Meningitis

Classification

1. Acute (<24 hrs): usually bacterial in origin (25%)
2. Subacute (1-7 days): viral or bacterial
3. 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, dormitory)
• Alcoholism/cirrhosis
• Recent exposure to someone with meningitis
• Contiguous infection/ dural defect (traumatic, surgical (VP shunt))
• 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)
• papilledema

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
  • Glucose and protein (Tube 1)
  • Gram stain and culture (Tube 2)
  • Cell count and differential (Tube 3)
  • Special studies if indicated (e.g. HSV PCR or india ink in HIV pt) - Tube 2

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 given 2 hr prior to LP will NOT decrease the sensitivity of CSF culture

Antibiotics

• Ampicillin + cefotaxime or amp +gent
• Ampicillin + Cefotax or Ceftriaxone
• Cefotax or Ceftriaxone </nowiki>
• 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/ benefit

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)</nowiki>

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