RT Journal Article SR Electronic T1 Tuberculous arthritis of the ankle joint masquerading as rheumatoid arthritis in a patient with lupus nephritis JF Clinical Medicine JO Clin Med FD Royal College of Physicians SP e108 OP e109 DO 10.7861/clinmed.2020-0882 VO 21 IS 1 A1 Mohd N bin Ismail A1 Siti M Ab Rahim YR 2021 UL http://www.rcpjournals.org/content/21/1/e108.abstract AB Tuberculosis is an airborne multisystemic disease which primarily infects the lungs. Isolated tuberculous arthritis is rare. We present a case of a 41-year-old woman with a known case of lupus nephritis class IV who complained of pain and swelling over her left ankle joint for several months. She was treated for rheumatoid arthritis and was started with immunosuppressive agents. However, she did not improve with treatment and was later diagnosed with tuberculous arthritis based on a molecular study from joint aspiration. She was started on antituberculosis medication and showed improvement. We highlight the challenges in reaching the diagnosis and the importance of including tuberculous arthritis in differential diagnoses in cases with persistent ankle swelling.