CHAPTER 72 ■ SEIZURES AMIR A KIMIA, VINCENT W CHIANG Seizures are the clinical expression of abnormal, excessive, synchronous discharges of neurons residing primarily in the cerebral cortex This paroxysmal activity is intermittent and its duration may last from a few seconds to many hours Seizures represent a neurologic emergency either due to the underlying cause (e.g., bleed, infection) or the potential for neuronal death as a result of a prolonged seizure Approximately 5% of children will have at least one seizure in the first 16 years of life The immature brain, particularly in the neonate and young infant, differs from the adult brain in the basic mechanisms of epileptogenesis and propagation of seizures It is more prone to seizures, but seizures are also more apt to disappear as the child grows Physicians must have a fundamental knowledge of seizure classification (semiology), all aspects of seizure management (including initial stabilization), determination of cause (differential diagnosis), appropriate definitive treatment, and patient disposition BACKGROUND A seizure is defined as a transient, involuntary alteration of consciousness, behavior, motor activity, sensation, and/or autonomic function caused by an excessive rate and hypersynchrony of discharges from a group of cerebral neurons A convulsion is a seizure with prominent alterations of motor activity Epilepsy, or seizure disorder, is a condition of susceptibility to recurrent seizures Seizures may be generalized or partial Generalized seizures reflect involvement of both cerebral hemispheres These may be convulsive or nonconvulsive Consciousness may be impaired and this impairment may be the initial manifestation Motor involvement is bilateral Types of generalized seizures include absence (petit mal), myoclonic, tonic, clonic, atonic, and tonicclonic (grand mal) seizures Partial (focal, local) seizures reflect initial involvement limited to one cerebral hemisphere Partial seizures are further classified on the basis of whether consciousness is impaired When consciousness is not impaired, the seizure is classified as a simple partial seizure Simple partial seizures may have motor, somatosensory/sensory, autonomic, or psychic symptoms When consciousness is impaired, the seizure is classified as a complex partial seizure Both simple and complex partial seizures may evolve into generalized seizures (Jacksonian spread) The spread to deep subcortical regions and evolution to a bilateral tonic-