One of the first definitions of epileptic status was given in 1904 by Clark and Pront: “ES is a condition in which seizures recur with such frequency that coma and exhaustion are constant between them.”
In 1984, the International Antiepileptic League gave the following definition of epileptic status: “Epileptic status is determined by a seizure lasting more than 30 minutes, or repeated seizures, between which the patient does not return to consciousness.”
However, this definition did not satisfy the clinicians: first, there is not always an invariant point of reference for time (the patient was delivered from the street or the status originated from serial seizures); secondly, the time of 30 minutes is chosen arbitrarily and not justified by convincing arguments.
At present, it is considered that status epilepticus is a fixed
epileptic condition. ES compared with a single attack or even a series of seizures is another qualitative condition of the patient, in which each successive attack occurs before the patient leaves the previous attack. There appear to be as many forms of epileptic status as there are types of epileptic seizures. In practice, however, convulsive epileptic status, status of absences, status of complex partial seizures are distinguished. Only the status of convulsive seizures, especially generalized tonic-clonic ones, is life-threatening.
It is necessary to distinguish symptomatic ES arising from acute brain lesions (TBI, ONMK), and ES itself in patients with epilepsy. In the latter case, it is an extreme manifestation of exacerbation of epilepsy. ES is a self-sustaining condition in which, as a result of frequently repeated seizures, disorders of all the life support systems of the body occur. Respiratory disorders are associated with the rhythm of convulsions: apnea during seizures is compensatory hyperpnea after them. Accordingly, fluctuations occur in the gas composition of the blood — hypoxemia and hypercapnia — hypocapnia. Both hypoxia and hypocapnia increase the convulsive readiness of the brain. There is a vicious circle. Later, due to unconsciousness of the patient, loss of the pharyngeal reflex in combination with hypersalivation and regurgitation, an obstructive type respiratory disorder develops. Each convulsive seizure is accompanied by high tachycardia, increased blood pressure; pulse deficit occurs. In the future, there may be a depletion of hemodynamic reserves and collapse develop.
Due to excessive muscular load, rhabdomyolysis, myoglobinuria, and tamponade of the renal tubules appear. Metabolic acidosis develops, which, when protracted ES can threaten the life of the patient.
High leukocytosis in the blood with neutrophilia and a shift of the white blood formula to the left is a common consequence of ES, which makes it difficult to recognize somatic complications. In children, ES quickly leads to exsicosis, hypovolemia, hypernatriemic hydration followed by a cascade of adverse reactions, including swelling of the brain.
The epileptic status of absences is manifested by the stunning of the patient, minimal motor phenomena — myoclonias, elementary automatisms. It is also called the “peak-wave stupor”, since drowsiness often occurs clinically, and on the EEG there are generalized synchronous peak-wave discharges. There are two variants of this type of status – typical absences with a rhythm of peak-wave discharges of 3 per second and atypical ones with a slower rhythm.
In rare cases, ES absences can occur in older people as a reaction to the withdrawal of benzodiazepines and some other psychotropic drugs, as well as one of the manifestations of withdrawal syndrome. Absanse peak-wave activity, indistinguishable from the status of small seizures, in combination with confusion of consciousness can occur during frontal epilepsy.
The status of complex partial seizures occurs mainly in the prefrontal and less frequently in temporal epilepsy. Characterized by confusion of consciousness of varying degrees – from mild to severe and behavioral disorders. Disturbances of consciousness – from almost imperceptible with moderate excitement to severe psychomotor manifestations or stupor. Perception disorders are frequent – illusions, hallucinations, as well as paranoid, autism, schizophren-like states are possible. With the predominance of the latter, diagnostic errors are frequent, especially since the scalp EEG may not have typical manifestations that are characterized by focal or widespread peaks and peak waves, interspersed with periods of desin-chronization.