Micro: Other Neuro infections Flashcards
transmissible spongiform encephalopathies (TSE)
caused by prions
FATAL dementias
LONG INCUBATION but rapidly progressive
multifocal spongiform changes
kuru
to tremble with fear
transmitted by ritual cannibalism
Creutzfeldt-Jakob disease (CJD)
most common human TSE Sx: dementia, myoclonus, ataxia end stage: akinetic mutism cerebellar spongiform change, lack of amyloid plaques check CSF to rule out other disease
CJD
- sporadic
- iatrogenic
- familial
- most cases; 60 yrs; most dead in a year; PERIODIC COMPLEX on EEG
- dural/corneal grafts, hGH (NO blood transmission); short incubation
- AD inheritance; specific mutations; 45-50 yrs; 2-4 yr survival
Gerstmann-Straussler-Scheinker disease (GSS)
AD inheritance
mutation
48 y/o, 5 yr survival
Sx: ataxia, gait abnormalities (dementia less common)
atypical EEG (no characteristic findings)
amyloid plaques and spongiform changes
fatal familial insomnia (FFI)
AD inheritance mutations 49 y/o, 13 mo survival SLEEP DISTURBANCE, AUTONOMIC dysfunction Neuronal loss (no plaques or spongiform change)
variant CJD
mad cow disease (cow got it from sheep)
blood transmission (France, Great Britain), CONSUMPTION of CONTAMINATED BEEF
detected in LYMPH tissue
age: 29 y/o, 14 mo survival
HOMOZYGOUS for METHIONINE at codon 129
Sx: ANXIETY, DEPRESSION, VISUAL PROBs, akinetic mutism
Dx: atypical EEG, TONSIL Bx, neuropsych probe for more than 6 months
FLORID (daisy-like) plaques, spongiform change in BASAL GANGLIA
scrapie
sheep and goats
ataxia
alimentary tract transmission
bovine spongiform encephalopathy
cow
chronic wasting disease
elk and deer
prion
cell surface glycoprotein anchored by fatty acid addition
highly conserved
exon on chromosome 20: neurons and lymphocytes
PrPc
normal
inhibits BACE1: inhibit beta amyloid
req. for PrPSc formation
PrPSc
disease causing: chain rxn causing more proteins to misfold spontaneous or infection or ingestion misfolded (same AA seq. as PrPc) resistant to proteases aggregates in cells: apoptosis CNS disease SPECIES BARRIER exists
polyoma virus
circular dsDNA around histone
non-enveloped icosahedral capsid
replicate in respiratory tract
polyoma virus
- permissive cells
- non-permissive
- replication, assembly, cell lysis
2. transformation of cell, integration into host genome
T antigens
- immortalize cells
- transform cells
early genes of polyoma initiate DNA replication responsible for transformation 1. small and large 2. small and middle
polyoma late genes
encode structural proteins
BK virus
polyoma virus
most people seropositive
isolated in urine of AIDS pts
little disease
JC virus
polyoma virus most people seropositive only problem in immunodeficient PML: progressive demyelinating leukoencephalopathy Dx;
PML
JC
lyses oligodendrocytes
Sx: clumsy, progressive weakness, speech probs
Dx: PCR amplification of virus from CSF or brain biopsy , MRI white matter lesions
high FATALITY rate
Tx: AIDS: change HAART, transplant: alter suppression chemo
poliovirus
non-enveloped icosahedral capsid ssRNA fecal-oral initial replication: lymph, gut secondary viremia flaccid paralysis: motor neurons destroyed
- abortive poliomyelitis
- aseptic meningitis
- paralytic poliomyelitis
- nonspecific febrile illness; NO CNS involvement
- febrile illness and stiff neck, limited CNS infection
- febrile illness, flaccid paralysis; gradual recovery over 6 mo: lingering paralysis is permanent; some die
Dx of polio
virus isolation from stool, rectal or throat swab and CSF
inactivated polio vaccine (IPV)
advantages: no reversion to virulence
disadvantage: 3 injections and booster; protects against paralysis but does NOT prevent spread of wild virus
only one recommended in US now
