Viral CNS Infection Flashcards
important physical exam findings to rule out when suspecting viral meningitis
pulmonary: rule out pneumonia; dermatological: rash could indicate bacterial
important lab tests to rule out when suspecting viral meningitis
test for syphilis, HIV; looks at WBC count and determine if monocyte or neutrophil predominance (neutrophil means bacterial); urine; chest x-ray for TB; CSF glucose and protein, CSF gram stain
when a person presents with fever and headache, what are our two largest concerns?
meningitis & encephalitis (or combination)
if it is acute meningitis, what organisms would we suspect?
enterovirus, strep pneumo, neiss meningitidis
if it is chronic meningitis, which organisms would we suspect?
mycobacteria TB, fungal, sarcoid, malignancy
encephalopathy
altered consciousness with no evidence of inflammation in the CNS on imaging or CSF analysis
encephalitis
altered consciousness, evidence of CNS inflammation or imaging (virologically confirmed if pathogen identified in CSF by culture/PCR)
meningism
headache with neck stiffness and/or photophobia; NO evidence of altered consciousness or inflammation
purulent meningitis
meningism (headache, photophobia and/or stiff neck) with high WBC, predominance of PMNs, low glucose, high protein (microbiologically confirmed if pathogen identified)
aseptic meningitis
meningism with moderately high WBC (lymphocyte predominance), normal CSF glucose, high CSF protein (viral, TB)
prisoner, homeless, or immigrant is at greatest risk for what type of meningitis?
chronic from mycobacterium TB
Ohio River Valley is associated with what bacterial meningitis?
subacute histoplasma
agammaglobulinemia is associated with what form of meningitis?
chronic enterovirus meningitis
NSAID use is assoc. with what form of meningitis?
drug-induced acute meningitis
HIV is assoc with what meningitis organisms?
toxoplasma abscess, cryptococcal meningitis, HIV/CMV meningoencephalitis
splenectomies increase susceptibility to meningitis with what organisms?
encapsulated orgs like n. meningitidis
what organism causes recurrent meningitis?
HSV-2
what are the 4 ways in which viruses can enter the CNS?
- directly across cerebral capillary endothelial cells (infect endo cell, infect glial cell, carried by infected monocyte), 2. infect choroid plexus epithelium (more permeable), 3. along olfactory nerves, 4. along peripheral sensory nerves
name 2 noninfectious causes of meningitis
auto-immune diseases (looks like viral), NSAIDS, sulfa drugs (looks like bacterial)
emergency management for a patient with suspected meningitis
1) drop/air precautions, 2) resuscitate if necessary, 3) blood cultures from 2 locations, 4) lumbar puncture within 30 min, 5) empiric antibiotics, 6) CT or MRI if lesion expected
74% of aseptic meningitis cases in children were a result of _____________.
enterovirus
the top 3 bacterial causes of meningitis in children were?
strep pneumo, neiss meningitidis, GBS
major causes of viral meningitis
enterovirus (very common, in the summer, coxsackie, echo, dx by PCR) & herpesviruses (HSV, VZV, CMV, HHV6); also influenza A, HIV, West Nile
bacterial causes of aseptic meningitis
spirochetes, mycoplasma, mycobacteria
evidence of enteroviral meningitis
exanthem, conjunctivitis, pericarditis, HFM disease, herpangina, pleurodynia in late summer/early fall
CEMA
(rare) chronic enteroviral meningoencephalitis in agammaglobulinemia: HA, seizures, hearing loss, coma, weakness, ataxia, loss of cognitive skills
who dies from enteroviral meningitis?
the very young and the old (about 5% of each)
what is the greatest cause of encephalitis in the US?
UNKNOWN (as much as 86% of deaths, 60% of hospitalizations)
symptoms of HSV encephalitis
abnormal CSF with high protein, normal glucose, lymphocyte predominance, and RBCs in CSF; focal EEG or MRI positive necrotizing, usually temporal lobe lesion
what % of West Nile virus infections are asymptomatic, fever, or neuroinvasive?
80% asymptomatic, 20% fever, less than 1% neuroinvasive disease (usually elderly)
diagnosing CMV encephalitis
acute deterioration in mental status with elevated protein in CSF (HIV, transplant patients)
subacute sclerosis panencephalitis
acute encephalitis secondary to measles; causes personality changes, myoclonic jerks, recurrent falls, rigidity – death within 3 years
JC virus
polyoma virus, 90% sero+ by middle age, causes PML in immunocompromised due to reactivation
PML
cytolytic replication of JC polyomavirus in oligodendrocytes of brain (demyelinating) – focal motor and sensory deficits, gait abnormalities, speech, HA, visual impairment
how do you dx PML?
brain biopsy (invasive), JC DNA in CSF, MRI shows lesions in white matter
spongiform encephalopathy
prion disease: Kuru, Creutzfelt-Jakob disease; prions cause protein aggregation and fibril formation
