Reactive arthritis
Reactive Arthritis is an acute inflammatory arthritis occurring with, or following, an intercurrent infection, but without evidence of the causative organism in the joint.
- Reactive arthritis can occur at any age and typically follows 7-10 days after gastroenteritis (young children), involving lower limb large joints (knee>ankle>hip). Infections are usually due to Shigella, Salmonella, Yersinia, Campylobacter organisms.
- Acute phase reactants are usually very high, blood cultures and autoantibodies are negative. Diagnosis rests on serology, stool cultures or may be one of exclusion of infection.
- There is an association with HLA-B27 antigen being positive and a chronic course. NSAIDS and intra-articular steroid injections are often helpful with persistent arthritis (defined as >4-6 weeks) and after septic arthritis has been excluded.
- In adolescents, it is important to consider sexually acquired infection and a sexual history needs to be explored sensitively. Patients may have multiple infections: Chlamydia, Gonococcus and Human Immunodeficiency Virus.
- Safeguarding (child abuse) concerns may be warranted with suspicion of sexually acquired infection in a child or young adolescent.
- Red eyes due to conjunctivitis may also be present with the triad of urethritis, conjunctivitis and arthritis (sometimes referred as Reiter's disease or syndrome).
- Gonococcal Arthritis may present with fever, rigors, skin lesions (macular rash, pustules, or blisters), tenosynovitis, and polyarthritis. The sexual history needs to be explored but the possibility of sexual abuse should be considered. The knee is most commonly affected, but any joint may be involved. If suspected, Gram stain, and cultures of synovial fluid, blood cultures are done but can be falsely negative. Coexistent sexually acquired infections need to be considered.
- A reactive arthritis to mycobacterial infection is also observed (called Poncet's disease) and is thought to be due to a hypersensitive immune response to tuberculoprotein; this is similar to erythema nodosum occurring in the skin with active TB.
- Poncet's disease predominantly occurs in young adults and children and usually presents with a fever of 3-16 weeks duration followed by an acute / subacute polyarthritis. Poncet’s disease tends to be a symmetrical oligoarticular arthritis of predominantly the large joints (the knees are most commonly involved). Cervical and axillary lymphadenopathy is a consistent finding.
- Poncet’s disease is more commonly associated with active extra pulmonary TB - notably that involving the lymph nodes.
- The diagnosis of Poncet’s disease is largely clinical and is made by excluding other causes of polyarthritis in a patient with documented active TB. The arthritis resolves on treatment with anti-tuberculosis therapy.
- Acute Rheumatic Fever - ARF - is an auto-immune reaction which follows Group A streptococcus infection with multisystem involvement of heart, joints, brain and skin.
- Arthritis tends to occur early and is often migratory (sometimes called 'migratory' or 'fleeting' as it moves from joint to joint). ARF arthritis tends to affect large joints (often legs first) and multiple joints although a monoarthritis is described.
- Rheumatic heart disease is a serious complication with high morbidity and mortality. Treatment of ARF is with prolonged antibiotics and management of organ involvement such as heart failure from carditis or valvular disease. Neurological complications include chorea (erratic limb movements from extrapyramidal involvement).
- More information is available about ARF is available.
- Diagnosis rests on the application of the Jones criteria (revised 2015). Revision of the Jones Criteria for the Diagnosis of Acute Rheumatic Fever in the Era of Doppler Echocardiography. A Scientific Statement From the American Heart Association Endorsed by the World Heart Federation. Gewitz MH et al
