Epilepsia partialis continua of Kozhevnikov

C P Panayiotopoulos MD PhD (Dr. Panayiotopoulos of St. Thomas' Hospital has no relevant financial relationships to disclose.)
Jerome Engel Jr MD PhD, editor. (Dr. Engel of the David Geffen School of Medicine at the University of California, Los Angeles, has no relevant financial relationships to disclose.)
Originally released October 18, 1993; last updated March 17, 2017; expires March 17, 2020

This article includes discussion of epilepsia partialis continua of Kozhevnikov, epilepsia partialis continua Bancaud type I, focal motor epilepsia partialis continua, focal motor status epilepticus, Kozhevnikov syndrome type 1, and partial motor status epilepticus. The foregoing terms may include synonyms, similar disorders, variations in usage, and abbreviations.

Overview

Epilepsia partialis continua is a rare form of simple focal motor status epilepticus of mainly cerebral cortical origin. It manifests with repetitive, regular or irregular localized clonic muscle twitching, lasting for a few milliseconds and repeated at least every 10 seconds for hours, days, or months without impairment of consciousness. Onset occurs at any age but in a third of cases starts before 16 years of age. Both sexes are equally affected. Prevalence is extremely small, probably less than 1 per million population.

Causes are multiple and diverse. Rasmussen syndrome and malformations of cortical development are the main causes in children; cerebrovascular disease and brain space-occupying lesions are the main causes in adults. Nonketotic hyperglycemia is the most common reversible cause. The long-term prognosis is cause-dependent and usually poor. Most patients will continue with intractable epilepsia partialis continua and also develop neurologic and cognitive defects. Only a few patients may have a remission. Epilepsia partialis continua is drug resistant. When resective surgery is not possible, successful treatment with multiple subpial transections has been reported in a minority of operated patients. In this update, the author details the historical aspects, classification, clinical manifestations, pathophysiology, diagnostic workup, differential diagnosis, and management of epilepsia partialis continua, paying particular attention to recent advances.

Key points

 

• Epilepsia partialis continua is a rare type of simple focal motor status epilepticus characterized by continuous, involuntary focal muscle jerking of mainly cortical origin occurring at least every 10 seconds for at least 1 hour and not impairing awareness.

 

• Epilepsia partialis continua is a rare condition with a wide range of underlying etiologies; in children, the most common cause is Rasmussen syndrome, and in adults, the most common causes are cerebrovascular disease and neoplasm.

 

• Epilepsia partialis continua is typically resistant to medications, and whenever possible, treatment should focus on the underlying cause.

 

• The outcome of epilepsia partialis continua is variable and is highly dependent on underlying cause: seizures are more likely to remit in patients with stroke or other acute insults than in patients with chronic encephalitis.

Historical note and terminology

Aleksei Yakovlevich Kozhevnikov in 1894 gave a superb description of epilepsia partialis continua (“corticalis sive partialis continua” as he called it), detailed the clinical manifestations of 4 patients, localized the cause around the motor center, and accurately attributed the disease to chronic encephalitis (Kozhevnikov 1894; Kozhevnikov 1895).

Image: Alexey Yakovlevich Kozhevnikov (1836-1902)
See English translation by Asher and Gadjusek and other details in more recent publications (Asher and Gadjusek 1991; Vein and Maat-Schieman 2008; Mameniskiene et al 2011; Vein and van Emde Boas 2011; Gitlevich et al 2016).

 

Kozhevnikov described the seizure as follows:

 

In recent years I happened to observe several cases of cortical epilepsy that differed to a significant degree from the usual topical form of this disease. In these patients there were, together with epileptic seizures, an additional series of constant neurologic phenomena that were even worse for the patient than the seizures themselves....The 4 patients that we described...had seizures characteristic of cortical epilepsy, but they had no free intervals between seizures. They had constant clonic convulsions in strictly defined parts of the body. These convulsions sometimes became more severe and sometimes less, but when they increased to a significant degree, they could easily and sometimes did develop into complete epileptic seizures. The epileptic seizure thus represented only the most extreme degree of development of these constant convulsions. In other words, the constant convulsions here represented the onset or mild degree of an epileptic seizure. Consequently, it can be said that in our patients the convulsive epileptic seizure did not stop and was constant to a greater or lesser degree. In this, the illness of our patients differed markedly from ordinary cortical epilepsy. To differentiate this form from ordinary cortical epilepsy, it may be called epilepsia corticalis sive partialis continua, in that here the convulsive manifestations were continuous. In all these cases, the illness was exceptionally recalcitrant. In the first case it was present for 5.5 years. In the second it had already lasted 4.5 years, in the third, 5 years, and in the fourth, 3.5 years, not responding to the usual means of therapy.

 

In regards to localization:

 

Without doubt, the damage was in the hemisphere opposite the site of the continuous convulsions, and it was near the cortical motor centers. Nevertheless, the disease process could hardly have destroyed these centers completely. If that had been the case, in all likelihood we would have observed more markedly expressed paralyses...Thus, it seems most probable to me that the site of the disease process must be sought in the corresponding portion of the frontal lobe.

 

And regarding the etiology:

 

The question of the nature of the disease process is much more difficult. In none of these cases could we find a specific etiologic event eliciting the illness by physical examination either of the skull or internal organs.... Evidently, in none of these cases was there any kind of acute disease process, such as acute inflammation, hemorrhage, obstruction of vessels. On the contrary, in all cases the illness developed little by little and once it had developed persisted for a very long time, so that we can postulate only chronic processes here. Thus, of the chronic processes, encephalitis with transition to secondary hardening of the brain, or sclerosis cerebri, is almost the only possibility... Thus, not knowing precisely what we are dealing with, and proposing the presence of chronic encephalitis.

Encephalitis as a definite cause of epilepsia partialis continua was also established in the Western literature by Wilson and Winkelman in 1924 who described 3 cases with neuropathologic confirmation (Wilson and Winkelman 1924).

Omorokov reviewed 42 cases of “Kozhevnikov syndrome” (as he called it) in the literature and described a further 52 cases from his own Siberian clinic (Omorokov 1927). Many of his cases with epilepsia partialis continua in Siberia (Kozhevnikov was practicing in Moscow) had acute encephalitis, and a few had cysticercosis. It was much later in 1937 that patients with acute encephalitis and epilepsia partialis continua proved to have Russian spring-summer tick-borne encephalitis (Omorokov 1927; Omorokov 1951; Vein and van Emde Boas 2011; Mukhin et al 2012).

Dereux described over 100 cases of Kozhevnikov syndrome, with many having chronic encephalitis (Dereux 1955).

Subsequently, it was Theodore Rasmussen who documented epilepsia partialis continua as a cause of chronic encephalitis in children (Rasmussen et al 1958; Rasmussen and McCann 1968). See details in the article on Rasmussen syndrome.

In 1966, Juul-Jensen and Denny-Brown published a case series and review of the literature, observing that epilepsia partialis continua could be caused by a number of different pathologic lesions in both cortical and subcortical structures (Juul-Jensen and Denny-Brown 1966). They proposed a definition of the clinical syndrome as “clonic muscle twitching repeated at fairly short intervals in 1 part of the body for a period of days or weeks.” They suggested that this syndrome differed from most focal epilepsies because in epilepsia partialis continua, there is no progression from the tonic to clonic phase and no Jacksonian march from 1 body area to another.

In 1974, Thomas and colleagues refined the definition of epilepsia partialis continua, based on the review of the clinical characteristics of 32 patients, as a syndrome “characterized by regular or irregular clonic muscular twitches affecting a limited part of the body, occurring for a minimum of 1 hour, and recurring at intervals of no more than 10 seconds” (Thomas et al 1977).

In 1985, Obeso and colleagues added 3 additional features to this definition: (1) the muscle jerks should occur spontaneously, (2) action and somesthetic stimuli could provoke jerks in some patients, and, perhaps most significantly, (3) the movements should be of cortical origin (Obeso et al 1985).

In 1996, Cockerell and colleagues reported 16 patients who underwent detailed clinical and neurophysiological assessments: only 6 had direct EEG and EMG evidence of a cortical origin of their jerks; 5 patients had indirect evidence of a cortical origin; 2 did not have myoclonus of cortical origin but of some other source (brainstem and basal ganglia); and the origin in the remaining 3 patients was uncertain. The authors simplified the definition of epilepsia partialis continua to “continuous muscle jerks of cortical origin” and suggested the term “myoclonia continua” for situations in which the cause is extracortical (Cockerell et al 1996).

In 2011, a European survey and analysis of 65 cases of the clinical course and variability of non-Rasmussen, nonstroke, motor and sensory epilepsia partialis continua was published (Mameniskiene et al 2011).

Other authors have noted that epilepsia partialis continua can be defined in 2 ways: based on the clinical features alone, or by combining clinical with neurophysiologic evidence in order to confirm the cortical origin of the abnormal movements (Bien and Elger 2008). The previous authors of this article proposed maintaining many of the aspects of the above definitions, defining epilepsia partialis continua, as with other epileptic syndromes, on the basis of combined clinical, neurophysiologic, and diagnostic imaging features. Epilepsia partialis continua is a continuous, involuntary focal muscle jerking of cortical origin occurring at least every 10 seconds for at least 1 hour and not impairing awareness.

ILAE classification, nomenclature, and definition. The ILAE Commission on Classification in 1985 recognized “two types of Kozhevnikov's syndrome, but only 1 of these 2 types is included among the epileptic syndromes of childhood, because the other one is not specifically related to this age” (Commission 1985).

“Kozhevnikov syndrome type 1” referred to epilepsia partialis continua and was defined as follows:

 

This type represents a particular form of rolandic partial epilepsy in both adults and children and is related to a variable lesion of the motor cortex. Its principal features are: (a) motor partial seizures, always well localised; (b) often late appearance of myoclonus in the same site where somatomotor seizures occur; (c) an EEG with normal background activity and a focal paroxysmal abnormality (spikes and slow waves); (d) occurrence at any age in childhood and adulthood; (e) frequently demonstrable aetiology (tumor, vascular); and (f) no progressive evolution of the syndrome (clinical, electroencephalographic or psychological, except in relation to the evolution of the causal lesion). This condition may result from mitochondrial encephalopathy (MELAS).

“Kozhevnikov type 2 syndrome” was defined as:

 

Childhood disorder, suspected to be of viral etiology, has onset between 2 and 10 years (peak, 6 years) with seizures that are motor partial seizures but are often associated with other types. Fragmentary motor seizures appear early in the course of the illness and are initially localized but later become erratic and diffuse and persist during sleep. A progressive motor deficit follows, and mental deterioration occurs. The EEG background activity shows asymmetric and slow diffuse delta waves, with numerous ictal and interictal discharges that are not strictly limited to the Rolandic area.

In the 1989 ILAE classification, Rasmussen syndrome was introduced as a synonym of Kozhevnikov type 2 syndrome (Commission on Classification and Terminology of the International League against Epilepsy 1989). In ILAE revisions on classification and terminology (Engel 2001; Engel 2006), the name Kozhevnikov was removed (Panayiotopoulos 2010). The revision of seizure terminology by the ILAE Commission on Classification and Terminology lists Rasmussen syndrome under the category “distinctive constellations” (Berg et al 2010), a name that is now abandoned (Commission on Classification and Terminology of the International League Against Epilepsy 2014). See the article on Rasmussen syndrome for more information.

Epilepsia partialis continua of Kozhevnikov is a seizure type (Engel 2001; Engel 2006), though this it is not mentioned in the ILAE positional papers of the operational classification of seizure types (Fisher et al 2017a; Fisher et al 2017b).

According to the ILAE epilepsy diagnosis manual, “Epilepsia partialis continua refers to recurrent focal motor seizures (typically affecting hand and face, although other body parts may be affected that occur every few seconds or minutes for extended periods (days or years). The focal motor features may exhibit a Jacksonian march. A Todd's paresis may be seen in the affected body part” (Commission on Classification and Terminology of the International League Against Epilepsy 2014).

In the most recent ILAE report on the definition and classification of status epilepticus, epilepsia partialis continua is listed amongst those with prominent focal motor symptoms (Trinka et al 2015).

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