A seizure is an abnormal paroxysmal electrical activity in the brain resulting in motor, sensory or autonomic manifestations. A seizure with involuntary motor activity is called a convulsion.  About 5% of children would experience a seizure in the first 5 years of life.   Most often, parents come with the complaint of a seizure in their child and the physician has to decide whether it was truly a seizure. A seizure is therefore a clinical diagnosis based mostly on history. A detailed account of the sequence of events from an eyewitness should be taken.  A carefully taken history is more useful than investigations. Often there is a history of an aura followed by sudden loss of consciousness, a tonic phase and a clonic phase followed by postictal sleep. Features which favour true seizure are history of fall, tongue bite, incontinence, uprolling of eyes, frothing at the mouth and twitching of the face.  However, not all seizures would have these features. Neonatal seizures can be subtle and hard to recognize.

Box  1  gives the causes of seizures. All the causes of recurrent seizures would also apply to first seizure.

Investigation of seizures: Blood biochemistry – glucose, calcium,  magnesium and electrolytes may be done, especially in newborns, young infants or those with a clinical setting for such abnormalities.

EEG: This is a widely used supportive investigation.  Presence of interictal epileptiform discharges favour the diagnosis of seizures.

Neuroimaging:  X rays of the skull have a low yield.  Cranial CT scan may be useful, but MRI brain is the most useful neuroimaging technique as it brings out subtle abnormalities like neuronal migration defects etc.