Evaluation of joints using Tc 99m-MDP bone scintigraphy in patients with familial Mediterranean fever: should bone scans be used for diagnosis and follow-up?
Familial Mediterranean fever (FMF) is an autosomal recessively-inherited disorder typically manifested by recurrent attacks of fever and polyserositis. The articular disease occurs in 50-70% of patients. Bone scintigraphy is more sensitive in the diagnosis of arthritis than clinical examination or conventional radiological imaging, allowing earlier diagnosis through the visualization of disease in multiple sites. To assess joint involvements in FMF patients with or without joint symptoms, bone scintigraphy was performed in 36 patients with FMF and in 25 controls. There was arthritis in 72% of patients. Of these, 65% knee, 42% ankle, 50% sacroiliac, 8% elbow, 8% wrist, 4% sternoclavicular and 4% hip involvements were found. The sacroiliac joints with sacroiliac index higher than 1.34 were diagnosed as sacroiliitis, which was higher than 2 SD of normal. FMF is frequently associated with joint disease such as knee and ankle arthritis and sacroiliitis. This high incidence of sacroiliitis in our study has not been previously reported. This difference could be explained by the different methodology used for the screening of the joints. Thus, we recommend that bone scintigraphy can be used in patients with FMF to determine the presence of arthritis, especially in sacroiliac joints, even asymptomatic.