Meningitis

Introduction

Meningitis is an infection of the meninges with the presence of pus and inflammatory cells in the cerebrospinal fluid. It is a medical emergency, and associated with considerable morbidity and mortality.
It may be bacterial (pneumococcus,
meningococcus, tubercle bacilli,
Haemophilus), viral, fungal, protozoal,
neoplastic or chemical. Organism may vary with age of the patient. It may occur in epidemics in the Savannah region
Epidemic meningitis is usually due to Neisseria meningitidis

Clinical features

  • Fever
  • Headache
  • Vomiting
  • Photophobia
  • Alteration in level of consciousness
  • Neck stiffness and positive Kernig’s sign
  • It may be present in epidemics

Systemic features of infection by offending organisms include:

  • Pneumococcal and Haemophilus infection: Jaundice, pneumonia, heart failure
  • Meningococcal infection: Joint pain, joint swelling, red eyes, skin rash
  • Tuberculous infection: Weight loss, cough with blood in sputum
  • HIV infection: Severe weight loss, diarrhea, mouth lesions, skin rash

Other presentations:

  • Fever of unknown origin: chronic meningitis
  • Mass lesion with focal neurological deficits: tuberculoma, empyema
  • Stroke-like syndrome: resulting from inflammation of blood vessels
  • Seizures which may be uncontrolled and prolonged (status epilepticus)
  • Acute psychosis (Organic Brain Syndrome)
  • Dementia

Differential diagnoses

  • Tetanus
  • Subarachnoid haemorrhage
  • Brain abscess
  • Septicaemia with meningism
  • Cerebral malaria

Complications

  • Cranial nerve palsies notably blindness and deafness
  • Subdural pus collection (empyema)
  • Stroke
  • Epilepsy
  • Heat stroke
  • Syndrome of Inappropriate Anti-Diuretic Hormone secretion (SIADH)

Investigations

  • Lumbar puncture for CSF analysis
    • To demonstrate presence of
      inflammatory cells (after exclusion of raised intracranial pressure by fundoscopy or CT scan)
  • Full Blood Count and differentials
  • Blood culture
  • Erythrocyte sedimentation rate
  • Random blood glucose
  • Electrolytes, Urea and Creatinine
  • Chest radiograph
  • Mantoux test (if tuberculosis is suspected)
  • HIV screening

Management

Treatment objectives

  • Eliminate the organism
  • Reduce raised intracranial pressure
  • Correct metabolic derangements
  • Treat complications (if any)

Non-drug treatment

  • Tepid-sponging
  • Attention to calories and fluid/electrolyte balance
  • Physiotherapy (for passive muscle exercises)
  • Nursing care (e.g. frequent turning and bladder care) to prevent decubitus ulcers and urinary tract infection

Drug treatment

  • Initial therapy will depend on the age of the patient (and causative agent)

A. Bacterial infections

Third generation cephalosporins:

  • Ceftriaxone is the drug of first choice 1 g daily by deep intramuscular injection, or
    by intravenous injection over at least 2-4 minutes, or by intravenous injection; 2-4 g daily in severe infections; intramuscular
    doses over 1 g should be divided between more than one site; single intravenous doses above 1 g by intravenous infusion only

Neonate

  • By intravenous infusion over 60 minutes, 20 50 mg/kg daily (max. 50mg/kg daily)

Children under 50kg,

  • By deep intramuscular
    injection or by intravenous infusion, 20-50 mg/kg daily; up to 80mg/kg daily in severe infections; doses of 50 mg/kg and over by intravenous infusion only

Or:

Penicillin V

  • 2 – 4 g by slow intravenous injection every 4 hours

Or:

Chloramphenicol
100 mg/kg intravenously every 6 hours
Chloramphenicol may be useful for. influenza infection

B. Tuberculosis:

  • Standard anti-tuberculous drugs (including pyrazinamide and isoniazid for their good penetration of the blood-brain barrier)

Anti-pyretics: Aspirin (acetylsalicylic acid)

  • Adult: 300 mg – 1 g orally every 4 hours after food; maximum dose in acute conditions 8 g daily
  • Child: not recommended for use

Diazepam (for seizures)

  • Adult: 10-20 mg at a rate of 0.5 ml per 30 seconds, repeated if necessary after 30 – 60 minutes; may be followed by intravenous
    infusion to a maximum of 3 mg/kg over 24 hours
  • Child: 300-400 micrograms/kg (maximum 20 mg) by slow intravenous injection into a large
    vein for protracted or frequent recurrent convulsions
  • Not required in single, short-lived convulsions
  • Acute cerebral decompression:

Furosemide

  • Adult: 40 – 80 mg every 8 hours by slow intravenous injection (for a maximum of 6 doses)
  • Child: neonate 0.5 – 1 mg/kg every 12 – 24 hours (every 24 hours in neonates born before 31 weeks gestation)
  • 1 month-12 years: 0.5-1 mg/kg (maximum 4 mg/kg), repeated every 8 hours as necessary
  • 12 – 18 years: 20 – 40 mg, repeated every 8 hours as necessary; higher doses may be required in resistant cases

Or:

Mannitol 20% solution

  • Adult: 50-200 g by intravenous infusion over 24 hours, preceded by a test dose of 200 mg/kg by slow intravenous injection
  • Child: neonate 0.5-1 g/kg (2.5 – 5 ml/kg of 20% solution) repeated if necessary 1-2 times after 4-8 hours
  • 1 month – 18 years: 0.5 1.5 g/kg (2.5 – 7.5 ml/kg of 20% solution); repeat if necessary 1 – 2 times after 48 hours

Chemoprophylaxis

Treat contacts during meningococcal
epidemics with either ciprofloxacin or
rifampicin
Rifampicin

  • Adult:600mg orally every 12 hours for 5 days
  • Child: 10 mg/kg orallyevery 12 hours for 5 days
  • Under 1 year: 5 mg/kg orallyevery 12 hours for 5 days

Ciprofloxacin

  • Adult: 500 mg orally as a single dose
  • Child: 5-12 years 250 mg orally as a single dose

Notable adverse drug reactions, caution and contraindications

Diazepam

  • Must be administered slowly
    intravenously to avoid respiratory depression

Chloramphenicol

  • May cause aplastic anaemia

Mannitol

  • May cause chills and fever
  • Extravasation causes inflammation and thrombophlebitis
  • Contraindicated in congestive cardiac failure and pulmonary oedema

Prevention

  • Immunize against communicable diseases
  • Meningococcus, heamophilus,
    streptococcus (especially for sicklers).
  • Chemoprophylaxis (Rifampicin or
    ciprofloxacin)

    • As determined by national policy
  • For close contacts of clinical cases