Subacute sclerosing panencephalitis

December 31, 2014

Synonyms

Overview

Subacute sclerosing panencephalitis a rare condition that is caused by a measles infection acquired earlier in life. Signs and symptoms of the condition primarily affect the central nervous system and often develop approximately 7 to 10 years after a person recovers from the measles. Affected people may initially experience behavioral changes, dementia, and disturbances in motor function. In the late stages of the disease, affected people often progress to a comatose state, and then to a persistent vegetative state. Ultimately, many people with SSPE succumb to fever, heart failure, or the brain's inability to continue controlling the autonomic nervous system. It is unclear why some people develop SSPE after they have seemingly recovered from the measles while others do not. Researchers suspect that SSPE may be due to an abnormal immune response or a mutant form of the measles virus that causes a persistent infection within the central nervous system.

Symptoms

Subacute sclerosing panencephalitis generally develops approximately seven to ten years after a person recovers from the measles. Early signs and symptoms of the condition can include behavioral changes and mild mental deterioration (affecting memory, thinking, language, and judgment). As the condition progresses, affected people may experience disturbances in motor function, such as an unsteady gait (style of walking) and myoclonic jerks (uncontrollable involuntary jerking movements of the head, trunk, or limbs). Some affected people may also become blind and/or develop seizures. The muscles of the leg can be very tense or lack tone, and some affected people experiencing weakness and spasms in both legs. Because this can interfere with the ability to walk, people with SSPE may require devices to assist with mobility. In the late stages of the disease, affected people often progress to a comatose state, and then to a persistent vegetative state. Ultimately, many people with SSPE succumb to fever, heart failure, or the brain's inability to continue controlling the autonomic nervous system.

Symptoms:

Intellectual deterioration
Memory loss
Irritability
Involuntary movements
Seizures
Blindness
Brain inflammation
Behavioral changes
Myoclonic jerks
Progressive dementia
Neurological deterioration
Spasticity
Cortical blindness
Optic atrophy
Hyperthermia
Homeostasis disturbances
Death
Abnormal EEG
Increased measles antibodies in blood
Increased measles antibodies in cerebrospinal fluid
Increased gammaglobulin levels in cerebrospinal fluid

Causes

Subacute sclerosing panencephalitis is caused by a measles infection that is acquired earlier in life (often 7-10 years prior to the onset of SSPE symptoms). It is unclear why some people develop SSPE after they have seemingly recovered from the measles while others do not. Researchers suspect that SSPE may be due to an abnormal immune response or a mutant form of the measles virus that causes a persistent infection within the central nervous system (brain and spinal cord).

Although the underlying cause of SSPE is poorly understood, several risk factors appear to be associated with the condition. SSPE affects males more often than females and is generally diagnosed in children and adolescents. The risk of developing SSPE may be higher for a person who gets measles before they are two years of age.

Diagnosis

A diagnosis of subacute sclerosing panencephalitis is often suspected based on the presence of characteristic signs and symptoms in a person with a history of the measles. Additional testing can then be offered to confirm the diagnosis. This may include:

Electroencephalogram (EEG)
Imaging studies, such as MRI or CT scan
Serum antibody titer to look for signs of previous measles infection
Spinal tap

Prognosis

The long-term outlook (prognosis) for people with subacute sclerosing panencephalitis is poor. The condition is always fatal. Although most affected people die within one to three years, the average lifespan following diagnosis can vary. Studies show that a small group of people with SSPE will have a rapidly progressive form of the condition, leading to death within three months of diagnosis. Although rare, another small group will have a chronic, slowly progressive form that is associated with a relapsing and remitting course.

Treatment

Unfortunately, there is currently no cure for subacute sclerosing panencephalitis (SSPE). Treatment is supportive and primarily based on the signs and symptoms present in each person. For example, anticonvulsant and antispasmodic drugs may be given, as needed, to address some of the motor disturbances associated with the condition.

Recent studies have shown that certain medications (called antiviral and immunomodulatory drugs) may slow the progression of the condition when given alone or in combination. Although these drugs can prolong life, the best treatment regimen and their long-term effects in people with SSPE are currently unknown.