Epilepsy can be diagnosed when the first two seizures occur on the same day

Experts have suggested that when the first two (or more) unprovoked seizures occur on the same day, they should be considered as a single event and the diagnosis of epilepsy await a further seizure. We have studied the subsequent clinical course of children with their first two seizures on the same day ("same day" group) compared with children with their first two seizures separated by more than one day ("different day" group).

The Nova Scotia childhood epilepsy database documented all newly diagnosed children with epilepsy from 1977 to 1985 with follow-up in 1990 and 1991. Epilepsy was defined as two or more unprovoked seizures regardless of the interval between seizures provided that consciousness fully returned between seizures. All patients had their first seizure between the ages of 1 month and 16 years. Seizure types were restricted to partial, generalized tonic-clonic, and partial with secondary generalization.

Of the 490 children with partial or generalized tonic-clonic seizures and follow-up of more than 2 years, 70 had their first two or more seizures on the same day and 420 had their first two seizures on different days. Eighty percent (56 of 70) of the "same day" group subsequently had one or more further seizures with (n = 14) or without (n = 42) medication; 80.9% (340 of 420) of the "different day" group had one or more further seizures with (n = 115) or without (n = 225) medication. Seizure types were nearly identical. Cause was the same (except for fewer idiopathic "genetic" cases in the "same day" group: 1 of 70 vs. 42 of 420; p = 0.02). Rates of mental handicap and previous febrile seizures were the same. Children in the "same day" group were younger on average (60 vs. 84 months; p = 0.001) and were somewhat more likely to have neurological impairment. Outcome after 7 years average follow-up was the same: 58% of the "same day" group and 56% of the "different day" group were in remission.

If two or more unprovoked seizures (with normal consciousness between) occur on the same day, the child appears to have epilepsy and will have a clinical course identical to that of the child with a longer time interval between the first two seizures.