Tuberculous synovitis of the knee with unusually thick synovial granulation tissue: A Case Report

摘要

Tuberculosis (TB) is no longer confined to undeveloped or developing nations. An increased incidence of patients with TB has been observed even in developed countries due to pandemic human immunodeficiency virus infection, immigration from endemic areas, alcoholism, chronic kidney disorders, immuno-suppressive therapy, drug addiction, intraarticular steroid injection and systemic illness. Tuberculosis (TB) of the appendicular skeleton is an uncommon infection caused by tuberculous bacilli and constitutes 1-3% of all forms of TB. 30% of skeletal TB involves the joints, the knee being the third most commonly affected after the spine and the hip. We report a case of a 15-year old girl with pulmonary tuberculosis as well as tuberculous arthritis of the right knee with unusually thick synovial granulation tissue on MR imaging. Introduction Tuberculosis (TB) of the appendicular skeleton is an uncommon infection caused by tuberculous bacilli and constitutes 1-3% of all forms of TB. 30% of skeletal TB involves the joints, the knee being the third most commonly affected after the spine and the hip. The incidence of skeletal TB is increasing due to the emergence of multi-drug resistant mycobacteria, increase in the number of immuno-compromised patients and the AIDS pandemic. We report here a case of tuberculous synovitis of the knee joint with unusually thick synovial granulation tissue. Case report We report a case of a 15-year old girl who presented with a 3-week history of fever and insidious right knee swelling associated with pain. The patient had no cough or history of recent contact with tuberculous individuals. She also complained of loss of appetite and loss of weight. She was vaccinated with BCG as part of the national immunization programme during childhood. She comes from a low socio-economic background living in one of the places with the highest prevalence of tuberculosis in Malaysia (1). Physical examination showed a swollen and erythematous right knee with reduced flexion ability. There was no sinus tract seen. The other joints were normal. Respiratory system examination revealed occasional crepitations in both lung fields. Otherwise the rest of the systemic examination was unremarkable.On plain radiography, the affected knee appeared normal other than subtle soft tissue swelling (Figure 1). A synovial biopsy was contemplated for which a preprocedural chest radiograph was done. It showed bilateral diffuse miliary shadows (Figure 2), prompting a diagnosis of tuberculosis. This was further supported by a positive sputum result for acid fast bacilli (AFB).