Reiter's syndrome and genetics

ALSO KNOWN AS: Reactive arthritis

DEFINITION Reiter’s syndrome is an inflammatory reaction to an infection somewhere in the body. It usually follows a urogenital or intestinal infection. Symptoms of the disorder primarily involve three body systems: the joints, the eyes, and the urinary or genital tract.

Risk Factors

Risk factors include having family members with Reiter’s syndrome and inheriting the genetic trait associated with Reiter’s syndrome, HLA-B*27, an allele of the HLA-B gene. While this allele does not itself cause Reiter's syndrome, it does predispose one to contract the disease. Other risk factors include having or contracting a sexually transmitted disease (STD) and eating improperly handled food. The disease is most common in young males between the ages of twenty and forty. According to the US National Library of Medicine, Reiter’s syndrome was a rare disorder, occurring in between 0.6 to 27 people out of 100,000.

Etiology and Genetics

The causes of Reiter’s syndrome are not well understood, but it seems clear that both genetic and environmental factors play contributing roles. Approximately 80 percent of affected individuals carry the HLA-B*27 allele, but not all individuals who express this gene will develop the disease; statistically speaking, while 50 percent of the children of an affected parent will inherit the HLA-B*27 allele, only about 25 percent of these will subsequently develop Reiter’s syndrome.

The HLA-B gene is one of a family of genes known as the human leukocyte antigen (HLA) complex, found at the major histocompatibility locus on chromosome 6. HLA-B, located at position 6p21.3, encodes a protein that is present on the surface of almost all cells and functions to display protein fragments (peptides) that have been exported from the cell to components of the immune system. If the antigens are recognized as foreign, an inflammatory response is triggered. The conditions under which the protein encoded by this gene initiates an inflammatory response that results in reactive arthritis are not clear, and theories range from the improper presentation of peptides to the misfolding of the protein itself. This gene variant is also associated with a group of autoimmune disorders known as the seronegative spondyloarthropathies, the most common of which are ankylosing spondylitis and psoriatic arthropathy.

The of the HLA-B*27 allele varies quite widely among different human populations. It is found in approximately 8 percent of northwestern Europeans and only about 3 percent of African Americans, but it may be present in as many as 25–40 percent of the native North American Arctic populations and 20–50 percent of those indigenous to northwestern Canada and the Pacific Northwest. A simple blood test is available to determine if an individual carries this gene.

Symptoms

Symptoms occur in three main areas of the body: the joints, the eyes, and the urinary tract and genitals. Men and women may experience different symptoms. The disease may be milder in women. Symptoms may come and go. In rare cases, heart problems may develop later in the disease.

Specific symptoms in the joints include swelling, pain, and redness, especially in the knees, ankles, and feet; heel pain; shortening and thickening of fingers and toes; and back pain and stiffness. Symptoms in the eyes include redness, pain, irritation, blurred vision, tearing, discharge, and sometimes sun sensitivity or swollen eyelids. Symptoms in the male urinary tract and reproductive system include frequent urination, a burning sensation when passing urine, penile discharge, sores at the end of the penis, fever, and chills. Symptoms in the female urinary tract and reproductive system include a burning sensation when passing urine and an inflamed vagina and cervix. Other symptoms include rash, especially on the palms or soles; ulcers in the mouth or on the tongue; weight loss; poor appetite; fatigue; and fever.

Rare complications may include heart problems such as arrhythmia, a heart murmur (aortic insufficiency), or pericarditis (an inflammation of the outer lining of heart) and lung problems such as pneumonia, pulmonary fibrosis, and fluid on the lung (pleural effusion). There may also be nervous-system problems such as neuropathy, which may include a tingling or loss of sensation, or behavior changes.

Screening and Diagnosis

The doctor will ask about a patient’s symptoms and medical history and will perform a physical exam. The doctor uses these findings to help make the diagnosis. There is no specific test to check for Reiter’s syndrome.

Testing may include blood tests to check for signs of inflammation (sedimentation rate), signs of infection (complete blood count), and the allele associated with Reiter’s syndrome (HLA-B*27). Additional tests may include culture, gram stain, or other tests to look for bacteria that commonly cause infections associated with Reiter’s syndrome; the removal of synovial fluid from around the joints to check for infection; x-rays, which use radiation to take pictures of structures inside the body, such as the joints; ultrasound, which uses sound waves to examine the inside of the body; a magnetic resonance imaging (MRI) scan, which uses magnetic and radio waves to make pictures of the inside of the body; or a computed tomography (CT) scan, a type of x-ray that uses a computer to make pictures of the inside of the body.

Treatment and Therapy

There is no cure for Reiter’s syndrome. However, early treatment of the infection may slow or stop the course of the disease. Most patients recover from the initial episode within six months, although some develop a mild, chronic arthritis. Some patients suffer from additional bouts of the disorder.

Treatment aims to relieve symptoms and may include short-term bed rest to take the strain off the joints. Another treatment option is exercise, including gentle range-of-motion exercises to improve flexibility, strengthening to build muscles that can better support the joints, and physical therapy with specific exercises to keep muscles strong and joints moving. Treatment also aims to protect the joints, which may include the use of assistive devices as recommended by the doctor and occupational therapy to learn how to take it easy on joints during daily activities.

The doctor may prescribe medications, including nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin and ibuprofen (Motrin, Advil). Additional medications may include sulfasalazine (Azulfidine), steroid injections into the inflamed joint, topical steroid creams applied to skin lesions, and in some cases antibiotics to treat the triggering infection. Immunosuppressive drugs (drugs that decrease the immune system’s ability to function), such as azathioprine (Imuran) and methotrexate, may also be prescribed.

Prevention and Outcomes

The key to preventing Reiter’s syndrome is to avoid the triggering infection. To do so, a patient should avoid STDs, either by abstaining from sex or by practicing safe sex. A patient can practice safe sex by always using a latex condom during sexual activity, asking sex partners about any history of sexual disease, having sex with only one partner who only has sex with the patient, not going back and forth between sexual partners, and having regular checkups for STDs.

Patients should also take steps to prevent chlamydia urogenital infections. Sexually active women who are age twenty-five or younger should be tested for chlamydia annually. Pregnant women should also get tested.

Patients can take certain precautions to reduce their risk of intestinal infections. These include washing hands before eating or handling food and only eating foods that have been stored and prepared properly.

Bibliography

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