Subacute sclerosing panencephalitis
Encyclopedia
Subacute sclerosing panencephalitis (SSPE) is a rare chronic, progressive encephalitis
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). No cure for SSPE exists, but the condition can be managed by medication if treatment is started at an early stage. Much of the work on SSPE has been performed by the National Institute of Neurological Disorders and Stroke (NINDS).
SSPE is also known as Dawson Disease, Dawson encephalitis and measles encephalitis. It should not be confused with acute disseminated encephalomyelitis
which has a similar etiology but very different timing and course.
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
, ataxia
, photosensitivity
, ocular abnormalities, spasticity, and coma
.
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
.
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.
showing widespread cortical dysfunction; pathologically, the white matter
of both the hemispheres and brainstem are affected, as well as the cerebral cortex
, and eosinophilic
inclusion bodies
are present in the nuclei of neuron
s and glial cell
s.
Diagnosis of SSPE is often difficult due to a normal CSF
profile — noted changes in the CSF profile only include a marked elevation in CSF immunoglobulin. Rubeola Ig G Antibody Titres will be high.
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
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:
Encephalitis
Encephalitis is an acute inflammation of the brain. Encephalitis with meningitis is known as meningoencephalitis. Symptoms include headache, fever, confusion, drowsiness, and fatigue...
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). No cure for SSPE exists, but the condition can be managed by medication if treatment is started at an early stage. Much of the work on SSPE has been performed by the National Institute of Neurological Disorders and Stroke (NINDS).
SSPE is also known as Dawson Disease, Dawson encephalitis and measles encephalitis. It should not be confused with acute disseminated encephalomyelitis
Acute disseminated encephalomyelitis
Acute disseminated encephalomyelitis is an immune mediated disease of the brain. It usually occurs following a viral infection but may appear following vaccination, bacterial or parasitic infection, or even appear spontaneously. As it involves autoimmune demyelination, it is similar to multiple...
which has a similar etiology but very different timing and course.
Symptoms
Characterized by a history of primary measlesMeasles
Measles, also known as rubeola or morbilli, 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. Brief twitches are perfectly normal. The myoclonic twitches are usually caused by sudden muscle contractions; they also can result from brief...
, ataxia
Ataxia
Ataxia is a neurological sign and symptom that consists of gross lack of coordination of muscle movements. Ataxia is a non-specific clinical manifestation implying dysfunction of the 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.- Human 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 state of unconsciousness, lasting more than 6 hours in which a person cannot be awakened, fails to respond normally to painful stimuli, light or sound, lacks a normal sleep-wake cycle and does not initiate voluntary actions. A person in a state of coma is described as...
.
Progression
The progression of symptoms begins with stage 1 — in this stage the individual's behaviour becomes more abnormal and erratic: they 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....
.
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 EEGEEG
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 sheet of neural tissue that is outermost to the cerebrum of the mammalian brain. It plays a key role in memory, attention, perceptual awareness, thought, language, and consciousness. It is constituted of up to six horizontal layers, each of which has a different...
, and eosinophilic
Eosinophilic
Eosinophilic 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 nuclei of neuron
Neuron
A neuron is an electrically excitable cell that processes and transmits information by electrical and chemical signaling. Chemical signaling occurs via synapses, specialized connections with other cells. Neurons connect to each other to form networks. Neurons are the core components of the nervous...
s and glial cell
Glial cell
Glial cells, sometimes called neuroglia or simply glia , are non-neuronal cells that maintain homeostasis, form myelin, and provide support and protection for neurons in the brain, and for neurons in other parts of the nervous system such as in the autonomous nervous system...
s.
Diagnosis of SSPE is often difficult due to a normal CSF
Cerebrospinal fluid
Cerebrospinal fluid , Liquor cerebrospinalis, is a clear, colorless, bodily fluid, that occupies the subarachnoid space and the ventricular system around and inside the brain and spinal cord...
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, 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 interferonInterferon
Interferons are proteins made and released by host cells in response to the presence of pathogens—such as viruses, bacteria, or parasites—or tumor cells. They allow communication between cells to trigger the protective defenses of the immune system that eradicate pathogens or tumors.IFNs belong to...
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 a specialized area of healthcare that focuses on relieving and preventing the suffering of patients...
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"- PubMedPubMedPubMed is a free database accessing primarily the MEDLINE database of references and abstracts on life sciences and biomedical topics. The United States National Library of Medicine at the National Institutes of Health maintains the database as part of the Entrez information retrieval system...
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