Meningococcaemia

Meningococcaemia is bloodstream infection with Neisseria meningitidis. It spans a spectrum from transient bacteraemia and mild illness, through acute meningococcal septicaemia, to fulminant disease with shock, and rarely a chronic relapsing form lasting weeks.

Epidemiology. Annual incidence is about 0.5 to 1 case in 100,000 in vaccinated populations and much higher in epidemics (African meningitis belt). Highest rates occur under 5 years and at 15 to 24 years. Case fatality is around 10% and higher with shock.

Risk factors. Complement deficiency, asplenia, HIV, terminal complement inhibitor use, crowding (halls of residence), pilgrimage travel, active or passive smoking, and household contact.

Pathophysiology. Nasopharyngeal carriage (10% or more of adolescents) precedes invasion. Capsule, pili and lipo oligosaccharide enable survival, endothelial adhesion and a strong inflammatory response with coagulation activation.

Early features are fever, headache, vomiting, malaise, limb or joint pain and cold hands and feet. A maculopapular or petechial rash appears at 12 to 24 hours in most. Later signs are non-blanching purpura, shock, confusion, meningism and arthritis. Chronic meningococcaemia gives intermittent fever, arthralgia and rash over weeks.

Red flags.

• Non-blanching rash or rapidly spreading petechiae, especially with fever.
• Cold peripheries, poor perfusion, hypotension or drowsiness.
• Neck stiffness, photophobia or seizure suggesting meningitis.

Take blood cultures before antibiotics where it does not delay treatment, and send blood for nucleic acid amplification testing, full blood count, coagulation, glucose, lactate, creatinine and C-reactive protein. Lumbar puncture only when safe (no shock, rash with deterioration, coagulopathy, raised intracranial pressure signs). Throat swab culture may help in contacts. Send a skin aspirate for Gram stain when available.

Differential diagnosis. Viral exanthems, enteroviral rash, septic shock from other organisms, toxic shock syndromes, vasculitis, immune thrombocytopenia, leukaemia and dengue.

Immediate antibiotic. Benzylpenicillin 1.2 g IV or IM (adults), 600 mg for ages 1 to 9 years, 300 mg for infants under 1 year, at the first suspicion before hospital arrival. In hospital give ceftriaxone 2 g IV every 12 hours (adults; children 80 mg/kg once daily to a maximum of 4 g) within 1 hour of arrival. Duration 5 to 7 days.

Resuscitation. Oxygen, IV or intraosseous access, crystalloid boluses of 20 mL/kg (500 mL adults) with reassessment, and early noradrenaline or adrenaline for shock. Correct glucose, potassium, calcium and acid base balance.

Meningitis component. Dexamethasone 10 mg IV every 6 hours for 4 days, before or with the first antibiotic dose, when meningitis is present.

Contacts and public health. Notify at once. Droplet isolation for 24 hours after effective antibiotics. Chemoprophylaxis for close contacts within 24 hours: ciprofloxacin 500 mg orally once (adults), rifampicin 600 mg orally every 12 hours for 2 days, or ceftriaxone 250 mg IM once (pregnancy, 125 mg for children under 12 years). Also vaccination as directed by public health.

Long term care. Test for complement deficiency after recurrent or unusual serogroup disease, and vaccinate asplenic patients. Check hearing after meningitis.

Monitoring. Observations every 15 to 30 minutes in the first hours, fluid balance, rash progression, coagulation and neurology.

Referral and escalation. Intensive care for shock, rapid rash progression or altered consciousness.

Special groups. In pregnancy, ceftriaxone is acceptable, and ciprofloxacin is avoided for prophylaxis. In children, weight based doses and early intraosseous access.