P046 Pointing the finger: an unusual presentation of dactylitis

Abstract

Abstract Background/Aims Dactylitis is commonly associated with psoriatic arthritis, and regularly presents at Rheumatology clinics. We discuss a case where progressive systemic symptoms lead to the consideration of alternate diagnoses. Methods A 46-year-old Nepalese woman presented to the Rheumatology department with a 3 month history of diffuse swelling of the right middle finger proximal interphalangeal joint, with the appearance of dactylitis. There was pain on movement, but no other joint involvement. Simultaneously she noticed blurred and decreased vision, which on review by the ophthalmologists, was diagnosed with bilateral uveitis. There was no history of psoriasis, inflammatory bowel disease, or other past medical history of note. There was no travel history in the past 12 months. A diagnosis of a presumed inflammatory arthritis was made. Results Blood tests showed elevated c-reactive protein 55 (normal <4 mg/l), erythrocyte sedimentation rate 138 (normal 0-22 mm/hr) and an iron deficiency anaemia. Rheumatoid factor and Anti-CCP antibody were negative. Hand radiographs were reported as normal. MRI of the third digit confirmed an enhancing soft tissue collection at the proximal phalanx of the right middle finger. She was referred for a biopsy of this lesion. Interestingly over the subsequent few months, she developed progressive breathlessness. Chest radiograph showed a left pleural effusion. Further tests showed negative serum ACE, Lyme and Toxoplasma screen. Quantiferon test was negative. Pleural aspirate showed a transudate with negative Acid-fast bacillus (AFB) test and culture. CT chest and abdomen showed a persistent pleural effusion, inflammatory changes in the small bowel and thickening of the peritoneum and omentum. In view of the systemic involvement, a peritoneal tissue biopsy was performed. This confirmed chronic granulomatous inflammation with positive AFB stain for mycobacterium tuberculosis. Our patient was started on quadruple anti- TB antibiotics for 6 months. Her systemic symptoms and dactylitis have improved, although there is on-going treatment for her ocular involvement. Conclusion Approximately 10% of all cases of extrapulmonary TB have osteoarticular involvement. Dactylitis is a variant of tuberculous osteomyelitis affecting the long bones of the hands and feet. It occurs mainly in young children; however adults may be affected also. The first manifestation is usually painless swelling of the diaphysis of the affected bone followed by trophic changes in the skin. The radiographic changes are known as spina ventosa, because of the ballooned out appearance of the bone, although this was not seen in our case. Fibrous dysplasia, congenital syphilis, sarcoidosis and sickle cell anaemia may induce similar radiographic changes in the metaphysis of long bones of hands and feet, but do not cause soft tissue swelling or periosteal reaction. This case highlights the importance of testing for TB, especially in atypical cases of dactylitis, with other systemic features. Disclosure N. Cernovschi - Feasey: None. J. Wajed: None.