Neuropathology Part IV- Demylinating (10) Flashcards
what do demylenating diseases affect (2)
- Olgodendroglia cells
- Mylein sheath cells
(result in a net loss of myelin)
What are the 2 forms of demylating disoders
Primary (leukodystrophies
Acuired (ms)
What is Ms and what does it affect
m/c demylenating disorder of the CNS
characterized by recurrent episodes of demylenation in the brain (optic nerve first) and spinal cord
epidemiology of MS
1/1000 w higher prevelence in northern countries
women double risk
-usual onset in 3/4th decade
what genetic factor is associated w MS
HLA DR2
what immune factors are associated w MS
Cd4 and CD8 are inflitrated in lesions associated w MS
3 clinical forms of MS
devic disease
acute ms (marburg)
Balo disease
Devic disease
classical ms pres
-bilat optic neuritis and spinal cord involvement, rapidly progressive
Acute MS
widespread myelin injury, affects younger pts and has rapid death
Balo disease
Rare MS, progressive varient associated w the development of lesions containing rings of myelinated and demylinated white matter
Morphology of MS and where does it like to affect
Grey/white translucent plaques in the white matter
loc- corner of lat ventricles, optic nerves and spinal cord
What are the types of plaques in MS (4)
Acute- soft/slightly pink
Remote- more firm, pearly grey and relatively circumscribed
Active plaque- sharply defined collections of foamy macrophages, associated with relative preservation of neurons
Shadow- axons w thin layer of myelin at edge (partial demylenation)
What are the common S/s of MS
- unilateral optic neuritis and transversemyelitis
- diplopia, ataxia, spatisity, weakness
What lab results will you see with MS
CSF
- myelin in csf
- Basic pro (due to active myelin breakdown)
- Oligoclonal bands
- elevated CSF igG index
What is acute disseminated encephalomyelitis
Immune mediated demylinating disease that follows a viral illness
clinical course of acute disseminated encephalomyelitis + s/s
- monophasic (no remissions) with abrubt onset
- seizures, coma, focal neurological defits
-collection of foamy macrophages similar to MS
What causes acute necrotizing hemorrhagic encephalomyelitis
immune mediated demyelinating disease that follows an upper respiratory inf (mycoplasma pneumonia)
Acute necrotizing hemorrhagic encephalomyelitis- clinical course/ morphology
acute onset, fulminant course
-has white and grey matter necrosis, neutrophilic infiltrate and fibrin deposision
What causes progressive multifocal leukoencephalopathy
Demyelination as result of viral inf involving oligodendroglial cells
cause- JC virus in association w immunosupression
What is central pontine myelinolysis- what does it affect and cause
Focal demylinisation of central basal pons
-pts who have low lvls of sodium- Severly malnourished, alcoholics, liver disease
What is an axonal neeuropathy
associated w the formation of fragmented axonal processes
-wallerian degen)
-mc type of neuropathies
what does demylinating neuropathy affect
Primary damage to schwann cells (characterized by selective myelin injury and relative sparing of axons)
What is the course of guillain barre syndrome
-usually begins with weakness in the distal extremities and progresses to involve the prox mm groups
what predisposes guillain barre syndrome
2/3 follow influenza like illness (CMV, epsien barr etc)
what is the mc metabolic neuropathy
Diabetes mellitis- distal symmetric sensory or sensorimotor/autonomic
Pathology of diabetic neuropathy (3)
increased glu leads to:
vasa nervorum- capillary basement thickening (leading to improper profession)
Nerve glycoxidation- impaired axonal transport, slow
Imflammation
What are the causes of infectious neuropathy (3)
leprosy
diptheria
varicella zoster
What causes paraneoplastic neuropathy (5)
POEMS
- polyneuropathy
- organomegaly
- endocrinopathy
- monoclonal gammopathy
- skin changes
