Panayiotopoulos syndrome: a benign childhood autonomic epilepsy frequently imitating encephalitis, syncope, migraine, sleep disorder, or gastroenteritis.

BACKGROUND: Panayiotopoulos syndrome is a common idiopathic childhood-specific seizure disorder formally recognized by the International League Against Epilepsy. An expert consensus has defined Panayiotopoulos syndrome as "a benign age-related focal seizure disorder occurring in early and mid-childhood. It is characterized by seizures, often prolonged, with predominantly autonomic symptoms, and by an EEG [electroencephalogram] that shows shifting and/or multiple foci, often with occipital predominance."

OBJECTIVE: The purpose of this review is to provide guidance for appropriate diagnosis and management of Panayiotopoulos syndrome.

CLINICAL FEATURES: Autonomic epileptic seizures and autonomic status epilepticus are the cardinal manifestations of Panayiotopoulos syndrome. Autonomic seizures in Panayiotopoulos syndrome consist of episodes of disturbed autonomic function with emesis as the predominant symptom. Other autonomic manifestations include pallor (or, less often, flushing or cyanosis), mydriasis (or, less often, miosis), cardiorespiratory and thermoregulatory alterations, incontinence of urine and/or feces, hypersalivation, and modifications of intestinal motility. In approximately one fifth of the seizures the child becomes unresponsive and flaccid (ictal syncope) before or often without convulsions. Cardiorespiratory arrest is exceptional. More-conventional seizure symptoms often appear after the onset of autonomic manifestations. The child, who was initially fully conscious, becomes confused and unresponsive. Eyes turn to one side or gaze widely open. Only half of the seizures end with brief hemiconvulsions or generalized convulsions. Convulsive status epilepticus is extremely rare. Autonomic symptoms may be the only features of the seizures. Half of the seizures in Panayiotopoulos syndrome last for >30 minutes, thus constituting autonomic status epilepticus, which is the more common nonconvulsive status epilepticus in normal children. Two thirds of seizures occur during sleep.

EPIDEMIOLOGY: Panayiotopoulos syndrome probably affects 13% of children aged 3 to 6 years who have had 1 or more afebrile seizures and 6% of such children in the 1- to 15-year age group.

DIAGNOSTIC TESTS: An electroencephalogram is the only investigation with abnormal results, usually showing multiple spikes in various brain locations.

PATHOPHYSIOLOGY: Panayiotopoulos syndrome is probably the early-onset and Rolandic epilepsy the late-onset phenotype of a maturation-related benign childhood seizure-susceptibility syndrome. Ictal epileptic discharges in Panayiotopoulos syndrome, irrespective of their location at onset, activate autonomic disturbances and emesis, to which children are particularly vulnerable. The symptoms/sequence of autonomic seizures and autonomic status epilepticus in Panayiotopoulos syndrome are specific to childhood, and they do not occur in adults.

PROGNOSIS: Panayiotopoulos syndrome is remarkably benign in terms of seizure frequency and evolution. Autonomic status epilepticus imparts no residual neurologic deficit. The risk of epilepsy in adult life seems to be no higher than in the general population. However, autonomic seizures are potentially life-threatening in the rare context of cardiorespiratory arrest, an area in which additional study is required. MISDIAGNOSIS: The clinical features of Panayiotopoulos syndrome are frequently mistaken as nonepileptic conditions such as acute encephalitis, syncope, migraine, cyclic vomiting syndrome, motion sickness, sleep disorder, or gastroenteritis. The consequence is avoidable misdiagnosis, high morbidity, and costly mismanagement.

MANAGEMENT: Education about Panayiotopoulos syndrome is the cornerstone of management. Prophylactic treatment with antiepileptic medication may not be needed for most patients. Autonomic status epilepticus in the acute stage needs thorough evaluation; aggressive treatment may cause iatrogenic complications including cardiorespiratory arrest.