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In January 2002 a 14 year old Turkish teenager presented to his doctor with a history of 3 months’ swelling of the proximal interphalangeal (PIP) joints of both hands. As arthritis was suspected, he was referred to an orthopaedic surgeon. Blood tests, including C reactive protein, rheumatoid factor, were normal, conventional radiography of both hands showed only soft tissue swellings of the PIP joints. Under the diagnosis of “juvenile rheumatoid arthritis”, treatment with a non-steroidal anti-inflammatory drug was started. As the “polyarthritis” persisted, he was introduced to another orthopaedist. Three phase bone scintigraphy (technetium-99m) disclosed intensive “hot spots” at the PIP joints (phase 2) and at the epiphysial growth plate of the upper and lower extremities (static bone phase).
In July 2003, after three other medical consultations, he was admitted to our department. He denied any other symptoms or complaints besides finger swellings (fig 1), predominantly of PIP 2 and 3 of both hands, without signs of hypermobility and functional restriction. Routine blood tests, erythrocyte sedimentation rate, C reactive protein, rheumatoid factor, cyclic citrullinated peptide, antinuclear antibodies, and HLA-B27 were normal. Follow up radiographs of hands and feet (posteroanterior and oblique) were normal (Larsen score 1) and showed non-consolidated epiphyses. Tendon or ligament injuries, signs of synovial effusion, or active synovitis were not detected by ultrasound (12.5 MHz high frequency transducer). To detect early signs of arthritis, magnetic resonance imaging (MRI; 1.5 T) of the right hand was performed, showing periarticular swelling of the joint capsules of the PIP joints (fig 2); no osseous oedema, erosions, cystic lesions, or synovitis after intravenous gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA; Magnevist, Schering AG, Berlin; not shown) was seen.
We discussed the discrepancy between the clinical findings and diagnostic results, and he finally reported a nervous habit that he had had for at least 2 years: cracking his fingers 10 times a minute. This psychiatric disorder had remained undetected during various medical consultations. In view of these new aspects, the MRI sections were re-evaluated, but tendon, ligament, or finger pulley injuries could be ruled out. The patient was discharged with the diagnosis of an “overuse syndrome secondary to a nervous tick” and was referred to a psychiatric consultant for behaviour therapy, which he stopped after a few sessions without having benefited.
In our patient only severe swellings of the PIP joints of both hands correspond to the revised criteria of juvenile idiopathic arthritis (JIA).1 Because of the discrepancies in the former diagnostic findings, we performed MRI, which disclosed periarticular swellings of the PIP joints but neither synovitis nor damage to cartilage or bone. Based on this, we re-evaluated the patient’s history radically. Finally, the young man admitted cracking his fingers continuously for the past 2 years, a fact that led to the diagnosis of an “overuse syndrome secondary to a nervous tick”2 as a psychiatric disorder and not to JIA. Neither specific hints in his history for a factitious disease/Munchhausen syndrome3 nor criteria for joint hypermobility syndromes,4 heritable disorders of connective tissue or storage diseases, Thiemann’s disease5 or osteochondrodysplasia could be found. The patient’s swellings were most probably due to chronic overuse and extensive stress of the PIP joints, a phenomenon known to some extent in, for example, extreme rock climbers.2
Ultrasound and MRI have emerged as alternatives or supplements to conventional radiography in imaging small joint abnormalities in patients with arthritis or trauma.6,7,8,9,10 MRI visualises structural bone damage (oedema and erosions) as well as signs of disease activity (synovitis) as indicated by Gd-DTPA. However, MRI is not usually necessary to reach a diagnosis of JIA, but when there are atypical features and diagnostic doubt, it is a useful additional investigative tool. In our case, MRI helped to exclude both JIA and minor traumatic lesions, once we had become aware of the patient’s overuse syndrome.
Editor: Anthony D Woolf