This syndrome consists of the triad of a seronegative reactive arthritis, non-specific urethritis and conjunctivitis.
Two types are recognized:
1 Following a gastrointestinal infection with Shigella, Salmonella, Yersinia or Campylobacter (enteric)
2 Following non-specific urethritis (venereal) The male-to-female ratio is 20 : 1 and most cases occur in young adults. HLA-B27 is present about 60% of cases.
ARTHRITIS begins within 2 weeks of the enteric or venereal infection, which may have been mild and asymptomatic. The joints of the lower limbs are particularlyaffected in an asymmetrical pattern; the knees, ankles and feet are the commonest sites. The wrists and other joints of the upper limbs are occasionally involved, and there may be localized pain and tenderness in the spine due to sacroiliitis. The arthritis is often very acute at presentation but resolves over the course of a few months. It is occasionally associated with non-articular inflammatory lesions, including plantar fasciitis and Achilles tendinitis.
URETHRITIS is associated with a sterile urethral discharge and mild dysuria. Prostatism can occur. Circinate balanitis, a superficial penile lesion characterized by a circle of erythema with a pale centre, is rare.
CONJUNCTIVITIS is usually mild and bilateral, resolving spontaneously. It occurs in only one-third of patients. Acute anterior uveitis develops later in the disease, in approximatelylO% of patients.
KERATODERMA BLENNORRHAGICA is seen in 10% of patients with postvenereal Reiter’s syndrome. It is characterized by intense scaling of the skin of the soles of the feet, resembling pustular psoriasis. Nail dystrophy with subungual keratosis may lead to shedding of the nails.
Patients with Reiter’s syndrome may have a low-grade fever. Very rarely cardiac (e.g. pericarditis, aortitis), respiratory (mainly pleurisy) or neurological (peripheral neuropathy) complications occur.
The diagnosis in these conditions is entirely clinical; there are no diagnostic blood tests. The ESR is raised in the acute stage. Tests for rheumatoid factor and other autoantibodies are negative; 60% of patients are HLAB27 positive. X-rays are of no value in the acute stage of the disease, though signs of sacroiliitis may appear with the development of ankylosing spondylitis. Aspirated synovial fluid is inflammatory in nature, with a high polymorphonuclear leucocyte count; the fluid is sterile.
Treatment is with NSAIDs such as indomethacin. It is often useful to aspirate acutely inflamed joints and to inject them with a corticosteroid preparation. If the acute arthritis fails to resolve quickly, and in rare chronic cases, sulphasalazine or azathioprine can be used.
Although the acute arthritis resolves within a few months, there is a very high incidence of long-term problems. About 50% of patients with Reiter’s syndrome will go on to develop recurrences of arthritis, iritis or ankylosing spondylitis. Recurrent synovitis is the commonest problem and typically presents with effusions in the knee. Recurrences are not necessarily preceded by further enteric or venereal infection and are not associated with progressive deterioration of joints.
This has all the characteristics of the arthritis described above but without the other associations of Reiter’s syndrome and is called reactive arthritis. The full triad of Reiter’s syndrome is rare, but reactive arthritis following enteric or venereal infection is common. It is the commonest cause of arthritis in young men.
This is a seronegative arthritis occurring in 10% of patients with psoriasis. The aetiology is unknown, but there is an increased incidence of HLA-B27 and of a history of psoriasis in the family. The skin lesions, which are described , may be minimal or absent. The nail changes of psoriasis are usually present (85%). Differing patterns of arthritis are seen.
The commonest pattern of psoriatic arthropathy is a polyarthritis affecting the small joints of the hands, including the distal interphalangeal joints, in an asymmetrical pattern. This is a mild but chronic condition, and in most cases is benign. It can usually be controlled with analgesics but NSAIDs are sometimes necessary. Less often the pattern of the arthritis is similar to that in RA, i.e. bilateral, symmetrical polyarthritis. Rarely the disease is rapidly progressive, producing destruction of the ends of the small bones of the hands and feet (arthritis mutilans), a condition that can also occur in RA. Because of the shortening of the bones of the fingers there is an excess of soft tissue and the fingers can be pulled in and out like an opera glass, after which the condition is sometimes named. Finally, patients with psoriasis have an increased incidence of ankylosing spondylitis.
Blood tests are unhelpful in the diagnosis. The ESR is often normal and tests for rheumatoid factor are negative. X-rays may show characteristic changes in the terminal interphalangeal joints, with erosions and periarticular osteoporosis.
Treatment is with analgesic and anti-inflammatory drugs. In progressive cases, immunosuppressive drugs such as azathioprine are particularly effective. Gold is sometimes effective in psoriatic arthropathy, but penicillamine is not.
Juvenile chronic arthritis
Juvenile ankylosing spondylitis, which accounts for 50% of cases of juvenile chronic arthritis, can be classified as a spondylarthropathy and is discussed.
Enteropathic synovitis occurs in 11% of patients with ulcerative colitis and 14% of patients with Crohn’s disease. This type of arthritis is always related to the activity of the underlying disease, although in a small proportion of cases it is the first manifestation of underlying bowel problems. The aetiology is unknown but deposition of immune complexes in the joint may playa part. Enteropathic synovitis usually affects the knees and ankles as a mono arthritis or asymmetrical oligo arthritis. It presents with painful swollen joints and large effusions. Attacks last for a few months only and resolve without joint damage. Enteropathic synovitis should be distinguished from ankylosing spondylitis. The latter occurs in about 5% of patients with inflammatory bowel disease but is an associated lesion rather than a complication of the bowel disease and is not therefore related to disease activity. Other non-articular features of inflammatory bowel disease, e.g. iritis, may be present.
X-rays of affected joints are normal and investigations are otherwise unhelpful. The first priority for treatment is to control the underlying inflammatory bowel disease. Aspiration and injection of affected joints and oral antiinflammatory drugs may help the symptoms while the underlying disease is being brought under control.