Reiter's syndrome

(Hans Reiter, 1881 - 1969, Norwegian physician), a joint disease (seronegative spondyloarthropathy) with skin involvement in which a classic triad of urethritis, arthritis and conjunctivitis is common. An infectious cause is suspected, as the disease often follows an infection of the bowel or lower genitourinary tract. Men are affected much more commonly than women, who tend to develop the disease after intestinal disorders, including bacillary dysentery, amoebic dysentery and shigellosis.

The characteristic skin lesion, termed keratoderma blenorrhagicum, affects the palms and soles most frequently. Superficial erythematous ulcerations may also be evident on the buccal mucosa and the tongue. The serum histocompatibility antigen HLA-B27 may be present in as many as 75% of patients.

Involvement of the lower extremity usually becomes evident initially in the knee and the ankle, followed in descending order of frequency by the metatarsophalangeal joints, the heel, the shoulder, the wrist, the hip and the lumbar spine. Heel pain and tenderness are sometimes initial manifestations of Reiter's syndrome. The arthritic attacks of in this disease are usually self-limiting and of short duration; recurrences are frequent, however.

On radiographs the features of joint involvement in Reiter's syndrome are similar to those in the other seronegative spondyloarthropathies and differ from the findings of rheumatoid arthritis (Fig.1) (Fig.2). Soft tissue prominence, sometimes leading to a sausage digit, may be present, as may regional or periarticular osteoporosis. Loss of joint space, erosion of articular surfaces, and superficial bone resorption beneath inflamed bursae and tendon sheaths are additional findings.

Bone proliferation is one of the prominent features and is the most helpful sign in distinguishing these conditions from rheumatoid arthritis. Fluffy periosteal bone proliferation is not uncommon in Reiter's syndrome. Subchondral sclerosis and eburnation with adjacent periostitis are additional radiographic findings.

Calcification and ossification of tendons have also been observed in patients with Reiter's syndrome.

Subluxation and deformity of the metatarsophalangeal joints has been termed Launoiss deformity. Retrocalcaneal bursitis is observed as a radiodense shadow that obliterates the normal lucent area between the top of the calcaneus and the adjacent Achilles tendon and projects into the preachilles fat pad on lateral radiographs. Poorly defined calcaneal enthesophytes may develop.

Paravertebral ossification about the lower three thoracic and upper three lumbar vertebrae is a frequent early finding in Reiter's syndrome. This is manifested as elongated vertical osseous bridges extending across the intervertebral disc but separated by a clear space from the lateral margins of both the disc and the vertebral body. Spondylosis deformans is commonly seen.

On scintigraphy with bone-seeking radiopharmaceutical agents, early findings of Reiter's syndrome include asymmetric involvement of the joints of the lower extremity, sometimes with striking increased radioactivity on the plantar and posterior aspects of the calcaneus and asymmetric sacroiliitis.

DR/RB