Running and laughing fits as the sequelae of the neonatal hyperviscosity syndrome.

A 5-year-old Japanese male with intractable running and laughing fits was reported to have had status epilepticus from 18 hours after birth. This intractable convulsions were thought to be due to hyperviscosity syndrome induced by neonatal idiopathic polycythemia. A phlebotomy ended the convulsions in the neonatal period, but the EEG continued to display right temporal spikes afterwards. He suffered from running and laughing fits 3 to 5 times daily from the age of 2 years up to 4 years 8 months. EEG revealed generalized dysrhythmia and poly-spikes and waves, mainly in the right side. Computerized tomography showed dilatation of all the ventricles plus multiple low density areas in the right temporal lobe. This case of running and laughing fits was presumed to be one of the temporal lobe epilepsy induced by the hyperviscosity syndrome brought on by neonatal polycythemia.