How can clinicians distinguish among seizures, syncopal events, and other causes of spells?
What historical features are helpful? What diagnostic tests are appropriate?
Which patients with new-onset seizures require an antiepileptic drug?
How should patients with status epilepticus be managed?
A seizure is defined as a sudden attack of involuntary behavior or experiences resulting from abnormal cortical neuronal activity. About 5% of the population of the United States will experience one at some point during their lifetime. Epilepsy, the chronic disease defined by the occurrence of two or more unprovoked seizures, is seen in approximately 2 million to 4 million people in the United States alone. The World Health Organization (WHO) reports that in primary care settings worldwide, epilepsy is the second most common neurologic condition, after headache.
Epilepsy and seizures are also common in the inpatient setting. In a large multicenter study in both community and academic hospital emergency departments, 1.2% of 31,508 patient visits were related to seizures. Overall, 27% of these patients were admitted. Of those patients suspected of having new-onset seizures, 63% were admitted. Reasons for admission for patients with seizures include diagnostic evaluation (especially when the diagnosis of seizure is unclear), uncontrolled seizures, toxicity from antiepileptic drugs (AEDs), and injuries sustained during a seizure.
Seizures are classified into two broad categories: primary generalized and partial (Table 212-1). Generalized seizures by definition are characterized by loss of consciousness. Absence seizures are typically brief staring spells, lasting seconds. These usually begin in early childhood and remit in adolescence in childhood, but they may persist into adulthood. Patients with myoclonic epilepsy have quick jerking movements, most often in the morning after awakening. They are often not diagnosed until a generalized tonic-clonic seizure occurs. Generalized tonic-clonic seizures, also known as convulsions, are recognized by tonic extension of the extremities, followed by clonic jerking (Figure 212-1). Variations of these include generalized seizures with either a primarily tonic or clonic component. Atonic seizures are characterized by sudden loss of tone. These patients are especially prone to injuries as a result of falling without warning.
++ Table Graphic Jump Location Table 212-1 Seizure Types in Adults ||Download (.pdf)
Table 212-1 Seizure Types in Adults
|Tonic||Partial with secondary generalization|
|Other idiopathic generalized|
Figure 212-1Graphic Jump Location
Generalized tonic-clonic seizure. In the tonic phase (top), lasting 10 to 30 seconds, the patient has tonic muscle contractions leading to flexion, then extension, of the neck and trunk. The vocal muscles contract, and the patient may cry out and become cyanosed. Jaw contraction may lead to tongue injury. This is followed by the clonic phase (bottom), with symmetric muscle contraction and relaxation that produces limb jerking. The clonic phase diminishes in intensity and usually ends after approximately one minute. (Reproduced, with ...