Pneumococcal Meningitis

Pneumococcal meningitis is infection of the meninges by Streptococcus pneumoniae, the commonest cause of bacterial meningitis in older children and adults in Africa. It has the highest rates of death and neurological sequelae among bacterial causes.

• Arises from nasopharyngeal colonisation with bloodstream invasion, or direct spread from otitis media, sinusitis, mastoiditis, skull fracture or cerebrospinal fluid leak.
• Risk groups: young children, elderly, HIV, sickle cell disease and other asplenia, alcohol dependence, diabetes, cochlear implant.

Abrupt fever, headache, neck stiffness, vomiting, photophobia, confusion, seizures and coma; ear discharge or pneumonia may precede.

• Focal deficits, cranial nerve palsies (VI, VII, VIII), cerebral infarction.
• Differential diagnosis: meningococcal and Hib meningitis, viral meningitis, tuberculous and cryptococcal meningitis, cerebral malaria, brain abscess, subdural empyema, encephalitis, subarachnoid haemorrhage, sepsis.
• Complications: sensorineural deafness (up to 30 percent), hydrocephalus, cerebral infarction, cerebral oedema, seizures, subdural empyema, cognitive and motor deficits, epilepsy, persistent CSF leak, recurrence, death (15 to 30 percent).

Blood and CSF tests with antigen or PCR.

• Blood cultures before antibiotics; CT head if focal signs, papilloedema, Glasgow Coma Scale under 10 or immunosuppression; lumbar puncture: neutrophilic pleocytosis, high protein, low glucose, Gram positive lancet shaped diplococci, culture with penicillin and ceftriaxone susceptibility, latex agglutination, PCR.
• Search for a source: chest radiograph, ear and sinus examination, CT of skull base for CSF leak, echocardiography if endocarditis suspected.
• HIV test, splenic function, immunoglobulins.

Start combination antibiotics with dexamethasone immediately.

• Supportive: high dependency care, oxygen, treat shock, glucose, correct sodium, head up 30 degrees, treat seizures, paracetamol 1 g four times daily, avoid hypotonic fluids.
• Pharmacological: ceftriaxone 2 g IV every 12 hours (children 100 mg/kg/day in 1 or 2 doses, maximum 4 g/day) plus vancomycin 15 to 20 mg/kg IV every 8 to 12 hours (children 15 mg/kg every 6 hours; adjust to trough 15 to 20 mg/L) until susceptibility is known; if penicillin MIC is 0.06 mg/L or less, change to benzylpenicillin 4 million units IV every 4 hours (children 250,000 units/kg/day in divided doses); continue for 10 to 14 days. Dexamethasone 0.15 mg/kg (usual 10 mg) IV every 6 hours for 4 days, started with or before the first antibiotic dose. Seizures: diazepam 10 mg IV or 0.3 mg/kg rectal, then phenytoin 15 to 20 mg/kg IV over 30 minutes. If penicillin allergic: chloramphenicol 25 mg/kg IV every 6 hours (maximum 1 g) or meropenem 2 g IV every 8 hours.
• Procedures: CT head, repeat lumbar puncture if no improvement at 48 hours, external ventricular drain or shunt for hydrocephalus, surgical repair of CSF leak, drainage of empyema.
• Special groups: pregnancy, ceftriaxone with dexamethasone; sickle cell disease and asplenia, lifelong penicillin V 250 mg twice daily (children under 5 years 125 mg twice daily) plus vaccination; HIV, antiretroviral therapy; children, weight based dosing and audiology.
• Red flags: falling consciousness, seizures, papilloedema, cranial nerve palsies, shock, new focal deficit, persistent fever beyond 5 days.
• Follow-up: audiology within 4 weeks, repeat if hearing loss; neurodevelopmental review at 3 and 12 months; vaccination: pneumococcal conjugate vaccine at 6, 10 and 14 weeks in infants, and a conjugate or polysaccharide vaccine for high risk adults; CSF leak repair to prevent recurrence.