Flashcards in Micro U3 L2. Deck (37):
inflammation of the lining of the brain (aseptic meningitis not caused by bacteria)
inflammation of brain tissues
widespread infection of the meninges and brain
aseptic meningitis causes
viruses, fungi, TB, infections near CNS
MC virus for aseptic meningitis
symptoms of aseptic meningitis
mental status remains normal, headache, fever, chills, stiff neck, also malaise, sore throat, nausea, vomiting, ab pain, rash, muscle pain, photophobia
how is aseptic meningitis distinguished from encephalitis?
mental status normal in meningitis
diagnosis of aseptic meningitis
elevated WBC in spinal fluid - NO BACTERIA
treatment for aseptic meningitis
supportive care (usually benign), drugs for herpesvirus, fungal, and mycobacterial infections
symptom of meningitis - neck so stiff that knees flex when neck is flexed
infants and elderly
influx of immune cells to brain
distinguishing feature for encephalitis
mental status altered (due to increase pressure/injury), confusion, sleepiness, irritability, stumbling, also fever, headache, vomiting, photophobia, still neck
diagnosis of encephalitis
spinal tap = inflammation (PCR gold standard for definitive diagnosis), EEG suggestive of seizures, brain MRI/CT show inflammation/hemorrhage
treatment for encephalitis
supportive care and symptom relief, antivirals for herpes, anti seizure medications, anti-inflammatories, sedatives
prognosis for encephalitis
benign with full recovery but can also be severe and fatal
pathogenesis of viral CNS disease
death of neurons (cytolytic viruses), infants and elderly more susceptible, immunosuppressive, genetics, exercise increase dissemination of viruses to CNS
acute disseminated encephalomyelitis (ADEM)
postinfectious encephalitis follows viral infection 1-2 weeks - associated with measles, mumps, VZV, influenze, parainfluenza viruses, autoimmune disorder
Which herpes viruses can often cause meningitis (from most likely to only in immunocompromised)
HSV-2, HSV-1, VZV, CMV, EBV
What should herpes viruses be treated with?
MCC of sporadic viral encephalitis
Route of infection HSV-1 encephalitis
primary HSV-1 in oropharynx -> trigem nerve -> CNS
What is the hallmark for HSV-1 encephalitis diagnosis?
brain imaging: MRI shows unilateral temporal lobe abnormalities
How is rabies neurovirulent and how does it do it?
-infects peripheral nerves and travels to brain -> transmitted from salivary glands
Symptoms of rabies (what are they due to)
hydrophobia, seizures, hallucinations, paralysis, coma, death due to replication in brain
When does enterovirus cause disease? How? In who?
MC in summer; fecal-oral; newborns and neonates
polio, coxsackie, echoviruses, enterovirus
Where does replication of picornaviruses take place? Where does it disseminate?
replicates in oropharynx and intestine (mucosal surfaces) disseminates via lymph nodes to blood and endes in skin, muscle, brain, and meninges
VEE, EEE, WEE, rubella
How are toga viruses transmitted? Which cause encephalitis?
via mosquito bite usually (also birds) to skin, blood, brain - VEE, EEE, WEE
What are the flaviviruses that cause encephalitis?
Japanese encephalitis, west nile, st louis encepalitis, russian spring-summer, powassan virus
transmission of flaviviruses
mosquito or tick; more common in summer
Which flavivirus has a vaccine?
What is the dissemination of flaviviruses?
mucosal surface -> lymph -> primary viremia (blood, liver, spleen, macrophages) -> secondary viremia (encephalitis, yellow fever, hemorrhagic fever)
west nile virus meningoencephalitis symptoms
less than 1% WNV infections; headache, high fever, stiff neck, disorientation, coma, tremors, seizures, paralysis