[Valproate sodium and zonisamide associated interstitial pneumonitis in an infant]

A six month-old female infant developed dyspnea when she was treated with valproate sodium (VPA) and zonisamide (ZNS) for epileptic spasms. Two weeks after its onset, her dyspnea was exacerbated by respiratory syncytial virus (RSV) infection. We diagnosed interstitial pneumonitis (IP) based on her chest CT and high serum concentrations of KL-6 and surfactant protein D. Her dyspnea improved with the treatment which included steroids, neutrophil elastase inhibitor and discontinuation of VPA and ZNS. An allergic reaction probably explains the IP in our patient because steroids were effective. Her IP might have been exacerbated by several factors including the use of two anticonvulsants (VPA, ZNS), RSV infection, and physiological low serum IgA level of infants. Drug-induced interstitial lung disease should be remembered as a possible complication of anticonvulsant treatment, such as VPA and ZNS.