Definition

Reactive arthritis is a condition that causes pain and swelling in several joints of the body, particularly the knees, feet, ankles, and pelvis. This condition is triggered by an infection in another part of the body, most often the intestines, genitals, or urinary tract. Previously, reactive arthritis was often referred to as "Reiter's Syndrome."

Reactive arthritis is a relatively rare disease. In most cases, symptoms may wax and wane, gradually disappearing within a year. Typically, reactive arthritis emerges and develops after certain infections, especially sexually transmitted infections or food poisoning.

Men and women of any age can suffer from this disease, but it most commonly occurs between the ages of 20 and 40.

Causes

Reactive arthritis is triggered by an infection, particularly sexually transmitted infections or bacterial infections from food. Bacteria that frequently trigger reactive arthritis include Salmonella, Yersinia, Campylobacter, Shigella, and Chlamydia.

• Chlamydia trachomatis: This bacterium spreads through sexual contact. The infection can begin in the vagina, bladder, or urinary tract.
• Salmonella, Yersinia, Campylobacter, Shigella: These bacteria typically infect the digestive tract.

These bacteria can enter the human body in two ways:

1. Urinary tract: Bacteria can enter through the vagina or urinary tract during sexual contact and spread to the bladder.
2. Digestive tract: Bacteria can enter the body through contaminated food or consumption of expired or spoiled food.

Scientists do not yet know exactly why some people infected with the above bacteria develop reactive arthritis while others do not. However, researchers have found a genetic link to reactive arthritis. Individuals with the human leukocyte antigen (HLA) B27 gene are more likely to develop reactive arthritis. However, not all people with this gene will develop the condition.

Risk factor

Several factors can increase the risk of developing reactive arthritis, including:

• Gender: Both men and women have an equal chance of developing reactive arthritis from foodborne infections, but men are more likely to suffer from reactive arthritis caused by sexual infections.
• Age: Reactive arthritis is more common in adults between the ages of 20 and 40.
• Genetics: People with the HLA-B27 gene have a higher risk of developing more severe and prolonged symptoms of reactive arthritis.
• Weakened immune system: Individuals with weakened immune systems, such as those with HIV and AIDS, have an increased risk of developing reactive arthritis.

Symptoms

Symptoms of reactive arthritis typically appear within 1 to 4 weeks after exposure to an infection. These symptoms may include:

• Pain and stiffness: Joint pain associated with reactive arthritis most often occurs in the knees, heels, and feet. Pain can also occur in the lower back or hips.
• Eye inflammation: Individuals with reactive arthritis often experience conjunctivitis (infection of the conjunctiva).
• Urinary problems: Increased frequency and discomfort during urination may occur due to possible inflammation of the prostate or cervix.
• Inflammation of tissues (tendons and ligaments) attached to bones: This inflammation most frequently occurs in the heels and soles.
• Swelling of the toes or other fingers: In some cases, the toes or other fingers can become swollen, appearing like "sausages."
• Skin problems: Reactive arthritis can cause skin issues, including rashes on the soles of the feet, palms of the hands, and sores around the mouth.
• Back pain: Lower back pain usually worsens at night or in the morning.

Diagnosis

To diagnose reactive arthritis, the doctor will perform a combination of anamnesis (patient interview), physical examination, and supporting tests.

Anamnesis
During anamnesis, the doctor will inquire about the patient's main complaints, accompanying symptoms, onset of symptoms, previous medical history, family medical history, lifestyle, and previous treatments, if any.

Physical examination
In the physical examination, the doctor will check vital signs such as blood pressure, body temperature, pulse, and respiratory rate. The doctor will also examine the joints, including those in the hands and feet, to detect swelling, changes in joint temperature, and pain.

The doctor will assess the Range of Motion (ROM) or the ability of the joints to move, especially in the spine and affected joints. Additionally, the doctor may examine the eyes, skin, and genitals for signs of inflammation or rash.

Supporting tests
The doctor may conduct laboratory tests and radiological examinations.

Laboratory tests
Blood, urine, and stool tests can help in diagnosing reactive arthritis by identifying inflammation or infection, inflammation-related antibodies, and the HLA-B27 gene commonly found in patients with reactive arthritis.

Tissue sampling
Tissue samples from the throat, urinary tract (in men), and cervix (in women) can be taken to detect signs of infection.

Joint Fluid examination
The doctor might extract joint fluid from the knee to check for infection or inflammation and to rule out gout, indicated by the presence of uric acid crystals in the fluid.

Radiological examination
Radiological tests such as X-rays of the lower back, pelvis, and joints can reveal signs of reactive arthritis and help exclude other types of arthritis.

Read more: Gout Arthritis Disease - Definition, Causes, Symptom, and Management.

Management

The management of reactive arthritis depends on the symptoms, age, overall health, and severity of the condition. Treatment options include:

• Antibiotics to treat bacterial infections.
• Non-steroidal anti-inflammatory Drugs (NSAIDs) to reduce inflammation.
• Corticosteroids to alleviate inflammation.
• Immunosuppressants like methotrexate to control inflammation.
• Steroid eye drops for eye symptoms.
• Steroid-containing creams for skin symptoms.

These treatments should be taken under a doctor's guidance. Physical therapy can also help improve joint and muscle function, increase flexibility, and reduce joint stiffness.

Complications

Complications of reactive arthritis include persistent arthritis, with symptoms fluctuating and potentially recurring due to reinfection. Other conditions like ankylosing spondylitis, a spinal joint disease, may also arise as complications.

Prevention

Genetic factors influence susceptibility to reactive arthritis. While genetic makeup cannot be changed, exposure to bacteria causing reactive arthritis can be avoided. Proper food handling and cooking can prevent bacterial infections such as Salmonella, Shigella, Yersinia, and Campylobacter. Since some reactive arthritis cases stem from sexually transmitted infections, using condoms can help reduce the risk.

When to see a doctor?

Consult a doctor promptly if you experience joint pain within a month accompanied by diarrhea and genital infection, especially if you have risk factors for reactive arthritis.

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