Infants ≤30 days old are at risk for meningitis due to an immature immune response. Symptoms in this age group are variable and nonspecific and include both fever and hypothermia. Neonates can present with a history of lethargy, poor feeding, fussiness, bulging fontanelle, vomiting, diarrhea, seizures, grunting, or respiratory distress. Elements in the birth history that increase the likelihood of bacterial meningitis include prematurity, low birth weight, delivery complications, maternal infection, and maternal colonization with group B streptococci or herpes simplex. Some neonates present with few symptoms early in the course of their illness, so maintain a high degree of suspicion for early meningitis when confronted with a potentially sick newborn.
Certain signs and symptoms are especially helpful for diagnosing bacterial meningitis in infants and children. Caregiver reports of bulging fontanelle (likelihood ratio [LR] 8, 95% CI 2.4–26), or neck stiffness (LR 7.7, 95% CI 3.2–19), or seizures (outside of the febrile seizure range of 6 months to 6 years; LR 4.4, 95% CI 3.0–6.4), or reduced feeds (LR 2, 95% CI 1.2–3.4) are concerning for meningitis.4 Children with meningitis can present with the rapid onset of shock and altered mental status or with more gradual symptoms including fever, headaches, photophobia, upper respiratory symptoms, GI symptoms, irritability, and rash.
The World Health Organization's Pocket Book of Hospital Care for Children reported the performance of signs and symptoms for bacterial meningitis in infants and children and did not find any single clinical feature distinctive enough to make a "robust diagnosis of bacterial meningitis."5 However, the combination of fever, seizures, meningeal signs, and altered consciousness was consistently associated with bacterial meningitis.6
Infants with viral meningitis typically present with irritability and decreased activity. Headache and fever are the usual complaints in children. Other symptoms include photophobia, rashes, nausea, vomiting, and pain in the neck, back, and legs. Most children with West Nile virus will be asymptomatic or have mild illness. Severe neurologic illness from West Nile virus is more common in adults than in children.7 Arboviruses can cause viral meningitis, encephalitis or acute flaccid paralysis.
Herpes simplex virus can cause devastating infection in neonates. Infection can present in three ways: (1) as disseminated disease with involvement of the CNS in 60% to 75% of cases; (2) as primary CNS disease; or (3) as disease localized to the skin, eyes, and/or mouth. About two thirds of infants with disseminated or CNS disease will have skin lesions, but these may not be present at the time of diagnosis. Neonatal herpes infections, including herpes simplex meningitis, can occur at up to 6 weeks of age.8 Herpes infection can be transmitted through an infected maternal genital tract but may also be transmitted from a nongenital maternal infection, for example, if a mother with oral herpes kisses the baby. Herpes simplex encephalitis (HSV-1) beyond the neonatal period presents with fever, altered mental status, seizures, and focal neurologic findings. It occurs sporadically.
Neonates and infants <90 days old may have fever, normal temperature, or hypothermia. A normal temperature does exclude meningitis. Toxic appearance, lethargy, mottling, bulging fontanelle, abnormal cry, grunting, respiratory distress, and increased or decreased tone are all supportive of the diagnosis, but these signs can be absent. Jaundice or rash may occasionally be seen. Infants in the first months of life are unlikely to have a stiff neck. Fever in neonates (rectal temperature of 100.5°F or higher) should always prompt suspicion for meningitis. In the absence of fever, a clinician should be concerned about infants who are ill appearing, have the signs or symptoms listed earlier, or are just not "acting right" according to their caregivers.
Older infants (>90 days old) with meningitis may also have fever, hypothermia, toxic appearance, lethargy, mottling, bulging fontanelle, abnormal cry, grunting, and respiratory distress at presentation. Children (>36 months of age) may have fever and nuchal rigidity. The Kernig sign (with the patient lying supine and the hip flexed at 90 degrees, the patient cannot extend the knee fully without pain) and Brudzinski sign (with the patient lying supine, there is involuntary flexion of the legs with passive neck flexion) may be present. Children may have altered mental status, shock, focal neurologic signs, or signs of increased intracranial pressure. Rash or another focal sign of infection may be present. Consider bacterial meningitis in the child with seizures, outside the range of 6 months to 6 years.