Central Nervous System Flashcards
What are common causes of hydrocephalus?
Cerebral aqueduct stenosis
Dandy-Walker
Arnold-Chiari( type I)
Sequale of Meningitis(due to fibrosis)
What are common causes of meningomyelocele?
Spinal Bifida
Arnold-Chiari Syndrome
What is syringomyelia?
Cystic degeneration of the spinal cord
What are the cause of syringomyelia?
Trauma
Arnold-Chiari malformation
What are the causes of anterior motor horn damage?
Poliomyelitis(poliovirus)
Werdnig-Hoffman Disease(autosomal recessive-floppy baby)
What is ALS?
Degenerative disorder of UMN and LMN.
What is the early sign of ALS?
Atrophy & weakness of hands
How do you distinguish ALS from syringomyelia?
Lack of sensory impairment distinguishes(Spinothalamic Tract is not affected).
Mutation of what enzyme is seen in ALS?
Superoxide dismutase mutation(SOD1)
What is Friedrich Ataxia?
Degenerative disorder of the cerebellum and spinal cord.
Ataxia & multiple spinal cord tracts
What is the cause of Friedrich Ataxia?
Unstable trinucleotide repeat(GAA) i the Frataxin gene.
Essential for mitochondrial iron regulation(free radical damage via fenton reaction)
Friedrich Ataxia is associated to what disorder?
Hypertrophic cardiomyopathy
Cause of Meningitis in neonate?
GBS
E. coli
Listeria monocytogenes
Cause of Meningitis in teenagers?
N. meningitidis
Cause of Meningitis in adults & elderly?
S. pneumoniae
Cause of Meningitis in children(virus)?
Coxsackievirus(fecal-oral)
Cause of Meningitis in immunocompromised individuals ?
Fungi
Symptoms of meningitis?
Headache, Nuchal rigidity(neck stiffness), and Fever
What layers are crossed for a lumbar puncture?
Skin –> ligament –> epidural space –> dura mater –> arachnoid–>CSF(subarachnoid space)
Various levels of CSF and glucose(viral, fungal, and bacteria)?
Bacterial meningitis: Neutrophils and low glucose
Viral meningitis: lymphocytes w/ normal glucose
Fungalmeningitis: Lymphocytes with low glucose
What is the normal CSF glucose level in comparison to blood glucose(fraction)?
2/3
100 * 2/3 = 66 in CSF
What are 2 sequalae of bacterial meningitis?
Death: Herniation secondary to cerebral edema.
Fibrosis: Hydrocephalus
What is the symptoms of mild global ischemia?
Transient confusion with prompt recovery.
E.g. Insulinoma given sugar.
What histologic finding is seen in severe global ischemia?
Diffuse necrosis
What is the sequalae if you survive severe global ischemia?
Vegetative state
What is the cause of moderate global ischemia?
Infarcts in watershed areas
What is the classic example of moderate global ischemia?
Regions between anterior and middle cerebral artery
What are the highly vulnerable regions of moderate global ischemia?
Pyramidal neurons of the cerebral cortex(3,5,&6): Laminar necrosis.
Pyramidal neurons of the hippocampus(temporal lobe): important in long-term memory
Purkinje layer of the cerebellum: Integrates sensory perception with motor control(cerebellar signs)
What is the difference between thrombotic stroke and embolic stroke?
Thrombotic(branch points): rupture of an atherosclerotic plaque–> thrombus reforms because of exposure of subendothelial collagen–> Pale infarct
Embolic stroke(atrial fibrillation): Middle cerebral(branch of internal carotid) –> hemorrhagic infarct(clot is broken down)
What is the cause of lacunar stroke?
Hypertension or diabetes –> Hyaline arteriosclerosis –> lacunar stroke.
What is the most common artery affected in lacunar stroke?
Lenticulostriate vessels
Stages of ischemic stroke?
Eosinophilic(red neurons) 12 hours –> necrosis(neutrophils & microglial cells) –> Gliosis-reactive astrocyte(2-3 weeks) –> Gliotic cyst with connective tissue
What causes intracerebral hemorrhage?
Rupture of lenticulostriate vessels(basal ganglia)
Due to charcot-Bouchard microaneurysms
What is patient complaint for subarachnoid hemorrhage?
Worst headache of my life
Nuchal rigidity
LP of patient with subarachnoid hemorrhage shows?
Xanthochromia(yellow hue due to bilirubin breakdown)
What is the most common location for berry aneurysm?
Anterior communicating artery(lack of media)
What are associated causes of subarachnoid hemorrhage?
Marfan syndrome
Autosomal dominant polycystic kidney disease
Trauma causes what 3 conditions in the brain?
Epidural Hematoma
Subdural Hematoma
Herniation
A patient presents with a lens-shaped lesion on CT. What is the patient’s condition?
Epidural hematoma
What is affected in epidural hematoma?
Middle menigeal artery
Patient has a “talk and die” episode. What condition causes this?
Epidural hematoma
What vessels are affected in subdural hematoma?
Bridging veins between the dura and arachnoid.
A patient presents with a crescent-shaped lesion on CT. What is the patient’s condition?
Subdural hematoma
What are causes of subdural hematoma?
Elder: cerebral atrophy stretching the vein.
Others: tearing of bridging veins between dura and arachnoid
Describe a tonsillar herniation and symptoms observed?
Displacement of cerebellar tonsils into foramen magnum –> Cardiopulmonary arrest.
What is a subfalcine herniation & what vessel does it compress?
Displacement of the cingulate gyrus under the falx cerebri -> compresses anterior cerebral artery
What is an uncal herniation?
Displacement of the temporal lobe uncus under the tentorium cerebelli
Tentorium cerebelli is the extension of the dura mater that separates cerebellum from temporal lobe.
What are the 3 results of uncal herniation?
Cranial nerve III(oculomotor) –> down and out and a dilated pupil.
Compressionof PCA –> contralateral homonymous hemianopsia(E.g. right side of brain having visual deficits for left field of both eyes)
Rupture of the paramedian artery leads to?
Duret(brainstem) hemorrhage
What cells form the myelin structures in the CNS and PNS?
Oligodendrocytes - CNS
Schwann cells - PNS
Which are destroyed in demyelinating disorder?(axons, myelin or both)
Axons are generally preserved, but the conduction of impulse along the axon is impaired.
What are leukodystrophies?
White matter problems
Inherited mutation in enzymes necessary for production or maintenance of myelin.
What are the 3 leukodystrophies?
Metachromatic leukodystrophy
Krabbe disease
Adrenoleukodystrophy
Describe metachromatic leukodystrophy?
Deficiency of arylsulfatase
Sulfatides cannot be degraded & accumulate in oligodendrocytes(lysosomal storage disease)
AKA you can’t degrade myelin
Describe Krabbe disease?
Deficiency of galactocerebrosidase
Accumulates in macrophages
Describe Adrenoleukodystrophy?
impaired addition of coenzyme A to long-chain fatty acids
X-linked
Accumulation of fatty acids damage adrenal glands & white matter of the brain.
What is the etiology & pathogenesis of multiple sclerosis?
Autoimmune destruction of CNS myelin and oligodendrocytes
Environmental + genetic = Away from equator + HLA-DR2.
Name 2 high yield symptoms of M.S.?
Scanning speech: Mimicking alcohol intoxication(brainstem)
Internuclear ophthalmoplegia(Medial longitudinal fasciculus): If you’re trying to look left, right eye will not be albe to be pulled to the left. Because CN. 6 of left eye cannot communicate with CN. 3 of right eye.
What are the 3 labs to look for in M.S.?
Increased lymphocytes
Increased immunoglobulins(with oligoclonal IgG bands)
Myelin basic protein(Due to destruction of myelin)
What is the treatment for M.S.?
High-dose steroids: Autoimmune
Interferon beta: slows progression of disease
What causes Subactue Sclerosing Panencephalitis?
Slowly progressing, persistent infection of measles virus.
What are the histological finding in subactue sclerosing panencephalitis?
Viral inclusions within neurons(gray matter) and oligodendrocytes(white matter)
What causes progressive multifocal leukoencephalopathy?
JC virus infection of white matter.
reactivation caused by immunosuppression
What causes central pontine myelinolysis?
Rapid intravenous correction of hyponatremia –> focal demyelination of pons(anterior brain stem) –> “locked in” syndrome.
