The surge in H1N1 cases this epidemic season, followed by reports of increasing incidence of influenza-associated encephalitis/encephalopathy (IAE) in young children from across the State is emerging as a serious concern.
Clinicians began recognising the increase in neurological involvement in influenza cases in the State, following the reporting of a few sudden and unexpected deaths in young children in the last two months.
Influenza primarily presents as a mild respiratory disease. But neurological manifestations of influenza, especially due to the sub type A H1N1, are known to occur during outbreaks, and young children are the most vulnerable. The reported frequency of neurological complications in hospitalised children with influenza ranges from 1.7 to 15% in different studies, according to literature.
Once the neurological involvement happens (altered consciousness is the commonest symptom), the infection has a rapid course with some children going into complete brain herniation and death in a matter of hours. Some miraculously make full recovery after intensive and prolonged ICU care but many survivors are left with severe neurological sequelae.
Paediatricians said that all clinicians and primary care physicians in the periphery need to be made aware that if a child with fever has febrile seizures or is showing signs of altered consciousness, then he/she should be evaluated for influenza-associated encephalitis, even in the absence of respiratory symptoms.
“In 2019 also we had noticed the increase in IAE in children. It is possible that many of these cases are being underreported or missed because in the majority of cases, it is impossible to isolate the influenza virus from cerebrospinal fluid. This has been the pattern world over also,” pointed out Sheeja Sugunan, Associate Professor of Paediatrics, SAT Hospital.
Rapid progression
The rapid manner in which the disease progresses once the brain is affected leaves little room for early intervention and management. The median time from onset of respiratory signs to onset of neurological symptoms could be as short as 24 hours or within five days.
In a study conducted at SAT Hospital during the seasonal epidemic flu in 2019, doctors had reported cases of 16 children who had influenza-associated neurological manifestations and 44% were children less than two years of age. Intensive care management was required for 81% of children and the cause specific mortality was 18.75%. Ten children recovered completely without any neurological deficit.
Focus on disease prevention
“The normal incidence of IAE is one in one lakh population and we expect a mortality rate of 10 to 40%. Given the fact that the general outcome of IAE in children is uncertain or poor and that even some survivors may be left with long-term neurological damage, there is a lot of emphasis on disease prevention. Wearing masks is protective against all respiratory infections and this practice should be promoted during this flu season,” Dr. Sugunan said.
The Health department has taken cognisance of the emerging concerns and the uncertainties that clinicians are facing in the field, in the early recognition and optimised management of children presenting with IAE.
“There is an increase in IAE this season but there is no need to be alarmed. We are collecting data and reports from across the State and evaluating the situation because there is a clear variance in the nature of influenza this season. A State-wide training session with the Health department is being organised soon to evolve a consensus on clinical management of cases,” the President of Indian Association of Paediatrics, Kerala, O. Jose, said.
