Tuberculous cold abscess of sternoclavicular joint: a case report

Bone and joint tuberculosis is a serious medical problem; tuberculosis of sternoclavicular joint is rare. We present a case of a healthy 37-year old man with sternoclavicular joint tuberculosis. The subject presented with a three weeks history of left sternoclavicular joint painless swelling without fever or weight loss. He had no previous history of pulmonary tuberculosis. Laboratory testing revealed erythrocyte sedimentation rate of 70 mm/hour, C-reactive protein of 30 mg/liter and a normal leucocyte count. Biopsy of the lesion showed caseous necrosis and pus culture revealed Mycobacterium tuberculosis. He was treated with joint debridement and anti-tuberculous medications. Tuberculosis resolved completely but post-infection patients had residual joint arthritis. Tuberculosis may infect unusual joints such as the sternoclavicular joint.


Introduction
Tuberculosis (TB) is still a very common disease in developing countries. TB arthritis is seen among children and young adults in endemic regions of the developing countries whereas in the developed countries it is seen in the older population and immunocompromised patients. It is a chronic disease that may affect any part of the human body. TB of the sternoclavicular joint is extraordinarily rare and can raise diagnostic problems. Osteoarticular lesions usually occur following paucibacillary haematological dissemination by fixation of a colony inside the active bone marrow. Tuberculous etiology should be considered for patients presenting with atypical sites of skeletal inflammation. A high degree of clinical suspicion and familiarity with the various radiologic manifestations of tuberculosis and sending specimens for mycobacterial culture allow early diagnosis and timely initiation of appropriate therapy, thereby reducing patient morbidity [1]. We describe a case of an adult who had a tuberculous infection in the sternoclavicular joint and the surrounding tissues.
Computerized tomography greatly enhanced the understanding of the extent of the disease process. Tuberculosis (TB) is still a very common disease in developing countries. TB arthritis is seen among children and young adults in endemic regions.

Discussion
Tuberculosis is a major cause of morbidity and mortality worldwide especially in Southeast Asia and posing threat owing to the population growth worldwide. In Malaysia, there has been an increase in the number of cases of tuberculosis (TB) in the past few years [2]. Sternoclavicular joint TB arthritis is rare, comprising only 1-2% of TB arthritis cases [3], but there are always residual sequelae of the disease which may be due to delay in the diagnosis [4]. Dhillon et al.
have described two types of sternoclavicular joint TB arthritis: an aggressive course with constitutional symptoms of joint destruction and a less aggressive type without constitutional symptoms and with minimal joint destruction [3]. This difference may be due to differences in the virulence of the organisms and host resistance. Sternoclavicular joint TB usually has a less aggressive course with swelling of the joint and minimal pain unlike that seen with other types of septic arthritis [5]. Jain et al. reported 13 cases of tuberculosis of the sternoclavicular joint in which all had painful swelling and only one culture was positive for TB [6]. In our case, there was no pain which suggests that it was not a regular bacterial infection. In our case, ESR, and CRP were markedly elevated suggesting infection. It is uncommon for a healthy patient to have extrapulmonary tuberculosis (EPTB). TB arthritis is often secondary to the common reason for tuberculosis arthritis and is secondary to either new or reactivated pulmonary TB [7]. Patients may have EPTB without pulmonary TB such as a case of sternoclavicular joint TB reported by Sahu, [1], and a case of TB pyomyositis of arm reported by Momin et al. [8]. A sternoclavicular joint TB is difficult to diagnose which may result in a delayed diagnosis and treatment. Conventional radiography is often not helpful for diagnosing sternoclavicular joint TB but computed tomography (CT) scan may be more useful. CT scan finding of sternoclavicular joint TB has been described by Shah et al. [5], which are bone and cartilage destruction, soft tissue masses crossing fascial planes with rim and diffuse enhancement (granulation tissue), calcifications and underlying pleuro-parenchymal tubercular. Surgical debridement at the time of open biopsy can promote healing [9]. A swollen sternoclavicular joint in a patient with a history of TB should raise the suspicion of sternoclavicular joint TB. But in our case due to the absence of the previous history of tuberculosis, constitutional symptoms and normal laboratory parameters, diagnosis becomes difficult. We agreed with Yasuda et al. [7], that advanced tuberculous arthritis and osteomyelitis in the sternoclavicular joint should be treated with a combination of thorough operative debridement and systemic administration of anti-tuberculous agents. This disease did not recur in our patient but Enarson et al. [3] reported that the risk for reactivation necessitates careful long-term follow-up. Based on our experience, sternoclavicular joint TB should be treated with a combination of surgical debridement and systemic anti-tuberculous medications.

Conclusion
In conclusion, we report here a case of sternoclavicular joint TB successfully treated with surgical debridement and anti TB