Behcet Disease
What is Behcet disease?
Behcet disease is a condition marked by the repeated formation of open sores (ulcers) in the mouth, on the genitals, skin lesions and inflammation of the uvea of the eye. It is also known as Behcet’s syndrome since it is a collection of different symptoms without a clear explanation for the occurrence of these symptoms. Behcet’s disease is believed to be an autoimmune disease that is triggered by a previous viral or bacterial infection in a genetically susceptible person.
There is chronic inflammation of many tissues throughout the body, although ulcers in the mouth, genitals and uveitis are the main presenting features. Overall, it is an uncommon condition affecting only about 1 in 500,000 people in the United States. It tends to affect people between the ages of 20 to 40 years and on average, it tends to start around 25 to 30 years of age.
Is Behcet disease fatal?
Behcet disease can be fatal but death is uncommon these days with the appropriate medical treatment and early intervention for complications. Death is a result of complications like a ruptured aneurysm or involvement of the central nervous system (CNS). Studies on the mortality associated with Behcet disease varies between 16% to 20% at 5 years or 7 years respectively. However, there are multiple factors that need to be taken into consideration and each case needs to be assessed and treated individually.
About the Syndrome
Currently the accepted hypothesis is that Behcet disease is an autoimmune condition. As with any autoimmune disease, the body’s immune system attacks its own healthy tissue. Normally the immune system can identify the body’s own cells. However, with some derangements in the immune system where certain of the body’s tissues are mistakenly identified as being foreign, the immune defenses are directed at the body’s own tissues. This is basically the process that occurs in Behcet’s disease as well. It is believed that a prior infection or action against microbes normally occurring in the body is the trigger.
When the immune system comes into contact with foreign microbes, the body forms antibodies against the proteins on the surface of the microbe (antigens). These antigens may resemble proteins on the cell membrane of the body’s cells. The antibodies may attach here and the subsequent immune response is initiated at the specific site. The process of inflammation then ensues which leads to the symptoms seen in Behcet disease. People with the syndrome appear to have a genetic susceptibility to Behcet disease which is then triggered by a bacterial or viral pathogen.
Signs and Symptoms
Behcet disease can affect any part of the body. Usually multiple systems are affected simultaneously and is marked by the features of chronic inflammation. The main systems and organs affected in Behcet disease is discussed below but it is important to note that any system can be afflicted.
Mouth
One of the common defining features of Behcet disease is painful mouth ulcers. These lesions initially starts as round lumps which becomes open sores. These ulcers heal on its own within a few weeks. Recurrence is common.
Genitals
Ulcers on the genitals are another major feature of Behcet disease. It is typically painful sores but various other types of skin symptoms may also arise on the genitalia. It more commonly occurs on the scrotum in men and labia in women
Eyes
Eye symptoms are a result of inflammation of specific tissues within the eyeball like the uvea or tiny blood vessels of the retina. This presents as blurred vision, excessive tearing, redness (bloodshot eyes), light sensitivity and pain around the eye.
Skin
There are various skin lesions that may occur anywhere on the body apart from just the genitals. A rash that resembles acne (acneiform papulopustular) may be seen on the chest, back or abdomen. This is more common in men. Tender red lumps similar to erythema nodosum may be seen on the legs and is more common among women.
Joints
Arthritis (joint inflammation) and arthralgia (joint pain) are common joint symptoms that affects the extremities, particularly the lower limb and especially the knee. Sometimes a single joint is affected while at other time there is multiple joint involvement.
Blood Vessels
Both veins and arteries can be affected in Behcet disease. The inflamed vessels (vasculitis) in turn causes various symptoms depending on the location of the affected vessels. Clot formation (thrombus) may occur and one of the more serious complications is weakening and bulging of the wall (aneurysm). It is the rupture of these aneurysms, especially in the vessels of the lungs, that is potentially fatal.
Brain and Spinal Cord
Central nervous involvement is not an early feature of Behcet disease. It can present in several ways including memory loss, behavioral changes and seizures.
Gut
Parts of the gut may be inflamed anywhere from the esophagus to the end of the small intestine. Patients experience non-specific symptoms like bloating and abdominal pain. In more severe cases there may be bleeding from the gut wall.
Causes and Risk Factors
The exact cause of Behcet disease is unknown. It appears that people who develop the disease have a genetic susceptibility towards it. Certain ethnic groups appear to be at a greater risk due to the prevalence of HLA-B51 within these populations. This includes people of Middle Eastern and Japanese descent. Subsequent exposure to an infectious agent, bacterial or viral, may then trigger the onset of the diseases. The symptoms seen in Behcet disease are due to inflammation, blood clot formation and hemorrhage.
Tests and Diagnosis
There is no specific test that will definitively confirm or exclude a diagnosis of Behcet disease. Various laboratory tests and imaging studies are conducted to verify the inflammatory state and monitor the severity of complications. Behcet disease is therefore diagnosed by the presence of the mouth sores, genital sores, eye problems and skin symptoms that all tend to occur together. Another test required for the diagnosis of Behcet disease is a positive pathergy test (skin prick test) which confirms the overactivity of the immune system.
Mouth ulcers have to be present, recurring at least 3 times in the past 12 months, along with at least two of the following – eye disorders, genital sores, skin lesions and/or a positive pathergy test.
Treatment for Behcets
Treatment of Behcet disease is aimed at easing the symptoms and reducing the severity of the condition. There is no cure for Behcet disease and long term management is necessary to minimize or at least prevent complications. Various treatments in a range of forms are prescribed for symptomatic relief of Behcet disease but do not reduce the severity of the condition itself. To achieve this, drugs that reduce inflammation or to suppress immune activity are the best options for the management of Behcet disease.
- Corticosteroids essentially ‘shut down’ the inflammatory process which is helpful but can also compromise the body’s defenses against other injuries.
- Immune regulators control the activity of the immune system
- Immunosuppressants ‘shut down’ the immune system in order to reduce the inflammation subsequently leaving the body prone to infections.
Often these drugs are used in combination and sometimes other medication such as methotrexate (known for its uses in severe rheumatoid arthritis) or colchicine (frequently used for gout) are also utilized.
References :
http://www.niams.nih.gov/health_info/behcets_disease/
http://www.mayoclinic.com/health/behcets-disease/DS00822/DSECTION=treatments-and-drugs
