor spasms Loss of vibratory and positional sense early in the disease; touch and pain sensation may diminish late in the process Optic atrophy may occur Structural changes include pes cavus (with hammer toes) and kyphoscoliosis Cardiomegaly in over half of the patients Diabetes mellitus in 10% of patients; another 10% have restricted glucose tolerance |
Friedrich's Ataxia
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Complete release of all sympathetic motor tone
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Spinal Shock
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a heterogenous group of progressive, degenerative hereditary ataxias associated with autosomal dominant mutations
Synonym: Autosomal dominant ataxia Natural History: Over 28 forms of spinocerebellar ataxia have been defined Most forms have been associated with a specific mutation The mutations have recently been clustered into three general groups: Polyglutamine disorders Channelopathies involving calcium or potassium channels Gene expression disorders Presentation: Progressive limb ataxia is the dominant finding |
Spinocerebellar ataxia
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a cavity that opens in the spinal cord. Essentially it results in a central cord syndrome.
Natural History: Two types of syrinxs are described: A true syrinx that opens in the white matter of the spinal cord and fills with extracellular fluids A dilation of the central canal of the spinal cord that fills with CSF, this is term hydromyelia Posttraumatic syrinxs are associated with whiplash types of injury A syrinx may be present at birth but not express itself clinically until early adult hood A syrinx is frequently associated with the Chiari type I malformation Presentation: Insidious onset and slow, unrelenting progressive lesion Head, neck or back pain Cape-like distribution of analgesia Flaccid weakness at the level of the lesion Spastic weakness below the level of the lesion Bladder & bowel can be involved |
Syringiomyelia
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suppurative infection located between the dural layer and the inner table of the skull.
Natural History: Rare, less common than brain abscess or subdural empyema. Often a complication of head trauma, surgery or spread of infection from contiguous structures |
Epidural Abscess
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a non-inflammatory demyelination of the pons secondary to the rapid correction of a hyponatremic state or production of a hypernatremic state.
Synonyms: CPM Osmotic demyelination syndrome Natural History: The exact incidence of CPM is unknown CPM was present in 29% of postmortem exams of liver transplant patients; Two thirds of these patients had serum sodium fluctuations of only ± 15-20 mEq/L In a consecutive series of 3548 autopsies, CPM was found in 9 cases or 0.25% More than half of the cases have appeared in association with severe alcoholism Other associated diseases include renal dialysis and hepatic failure and other severe terminal diseases Rapid correction of hyponatremia to normal or hypernatremic levels is the causal factor Lesion involves severe demyelination beginning in the geometric center of the pons Reactive phagocytes and glial cells are present but no signs of inflammation Lesions can also appear in the thalamus Presentation: Acute to subacute presentation Flaccid paralysis in all four limbs Inability to chew, shallow or speak Eye movements and facial expressions are often spared Survival is followed by the development of spasticity Locked-in syndrome can present |
Central Pontine myelinolysis
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Degeneration of the posterior and lateral columns of the spinal cord secondary to a deficiency in vitamin B12 (colbalmin)
Synonyms: Vitamin B12 deficiency Natural History: Vitamin B12 deficiency due to failure to transfer minute amounts of this substance across the intestinal wall Pernicious anemia is one associated consequence Can be precipitated by exposure to nitrous oxide gas Deficiency leads to spongy vacuolation, intramyelinic and interstitial edema of myelin sheaths and their eventual destruction and astrocytosis Initally, the heavily myelinated posterior and lateral columns of the spinal cord are prime targets With time both the large ascending sensory tracts and the descending motor tracts become demyelinated Presentation: Subacute and progressive development of ataxia, numbness and tingling in the lower extremities, often progressing to weakness and spasticity and increased reflexes (i.e. upper motor signs!). Pernicious anemia Spinal cord myelopathy Diffuse and symmetric presentation Paresthesias in hands and feet Loss of proprioception and vibratory sense Spasticity and ataxic weakness Peripheral neuropathy Dementia |
Subacute combined degeneration
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A malignant invasive embryonic tumor of the cerebellum most often seen in children and young adults.
Natural History: Medulloblastomas account for 20% of the CNS tumors in children Exclusive occurrence in the cerebellum Midline presentation in children; can be more lateral in adults Highly malignant tumor Five year survival rates are now greater than 50% at this time |
Medulloblastoma
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Tumors arising from the ependymal cells lining the ventricular system of the brain.
Natural History: Accounts for 5-10% of the primary brain tumors in the first two decades of life The most common tumor of the fourth ventricle Most often found in the fourth ventricle, but can present anywhere along the ventricular system Second most common site is supratentorally in the lateral ventricles Well-differentiated tumors with relatively slow growth Grade II tumors in the WHO classification Recurrence rate is high at 44% For fourth ventricle ependymomas, average survival post surgery is about 4 years Presentation: Under the age of three, clinical presentation involves (decreasing frequency): Vomiting Ataxia Headache Lethargy Increased head circumference Irritability Older children can show Ataxia Nystagmus Gaze palsy Hemiparesis Neck pain |
Ependymoma
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slow growing, benign tumors present on the meningeal layers surrounding the brain. They arise from the meningeal coverings of the brain
Natural History: Account for 13-20% of all primary intracranial neoplasms Most common in the 6thand 7th decade of life; rare in children More common in females than males When presenting in children, often associated with NF-2 neurofibromatosis Risk fractors: Established risk factor is radiation and radiation therapy Sex hormones could possibly play a role as well Viral infections (SV-40) have also been implicated Common locations Convexities of cranium Along the falx Skull base Usually solitary lobulated tumors attached to the meninges Most likely develop from meningothelial (arachnoid) cells Typical expand and replace CNS tissue but do not invade Can invade skull tissue, but not related to malignancy Grading: Grade I Meningioma (80%) Grade IIAtypical meningioma Grade IIIAnaplastic meningioma Grade IVMeningeal sarcoma Progression of tumor grade type does occur and is associated with loss of chromosomal arms Presentation: Can be asymptomatic and an incidental find on imaging Focal neurologic defects manifest due to compression of surrounding structures Seizures (Most common presenting complaint) Hemiparesis Gait disturbance |
Meningioma
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The spread of neoplastic growth to the central nervous system from a distant source.
Natural History: Intracranial masses appear in 25% of all patients with systemic cancer, of these: 15% are brain metastases 5% are leptomeningeal metastases 5% are metastatic lesion to the dura Brain metastases are 8 times more common than primary brain tumors Primary lesion location: Common Lung (35-64%) Non-small cell carcinoma of the lung is most common primary site However, melanoma and small-cell carcinoma, although less frequent, have greatest propensity to metastasise to brain Breast cancers (14-18%) Skin melanomas (4-21%) Renal cancers GI cancers Note: Lung, breast, kidney and skin account for <90% of all metastatic brain tumors Uncommon: Prostate cancers Pancreas cancers Uterine cancers Ovarian cancers Hodgkin lymphoma CENTRAL NERVOUS SYSTEM Neoplastic Diseases Metastasis Routes: Mainly hematogenous spread Rarely by direct spread from surrounding bone, meninges or pituitary Location: Can occur anywhere in CNS Cerebral hemispheres (80%) Cerebellum (10-15%) Arterial watershed zones are most common sites, specifically MCA and PCA Presentation: Temporal profile: Systemic disease usually presents initially, however CNS metastatic lesions can be initial presentation CNS metastatic lesion can manifest after primary systemic disease has been eradicated Distribution: Focal space-occupying lesions Penumbra of edema enhances ICP increase Specific symptoms: Headache (25%) Hemiparesis (25%) Seizures (15%) Cognitive or behavioural changes (15%) |
Metastasis
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enerally defined as a pain that persists for an arbitrary time (3 or 6 months) beyond the normally expected time of healing. Thus by definition, chronic pain, as a disease state itself. Chronic pain exists without a peripheral generating source and involves plastic changes in the central and/or peripheral nervous system. There is a tradition in the medical literature that if a nociceptive source can be identified from a given pain, then that pain, regardless of its duration, reflects acute pain and can not be considered as part of the disease state termed “chronic pain”. This serves to separates out long-term persistent pain with an obvious generator, such as that due to malignancy (cancer pain), from chronic pain with no apparent nociceptive generator. In reality, malignancy pain has components of both acute and chronic pain contained within it.
Natural History: Epidemiology 70,000,000 Americans report chronic pain and many are disabled by it. Characteristics of chronic pain Duration usually indeterminate; Persists after normal healing time, 3-6 months Often refractory to treatment Disrupts sleep and normal living Serves no adaptive purpose Etiology: injury malignancy non-life-threatening conditions may have no apparent cause May be a symptom or diagnosis May be nociceptive, neuropathic, or both CENTRAL NERVOUS SYSTEM Paroxysmal Disorders Chronic Pain Pathogenesis: Disruption or alteration in the normal nociceptive pathways of peripheral nerve, spinal cord, brainstem or cerebrum Plasticity in normal pathways involving sprouting of axons and loss of inhibitory interneurons Strong emotional and psychosomatic components based on prior experience Classifications of chronic pain By region effected (typically by body region e.g. head pain, chest pain, back pain etc..) By process involved: Neuropathic pain: neurogenic pain caused lesion anywhere in the nervous system Central pain: neurogenic pain caused by a lesion in the central nervous system Inflammatory pain: pain caused by inflammatory events Cancer pain: pain related the growth of a cancer Presentation: Fulminating or downward spiral of pain and suffering unrelated and out of proportion to tissue damage |
Chronic Pain
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The spinal cord is located in a narrow, articulated canal, the vertebral column. External injury to the vertebral canal or mass expanding lesions internal to the canal can result in traumatic spinal cord injury. Diseases of the spinal cord, while usually not leife-threatening, are devistating to the patient since they can render them paraplegic or quadraplegic. Thus accurate and rapid diagnosis is of the upmost importance.
It ias helpful to think of spinal cord lesions as being either compressive or non-compressive in nature. Compressive can be acute, subacute or chronic in temporal profile and involve some for of traumatic event as described below. Non-compressive lesions can be such events as vascular disease or autoimmune inflammatory disease. Compressive events will be dealt with in this section; non-compressive spinal cord damage will be considered under the headings of Vascular Diseases and Inflammatory Diseases. Natural History: Epidemiology Approximately 28 to 55 cases per 1,000,000 individuals with 10,000 new cases per year. Prevalence is estimated at 183, 000 to 230,000 Average age at injury is 31.7 years Etiology Acute compressive lesions Motor vehicle accidents (36-48%) Violence (5-29%) Falls (17-21%) Recreational activities (7-16%) Other forms of acute or subacute compressive lesions: Iatrogenic (surgical damage) Spinal epidural abscess Spinal epidural hematoma Spinal epidural neoplasms CENTRAL NERVOUS SYSTEM Traumatic Injury Traumatic Spinal Cord Injury Chronic compressive lesions include: Spondylitic myelopathy Syringomyelia Pathogenesis Primary injury Initial injury involves mechanical and compressive forces Edema and ischemia follow Secondary injury Hypoperfusion extends outward from the lesion blocking all neuronal activity Cells release glutamate creating an excitotoxic environment Neurons and oligodendroglial cells are affected Apoptosis leads to cell death |
Traumatic Spinal Cord Injury
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a bleeding event, are almost invariably the result of a traumatic accident. These hematomas involve the bleeding into the potential space between the dural layer and the inner table of cortical bone in the cranial vault. Typically such forceful bleeding results from a tear in the wall of a meningeal artery, however in 15% of the cases it is the result of a tear in a dural sinus.
Synonyms: Extradural hemorrhage Epidural hematoma Natural History: Epidemiology Incidence of traumatic brain injury is 1.5 million per year in the U.S. Epidural hemorrhages occur in up to 10% of severe head injuries Peak incidence is between 10 and 40 years of age Males twice as much as females Etiology Usually related to significant head injury, particularly to a blow to the lateral aspect of the head Typically the result of a tear in the wall of a meningeal artery, however in 15% of the cases it is the result of a tear in a dural sinus. Pathogenesis Outer dural layer separates from the inner table of cortical bone in the cranium, extravasated blood accumulates in this space The clot increases in size until the ruptured vessels compressed with the increasing pressure CENTRAL NERVOUS SYSTEM Traumatic Injury Epidural Hemorrhage Presentation: Preceding blow to the side of the head Brief loss of consciousness can occur Lucid interval for one or more hours; lucid interval is absent in over 50% of the cases Worsening headache, persistant vomiting, drowsiness and change in mental status following head trauma Advent of focal neurologic signs can occur; these can progress rapidly to bilateral posturing Rapid progression to unconsciousness and death if untreated |
Epidural Hemmorhage
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A collection of extravasated blood located between the inner layer of dura and the subarachnoid membrane. Subdural hemorrhages can be divided into acute and chronic. Acute subdural hemorrhages are medical emergencies.
Synonyms: Acute SDH Acute subdural hematoma Acute subdural bleed Natural History: Often associated with other signs of cerebral trauma Head need not strike an object; rapid velocity changes can suffice Acute SDH occurs in 20-30% of patients with severe head injury Incidence is 3 per 10,000 in the U.S. Occurs mostly in young males and in the elderly Rick factors include anticoagulants Presentation: Impaired consciousness (50% of patients loss consciousness) Up to 1/3 of patients have a lucid interval Headaches Can include focal neurologic defects Hemiparesis Aphasia Bradycardia and hypertension Unilateral pupillary dilation and oculomotor palsy Diagnostic Testing: CT scan is the mainstay of investigation MR imaging Clotting screen CBC and serum electrolytes (baseline against future changes) Mannitol |
Subdural Hemmorhage
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The brain is surrounded by blood vessels coursing in the subarachnoid spaces. Hemorrhage of these vessels is considered a form of stroke (see the Cerebrovascular Disease page). The almost exclusive non-traumatic origin of subarachnoid hemorrhage is a ruptured saccular aneurysm. Typically, the bleeding is into the subarachnoid space, thus blood contaminated the CSF.
Natural History: Annual incidence of nontraumatic aneurysmal SAH is 6-25 per 100,000 More than 27,000 Americans suffer ruptured intracranial aneurysms each year Annual incidence increases with age and probably is underestimated, because death is attributed to other reasons that are not confirmed by autopsies The incidence of SAH for people of African, asian or Hispanic decent is twice that of the Caucasian population SAH accounts for only 3% of all strokes Aneurysmal bleeding accounts for 85% of SAH Spontaneous bleeding of perimesencephalic vessels in the ambient cistern accounts for 10% The remaining 5% arise from AV malformations or other rare causes Most aneurysm form at the bifurcation or trifurcation of cerebral blood vessels SAD involves bleeding into the CSF; thus xanthochromic CSF is pathognomonic for SAH Formation of aneurysms is currently considered to be idiopathic, but several factors are clearly involved: Genetic Age Toxins (alcohol and smoking) Co-morbidities with aneurysms include: Polycystic kidney disease Ehlers-Danlos syndrome type IV Neurofibromatosis type 1 Of those suffering a SAH, 10-14% die before hospitalization and total mortality is approximately 40%, most occurring in the first 24 hours CENTRAL NERVOUS SYSTEM Vascular Diseases Subarachnoid Hemorrhage Presentation: Range from completely normal to deeply comatose Signs of meningeal irritation are present in one-third of the patients Headache (worst of their life) in 20% of patients with SAH Sudden onset of a mild headache can be a sentinel bleed especially if associated with transient cranial nerve dysfunctions |
Subarachnoid Hemorrhage
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a form of stroke (see page on Cerebrovascular Diseases). This topic includes bleeding within the CNS parenchyma (intraparenchymal) and into the ventricular system (intraventricular). Subarachnoid hemorrhage will be covered on a separate page in this section, while subdural and epidural bleeding will be covered in the section on trauma.
Synonyms: Intracerebral hemorrhage Intracerebral bleeding Intraparenchymal hemorrhage Intraparenchymal bleeding Spontaneous intracerebral hemorrhage Natural History: Epidemiology ICH affects approximately 12-15 per 100,000 individuals per year, including 350 hypertensive hemorrhages per 100,000 elderly individuals Significant age-dependent relationship ICH accounts for 10-15% of all strokes Mortality rate is 40% Race-dependent relationship; incidence is 2X higher in persons of Asian or African descent The overall incidence of ICH has declined since the 1950s Etiology Hypertensive hemorrhage accounts for 50-60% of all ICH Sympathomimetic drugs (e.g. cocaine) is the main cause of ICH in young people Head trauma is a significant cause of ICH CENTRAL NERVOUS SYSTEM Vascular Diseases Intraparenchymal Hemorrhage Pathophysiology Vessel rupture secondary to long-standing hypertension or acute hypertensive episodes Typical locations for spontaneous hypertensive ICH are, in descending order: Basal ganglia (putamen) Thalamus Cerebellum Pons Vascular abnormalities leading to ICH can be either congenital or acquired Parenchymal bleeding can remain entirely confined to the brain, in which case blood does not contaminate the CSF However, parenchymal bleeding can rupture into the ventricles, thus becoming an intraventricular hemorrhage and blood will contaminate the CSF Parenchymal bleeding almost never ruptures the outer surface of the cerebrum, thus the appearance of blood in the CSF is usually derived from the ventricles and indicative of an intraventricular hemorrhage Intraventricular bleeding is an ominous sign concerning the prognosis of the patient Presentation: Sudden onset of focal neurologic signs or symptoms Specific signs and symptoms depends on location of the ICH Often associated with a headache and nausea Rapidly progressing (less than a day) to loss of consciousness and neurologic demise secondary to increased intracranial pressure Midline shift present on imaging |
Intraparenchymal Hemorrhage
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