Benign partial epilepsy of infancy as defined by Watanabe: 2 case reports

Introduction: Benign partial infantile epileptic seizures of the Watanabe type occur rarely and show a good response to antiepileptic treatment. Clinically complex-partial seizures with dyscognitive features and a psychomotoric arrest can be seen, and a secondary generalization is possible. The seizures typically appear in clusters between the age of 3 and 20 months. Diagnosis can be difficult, as the interictal EEG as well as the neurological development of the infant is normal. The following case reports show the difficulty of securing this diagnosis.

Case report: Case 1: An 8-month-old infant presented with recurring episodes lasting a few seconds accompanied by facial pallor, cyanosis of the lips, decreased muscle tone and eye deviation. Neurological examination, MRI, ECG, and interictal EEG were normal. Some weeks later while recording an EEG a focal seizure occurred, and benign partial epilepsy could be diagnosed. Under treatment with carbamazepine the patient remained seizure-free.

Case 2: A normally developed 8-month-old infant first presented with a sudden loss of muscle tone, apnea, and cyanosis. The episode lasted approximately 1 minute and there was no reaction to stimuli. Investigations abroad with EEG, ECG, and a 4-day observation period were unremarkable. On the way home the child again showed loss of muscle-tone and cyanosis of the lips, lasting around 30 seconds. Cranial sonography, laboratory findings, and interictal EEG were normal. Because of persisting seizures therapy with carbamazepine was started, whereupon no more seizures occurred.

Conclusion: The diagnosis of benign partial epilepsy in infancy can be difficult, as only the ictal EEG shows epileptic discharges. Typical clusters can be observed, during which series of complex-partial seizures occur over a couple of days. It is justified to begin low dose carbamazepine in a normally developed infant presenting with a normal interictal EEG. If the patient remains seizure-free, the necessity of further investigations, such as MRI, in anesthesia must be questioned. Therapy should be continued for 6 to 12 months.