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

1. Age >60 or <5
2. Immunosuppressed/Immunocompromised (DM, adrenal insufficiency, HIV, cystic fibrosis, pts on steroids, Sickle Cell, etc)
3. Crowding (military, dormitory)
4. Alcoholism/cirrhosis
5. Recent exposure to someone with meningitis
6. Contiguous infection/ dural defect (traumatic, surgical (VP shunt))
7. IVDA/endocarditis
8. Malignancy

Signs/Symptoms

• Almost all patients present w/ at least 2 of the following:
  • Headache
  • Fever
  • Neck stiffness
  • Altered mental status
• Also may have:
  • Photophobia
  • Vomiting
  • Prodromal URI
  • Focal neuro sx

Physical Exam Findings

1. Signs of Meningeal Irritation
   1. Kernigs: passive knee extension while pt is supine causes neck pain and hamstring resistance
   2. Brudzinski: when you flex pts neck you see involuntary flexion of b/l lower ext
2. Jolt Test (100% Sn)
3. Fever
4. Rash
5. Abnl Neuro exam (altered, focal cranial nerve defect)
6. Papilledema / incr optic nerve diameter (UTZ)

Differential Diagnosis

1. encephalitis
2. brain mass
3. brain abscess
4. subarachnoid hemorrhage
5. migraine

Orders/Workup

1. Droplet Precautions (if suspect bacterial meningitis)
2. CBC, Chemistry, coags
3. Blood cx
4. CT head
   1. Consider LP w/o CT if:
      1. Normal mental status
      2. Normal neuro exam
      3. No immunocompromise
      4. No papilledema or normal optic nerve sheath diameter
5. CXR (50% of pts w/ pneumoccocal meningitis have e/o pna on CXR)
6. CSF studies
   1. Glucose and protein (Tube 1)
   2. Gram stain and culture (Tube 2)
   3. Cell count and differential (Tube 3)
   4. Special studies if indicated (HSV PCR, india ink) - Tube 2

Interpreting CSF

Measure	Bacterial	Viral	Fungal	Neoplastic
Opening Pressure	↑↑	Normal, mild ↑	Normal, mild ↑	Normal, mild ↑
Cell Count	>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

• Antibiotics
  • Give as soon as possible
  • Abx given 2hr prior to LP will not decrease Sn of CSF cx
• CTX 2g, Vanco
  • If young or old (age >60): add ampicillin for listeria coverage
  • If e/o AMS, neuro deficits: add acyclovir for HSV
  • If recent hospitalization: switch CTX to cefepime or imipenem for pseudomonas coverage
  • If immunocompromised and suspect TB: add rifampin
  • if immunocompromised and suspect fungal: add amphotericin
• Steroids
  • Give prior to or w/ abx
  • Dexamethasone 0.15mg/kg Q6hr x4d (10mg max)
  • Do not give to neonates (<6wk)

Prophylaxis

• For N. meningitis exposure
  • Close contact to nasopharyngeal secretions or those who were w/ the pt at least 4hr during week before onset of symptoms
  • Cipro 500mg PO x 1 or rifampin x 4 doses or ceftriaxone x1