Neuro Pathologies

Question 1

Osmotic Demyelination Syndrome (Central pontine Myelinolysis)

Answer 1

Demyelination due to osmotic changes- specifically rapid correction of HYPOnatremia
Results in demyelination of PONTINE white matter –> loss of consciousness, acute paralysis, dysarthria, dysphagia, diplopia –> locked in syndrome

Contrast - HYPERNATREMIA CORRECTION –> cerebral edema/herniation

Question 2

Huntingtons disease

Answer 2

Pathogenesis:

• Caused by CAG trinucleotide repeats
• Neuronal cell death via NMDA-R and glutamate toxicity
• Gain of function mutation of huntingtin protein: deacetylation of histones
• dec. GABA, dec Ach, Inc Dopamine
• Caudate atrophy with ex vaco dilitation of frontal horns

Loss of motor control (choriform movements)–> loss of memory, affect changes (aggression and depression),personality changes–> full blown dementia and

Autosomal Dominate
anticipation: increase number of repeats during spermatogenesis

Question 3

Charcot Bouchard Micro aneurysms

Answer 3

aneurysm of the small vessels- basal ganglia and lenticulostriate
Associated with HTN

Question 4

Charcot Bouchard Micro aneurysms

Answer 4

aneurysm of the small vessels- basal ganglia and lenticulostriate
Associated with chronic HTN

Question 5

Central post stroke Pain syndrome

Answer 5

Stroke affect thalamus –> parasthesias for a few weeks –> allodynia and dysesthesias.

Question 6

Anencephaly

Answer 6

Failure of closure of the anterior neural tube- no forebrain and open calvarium
Area cerebrovasculosa: disorganized brain tissue, ependymal cells, and choroid
No cranium
Posterior Fossa intact
AFP inc
Polyhydraminos- no swallowing center

Assoicated
with maternal Type 1 diabetes and folate deficiency

Question 7

Holoprosencephaly

Answer 7

Failure of the left and right hemispheres to separate

• may be association with FAS, or Patau syndrome (trisomy chromosome 13) with failure of SHH
• Most severe form: cyclopia
• Less severe: cleft palate, cleft lip, failure of CNI, can’t smell

Question 8

Communicating Hydrocephalus

Answer 8

Due to granulations failure to absorp
** post meningitis arachnoid scarring 
Inc. ICP
uncal hemorrhage 
HA

Question 9

Non-communicating Hydrocephalus

Answer 9

Blockage- as with a chiari 2 malformation (compression of the aqueduct) 
Inc. ICP
papilledema
HA
CN 3 palsy- eye down and out 
lethargy and personality change

Question 10

Normal Pressure Hydrocephalus

Answer 10

Old people
Idiopathic
No inc. in subarachnoid Volume
No inc ICP
Inc in ventricle dilation becuase of inc. fluid –> distort the Internal capsule (corona radiata)
–> incontinence, ataxia, REVERSIBLE dementia
(wet, wobbly, wacky)

Question 11

Hydrocephalus in infant Sx

Answer 11

• Poor feeding
• Hypertonicity
• Hyperreflexia
• • due to stretching of the paraventricular CST (pyramidal)

Question 12

Multiple Sclerosis

Answer 12

Inflammation and Autoimmune destruction of olgiodentroctyes (myelin) in the CNS
Sx:
- Marcus Gunn Pupil due to optic neuritis (periorbital pain and pain with eye motion)
- loss of sensory and muscle control
- incontinence
- scanning speech
- internuclear opthalmoplegia
- intention tremor
- waxing and waning symptoms- get progressively worse)
(SIINS- charcot “triad”)
- affects optic nerve and chiasm, brain stem and spinal cord, cerebellum

Dx:
CT:
1. Asymmetric periventricular lesions or white matter lesions - most commonly located at the ventricle angles (demyelination and reactive gliosis)
2. CSF: inc in protein, Ig light chain in CSF, olgioclonal bands are diagnostic

Pathogenesis:
TH1 CD4 cell activation to myelin self antigens –> Macrophages –> macrophages and released cytokines responsible for macrophage destruction

Question 13

Alzheimer’s Disease

Answer 13

Most common cause of dementia (loss of memory, change in behavior, and functioning, but INTACT consciousness)
Sx
Loss of memory –> loss of language, mathematical skills, and learned motor skills —> mute, incontinence, unable to walk–> die of pneumonia

Can be familial or sporadic
Familial:
- Chromosome 21- APP mutation- inc. AB protein
- Chromosome 1 missense or splicing mutation- Presenilin 2- inc. production of AB
- Chromosome 14 missense mutation- Presenilin 1- inc production of AB
- APOE4- dec. age of onset

Neurofibrillary Tangles: hypophosphorylated tau protein- insoluble (correlates with severity of dementia)
Amyloid Plaques- APP cleaved into Amyloid B, AB surrounded by enlarged dilated tortuous neurites
Vascular amyloidopathy- due to inc. in amyloid plaques

Dec Acetyl choline transferase activity - dec Ach
Corticol atrophy- degradation of gyri widening of sulci, hydrocephalus ex vaco

Question 14

Acute Disseminated Encephalomyelitis

Answer 14

Periventricular inflammation and demyelination due to infections:

• MEASLES
• VZV
• POX virus
• RABIES

Question 15

Charcot Marie Tooth

Answer 15

HMSN 
Pathogenesis: dec production of proteins needed for structure and function of peripheral nerves and myelin 
Sx: 
Calf atrophy
Hypertrophic nerves- palpable 
Onion skin
segmental demylination 

Autosomal dominant
Progressive
Related to scoliosis and foot issues (high arch)

Question 16

Krabbe Disease

Answer 16

Defect in enzyme galactocerebriase –> accumulation of galatocerebride and psychosine–> degradation of myelin sheath

Peripheral neuropathy, optic nerve atrophy, developmental delay, globoid cells

Question 17

Metachromatic Leukodystrophy

Answer 17

Defect in arly-sulftidase –> inc. in sulfatides –> dec production and destruction of peripheral and central myelin sheath

ataxia, dementia
peripheral and central demyelination

Question 18

Progressive multifocal Leukoencephalopathy

Answer 18

Demyelination of CNS due to JC virus in AIDs pts

Rapidly progressive and fatal