CNS Infections Flashcards
Encephalitis Causes
Herpesviruses (mot common)
arbovirus
enteroviruses
EBV
Meningitis Causes
Aseptic - viral cause
Septic - from another source (usually resp. source)
–Group A Strep and E. Coli in infants
–Listeria is very young and old
–Strep. pneumoniae and N. mennigitis in young adults
Meningitis Presentation
Classic is fever, stiff neck, headache - but only in 44% of meningitis cases
N/V, headache, photophobia can occur but not specific
Encephalitis Presentation
Similar to meningitis but more likely to have altered LOC, focal neuro signs, seizures
Kernig Sign
patient in the supine position resists passive knee extension when the hip is fully flexed on the abdomen
Brudzinski signs
patient in the supine position actively flexes the hips when the neck is passively flexed
Poor Prognosis Signs of CNS Infection
Purpura and petechiae are often associated with rapidly progressing meningococcemia - may indicate DIC
Lethargy, hypotension, neuro compromise signs are also poor prognosis signs
CNS Diagnostics
Blood cultures (2 sets) CBC, Coags, ESR, CRP Lumbar Puncture (but not if ICP is increased)
LP Findings
Bacterial Meningitis - Opening pressure increased, High WBC is CSF with 80% neutrophils, high protein, low glucose
Viral Meningitis - Opening pressure normal / slightly high, elevated WBC mostly lymphocytes, slight protein increase, glucose normal
Meningitis Management
ED Refer!
IV Dexamethasone to minimize inflammation
IV antibiotics after blood cultures but can be done before CT / LP
If viral, supportive care, careful fluid use to prevent increasing ICP
Consider antivirals if HSV or VZV suspected
A patient is brought to the emergency department with fever, lethargy, and headache without meningeal signs. The examination reveals hypotension and lethargy and the examiner notes petechiae on the patient’s trunk.
What do these findings indicate?
Petechiae are an ominous sign, indicating a rapidly progressing meningococcemia.
