Meningitis

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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
  • Haemorrhagic rash (N.meningitidis infection)
  • 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
  • Blood: for culture and sensitivity
  • Chest X-ray and ultrasound to look for possible primary site

Management - Adults and Children

Because of the potential severity of the disease, refer all patients to hospital after pre-referral dose of antibiotic. Carry out lumbar puncture promptly and initiate empirical antibiotic regimen

Treatment depends on whether the causative organisms are already identified or not.

Treatment  LOC

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

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
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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
 H

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 chloramphenicol 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 500mg single dose
    • Child <12 yrs: 10 mg/kg single dose
  • Alternative (e.g. in pregnancy): ceftriaxone 250mg 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

Neonatal Meningitis

Bacterial infection of the meninges in the first month of life.

Organisms causing neonatal meningitis are similar to those causing neonatal septicaemia and pneumonia, i.e. S.pneumoniae, group A & B streptococci, and enteric Gram-negative bacilli.

Meningitis due to group B streptococci: These organisms often colonise the vagina and rectum of pregnant women, can be transmitted to babies during labour, and cause infection. Meningitis and septicaemia during the 1st week after birth may be particularly severe.

Clinical presentation is aspecific with temperature disturbances, lethargy, irritability, vomiting, feeding problems, convulsions, apnoea, bulging fontanel

Management

Treatment LOC

Refer to hospital after initial dose of antibiotics

Supportive care

  • Keep baby warm
  • For high temperature control environment (undress), avoid paracetamol
  • Prevent hypoglycaemia (breastfeeding if tolerated/possible, NGT or IV glucose)
  • Ensure hydration/nutrition
  • Give oxygen if needed (SpO2 <92%)

Empirical regimen (for 21 days)

  • Ampicillin IV
    • Neonate < 7 days: 50-100 mg/kg every 12 hours
    • Neonate > 7 days: 50-100 mg/kg every 8 hours
  • Plus Gentamicin 2.5 mg/kg IV every 12 hours

If group B streptococci

  • Benzylpenicillin 100,000-150,000 IU/kg IV every 4-6 hours
    • Neonates <7 days: 50,000-100,000 IU/kg IV every 8 hours
  • Plus gentamicin 2.5 mg/kg IV every 12 hours
  • Continue treatment for a total of 3 weeks
 H

 

 

 

 

Cryptococcal Meningitis

Fungal meningitis caused by Crypotococcus neoformans and usually occurs in severely immunosuppressed patients (e.g. advanced HIV, usually CD4 < 100).

It commonly presents with headache, fever, malaise developing over 1 or 2 weeks, progressing into confusion, photophobia, stiff neck

Diagnosis is through identification of the microorganism in the CSF with Indian Ink stain, antigen in CSF or culture

Management

Treatment

  • Refer to hospital

TB Meningitis

Meningitis caused by M. tuberculosis. Onset may be gradual with fatigue, fever, vomiting, weight loss, irritability, headache, progressing to confusion, focal neurological deficits, meningeal irritation, till coma.

For diagnosis: check CSF (raised protein, lymphocytosis), look for possible primary TB site

Management 

Treatment

  • Refer to hospital
  • Treat as per pulmonary TB but continuation phase is 10 months instead of 4 (2RHZE/10RH)
  • See section on Management of TB for further details