Juvenile idiopathic arthritis involving mandibular condyle: a diagnostic muddle

A systemically healthy, 17-year-old, countryside male, presented to the department with a complaint of painful and stiff Temporomandibular Joint (TMJ) bilaterally with progressive trismus devoid of any click and deviation for 2 months. Examination of other joints was unremarkable. The differential diagnosis of osteoarthritis, condylar atrophy, idiopathic condylar resorption was made. Coronal and axial cut bony window of Computed tomogram (CT Head) showed osteophytic degenerative changes in TMJ (A,B), "sharpened pencil appearance" on transcranial view and "mouth-piece of flute appearance" (C,D) with the destructive bony architecture of condylar head. The hand, wrist, spine, and knee radiographs were demonstrated and found unremarkable. The biochemical laboratory tests were performed, they showed raised ESR (120 mm at end of 1^st hour), raised CRP (150 mg/dl) with positive RA factor (32 IU/ml) with normal uric acid level. After consulting with a rheumatologist, the patient was then started with disease-modifying anti-rheumatic drug therapy and corticosteroids for symptomatic relief, (Methotrexate 75 mg). Also, physiotherapy and a soft diet were advised. The patient was kept on a follow-up period of 6 months. The patient recovered from the symptoms uneventfully.