Meningitis

Def: inflammation of the leptomeninges and underlying subarachnoid CSF

3 types:

acute (<24 hrs): usually bacterial in origin (25%)
subacute (1-7 days): viral or bacterial
chronic (>7 days): viral, TB, syphilis, fungi, carcinomatous

Risk Factors:

Age >60 or <5
Immunosuppressed/Immunocompromised (DM, adrenal insufficiency, HIV, cystic fibrosis, pts on steroids, Sickle Cell, etc)
Crowding (military, college dorm rooms)
Alcoholism/cirrhosis
Recent exposure to someone with meningitis
Contiguous infection Dural defect (traumatic, surgical (VP shunt))
Thalassemia major IVDA Endocarditis Malignancy

Signs/Symptoms:

Headache
Nuchal rigidity (may not be present in those with AMS)
Fevers/chills
Photophobia
Vomiting
Prodromal URI
Focal neuro sx (ie seizure)
AMS (may be the only complaint esp in elderly)

Physical Exam Findings

Signs of Meningeal Irritation:
Kernigs: passive knee extension while pt is supine causes neck pain and hamstring resistanc
Brudzinski: when you flex pts neck you see involuntary flexion of b/l lower ext
Fever
Rash
Abnl Neuro exam (altered, focal cranial nerve defect)
papillaedema

Differential Diagnosis:

encephalitis
brain mass
brain abscess
subarachnoid hemorrhage
migraine

Orders/Workup

isolation of patient (if suspect bacterial meningitis)
cbc
blood cultures
coags
chem panel
CT head
CXR (50% of pts w/pneumoccocal meningitis have e/o pna on CXR)
CSF studies
cell count
gram stain
culture
glucose
protein
special studies if indicated (i.e. HSV PCR or india ink in HIV pt)

Interpreting CSF

Bacterial Viral Fungal Neoplastic Opening Pressure ↑↑ Normal, mild ↑ Normal, mild ↑ Normal, mild ↑ Cell Cnt >1000 <1000 <500 <500 % PMNs >80% 1-50% 1-50% 1-50% Glucose <40 >40 <40 <40 Protein >200 <200 >200 >200 Gram stain + (80% effective) neg AFB, India ink

Treatment

Goal is to initiate treatment within 30 minutes of presentation (if pt is acutely ill). Abx givein 2 hr prior to LP will NOT decrease the sensitivity of CSF culture

Antibiotics

Neonates: Ampicillin + cefotaxime or amp +gent
Infants(3 mo): Ampicillin + Cefotax or Ceftriaxone
Children: Cefotax or Ceftriaxone
Adults: Cefotaxime or ceftriaxone + vanco; Add Ampicillin if Listeria suspected

Steroids*

(Dexamethasone 0.15mg/kg Q6hrsx4dys; 10mg max) --give 15-20 minutes before antibiotics

Neonates (<6wks) --> No

Infants/child --> Yes

Adults --> Yes

prior to or with abx = only group w/ benifit

PROPHYLAXIS (N. meningit)

Rx primary caregivers (those in close contact to nasopharyngeal secretions or those who were with the patient at least 4 hours during week before onset of symptoms)

Cipro 500mg PO x 1 or rifampin x 4 doses or ceftriaxone x1

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