Poststreptococcal reactive arthritis (PSRA) is an inflammatory condition affecting one or more joints, developing after a person has experienced a Group A streptococcal (GAS) infection, such as strep throat. This condition is an autoimmune response, meaning the body’s immune system mistakenly attacks its own healthy tissues, leading to inflammation and discomfort in the joints. PSRA is considered an uncommon complication of these infections.
What Causes Poststreptococcal Reactive Arthritis
Poststreptococcal reactive arthritis arises from an abnormal immune response following an infection with Group A Streptococcus bacteria, specifically Streptococcus pyogenes. These bacteria cause throat infections like strep throat and can also lead to skin infections. The body’s immune system produces antibodies to fight off the streptococcal infection.
In some individuals, these antibodies mistakenly recognize and attack the body’s own tissues, particularly in the joints. This misdirected attack leads to the inflammation characteristic of PSRA.
Recognizing the Symptoms
The primary symptom of poststreptococcal reactive arthritis is inflammation of one or more joints, causing pain, swelling, and stiffness. This joint involvement usually has a sudden onset, appearing about 7 to 10 days after the initial streptococcal infection. The pattern of arthritis can vary, affecting a single joint or multiple joints simultaneously, and can occur on both sides of the body.
Joint pain may be severe, even without significant visible swelling. Beyond the joints, PSRA can also manifest with non-joint symptoms. These may include erythema nodosum, which are red, tender, raised nodules deep within the skin, or inflammation of the middle layer of eye tissues, known as uveitis. Inflammation of a kidney, or glomerulonephritis, is another possible manifestation.
Diagnosis and Management
Healthcare professionals diagnose poststreptococcal reactive arthritis through clinical evaluation, laboratory tests, and sometimes imaging studies. A detailed patient history focuses on a recent sore throat or skin infection and the timing of joint symptom onset. Clinicians look for persistent, non-migratory acute arthritis in one or more joints, coupled with evidence of a recent Group A Beta-Hemolytic Streptococcal (GABHS) infection.
Laboratory tests confirm recent streptococcal infection and assess inflammation. Elevated levels of antistreptolysin O (ASO) and anti-DNase B titers indicate recent GABHS exposure. Inflammatory markers like erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) are also measured. Imaging tests, such as X-rays, MRI, ultrasound, or CT scans, may evaluate joint involvement.
Management primarily focuses on alleviating symptoms and reducing inflammation. Nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen or naproxen, are often the first line of treatment to reduce joint pain and swelling. If NSAIDs do not provide sufficient relief, corticosteroids may be considered for their stronger anti-inflammatory effects. While antibiotics treat the initial streptococcal infection, their impact on the arthritis course is less clear. Long-term antibiotic prophylaxis, often for a year, is sometimes recommended, especially in children, to prevent potential complications like carditis.
Potential Outcomes and Recovery
Most individuals with poststreptococcal reactive arthritis can expect a complete recovery. The arthritis symptoms typically resolve on their own within weeks to months, with an average duration of about two months. Some reports indicate symptoms can persist for up to eight months.
While joint resolution is generally favorable, arthritis can recur, especially after discontinuing anti-inflammatory medications. A more serious, though rare, potential complication is carditis, or inflammation of the heart. This can occur in a small percentage of children with PSRA and may lead to chronic heart disease if not recognized and managed. Adults with PSRA appear to have a lower, or possibly no, risk of developing carditis. Monitoring for heart involvement is important, and antibiotic prophylaxis may be continued to prevent future streptococcal infections that could trigger recurrence or cardiac issues.