Neuro: CNS Infections Flashcards
Which part of the leptomeninges is most commonly infected in meningitis?
Arachnoid mater
What is the most common organism to cause bacterial meningitis?
Strep pneumo
What is the most common organism to cause healthcare associated meningitis?
Staph
You do a LP and find that CSF has extremely low glucose. What dx are you thinking of?
TB meningitis. Low CSF glucose is the hallmark
Increasing cause of meningitis in neonates, pregnant women, people >60, and the immunocompromised. Acquired by food contamination.
Listeria monocytogenes
How do bacteria gain access to the CSF in meningitis?
Colonize in nasopharynx, attach to epithelial cells and are then transported to the bloodstream. Once in the blood, the bacterai reach the intraventricular choroid plexus, thereby gaining access to the CSF.
What causes inflammation in meningitis?
Lysis of bacteria and release of cell wall components into subarachnoid space.
When can you expect to see TNF and IL in the CSF?
within 1-2 hours of beginning of inflammation cascade
What contributes to the permeability of the BBB in meningitis?
TNF and IL working synergistically.
What obstructs the flow of CSF in meningitis and leads to obstructive and communicating hydrocephalus in meningitis?
Subarachnoid exudate obstructs the flow of CSF
Classic triad of bacterial meningitis
Fever, nuchal rigidity, change in mental status. Do NOT have to have all 3 present, Headache is often present.
What would you look for in someone you suspect meningitis in on PE?
RASH of meningococcemia (diffuse erythematous maculopapular rash) on trunk and lower extremities, mucous membranes and conjunctiva, palms and soles
Spontaneous flexion of hips during attempted passive flexion of neck
Brudzinki sign
Inability to allow full knee extension when the hip is flexed to 90 degrees
Kernig sign
If you suspect someone has bacterial meningitis, what should your next course of action be?
Obtain blood cultures and initiate empiric antibiotic therapy and dexamethasone therapy without delay!
How is the diagnosis of meningitis done?
Examining CSF
Who might need neuroimaging prior to LP?
Altered LOC, papilledema, neuro deficits
After confirmation of diagnosis of meningitis, what’s done next?
MRI, biopsy petechial skin rash
What labs would you order in someone you suspect meningitis?
CBC
Blood cultures
LP
What would you expect to see in the lab results in someone with meningitis?
Elevated WBC (predom. neutrophils)
Elevated CSF protein
Low CSF glucose
Gram stain to show organisms
Treatment of strep pneumo and N. meningiditis meningitis infection?
Ceftriaxone IV AND Vancomycin IV AND Dexamethasone IV
What meds do you add in treatment of meningitis in patient over 50 or immunocompromised?
Ceftriaxone, Vacomycin, and Dexamethasone IV PLUS
Ampicillin IV and
Acyclovir IV (possible herpes meningitis)
What conditions worsen the prognosis for meningitis?
Decreased LOC on admission Seizure within 24 hours of admission Young age or age >50 Comorbid conditions SHock Need to mechanical ventilation Delay in dx/tx
Pt presents with fever, headache, altered MS, nuchal rigidity. LP shows mildly increased WBC and lymphocytes, normal protein, glucose and opening pressure. What’s the diagnosis?
Viral meningitis
