Makindo Medical Notes

Neonatal meningitis - Definitive diagnosis is made by CSF examination via lumbar puncture (LP), which should be performed in any neonate suspected of having sepsis or meningitis, though it should not delay treatment initiation.

About

• Neonatal meningitis is an inflammation of the meninges occurring within the first 90 days of life.
• It is predominantly bacterial in origin and is a serious, potentially life-threatening condition in neonates.

Clinical Presentation

• Classical signs of meningitis such as fever, vomiting, and stiff neck are often absent in neonates.
• Common symptoms may include:
  • Poor feeding, lethargy, irritability, apnea, listlessness, apathy, fever, hypothermia, and seizures.
  • Additional signs: jaundice, bulging fontanelle, high-pitched or shrill cry, hypoglycaemia, intractable metabolic acidosis, pallor, shock, and hypotonia.

Microbiology

• Group B Streptococcus (GBS): Most common pathogen (especially type III), accounting for about 50% of cases, often transmitted vertically from the mother during birth.
• Escherichia coli: Particularly strains with the K1 polysaccharide capsule, responsible for approximately 20% of cases.
• Listeria monocytogenes: Less common, accounting for about 5-10% of cases, typically acquired via contaminated food.
• Viral Causes: Includes Herpes Simplex Virus (HSV) and Varicella Zoster Virus (VZV), which can also cause meningitis.

Complications of Neonatal Bacterial Meningitis

• Cerebral palsy: Approximately 8% of cases.
• Learning disabilities: Seen in about 7% of survivors.
• Seizures: Persistent in around 7% of cases.
• Hearing impairment: Affects approximately 25% of neonates who recover from bacterial meningitis.

Causes of Meningitis in Older Infants

• Streptococcus pneumoniae
• Neisseria meningitidis
• Haemophilus influenzae type b (Hib)
• Note: These pathogens differ from those seen in neonatal meningitis and are more common in infants older than 3 months.