Focal Seizures and Progressive Weakness

Posted by • October 31st, 2014

In the latest Case Record of the Massachusetts General Hospital, a 7-year-old boy was evaluated because of focal seizures, twitching of the right arm and the right side of the face, and progressive weakness. Imaging revealed progressive left cortical atrophy and a focal lesion in the left parietal cortex. A diagnostic procedure was performed.

Rasmussen’s encephalitis, which was first described in 1958 by Dr. Theodore Rasmussen, is a progressive neurologic disease of unknown cause.

Clinical Pearls

What are the manifestations of epilepsia partialis continua?

Epilepsia partialis continua is defined as almost continuous regular or irregular muscular clonic twitching affecting a limited part of the body. Consciousness is typically preserved, and the twitching most commonly involves the face, arms, or both. According to the definition of epilepsia partialis continua, the twitching must last at least 1 hour (but may last hours or years) and the twitches must occur at least once every 10 seconds, typically in isolation or in clusters of 1 to 2 Hz.

What is the differential diagnosis of epilepsia partialis continua?

The differential diagnosis for epilepsia partialis continua is divided into nonprogressive and progressive causes. Nonprogressive causes include vascular causes, metabolic causes, neoplasm, infectious or immunologic causes, cortical dysplasia, mitochondrial causes, perinatal central nervous system injury, and cryptogenic causes. A progressive cause is Rasmussen’s encephalitis. Much of the literature on epilepsia partialis continua focuses on adults, but a recent study involving 51 children with epilepsia partialis continua showed that Rasmussen’s encephalitis was the most common cause, with other common causes including immune or inflammatory processes (e.g., acute and subacute encephalitis and subacute sclerosing panencephalitis), metabolic disorders (e.g., mitochondrial disease and neuronal ceroid lipofuscinosis), cortical malformations, and vascular causes.

Table 1. Differential Diagnosis of Epilepsia Partialis Continua.

Morning Report Questions

Q: What is Rasmussen’s encephalitis?

A: Rasmussen’s encephalitis is a progressive neurologic disease of unknown cause. Patients typically present in childhood with focal-onset seizures, which then progress over a period of months to refractory epilepsy with progressive hemiparesis. Epilepsia partialis continua develops in approximately 50 to 90% of persons with Rasmussen’s encephalitis, and fixed hemiparesis typically occurs within 2 to 3 years after the onset of seizures. Seizures are typically refractory to medication, but glucocorticoids and intravenous immune globulin can be effective in controlling seizures. Various other immunosuppressive medications have been tried, but the most effective therapy remains hemispherectomy. Hemispheric procedures are associated with a high rate of success in stopping seizures and also halting progression of the disease.

Table 2. Diagnostic Criteria for Rasmussen’s Encephalitis.

Q: What techniques are available for disconnection of the affected hemispheres in Rasmussen’s encephalitis, and what are the functional outcomes?

A: Over time, a number of techniques have been developed, ranging from complete anatomical hemispherectomy to newer, less extensive procedures that disconnect the affected hemisphere from the opposite hemisphere and from the remainder of the nervous system. With seizure activity but the discharges cannot propagate and do not produce symptoms. The less extensive procedures are associated with less blood loss and fewer long-term complications but with a slightly lower likelihood of seizure control. Hemispherectomy and hemispheric disconnection can each result in varying degrees of contralateral weakness, language and other cognitive dysfunction, and hemianopsia, depending on the degree to which such functions already have been or can be subserved by the contralateral hemisphere. After a patient has undergone anatomical hemispherectomy or hemispheric disconnection, the long-term outcome typically includes spastic hemiplegia with return of ambulation (patients can walk but have a spastic-type limp), development of a “helper” arm without fine motor manipulative abilities (patients can use the arm to help lift objects but cannot perform fine motor functions with the hand), permanent hemianopsia, and various degrees of language and cognitive function (depending on preoperative status and age at surgery).

One Response to “Focal Seizures and Progressive Weakness”

  1. andishae haasan says:

    Very informative thank you