Chap. 35). In presumptive clinical cases of SSPE, the findings of periodic complexes in the EEG, elevated gamma globulin and oligoclonal bands in the CSF, and elevated measles antibody titers in the serum and CSF are sufficient to make the diagnosis.
No effective treatment is available. The administration of amantadine and inosine pranobex (formerly inosiplex) was found by some investigators to lead to improvement and prolonged survival, but these effects have not been corroborated.
Whereas SSPE occurs in children who were previously normal, another rare type of measles encephalitis has been described that affects both children and adults with defective cell-mediated immune responses (Wolinsky et al). In this type, measles or exposure to measles precedes the encephalitis by 1 to 6 months. Seizures (often epilepsia partialis continua), focal neurologic signs, stupor, and coma are the main features of the neurologic illness and lead to death within a few days to a few weeks. The CSF may be normal, and levels of measles antibodies do not increase. Aicardi and colleagues have isolated measles virus from the brain of such a patient. The lesions are similar to those of SSPE (eosinophilic inclusions in neurons and glia, with varying degrees of necrosis) except that inflammatory changes are lacking. In a sense, this subacute measles encephalitis is an opportunistic infection of the brain in an immunodeficient patient. The relatively short interval between exposure and onset of neurologic disease, the rapid course, and lack of antibodies distinguish this form of subacute measles encephalitis from both SSPE and postmeasles (postinfectious) encephalomyelitis (see Chap. 35).
The deficits associated with congenital rubella infection of the brain are nonprogressive at least after the second or third year of life. There are, however, descriptions of children with the congenital rubella syndrome in whom a progressive neurologic deterioration occurred after a stable period of 8 to 19 years (Townsend et al; Weil et al). In 1978, Wolinsky described 10 instances, a few of them apparently related to acquired rather than to congenital rubella. Since then, this late-appearing progressive syndrome seems to have disappeared, no definite new cases having been reported in the past 30 years but it nonetheless remains of biological interest.
The clinical syndrome was quite uniform. On a background of the features of congenital rubella, a decade later there occurred a deterioration in behavior and school performance, often associated with seizures, and, soon thereafter, a progressive impairment of mental function (dementia). Clumsiness of gait was an early symptom, followed by a frank ataxia of gait and then of the limbs. Spasticity and other corticospinal tract signs, dysarthria, and dysphagia ensue.
Encephalitis Lethargica (von Economo Disease, Sleeping Sickness)
Although examples of a somnolent-ophthalmoplegic encephalitis dot the early medical literature (e.g., nona, fébre lethargica, Schlafkrankheit), it was in the wake of the influenza pandemic of World War I that this disease appeared prominently and continued to reappear for about 10 years. The viral agent was never identified, but the clinical and pathologic features were typical of viral infection. Nevertheless, recent testing of archived brain material has failed to reveal influenzal RNA, so that encephalitis lethargica may be considered a putative viral disease. An alternative view of an immune pathogenesis is presented below.