Meningitis

Revision as of 06:14, 12 March 2011 by Rossdonaldson1 (talk | contribs)

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

  • 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/ 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)

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