An adolescent is brought to the emergency depament following an episode of myoclonic jerks at morning after waking up. His consciousness was not impaired. His EEG shows generalized 3-4 Hz spike and slow wave complexes. Most probable diagnosis is?
High-Yield Explanation
Juvenile myoclonic epilepsy is a subtype of idiopathic generalized epilepsy with onset usually between 8 and 20 years of age. Myoclonic jerks, especially in the morning, are of variable intensity ranging from simple twitching ("flying saucer syndrome") to falls; consciousness is not impaired in it. It is precipitated by alcohol and sleep deprivation. Patients will have normal intelligence. The typical interictal EEG abnormality consists of a generalized 4- to 6-Hz spike or polyspike and slow-wave discharges lasting 1-20 seconds. Usually, 1-3 spikes precede each slow wave. Also know: In Generalized tonic clonic seizure EEG shows a normal background with generalized epileptiform discharges such as spike or polyspike wave complexes at 2.5 to 4 Hz. During absence seizures there is an abrupt onset of bilaterally synchronous and symmetrical 3 Hz spike-wave discharge, irrespective of whether typical absences are simple or complex. Ictal recordings from patients with typical temporal lobe epilepsy usually exhibit 5-7 Hz, rhythmic, sharp theta activity, maximal in the sphenoidal and the basal temporal electrodes on the side of seizure origin. Ref: A-Z of Neurological Practice: A Guide to Clinical Neurology By Andrew J. Larner, Alasdair J Coles, Neil J. Scolding, Roger A Barker, 2011, Page 368 ; Clinical Electroencephalography by Misra,2005, Page 188