Meningitis is acute inflammation of the meninges (the membranes covering the brain). Bacterial meningitis is a notifiable disease.
Causative organisms
- Most commonly bacterial: Streptococcus pneumoniae, Haemophilus influenzae type b (mainly in young children), Neisseria meningitidis, Enteric bacilli
- Viral (HSV, enteroviruses, HIV, VZV etc)
- Cryptococcus neoformans (in the immune-suppressed)
- Mycobacterium tuberculosis
Clinical features
- Rapid onset of fever
- Severe headache and neck stiffness or pain
- Photophobia
- Convulsions, altered mental state, confusion, coma
- In mycobacterial and cryptococcal meningitis, the clinical presentation can be sub-acute , over a period of several days or 1-2 weeks
Differential diagnosis
- Brain abscess
- Space-occupying lesions in the brain
- Drug reactions or intoxications
Investigations
- CSF: usually cloudy if bacterial, clear if viral. Analyse for white cell count and type, protein, sugar, Indian-ink staining (for Cryptococcus), gram stain, culture and sensitivity
- Blood: For serological studies and full blood count
- Chest X-ray and ultrasound to look for possible primary site
Management
Treatment depends on whether the causative organisms are already identified or not.
General measures
- IV fluids
- Control of temperature
- Nutrition support (NGT if necessary)
Causative organisms not yet identified
- Start initial appropriate empirical broad spectrum therapy
- Ceftriaxone 2 g IV or IM every 12 hours for 10-14 days
Child: 100 mg/kg daily dose given as above - Change to cheaper effective antibiotic if and when C&S results become available
- Ceftriaxone 2 g IV or IM every 12 hours for 10-14 days
If ceftriaxone not available/not improving
- Use chloramphenicol 1 g IV every 6 hours for up to 14 days (use IM if IV not possible)
Child: 25 mg/kg per dose
Once clinical improvement occurs
- Change to 500-750 mg orally every 6 hours to complete the course;
Child: 25 mg/kg per dose
Causative organisms identified
Streptococcus pneumoniae (10-14 day course; up to 21 days in severe case)
- Benzylpenicillin 3-4 MU IV or IM every 4 hours
Child: 100,000 IU/kg per dose - Or ceftriaxone 2 g IV or IM every 12 hours
Child: 100 mg/kg daily dose
Haemophilus influenzae (10 day course)
- Ceftriaxone 2 g IV or IM every 12 hours
Child: 100 mg/kg per dose
Only if the isolate is reported to be susceptible to the particular drug - Change to chloramphenicol 1 g IV every 6 hours
Child: 25 mg/kg per dose - Or ampicillin 2-3 g IV every 4-6 hours
Child: 50 mg/kg per dose
Neisseria meningitidis (up to 14 day course)
- Benzylpenicillin IV 5-6 MU every 6 hours
Child: 100,000-150,000 IU/kg every 6 hours - Or Ceftriaxone 2 g IV or IM every 12 hours
Child: 100 mg/kg daily dose - Or Chloramphenicol 1 g IV every 6 hours (IM if IV not possible)
Child: 25 mg/kg IV per dose
Once clinical improvement occurs
- Change to chloramphenical 500-750 mg orally every 6 hours to complete the course Child: 25 mg/kg per dose
Note: Consider prophylaxis of close contacts (especially children < 5 years):
- Adults and children >12 years: Ciprofloxacin 500 mg single dose
Child <12 yrs: 10 mg/kg single dose - Alternative (e.g. in pregnancy): ceftriaxone 250 mg IM single dose
Child < 12 yrs: 150 mg IM single dose
Listeria monocytogenes (at least 3 weeks course)
Common cause of meningitis in neonates and immunosuppressed adults
- Benzylpenicillin 3 MU IV or IM every 4 hours
- Or ampicillin 3 g IV every 6 hours
Notes
- Both medicines are equally effective
- Therapy may need to be prolonged for up to 6 weeks in some patients
Prevention
- Avoid overcrowding
- Improve sanitation and nutrition
- Prompt treatment of primary infection (e.g. in respiratory tract)
- Immunisation as per national schedules
- Mass immunisation if N. Meningitis epidemic