The functional significance of sacroiliitis and ankylosing spondylitis in Reiter's syndrome.

The frequent development of sacroiliitis and ankylosing spondylitis (AS) in patients suffering from Reiter's Syndrome (RS) has been stressed by a number of authors. This study was designed to ascertain the frequency of these problems in our RS patients, whether they were related to other clinical features of RS and what was the extent of the resulting disability. Fifty-five patients (50 men and 5 women) with RS with a mean duration of 9.3 years were assessed radiologically to determine the prevalence of sacroiliitis and thoracolumbar syndesmophyte formation. These radiological findings were correlated with HLA-B27, clinical features and functional status. Sacroiliitis was found in 22 patients (40%) but was mild in severity, frequently asymmetrical and very rarely associated with syndesmophyte formation. Sacroiliitis occurred significantly more commonly in patients with iritis and/or a prolonged disease duration (p less than 0.05) but although it was also found more frequently in HLA-B27 positive patients this was not significant (0.1 greater than p greater than 0.05). Some restriction in back movement was observed in 31 patients (56.3%) but only two patients satisfied New York criteria for AS and just one was functionally impaired by his back disease. Although the frequent finding of sacroiliitis in RS may provide an interesting insight into the interrelationship between RS and AS, our study shows that this sacroiliitis is commonly asymptomatic and does not provide a problem in management.