The 2009 A(H1N1) swine flu pandemic caused a higher incidence of neurological complications – especially seizures and encephalopathy (brain malfunction or damage) – in children than normal seasonal flu, scientists from the University of Utah, Clinical Neurosciences Center revealed in an article published in Annals of Neurology.

The H1N1 virus was detected in the USA and Mexico in April 2009; it spread rapidly around the globe. Soon WHO (World Health Organization) declared a pandemic. The CDC (Centers for Disease Control and Prevention) estimated that 89 million people became infected in the USA between April 2009 and April 2010. Between fourteen and twenty-eight million children aged up to 17 years were thought to have become infected. The pandemic officially ended in August 2010.

Josh Bonkowsky, M.D., Ph.D., and team carried out a retrospective study in which they examined childhood neurological complications from H1N1 infection, and compared them to those that occur in seasonal flu. They included all hospitalized children up to the age of 19 years who also had neurological complications between April 1st and November 30th 2009. They were compared to children hospitalized with seasonal flu who had neurological complications from July 1st to June 30th 2008.

Examples of neurological complications observed were:

Of the 303 children the investigators identified who were hospitalized with 2009 H1N1, 18 had neurological complications. 83% of those with complications had an underlying medical condition, two-thirds of them with neurological issues.

The investigators found that the most common neurologic symptoms among those with complications were seizures (67%) and encephalopathy (50%). Over 50% of the children who had seizures presented in a life-threatening state known as status epilepticus (continuous seizure occurs from five to 30 minutes).

Amongst those with seasonal flu, 234 children were hospitalized, 16 of whom experienced neurological issues; only 25% of them had underlying medical conditions. None of the children in this group had encephalopathy, aphasia or focal neurological deficits.

The researchers report that a higher percentage of children in the H1N1 group had abnormal EEG (electroencephalogram) findings.

Bonkowsky, an assistant professor of pediatrics in the University of Utah School of Medicine, said:

We found that more pediatric H1N1 patients had neurological deficits and required ongoing treatment with anti-epileptic medications upon discharge from the hospital.

The investigators also found that neither steroid use nor intravenous immunoglobulin helped in the treatment of encephalopathy.

Bonkowsky added:

The absence of proven treatments for influenza-related neurological complications underlines the importance of vaccination.

Source: University of Utah

Written by Christian Nordqvist