Atypical form of Adult-onset Still's Disease with Distal Interphalangeal Joints Involvement.

Background: A distal interphalangeal (DIP) joint involvement in the adult-onset Still's disease (AOSD) has been described in some publications but is rarely reported to be severe. We report severe DIP joints damages in a young patient with AOSD.

Case Report: A 22 years old patient presented to our department complaining of inflammatory joints pain associated with prolonged fever and cutaneous rash. Physical examination identified polyarthritis and hepatosplenomegaly but no lymphadenopathies. After an extensive screening for neoplastic, infectious or hematologic diseases, the patient was finally diagnosed with AOSD. Treatment based on corticosteroids was then initiated with a good response on systemic signs. However, the patient continued to have recurrent arthritis affecting wrists and proximal interphalangeal joints. A Few years later, he developed a severe and disabling DIP arthritis with signs of joint destruction on conventional radiographs and MRI. Despite the initiation of methotrexate with optimal dosage, the patient continued to have polyarticular flares. The combination of methotrexate and sulfasalazine was responsible for drug-induced hepatotoxicity and this treatment was stopped. Anti-TNFα treatment was then indicated as general signs improved but severe joints damage persisted. Unfortunately, and due to healthcare system considerations, the patient was not able to benefit from TNFα inhibitors, and remained on methotrexate treatment only.

Conculsion: The distal destructive arthritis during AOSD is rare and controversial. Our patient had a severe form with resistance to conventional therapies.