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

1. Headache
2. Nuchal rigidity (may not be present in those with AMS)
3. Fevers/chills
4. Photophobia
5. Vomiting
6. Prodromal URI
7. Focal neuro sx (ie seizure)
8. AMS (may be the only complaint esp in elderly)

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. Fever
3. Rash
4. Abnl Neuro exam (altered, focal cranial nerve defect)
5. papilledema

Differential Diagnosis

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

Orders/Workup

1. isolation of patient (if suspect bacterial meningitis)
2. cbc
3. blood cultures
4. coags
5. chem panel
6. CT head
7. CXR (50% of pts w/pneumoccocal meningitis have e/o pna on CXR)
8. 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 (e.g. HSV PCR or india ink in HIV pt) - 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

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

1. Ampicillin + cefotaxime or amp +gent
2. Ampicillin + Cefotax or Ceftriaxone
3. Cefotax or Ceftriaxone </nowiki>
4. Adults: Cefotaxime or ceftriaxone + vanco; Add Ampicillin if Listeria suspected

Steroids

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

1. Neonates (<6wks) --> No
2. Infants/child --> Yes
3. Adults --> Yes

^prior to or with abx = only group w/ benefit

Prophylaxis

• For N. meningitis
• 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