A seizure is an episode of abnormal neurologic function caused by inappropriate electrical discharge of brain neurons. Primary seizures are those without a clear cause. Secondary seizures result from another identifiable neurologic condition, such as a mass or stroke (Table 145-1).
Table 145-1 Common Causes of Secondary Seizures |Favorite Table|Download (.pdf)
Table 145-1 Common Causes of Secondary Seizures
Trauma (recent or remote)
Intracranial hemorrhage (subdural, epidural, subarachnoid, intraparenchymal)
Structural CNS abnormalities
Vascular lesion (aneurysm, arteriovenous malformation)
Mass lesions (primary or metastatic neoplasms)
Degenerative neurologic diseases
Congenital brain abnormalities
Infection (meningitis, encephalitis, abscess)
Hypoglycemia or hyperglycemia
Hyponatremia or hypernatremia
Hypocalcemia, hypomagnesemia (rare)
Toxins and drugs (many)
Eclampsia of pregnancy (may occur up to 8 weeks postpartum)
Anoxic-ischemic injury (cardiac arrest, severe hypoxemia)
Seizures are classified as generalized and partial. Generalized seizures are caused by nearly simultaneous activation of the entire cerebral cortex. The attacks begin with abrupt loss of consciousness. Generalized tonic-clonic seizures (grand mal) are the most familiar example. The patient suddenly becomes rigid, trunk and extremities are extended, and the patient falls to the ground. The rigid (tonic) phase is followed by a symmetric, rhythmic (clonic) jerking of the trunk and extremities, commonly associated with incontinence. After the attack, the patient is flaccid and unconscious. A typical episode lasts from 60 to 90 seconds, with gradual return of consciousness. Postictal confusion may persist for hours. Absence (petit mal) seizures are a subclass of generalized seizures. Typically seen in school-aged children, they usually last only a few seconds. Patients suddenly lose consciousness without losing postural tone. They appear confused, detached or withdrawn, and current activity ceases. The attack ends abruptly.
Partial seizures are due to electrical discharges beginning in a localized region of the cerebral cortex, often a brain lesion. The discharges may remain local or spread to other regions. Partial seizures may be simple, in which consciousness is not affected, or complex, in which consciousness is altered. Complex partial seizures are often due to discharges in the temporal lobe (also termed temporal lobe seizures). Symptoms include automatisms, visceral complaints, hallucinations, memory disturbances, distorted perception, and affective disorders.
Status epilepticus is continuous or intermittent seizures for more than 5 min without recovery of consciousness. Nonconvulsive status epilepticus is associated with minimal or imperceptible convulsive activity and is confirmed by EEG.
Eclampsia refers to the combination of seizures, hypertension, edema, and proteinuria in pregnant women beyond 20 weeks gestation or up to 3 weeks postpartum.
Obtain a detailed history, addressing the presence of preceding aura, abrupt or gradual onset, progression of motor activity, incontinence, whether the activity was local or generalized and symmetric or not, duration, and the presence of postictal confusion or lethargy. If the patient has a ...