Status epilepticus (SE) is the term given to prolonged seizure activity that is of sufficient duration to produce a “fixed and lasting epileptic condition” or neuronal injury and has a substantially increased risk of death.1 SE has been formally defined as seizures lasting longer than 30 minutes. The most common and easily understood form is generalized convulsive status epilepticus (GCSE), which is characterized by continuous or recurrent convulsive motor seizures of more than 30 minutes' duration (see Chapter 24). All other forms are grouped under the rubric of nonconvulsive status epilepticus (NCSE). NCSE is fundamentally divided into complex partial status epilepticus (CPSE) and absence status epilepticus (a form of generalized status epilepticus; see Chapter 26). This chapter focuses on CPSE, but it includes some discussion of absence SE because of inevitable overlap.
CPSE describes a variety of clinical entities in which impairment due to focal seizure activity persists for at least 30 minutes. The clinical presentations and natural history of CPSE are diverse. The diagnosis usually is straightforward when epileptic behavior and electroencephalographic (EEG) activity are evident. For example, in its pure form, there is the obvious recurrence of complex partial clinical and electrographic seizures (Figure 25-1). However, evidence of CPSE may be difficult to observe because it can occur in subtle forms within a spectrum of manifestations.
Recurrent, uncomplicated complex partial status epilepticus (CPSE) with return of awareness but persistent confusion between electrographic seizures. Nearly continuous epochs of electroencephalograms (EEG) are illustrated in each part. (A) The seizure cycle starts with moaning. (B) The patient stares and does not follow commands in the middle. (C) After the seizure ends, the patient spontaneously looks at the nurse and follows commands. Approximately 1 minute intervened between seizures. (D) MRI from patient with EEG illustrated in Figure 25-1 A-C. Coronal magnetic resonance imaging (MRI) illustrating left hippocampal sclerosis with increased T2 signal.
The diagnosis is usually contingent on the presence of focal seizure activity on EEG. EEG at the onset of CPSE shows focal discharges and seizures with complex partial symptomatology. It is the usual pattern of prolonged SE that discharges eventually appear generalized on the EEG even if they were focal at the onset. The EEG discharges of CPSE often generalize by the time an EEG is obtained. Thus, scalp EEG may show generalized or bilateral discharges, often with lateralized features, even when seizures are primarily occurring or originating in one region of the brain. If only the EEG is considered, then some patients with SE of focal origin will be considered to have generalized NCSE. To resolve this, the remainder of the clinical picture must be considered. Thus, presentation of CPSE varies by degree of symptoms, EEG focality, and presence of focal brain disease or epilepsy.