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

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