Meningitis


  Normal Bacterial Viral Fungal Tb Abscess
WBC/mL 0–5 >1000* <1000 100–500 100–500 10–1000
%PMN 0–15 >80* <50 <50 <50 <50
%lymph >50 <50 >50 >80 ↑ monos variable
Glucose 45–60 <40 45–65 30–45 30–45 45–60
Ratio ≥ 0.6 ≤0.4 45–65 <0.4 <0.4 0.6
Protein 15–45 150–1000 50–100 100–500 100–500 >50
Pressure 6–20 20–50 variable >20 >20 variable

 

General guidelines for meningitis

  • Perform blood cultures and lumbar puncture as quickly as possible
  • Start empiric antibiotics +/− adjunctive dexamethasone as soon as lumbar puncture completed or prior to CT scan if this precedes a lumbar puncture
  • Adjunctive dexamethasone administered prior to or concurrent with antibiotics
    • 10 mg IV q6h × 4 d for meningitis in adults if the CSF is purulent, CSF Gram stain is positive, or if CSF leukocytes >1000/mm3
      Little role for rapid bacterial antigen testing or Limulus lysate assays unless high likelihood of bacterial meningitis and patient has been receiving antibiotics
  • Repeat CSF analysis if no clinical improvement after 48 hr of antibiotics
  • Respiratory isolation × 24 hr indicated for any suspected meningococcal meningitis
  • Duration of IV antibiotics:
    • 7 d for N. meningitidis or H. influenzae
    • 10–14 d for S. pneumoniae
    • 14–21 d for Streptococcus agalactiae
    • 21 d for aerobic gram-negative bacilli or Listeria monocytogenes

Indication for CT Scan of Head prior to Lumbar Puncture

  • Age ≥ 60 years
  • Seizure in last week
  • Gaze or facial palsy
  • Papilledema
  • Recent neurosurgical operation or procedure
  • Cognitive impairment*
  • Altered level of consciousness
  • Immunosuppressed state
  • Dysphasia or aphasia
  • Focal neurologic deficits
  • Abnormal visual fields

Labs/Work-up

Labs

  • CBC w/ differential
    • May see very high WBCs
  • Electrolytes, +/- coagulation studies
  • Blood cultures x 2
  • Stool & throat cultures as appropriate
  • CSF
    • Tube # 1: Cell count & differential
    • Tube #2: Protein, glucose
    • Tube #3: Gram stain, C&S, AFB, cryptococcal antigen, india ink
    • Tube #4: Cell count & differential, rapid bacterial antigens
  • Characteristic CSF findings
    • Opening pressure
      • Elevated (may be 200-300)
    • WBC count
      • High, may be 100-5000, mostly PMNs (80%)
    • Glucose
      • Low, often <40 mg/dL
    • Protein
      • High, often >100 mg/dL
    • Gram stain
      • Pathogen seen in 60% (80% of cultures)
         

Diagnostic imaging

  • CXR to R/O pulmonary source
  • CT prior to LP
    • Patients in coma
    • Patients with focal neurologic signs
    • Patients with persistent seizures
    • Patients with known malignancy or HIV
 

CSF Test to identify Adult Bacterial vs Aseptic Meningitis

  • Individual predictors of bacterial meningitis:
    • CSF glucose <34 mg/dL
    • CSF/blood glucose <0.23
    • CSF protein >220 mg/dL
    • CSF with >1000 leukocytes/mm3
    • CSF neutrophils >1180/mm3  or
    • CSF lactate ≥31.5 mg/dL.
  • Serum C-reactive protein (CRP) <1 mg/L excludes bacterial etiology with 99% accuracy
  • CSF lactate ≥ 27 mg/dL predicts bacterial meningitis in postop neurosurgical patients
  • Acute meningoencephalitis:
    • Start IV acyclovir 10 mg/kg IV q8h, and send CSF for HSV RNA by PCR
    • Check an MRI of the brain with gadolinium and
    • EEG to assess for temporal lobe encephalitis
  • The workup of aseptic meningitis can be extensive and is beyond the scope of this website, call neurology.

Empiric ABx Therapy for presumed Bacterial Meningitis

16-50 yr

  • Vancomycin 30–45 mg/kg/d (per pharamcy protocol)
    plus
  • Ceftriaxone 2 g IV q12h

> 50 yr or presence of a Listeria risk

  • Vancomycin 30–45 mg/kg/d* 
    plus
  • Ceftriaxone 2 g IV q12h
    plus
  • Ampicillin 2 g IV q4h

Basilar skull Fx

  • Vancomycin 30–45 mg/kg/d
    plus
  • Ceftriaxone 2 g IV q12h

Penetrating trauma, CSF Shunt, Post-neurosurgical

  • Vancomycin 30–45 mg/kg/d
    plus
  • Cefepime 2 g IV q8h 
    or 
    Ceftazidime 2 g IV q8h

Hospital-aquired, neutropenic, or impaired cell-immunity

  • Ampicillin 2 g IV q4h
    plus
  • Ceftazidime 2 g IV q8h
    plus
  • Vancomycin 30–45 mg/kg/d
 

Admit Orders: Meningitis (Adult)

1. Admit to:

2. Diagnosis: Meningitis.

3. Condition:

4. Vital Signs: q1h. Call physician if BP systolic >160/90, <90/60; P >120, <50; R>25, <10; T >39°C or less than 36°C

5. Activity: Bed rest with bedside commode.

6. Nursing: Respiratory isolation, inputs and outputs, lumbar puncture tray at bedside.

7. Diet: NPO

8. IV Fluids: D5 ½ NS at 125 cc/h with KCL 20 mEq/L.

9. Special Medications:

No known immunodeficiency:

-Ceftriaxone (Rocephin) 2 g IV every 12 hours OR

-Cefotaxime (Claforan) 2 g IV every four to six hours PLUS

-Vancomycin 30 to 60 mg/kg IV per day in two or three divided doses PLUS

-In adults >50 years of age, ampicillin 2 g IV every four hours.

Impaired cell-mediated immunity:

-Vancomycin 30 to 60 mg/kg IV per day in two or three divided doses PLUS

-Ampicillin 2 g IV every four hours PLUS EITHER

-Cefepime (Maxipime) 2 g IV every eight hours OR

-Meropenem (Merrem) 2 g IV every eight hours.

Nosocomial Meningitis:

-Vancomycin 30 to 60 mg/kg IV per day in two or three divided doses PLUS

-Ceftazidime (Fortaz) 2 g IV every eight hours OR

-Cefepime (Maxipime) 2 g IV every eight hours OR

-Meropenem (Merrem) 2 g IV every eight hours.

Allergy to beta-lactams:

-Vancomycin 30 to 60 mg/kg IV per day in two or three divided doses PLUS

-Moxifloxacin (Avelox) 400 mg IV once daily PLUS

-If Listeria coverage is required (>50 and/or in those with defects in cell-mediated immunity), TMP-SMX: 10 to 20 mg/kg (of TMP component) IV per day divided q6-12h.

10. Symptomatic Medications:

-Dexamethasone (Decadron) 0.4 mg/kg IV q12h x 2 days to commence with first dose of antibiotic.

-Heparin 5000 U SC q12h or pneumatic compression stockings.

-Famotidine (Pepcid) 20 mg IV/PO q12h.

-Acetaminophen (Tylenol) 650 mg PO/PR q4-6h prn temp >39°C.

-Docusate sodium 100-200 mg PO qhs.

11. Extras: CXR, ECG, CT scan.

12. Labs: CBC, CMP. Blood C&S x 2. UA with micro, urine C&S. Antibiotic levels peak and trough after 3rd dose, VDRL.

Lumbar Puncture:

CSF Tube 1: Gram stain, C&S for bacteria (1-4 mL).

CSF Tube 2: Glucose, protein (1-2 mL).

CSF Tube 3: Cell count and differential (1-2 mL).

CSF Tube 4: Antigen tests for S. pneumoniae, H. influenzae (type B), N. meningitides, E. coli, group B strep, VDRL, cryptococcal antigen, toxoplasma titers. Fungal cultures, AFB (8-10 mL).