Meningitis in Children
Meningitis is a medical emergency that involves inflammation of the leptomeninges, the membranes that surround the brain and spinal cord. While the incidence of bacterial meningitis has significantly decreased in the UK due to widespread vaccination against S. pneumoniae, N. meningitidis, and H. influenzae, it remains a critical diagnosis to consider in a febrile child.
Aetiology and High-Risk Groups
Meningitis can be caused by a variety of pathogens:
Bacteria: Common causes include S. pneumoniae and N. meningitidis. In neonates, E. coli and Group B Streptococcus are the primary culprits.
Viruses: Viruses are the most common cause of aseptic meningitis and are usually self-limiting. Enteroviruses and herpes simplex are key examples.
Other: Fungal, mycobacterial, or parasitic infections can also cause meningitis, particularly in immunocompromised children.
High-risk groups for bacterial meningitis include:
Infants and unvaccinated children: Who have not received the full vaccination schedule.
Immunocompromised children: Those with HIV, asplenism, or on immunosuppressive therapy.
Children with specific risk factors: Such as a VP shunt, a history of head trauma with CSF leak, or perinatal risk factors like premature rupture of membranes.
Clinical Presentation
The presentation of meningitis can be non-specific, especially in young children.
Infants: Symptoms can be subtle, including poor feeding, irritability, lethargy, and a bulging fontanelle due to increased intracranial pressure (ICP).
Older Children: Typically present with a febrile illness, headache, vomiting, neck stiffness, and photophobia.
Meningococcal Septicaemia: A rapidly progressing, non-blanching purpuric rash is a classic but uncommon sign of meningococcal septicaemia. The absence of a rash does not rule out the disease.
Investigations
Prompt investigation is crucial but should not delay the initiation of antibiotics.
Bloods: A full septic screen is required, including a full blood count, C-reactive protein (CRP), and blood cultures.
Lumbar Puncture (LP): An LP is the gold standard for diagnosis and should be performed urgently unless contraindicated.
Contraindications to LP: LP is contraindicated if there are signs of raised ICP, shock, focal neurological deficits, or a bleeding diathesis.
Neuroimaging: A CT scan of the brain should be performed before an LP in older children with a closed fontanelle if there is a suspicion of raised ICP.
Management
Antibiotics: Do not delay giving broad-spectrum intravenous antibiotics.
>3 months: High-dose ceftriaxone or cefotaxime is the standard empirical treatment.
<3 months: Add amoxicillin to cover for Listeria.
Dexamethasone: In children over 3 months of age, dexamethasone is given to reduce the risk of neurological sequelae, especially hearing loss. The benefit is most proven for H. influenzae meningitis, and its use in other organisms is debated.
Supportive Care: This includes managing shock, seizures, and fluid balance. Monitor the child’s neurological status and, in infants with an open fontanelle, monitor head circumference for signs of hydrocephalus.
Public Health: Notify Public Health England of any confirmed cases of meningococcal or H. influenzae meningitis to arrange prophylaxis for close contacts.
Long-Term Follow-Up: All children with severe bacterial meningitis should have a follow-up assessment for neurodevelopmental and hearing deficits.
Complications
Neurological: Seizures, hydrocephalus, and long-term neurodevelopmental issues are all potential complications.
Sensory: Hearing loss is a significant and common complication of bacterial meningitis and requires a follow-up hearing test 2 months after discharge.
Mortality: The mortality risk, while low in developed countries, remains a significant concern.