Clinical CNS Microbiology Flashcards
What differs meningitis caused by craniopharyngioma breakdown and bacteria?
NORMAL glucose in craniopharyngioma meningitis
What two electrolyte abnormalities would you look for in bacterial meningitis?
SIADH, metabolic acidosis
What two serum markers are much higher in bacterial meningitis than viral?
Serum procalcitonin (>2ng/mL), C-reactive protein (>40ng/mL)
What should ALWAYS do before obtaining an LP in cases of meningitis?
Cranial CT to ensure no structural abnormalities
How do you identify bacterial etiology of meningitis on CSF analysis?
PCR for bacterial 16S ribosomal DNA
How do you identify Herpes or TB as specific etiology of meningitis?
PCR
How do you identify West Nile as the specific cause of meningitis?
IgM
Abx for bacterial meningitis?
Vanco, 3rd or 4th gen Cef or Meropenem, Amicillin (if Listeria), Acyclovir for HSV, Doxy for tick-borne
Steroids before abx in meningitis?
YES
Four CNS sequelae of infective endocarditis?
1) Metabolic encephalopathy, 2) Ischemic Stroke, 3) Cerebritis leading to abscess, 4) Mycotic aneurysm leading to subarachnoid hemorrhage
Why does an abscess or any mass (e.g., tumor) cause a headache to be worse at night?
Lose effect of gravity on CSF drainage –> increased total content with unchanged volume of space causes increased tension on pain sensing structures (dura)
MC causal organism of subacute bacterial endocarditis?
Strep viridans
Four key clinical clues to bacterial endocarditis?
Splinter hemorrhage, Osler nodes, Janeway lesions, Roth spots
Retinal hemorrhage with central clearing
Roth spot
Tender papulopustules on the pulp of the finger in bacterial endocarditis
Osler nodes
Erythematous painless macule on the palms of the hand and soles of the feet in bacterial endocarditis
Janeway lesions
What do you treat cerebral abscesses with? What if Bacteroides fragilis is the causal org?
Cephalosporins; Metronidazole
What parts of the spine does a spinal epidural abscess involve and spare in contrast to a tumor?
Disc(itis); spare bone
Why is pain worse on recumbency with spinal epidural abscess?
Increased venous back pressure in Batson’s plexus on inflamed part of dura
MC pathogen of spinal epidural abscess?
Staph aureus
Rx spinal epidural abscess?
High dose roids, Abx, surgery
Causal organism of RMSF?
Rickettsia
Structure of Rickettsia
G- obligate IC coccobacilli
Tropism of Rickettsia
Vascular endothelial cells
Hallmark clinical sign of RMSF?
Early petechial rash in distal extremities
Rx RMSF
IV Doxy
CSF normal/abnormal with RMSF?
Normal
Causal organism of Lyme?
Spirochete; Borrelia burgdorferi
First clinical hallmark of Lyme?
Target Rash
Symptoms of Lyme that dev. over weeks?
FLS, heart, myalgias, Bell’s, aseptic meningitis
How to dx and confirm Lyme, respectively?
ELISA, Western Blot
Rx Lyme?
IV Ceftriaxone
serum FTA+ and CSF VDRL+ in an HIV patient means?
Definite neurosyphilis
Serum FTA+ and CSF VDRL- with CSF lymphocytic pleocytosis or elevated CSF protein in an HIV patient means?
Probably neurosyphilis
What part of your spinal cord does tabes dorsalis (neurosyphilis) knock off?
Dorsal Column – Loss of proprioception and fine touch
How do you confirm dx of TB meningitis?
Stain for acid fast bacilli + send away for culture; immunofluorescence
What region of the brain does TB love to attack? Sequela?
Base; Block CSF flow leading to hydrocephalus (also can have arachnoid granulations scar over), CN palsies
MC abnormal finding in TB meningitis? 2nd MC?
Chest X-ray; PPD
Rx TB meningitis?
RIPES + corticosteroids
Which viral meningitis shows Mollaret cells?
Chronic viral meningitis D/T HSV-2
Lobe involvement of HSV1 encephalitis?
Temporal
Type of necrosis in HSV1 encephalitis?
Hemorrhagic
How to make definitive clinical dx of HSV1 encephalitis? Confirmatory test?
MRI; PCR
What do you need to watch out for if HZV reactivates in ophthalmic division of CN V? Rx?
Corneal ulceration; acyclovir + steroids
