Meningitis therapeutics Flashcards
3 membranes of meninges
dura mater
arachnoid
pia mater
meningitis location
subarachnoid space, between arachnoid and pia mater
meningitis pathophysiology sequence
- nasopharyngeal colonization
- bacterial release of proteases to degrade IgA
- adhere to mucosa
- polysaccharide capsule withstands neutrophil phagocytosis
- capsule typically activates alternate complement pathway, when this fails meningitis occurs
patients with increased risk of meningitis
- immune suppressed
- sickle cell
- dysfunctional spleen or asplenia
- immunoglobulin or complement deficiencies
physical results of meningitis
- cerebral edema
- increased intracranial pressure
- decreased cerebral perfusion with ischemia
neurologic complications of meningitis are the result of
host’s inflammatory pathways attempting to kill the bacteria
- bacterial cell wall components released
- cytokines, TNF, IL
- platelet activating factor
bacteria that can cause meningitis
in order:
- s.pneumoniae (58%)
- s.agalactiae
- N.meningitidis
- H.influenzae
- listeria monocytogenes
bacteria that kills most rapidly
neisseria meningitidis
role of the spleen
- phagocytosis of old RBCs and antibody coated bacteria
- stores platelets and monocytes
- matures B cells
role of polysaccharide layer that envelopes bacteria
- enhances virulence
- prevents phagocytosis
- enhances adhere to surfaces
bacteria with polysaccharide layer
- H.influenzae
- N.meningitidis
- Klebsiella pneumonoiae
- S.pneumoniae
- S.agalactiae
classic triad of symptoms for meningitis
fever
nuchal rigidity
mental status changes
headache also common
kernig’s sign
patient lies supine, flex knee and hip of one leg to 90 degrees
pain = +test
brudzinski’s sign
patient lies supine, lift pts neck off bed while having them try to touch chin to chest
involuntary flexion of hips and knees = +test
when it is ok to do lumbar puncture
no increase in intracranial pressure
signs of increased ICP
- severe headache
- vomiting
- decreased levels of consciousness
- seizures
- papilledema
- coma
in addition to increased ICP when do we also avoid lumbar puncture
pt has low platelets
papilledema
optic nerve swelling that is observable with eye exam
who should get a head CT prior to lumbar puncture
- immunocompromised patients
- hx of stroke
- over 60
- seizure in the last 7 days
- papilledema
- changing consciousness levels
labs for bacterial CSF infection
WBC 1000-5000 WBC diff - neutrophils dominate protein 100-500 glucose <40 decreased CSF/serum glucose ratio
effects of dexamethasone
- reduces intracerebral inflammation
- reduces antibiotic CNS penetration
dexamethasone dosing
0.15 mg/kg q6h for 2-4 days
when to use dexamethasone in relation to antibiotics
10-20 minutes before the first abx dose or with the first dose and continue for 2-4 days
