Background. This study evaluated the efficacy of a single dose of phenytoin/fosphenytoin (PHT) to control repetitive seizures in children with benign convulsions with mild gastroenteritis (CwG).

Methods. Children aged between 3 months and 5 years with CwG were retrospectively enrolled. Convulsions with mild gastroenteritis were defined as (a) seizures with acute gastroenteritis without fever or dehydration; (b) normal blood laboratory results; and (c) normal electroencephalography and brain imaging findings. Patients were divided into two groups according to whether or not intravenous PHT (10 mg/kg of phenytoin or phenytoin equivalents) was administered. Clinical manifestations and treatment efficacy were evaluated and compared.

Results. Ten of 41 children eligible for inclusion received PHT. Compared to children in the non-PHT group, those in the PHT group had a higher number of seizures (5.2 ± 2.3 vs. 1.6 ± 1.0, P < 0.001) and a lower serum sodium level (133.5 ± 3.2 mmol/L vs. 137.2 ± 2.6 mmol/L, P = 0.001). Initial serum sodium levels were negatively correlated with seizure frequency (r = -0.438, P = 0.004). In all patients, seizures were completely resolved with a single dose of PHT. There were no significant adverse effects from PHT.

Conclusions. A single dose of PHT can effectively treat CwG with repetitive seizures. The serum sodium channel may play a role in seizure severity.

Keywords: phenytoin; fosphenytoin; sodium channel; benign convulsions; mild gastroenteritis