35 - CNS Infections Flashcards
Two most common community acquired meningitis organisms?
strep pneumo (pneumococcus) neisseria meningitidis (meningococus)
Most common bugs for neonatal meningitis?
group B strep
E. Coli
Listeria
Most common bug for immuno suppressed or elderly meningtits?
listeria monocytogenes
Most common post-trauma meningitis?
staph aureus
Gram negatives (E. Coli)
Pneumococcus
How does meningococcus spread?
respiratory droplets (epidemics in tight quarters) three foot rule for bed spacing.
What can fulminant meningococcus cause (outside the brain)?
Waterhouse-Friderichesen syndrome - hemorrhagic necrotic adrenals
What is Kernig’s sign?
patient supine with hip flexed 90 degs, knee cannot be fully extended
What is Brudzinski’s sign?
passive flexion of neck causes flexion of both legs and thighs
A cyst in brain on autopsy is opened and reveals a dark fluid that looks like crank-case oil. Diagnosis?
Craniopharyngioma of Rathke’s pouch.
You suspect meningitis in a patient. CSF shows high PMN count and normal glucose. DIagnosis?
possibly a ruptured craniopharyngioma causing an acute chemical meningitis.
What usually happens to serum Na levels in meningitis?
they drop becuase of accompanying septic shock and SIADH, there is water retention and increased ICP
What happens to INR and prothrombin time in meningitis?
they become elevated due to consumption of clotting factors in DIC
What happens to CRP in bacterial meningitis?
increased
What happens to procalcitonin level in bacterial meningitis?
increased.
If blood glucose is 100, what should normal CSF glucose be?
2/3 of blood so about 66.
What should be given first in bacterial meningitis?
steroids first! dexamethasone within 15 minutes of antibiotics.
Then give Vancomycin (for penicillin resistant pneumococcus),
a cephalosporin like ceftriaxone
ampicillin for listeria
doxycycline for rickettsia and rocky mountain spotted fever.
Acyclovir for viral
What adverse effect can meropenem have?
can cause seizures
What should be given to those who have been in close contact with a bacterial meningitis patient?
prophylaxis of rifampin or cipro
How does bacterial endocarditis present?
fever, delirium --> coma. Possible miningeal signs. Septic emobli to brain causing stroke, cerebritis with absecesses, mycotic aneurysm Splinter hemorrages olser's nodes janeway lesions roth's spots
What is the difference between olser’s nodes and janeway lesions?
olser nodes are painful/tender (ulcer = pain)
janeway is painless macule on palms or soles (maryjane = no pain)
Patient presents with headache that is worse upon lying down and present when waking up, papilledma and transient visual obscurations, seizures, focal neuro deficits, contrast CT or MRI ring enhancing lesion. Dianosis?
cerebral abscess
What spares the disk and destroys the bone: infection or tumor?
tumor destroys bone
infection destroys disk (NP)
Presentation of spinal epidural abscess
severe back pain, worse lying down, point tenderness fever and malaise bowel an bladder dysfunction paraparesis or quadriparesis sensory loss high SED rate, left shif of WBC
What is most common causitive organism for spinal epidural abscess?
Staph aureus
What is cause of Rocky mountain spotted fever?
rickettsia rickettsia. a gram negative obligate intracellular coccalbacillary rod transmitted by ticks
What are the clinical signs of RMSF?
fever headache, flu like symptoms
Early petechial rash in distal extremities
normal CSF or mild lymohocytosis.
What is treatment for RMSF?
doxycycline
What is causitive agent of lyme disease?
spirochete Neuroborreliosis (borrellia) transmitted by ticks.
What is primary syphilis?
painless genital chancre 3 weeks after infection
What is secondary syphillis
2-3 weeks after chancre, macular-papular rash on palms, soles and body, arthirits, meningitis or meningo-vascular stroke
What is tertiary syphilis?
untreated progression to skin, osseus, cardiovascular and neuroligic compartments. occurs 15-20 years after infection.
How do you diagnose neurosyphilis?
serum VDRL, FTA, RPR, CSF .
positive FTA and CSF VDRL mean definite neurosyphilis
How do you treat neurosyphilis?
high dose IV penicillin
What does positve FTA but negative CSF VDRL mean?
probable neurosyphilis if there is lymphocytosis or elevated CSF rptoein.
How is TB meningitis diagnosed?
Chest xray. Positive PPD. CSF, tuburculoma on CT or MRI. ideally culture. Ribosomal RNA PCR. Clinical featueres of confusion, lethargy, low grade fever, stiff nick, vomiting, obtundation, coma, hemiparesis, crnailal nerve palsies, seizures.
How do you treat TB meningitis?
big 3 drugs (isoniazid, rifampin and pyrazinamide plus streptomycin or ethambutol.
Corticosteroids for over 6 weeks.
Most common causes of viral meningitis?
ECHO, coxsacki, enterovirus 71 (these 3 make up 80%)
What is likely cause if there is recurrent meningitis?
probably Herpes simplex 2.
Patient presents with muscle aches, cough, sore thorat, fever and bifrontal headache. Three days later she is disoriented and forgetful, on the fourth day tonic-clonic seizures. She has no rashes, no trauma or otitis.
Early papilledema, moderate neck stiffness,
Eyes tonically deviated to right, pupils reactive.
Withdraws limbs symmetrically to nailbed pinch.
DTRs are diffusely brisk.
CT shows temporal lobe edema
Herpes simplex 1 encephalitis.
What are major causative agents of viral encephalitis?
1/3 arborvirus = St. louis and west Nile
1/3 enterovirus
1/3 HSV1
How are arborviruses transmitted?
mosquitos (West nile and st louis)
What is treatment for HSV1 ecephalitis?
acyclovir
What is treatment for CMV encaphalitis?
ganciclovir
What is best tool to diagnose Herpes encephalitis?
MRI
What is most frequent CNS super infection after HIV?
toxoplasmosis by far.
What does toxoplasmosis MRI look like?
multifocal lesions on T1 MRI with a preference for basal ganglia
