Enteroviral Meningitis in Neonates and Children of Mashhad, Iran

The highest incidence of meningitis occurs during the neonatal period and (then) infancy. Although Bacterial agents are the most dangerous cause of neonatal and childhood meningitis yet viruses especially, enteroviruses (EV), are by far the most common cause of meningitis in this age group.

The aim of the current study was to evaluate the role of EVs in neonatal and childhood meningitis in the Mashhad city of Iran.

This was a descriptive study that was performed at Imam Reza hospital in a period of six months (March to September 2007), during which all of the cerebral spinal fluid (CSF) samples from the neonatal intensive care unit (NICU) and pediatrics ward were collected and real time-polymerase chain reaction (RT-PCR) for EVs was done on these samples. Clinical data were collected retrospectively from hospital files.

We collected 58 CSF samples (35 neonates and 23 children) during six months. Pleocytosis of CSF was seen in 51.1% of the subjects (28% of neonates, and 66.6% of infants and children). Enteroviruses PCR was positive in 37.1% (13) of neonates and 34.7% (8) of children. Pleocytosis of CSF was seen in 23% and 75% of EV positive neonates and children, respectively. Polymorphonuclear (PMN) dominance (PMN > 50%) of CSF was seen in 50% and 33% of EV positive neonates and children, respectively. There were three cases of bacterial meningitis in our group; EV PCR result was positive for one of these subjects. Concomitant bacterial infection (meningitis and sepsis) was seen in 9.5% (two cases) of EV positive CSFs in our study. Almost half of the available neonates (four of nine) with pure enteroviral meningitis (EVM) were discharged (in good condition) with final diagnosis of culture negative sepsis (CNS) and mean length of hospital stay (MLOS) of 4.3 days. One (12.5%) of the neonates with EVM, who had a very low birth weight (< 1500 mg), was expired, and two (25%) cases were discharged with brain damage and final diagnosis of severe asphyxia. The MLOS for children with pure EVM was 1.6 days (one to four days); they didn't have any sign of brain damage or mortality. Qualitative c-reactive protein (CRP) of serum was negative in 72.7% and 37.5% of EV positive neonates and children, respectively. The mean white blood cell count and PMN percentage in the peripheral blood was 11416/mm(3) and 60.8% for EV positive neonates, and 14500/mm(3) and 77.1% for EV positive children, respectively. Hyponatremia, due to possible syndrome of inappropriate antidiuretic hormone (SIADH), was seen in 30% of neonates and 57% of children with EVM.

Enteroviruses were a common cause (> 30%) of meningitis in our study group. Concomitant bacterial infection is not rare in neonates and children with EVM. Many of the neonates (50%) and almost all of the children with EVM did not require prolonged hospitalization. Both normal CSF and PMN dominancy of CSF was common in neonates and children with EVM. Positive qualitative CRP of serum (up to two plus) was common especially in children with EVM. Non-symptomatic mild hyponatremia/SIADH was common in early life EVM.