Differentials
Nonepileptic SE
SIGNS / SYMPTOMS
Defined as prolonged or repeated episodes of nonepileptic seizures.
May present as violent motor events mimicking generalized convulsive SE (more common) or subtle unresponsive events mimicking nonconvulsive SE (less common).
Key features that may help to distinguish from convulsive SE include long (>5 minutes) duration of individual seizures, fluctuating course (waxing and waning), asynchronous rhythmic movements, pelvic thrusting, side-to-side head/body movements during a convulsion, closed eyes, ictal crying, and later recall of items during the seizure.[32]
INVESTIGATIONS
The only method to differentiate epileptic from nonepileptic SE is video-electroencephalography (EEG). Video-EEG recording of a nonepileptic event will show no epileptiform activity.
Delirium
SIGNS / SYMPTOMS
This acute state of cognitive and perceptual decline can mimic nonconvulsive SE. In its broader definition, it may include all states of altered awareness or confusion that are commonly referred to as encephalopathy.
Encephalopathy may be secondary to metabolic, toxic, or infectious causes.
INVESTIGATIONS
Distinction between nonconvulsive SE and encephalopathy may be a challenging task, even for a well-trained epileptologist. Electroencephalogram (EEG) patterns are often confusing, especially in the case of metabolic encephalopathies such as hepatic or renal.
Laboratory findings such as high liver aminotransferases or ammonia in conjunction with clinical and EEG judgment may help in reaching the correct diagnosis.
Performing EEGs on patients with acute mental changes is strongly recommended.
Coma
SIGNS / SYMPTOMS
Defined as a state of absent cognitive and motor responsiveness.
Nonconvulsive SE can be mistakenly diagnosed as coma.[13] The distinction is crucial, because coma is usually irreversible, whereas nonconvulsive SE is often treatable.
INVESTIGATIONS
Electroencephalogram (EEG) may be very helpful in distinguishing coma from nonconvulsive SE. However, certain periodic EEG patterns can be difficult to differentiate from ictal patterns. Such EEG patterns are commonly seen in hepatic or postanoxic coma.
Performing EEGs on all patients with a presumed diagnosis of coma is highly recommended.
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