liveonearth (liveonearth) wrote,

Pathology of the CNS: Bugs that get in your BRAIN

progressive loss of mental and physical fx
Treponema pallidum, spirochete, invades CNS
four stages, if you will:
1) asymptomatic (painless chancre, condyloma lata, urethral discharge green)
2) meningovascular (perivascular inflam presents as stroke of MCA or basilar branch in young person, these vessels being in the base of the skull, may result in cranial nerve palsies)
3) paretic (20-30 years, progressive: spirochetes invade parenchymal tissue-->inflam kills brain cells-->chronic perivascular and meningeal inflammatory changes-->brain atrophy)
4) tabes dorsalis (present with loss of pain sensation, bladder incontinence, loss of peripheral reflexes, impairment of vibration sense and proprioception, progressive ataxia dt demyelination of posterior column, inflam and fibrosis of dorsal sensory nerve roots-->ataxia, loss of pain and proprioception-->demetia-->vegetative-->death)(Argyl-Robertson pupil does not react to direct light but is consensually reactive and accomodative)

What's MCA?

middle cerebral artery

What's ataxia?
sensory ataxia, per wikipedia:
--loss of proprioception (sensitivity to joint and body part position)
--dysfunction of the dorsal columns of the spinal cord which carry proprioceptive info to brain
--mbdt cerebellum, thalamus, and parietal lobes
--presents with an unsteady "stomping" gait with heavy heel strikes
--postural instability worsened when the lack of proprioceptive input cannot be compensated by visual input
--test: patient stand with his / her feet together and eyes shut (Romberg)
--test: finger-pointing with eyes closed
--test: arm drift and jerk: patient's finger will tend to "fall down" and be restored to the horizontal extended position by sudden extensor contractions ("ataxic hand")

What do the call the meningeal granulomas that may form due to Treponema invasion?
well circumscribed mass of granulation tissue
may occur anywhere in the brain or spinal cord (or on face?, other locations)
can cause a wide variety of neurologic deficits

Name the febrile reaction that occurs several hours following the treatment of early stages of syphillis?
high: reaction is to the dying spirochetes
fever, chills, headache, nausea, generalized arthralgias and myalgias, disappear within 24 hours

caused by JC virus in Papovavirus family
JC was pt from whom virus was 1st cultured
rare demyelinating dz which is progressive and results in loss of oligodendrocytes
SX: memory loss, loss of coordination, mentation, vision problems
vegetative state within 3 years
punctate hemorrhages in the FRONTAL LOBE
appears grossly as irregular areas of granulation in white matter

rare complication of MEASLES (rubeola virus)
1-20+ years after initial measles infx
hx of measles usu before age 2 followed by 5-15 ASX years, then gradual and progressive neuro decline
personality changes, seizures, ataxia
photosensitivity, spasticity and coma
CSF looks NORMAL (no low sug no high prot, mb high WBC's)
except for specially ordered immunoglobulin:
Rubeola IgG Antibody
white matter hemorrhage and gliosis are seen in 14 year old
EOSINOPHILIC INCLUSION BODIES in cytoplasm of neurons and glial cells

What virus likes to attack the frontal lobe? JCV (PML)
What likes to attack the temporal lobe? HSV
What virus will you find in temporal lobe and cerebellar purkinje cells? Rabies

fecal oral trans
replicates in nasopharynx and GI then invades lymphoid tissues-->hematologic spread
incubation: 5-35 days
after a period of viremia, virus becomes neurotropic
destroys motor neurons of anterior horn and brainstem-->flaccid paralysis of certain areas
if phrenic nerve involved: needs iron lung 1960 vaccine available
muscle wasting (skinny legs)
recurrent bouts of muscle weakness, same groups
may develop 20-50 years after infx
tx: anti-inflam

vasospasm in neck-->trouble swallowing-->hydrophobia
zoonotic: all warm blooded wildlife: racoons, skunks, bats, dogs, cats can carry it
transmitted by saliva, travels in nervous system from bite site to brain
1-3 months travel time
sx appear usu 30-60 days after exposure
SX: severe headache, fever, irritability, muscle spasm, dilated pupils, increased saliva (infectious)
SX: unusual sensitivity to sound, light, and changes in temperature
SX: mental status changes from anxiety and severe irritability-->confusion-->stupor-->coma
before stupor sets in pt may be violent, uncoordinated, wild
usu dies of cardiac or respiratory failure within a week of sx appearing
low survival rate
pt dying of rabies 1959 pictured in bed, arms bent, hands in fists, head back like siezure
DX: PCR on saliva, urine or CSF
Reference method for diagnosis is PCR or viral culture on brain samples taken after death
INCLUSION BODIES in neurons called NEGRI BODIES are 100% diagnostic but found in only 20% of cases
NEGRI bodies in temporal lobe and cerebellar purkinje cells are frequent sites of attack
rabies in humans is rare
18,000 Americans get the shot each year because they have been in contact with possibly rabid animals
WHO estimates that 40,000 people/year die of rabies worldwide

ADC = AIDS dementia complex (syndrome may occur without HIV? vaguely suggested by notes)
complicated syndrome
as CD4+ counts decrease, HIV increasing effect, more dementia
uncommon early in dz
rapid progression once it begins (months)
SX: difficulty concentrating, memory problems, irritability, unsteady gait
SX: difficulty with balance, poor hand writing, notable changes in HANDWRITING
movie on AIDS: "On Silver Street" recommended
SX: slowness in normal activities, difficulty speaking, motory dysfunction, muscle weakness
LATE: incontinence, spastic gait, psychosis or mania, apathy, confinement to bed
MECHanism not known
HIV appears to target CNS macrophages first
macrophages release toxic substances: quinolinic acid, cytokines and other signal molecules
these bind to nerve cells-->dysfunction and death
infected macrophage can shed part of an ingested HIV outer coat (gp120) which can also damage neurons
MRI shows cortical atrophy and market ventricular enlargement

unusual yet fatal encephalopathy
SX: fever, vomiting, fatty infiltration of liver, swelling of kidneys and brain
two phases
1) usu assoc with previous viral infx esp flu or chicken pox
2) develops after using aspirin for treating sx of viral infx
inhibition of CoxII enzyme causes NASH and kidney damage
recovery varies: complete---slight motor/learning disabilities---profound brain injury
Miller: no aspirin until mid or late teens

multiple and various sx
two kinds in humans: KURU and CREUTZFELDT-JAKOB DZ (cjd)
rapidly progressive dementia with death within a year in almost all cases
kuru in New Guinea, shaking palsy in women and kids, tribe devastated
eating flesh of dead people, men got good meat
women and children ate nerves and brains (dz in there)
since 1996 increasing evidence for causal relationship btw EUR outbreaks in cattle
(bovine spongiform encephalopathy = BSE, mad cow dz)
and variant CJD in humans = vCJD
both conditions invariably fatal
incubation: long, measured in years
scrapie is same thing in sheep, rub on fence, break skin, fall and die
TRANS: eating beef???
TRANS: iatrogenic in at least 250 pts worldwide so far
contaminated human growth hormone, dura mater and corneal implants,
and infected neurosurgical equipment
HISTOL: brain tissue VACUOLATED in pt with CJD
Tags: brain, cranial nerves, diagnosis, hiv/aids, microbes, nervous system, pets, prions, stds, vaccines, viruses

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