Subacute sclerosing panencephalitis

Subacute sclerosing panencephalitis (SSPE) is a rare chronic, progressive encephalitis

Encephalitis

Encephalitis is an acute inflammation of the brain.Encephalitis with meningitis is known as meningoencephalitis.-Bacterial and other:It can be caused by a bacterial infection such as bacterial meningitis spreading directly to the brain , or may be a complication of a current infectious disease...

 that affects primarily children and young adults, caused by a persistent infection of immune resistant measles virus (which can be a result of a mutation of the virus itself). 1 in 100,000 people infected with measles develop SSPE. SSPE is 'incurable' but the condition can be managed by medication if treatment is started at an early stage.

Subacute sclerosing panencephalitis (SSPE) is a rare chronic, progressive encephalitis

Encephalitis

Encephalitis is an acute inflammation of the brain.Encephalitis with meningitis is known as meningoencephalitis.-Bacterial and other:It can be caused by a bacterial infection such as bacterial meningitis spreading directly to the brain , or may be a complication of a current infectious disease...

 that affects primarily children and young adults, caused by a persistent infection of immune resistant measles virus (which can be a result of a mutation of the virus itself). 1 in 100,000 people infected with measles develop SSPE. SSPE is 'incurable' but the condition can be managed by medication if treatment is started at an early stage. Much of the work on SSPE has been completed by the National Institute of Neurological Disorders and Stroke (NINDS).

SSPE is also known as Dawson Disease, Dawson encephalitis and measles encephalitis.

Symptoms

Characterized by a history of primary measles

Measles

Measles is an infection of the respiratory system caused by a virus, specifically a paramyxovirus of the genus Morbillivirus. Morbilliviruses, like other paramyxoviruses, are enveloped, single-stranded, negative-sense RNA viruses...

 infection usually before the age of 2 years, followed by several asymptomatic years (6–15 on average), and then gradual, progressive psychoneurological deterioration, consisting of personality change, seizures, myoclonus

Myoclonus

Myoclonus is brief, involuntary twitching of a muscle or a group of muscles. It describes a medical sign and, generally, is not a diagnosis of a disease. The myoclonic twitches are usually caused by sudden muscle contractions; they also can result from brief lapses of contraction. Contractions...

, ataxia

Ataxia

Ataxia is a neurological sign and symptom consisting of gross lack of coordination of muscle movements. Ataxia is a non-specific clinical manifestation implying dysfunction of parts of the nervous system that coordinate movement, such as the cerebellum...

, photosensitivity

Photosensitivity

Photosensitivity is the amount to which an object reacts upon receiving photons, especially visible light.-Interpretation in medicine:Sensitivity of the skin to a light source can take various forms. People with particular skin types are more sensitive to sunburn...

, ocular abnormalities, spasticity, and coma

Coma

In medicine, a coma is a profound state of unconsciousness. A comatose person cannot be awakened, fails to respond normally to pain or light, does not have sleep-wake cycles, and does not take voluntary actions....

.

Progression

The progression of symptoms begins with stage 1 — in this stage the behaviour of person become more abnormal and erratic, the person can be irritable and personality alterations can occur. This is often accompanied by memory loss and mental deterioration characterised by intellectual difficulty. As the nervous system begins to lose control of movement, the person develops myoclonic spasms/jerks (these being involuntary motions and spasms in extremities).
As the disease progresses towards stage 2, the intensity of the spasms and the mental deterioration increases. The spasms can grow to such an extent that loss of the ability to walk can be a common sign. Also, the person will suffer speech impairment and increasingly deteriorated comprehension coupled with dysphagia

Dysphagia

Dysphagia is the medical term for the symptom of difficulty in swallowing. Although classified under "symptoms and signs" in ICD-10, the term is sometimes used as a condition in its own right. Sufferers are sometimes unaware of their dysphagia....

. At this point the infection is at stage 2.
The final, advanced stages of SSPE include the steady decline in body function with increased intensity of the stage 2 symptoms/signs and also blindness. At the end of the final stages the person is likely to be mute and/or comatose.

Diagnosis

Characteristic periodic activity (Rademecker complex) is seen on EEG

EEG

EEG commonly refers to electroencephalography, a measurement of the electrical activity of the brain.EEG may also refer to:* Emperor Entertainment Group, a Hong Kong-based entertainment company...

 showing widespread cortical dysfunction; pathologically, the white matter

White matter

White matter is one of the two components of the central nervous system and consists mostly of myelinated axons. White matter tissue of the freshly cut brain appears pinkish white to the naked eye because myelin is composed largely of lipid tissue veined with capillaries. Its white color is due to...

 of both the hemispheres and brainstem are affected, as well as the cerebral cortex

Cerebral cortex

The cerebral cortex is a structure within the brain that plays a key role in memory, attention, perceptual awareness, thought, language, and consciousness. It constitutes the outermost layer of the cerebrum. In preserved brains, it has a grey color, hence the name "grey matter"...

, and eosinophilic

Eosinophilic

Eosinophilic means loves eosin, and refers to the staining of certain tissues, cells, or organelles after they have been washed with eosin, a dye.Eosin is an acidic dye; thus, the structure being stained is basic....

 inclusion bodies

Inclusion bodies

Inclusion bodies are nuclear or cytoplasmic aggregates of stainable substances, usually proteins. They typically represent sites of viral multiplication in a bacterium or a eukaryotic cell and usually consist of viral capsid proteins...

 are present in the cytoplasm

Cytoplasm

The cytoplasm is the part of a cell that is enclosed within the cell membrane. In eukaryotic cells, the cytoplasm contains organelles, such as mitochondria, which are filled with liquid that is kept separate from the rest of the cytoplasm by biological membranes. The contents of the cell nucleus...

 nuclei of neuron

Neuron

A neuron is an excitable cell in the nervous system that processes and transmits information by electrochemical signaling. Neurons are the core components of the brain, the vertebrate spinal cord, the invertebrate ventral nerve cord, and the peripheral nerves...

s and glial cell

Glial cell

Glial cells, commonly called neuroglia or simply glia , are non-neuronal cells that provide support and nutrition, maintain homeostasis, form myelin, and participate in signal transmission in the nervous system...

s.
Diagnosis of SSPE is often difficult due to a normal CSF

CSF

-Biology:* Cerebrospinal fluid* Colony-Stimulating Factor* Cancer slope factor* Classical swine fever-Military:* Central Security Forces , an Egyptian paramilitary force* Combined Service Forces aka Combined Logistics Command-Education:...

 profile — noted changes in the CSF profile only include a marked elevation in CSF immunoglobulin. Rubeola Ig G Antibody Titres will be high.

Prognosis

Death usually occurs within 3 years. If the diagnosis is made during stage 1 of the SSPE infection then it is possible to treat the disease. However, once SSPE progresses to stage 2 then it is universally fatal in all occurrences. The standard rate of decline spans anywhere between 1–3 years after the onset of the infection. The progression of each stage is unique to the sufferer and cannot be predicted although the pattern or symptoms/signs can be. Although the prognosis is bleak for SSPE past stage 1, it should be noted that there is a 5% remission rate — this may be either a full remission or an improvement in condition giving a longer progression period or at least a longer period with the less severe symptoms. Regardless of the stage that the infection is at, treatment with inosine pranobex combined with interferon can give up to a 50% remission/improvement rate.

Treatment

Should the viral progression be diagnosed during stage 1 (even during late stage 1 when stage 2 symptoms start to manifest themselves) then treatment to combat the infection can be administered successfully — there is no cure for SSPE but if it is caught early enough then the sufferer can respond to the treatment and prevent symptom recurrence by taking the medication for the rest of their life. The treatment for the SSPE infection is the immunomodulator interferon

Interferon

Interferons are natural cell-signaling proteins produced by the cells of the immune system of most vertebrates in response to challenges such as viruses, parasites and tumor cells. They belong to the large class of glycoproteins known as cytokines and are produced by a wide variety of cells in...

 and specific antiviral medication — ribavirin and inosine pranobex are specifically used to greater effect than antivirals such as Amantadine.
For those who have progressed to stage 2 or beyond then the disease is incurable. For patients in the terminal phase of the disease there is a palliative care

Palliative care

Palliative care is any form of medical care or treatment that concentrates on reducing the severity of disease symptoms, rather than striving to halt, delay, or reverse progression of the disease itself or provide a cure. The goal is to prevent and relieve suffering and to improve quality of life...

 and treatment scheme — this involves anticonvulsant therapy (to help with the body's progressive loss of control of the nervous system causing gradually more intensive spasms/convulsions) alongside supportive measures to help maintain vital functioning. It is fairly standard as the infection's spread and symptoms intensify that feeding tubes need to be inserted to keep a nutritional balance. As the disease progresses to its most advanced phase, the patient will need constant nursing as normal bodily function declines to the complete collapse of the nervous system.
Combinations of treatment for SSPE include:

• Oral inosine pranobex (oral isoprinosine) combined with intrathecal (injection through a lumbar puncture into the spinal fluid) or intraventricular interferon alpha.
• Oral inosine pranobex (oral isoprinosine) combined with interferon beta.
• Intrathecal interferon alpha combined with intravenous ribavirin.

Global patterns of infection

SSPE is an incredibly rare condition although there is still relatively high incidence in Asia and the Middle East. However, the number of reported cases is declining since the introduction of the measles vaccine — eradication of the measles virus prevents the SSPE mutation and therefore the progression of the disease or even the initial infection itself.

External links

Subacute sclerosing panencephalitis was featured as a diagnosis in season 1 of the medical drama House, MD, episode 2 titled "Paternity"