How do you correctly distinguish epileptic seizures from other types of events?
Certain features of the history will lead one to consider a diagnosis other than an epileptic seizure. Syncope is often positional, preceded by nonspecific symptoms including lightheadedness or chest pain, and seen in the context of illness, dehydration, or to a strong emotional stimulus causing a vagal response. Eye closure can be seen with syncope or with psychogenic, nonepileptic seizures (PNES, often termed pseudoseizures). Brief, bilateral convulsions may be seen with syncope as well (termed convulsive syncope), but this can be confusing because some seizures, namely myoclonic seizures, might look similar. A typical seizure lasts for 2 to 3 minutes, so seizure durations of longer than 5 minutes either indicate status epilepticus or a nonepileptic event. A patient returning to baseline quickly (within a few seconds) without a period of postictal confusion or lethargy after a prolonged, convulsive event is less likely to have had a true epileptic seizure. Responsiveness during an event of bilateral clonic activity is also less likely to be an epileptic seizure, as involvement of the bilateral motor regions is unlikely to be seen in isolation without diffuse bilateral cerebral dysfunction causing altered state of awareness.
On the other hand, patients may vocalize incoherently during partial-onset seizures, and odd, complex, and almost psychotic-appearing behavior is common with frontal lobe seizures. An ictal cry is a disturbing sound made during tonic contraction of the diaphragm usually during a generalized tonic-clonic seizure. Lateral tongue bites, urinary or bowel incontinence, and injuries such as fractures or dislocations are also strongly suggestive of epileptic seizures. Cataplexy seen in narcolepsy may be another seizure mimic, but cataplexy is a sudden loss of muscle tone often at the knees that is triggered by an emotional response and has preserved consciousness.
The patient’s friend reports that they were walking together to the concession stand when the patient suddenly stopped, was not answering questions, and instead stared straight ahead. For a second or two his mouth twitched, then he suddenly fell down, his body stiffened then shook “all over”; the friend thinks the patient’s eyes were open and “rolled back” and he was “foaming” at the mouth. He thinks the seizure lasted less than 5 minutes altogether. He thinks his friend wet himself and bit his tongue because blood was coming out of his mouth.
On exam, the patient is afebrile, blood pressure is 125/80 mm Hg, pulse rate is 90/min, respiration rate is 14/min, and oxygen saturation is 100% on room air, and he is currently arousable but disoriented to time and place. His general exam reveals abrasions on his scalp and elbows and a left lateral tongue laceration. His pupils are 4 mm and equally reactive to light, and on his motor exam his left arm and leg drift downward slightly when raised. His reflexes are 2+ and symmetric and there is no Babinski sign.
