Meningitis

Meningitis is inflammation of the meninges — the protective membranes surrounding the brain and spinal cord. It is most commonly caused by bacterial or viral infection. Bacterial meningitis is a life-threatening emergency that can kill within hours or cause permanent disability without immediate treatment. Nigeria lies within the African "meningitis belt," where large seasonal epidemics of meningococcal meningitis occur, particularly during the dry season. Nigeria also has significant meningitis burden from pneumococcal infection in children and cryptococcal meningitis in people living with HIV/AIDS.

Symptoms develop rapidly — often within hours. Classic triad of bacterial meningitis: • Sudden, severe headache: often described as the worst headache ever experienced • High fever • Stiff neck: the person cannot bend the chin toward the chest without severe pain Additional symptoms in adults and older children: • Severe sensitivity to light (photophobia) • Sensitivity to loud noise • Nausea and vomiting • Confusion, agitation, or altered consciousness • Seizures • Drowsiness progressing to unconsciousness Non-blanching rash — meningococcaemia emergency sign: • A red or purple rash that does NOT turn white (blanch) when a glass is pressed firmly against the skin: seek emergency care immediately In infants and young children: • High-pitched or unusual cry • Bulging fontanelle (soft spot on top of the head) • Refusal to feed • Irritability: particularly when picked up • Pale, mottled, or bluish skin • Limpness or unusual stiffness

Bacterial meningitis (most severe): • Neisseria meningitidis (meningococcus): causes epidemic meningitis; particularly common in Nigeria's northern meningitis belt states • Streptococcus pneumoniae (pneumococcus): the most common cause in adults worldwide; also affects children • Haemophilus influenzae type b (Hib): greatly reduced by Hib vaccination • Group B Streptococcus: a major cause of neonatal meningitis • Listeria monocytogenes: more common in newborns, elderly, and immunocompromised Viral meningitis (more common, usually less severe): • Enteroviruses (most common cause of viral meningitis) • Mumps, herpes simplex virus, HIV Fungal meningitis: • Cryptococcus neoformans: almost exclusively in people with HIV/AIDS; a leading cause of meningitis deaths in HIV patients in Nigeria

• Unvaccinated against meningococcal disease, pneumococcus, or Hib • Northern Nigeria states in the meningitis belt during dry season (December–June) • Close contact with a confirmed meningitis case • Overcrowded conditions (dormitories, barracks, prisons, Hajj gatherings) • HIV infection or other immune suppression (risk of cryptococcal meningitis) • Sickle cell disease (impaired spleen function increases pneumococcal risk) • Neurosurgery or head trauma • Cochlear implants

• Death: bacterial meningitis kills 10–15% of patients even with optimal treatment • Hearing loss: one of the most common complications; can be permanent • Brain damage: seizures, cognitive impairment, learning difficulties • Hydrocephalus: excess fluid in the brain cavities • Meningococcal septicaemia: shock, multi-organ failure, tissue death requiring amputation • Stroke • Blindness • Long-term neurological disability and behavioural changes

Vaccination — the most effective protection: • Meningococcal conjugate vaccines: MenAfriVac dramatically reduced meningococcal A epidemics in the meningitis belt • Pneumococcal conjugate vaccine (PCV13): part of Nigeria's routine childhood schedule; also recommended for high-risk adults • Hib vaccine: part of routine childhood immunisation • Meningococcal vaccination is required for all Hajj and Umrah pilgrims Close contacts of a confirmed meningococcal case: • Household contacts should receive rifampicin or ciprofloxacin prophylaxis promptly to prevent spread For people living with HIV: • Early ART reduces risk of cryptococcal meningitis • Fluconazole prophylaxis may be recommended in severely immunocompromised individuals