Giant Subdeltoid Tubercular Bursitis: a Case Report

Osteoarticular tuberculosis comprises 1%–3% of all tubercular and one-third of extrapulmonary tuberculosis infections1, 2. The spine is the site affected in 50%–70% of cases2. The bones and joints of the lower limb are affected more commonly than are those of the upper limb. Tubercular infection of the shoulder joint accounts for 1%–2% of skeletal tuberculosis1. This infection usually starts in bone in the glenoid cavity or humeral head but sometimes in the synovium. Primary infection of extra-articular bursae or teno-synovial sheaths is very rare1, 3-5. Tuberculous bursitis has also been reported in the prepatellar, trochanteric and olecranon bursae6-9. Involvement of the subdeltoid bursa is extremely rare, only four cases having been reported10-12. Our patient had the largest bursal collection reported so far. We present here a case of a 70-year-old woman with tuberculous subdeltoid bursitis and a very large cystic collection. We treated the lesion with excision and anti-tubercular drug therapy; this achieved good results throughout 2 years of follow-up. A 70-year-old woman presented with swelling over the anterolateral aspect of her left shoulder. She had first noticed the swelling eleven months earlier and it had progressively increased in size. She had no fever, cough, weight loss, malaise or other constitutional symptoms. She was not diabetic and did not have any reason such as steroid or cytotoxic drug intake for immunosuppression. She had no history of pulmonary or extra-pulmonary tuberculosis. Routine bloods tests revealed a normal full blood count and increased erythrocyte sedimentation rate and serum C reactive protein concentration. The swelling measured 10 cm × 8 cm × 8 cm and was cystic in nature. There was no raised temperature or tenderness over the swelling. Overhead abduction was limited to 60° but movement of the shoulder joint in other planes was preserved. Plain radiographs showed generalized osteopenia in the region of the left shoulder, with a soft tissue shadow over the anterolateral aspect of the shoulder joint (Fig. 1). The joint space appeared normal and the bones of the shoulder joint were otherwise unremarkable. MRI revealed a 8 cm × 7 cm × 6 cm collection with multiple loculations within the subdeltoid bursa. The labrum and articular cartilage were within normal limits (Fig. 2). Other associated finding included a partial tear of the supraspinatus tendon and a few articular cartilage erosions suggestive of degenerative changes. There were no foci of infection within the glenoid cavity or the humerus. Plain anteroposterior radiograph of the shoulder joint showing a large soft tissue shadow in the region of the subdeltoid bursa. There is regional osteoporosis in the shoulder joint. The joint itself is preserved, though there are minor degenerative changes. There is some superior migration of the humeral head suggestive of rotator cuff disease. MRI images showing fluid in the subdeltoid and sub-acromial regions (dark T1W signals and bright T2W signals). The shoulder joint is not involved but there is some reactionary effusion in it. There are some signal changes in the humeral neck, which in the absence of any destruction and joint involvement suggest reactionary edema. We aspirated the lesion with diagnostic intent. Microscopy revealed a few pus cells but no organisms with Gram or acid fast stains. Cultures were negative. We therefore performed an excisional biopsy of the lesion via a delto-pectoral approach. We found a huge loculated collection in the subdeltoid space (Fig. 3) and excised it en bloc. The cyst was filled with a large volume of straw colored fluid with fibrinous flakes (rice-body-like particles) in it. There were multiple fibrous septations extending from the wall of the cyst. Intraoperative photographs of the lesion. (a) Preoperative clinical photograph showing the extent of the swelling. There are dilated veins and a tattoo mark visible over it. (b, c) The swelling exposed through a delto-pectoral approach. A well defined cystic lesion has been isolated in the subdeltoid plane. (d) Resected specimen from the subdeltoid region showing a well demarcated globular swelling, with no involvement of the surrounding tissues. Histopathology showed multiple areas of granulomatous inflammation with epithelioid cells and scattered multinucleated giant cells. Special staining did not reveal any organisms. These findings were highly suggestive of tubercular infection and the sample was positive for Mycobacterium tuberculosis on polymerase chain reaction. The patient was started on an antitubercular regimen comprising four drugs: isoniazid (5 mg/kg, daily), rifampicin (10 mg/kg, daily), pyrazinamide (25 mg/kg, daily) and ethambutol (15 mg/kg, daily). These four drugs were continued for 2 months, followed by isoniazid, rifampicin and ethambutol for another 4 months, followed by isoniazid and ethambutol for another 6 months. The total duration of antitubercular medication was 12 months. There was a good response to this medication with gradual resolution of pain and swelling. Laboratory markers such as the erythrocyte sedimentation rate and serum C-reactive protein concentration gradually improved after starting antitubercular medications and were within the normal range by 6 months. Tuberculous infection of juxta-articular bursae leads to cystic swellings with no active signs of inflammation; the range of motion of the affected joint is typically relatively well preserved. The symptoms are generally longstanding. The initial complaints are usually swelling and pain. Stiffness, if present, is a late feature1, 10-12. These typical features were present in our case. In contrast, tubercular disease of the shoulder joint starts in the head of the humerus, glenoid cavity or rarely, in the synovium13. Early loss of motion of the shoulder joint usually accompanies it. It most commonly presents as the dry or atrophic form, called "caries sicca". Formation of cold abscesses, swellings or sinuses around the shoulder is rare in tubercular infection of this joint. Despite this, secondary involvement of the soft tissues of the joint is much more common than primary infection of them. Another underlying disease of the joint should be excluded in all such cases. Osteopenia of the bones of the shoulder joint occurs in response to local hyperemia and disuse. In this patient, the bones were otherwise healthy; they were not themselves infected. It is believed that the bacilli reach the bursal sheath directly via a hematogenous route2, 9. Several authors have implicated frequent minor trauma and repetitive movement as factors in the pathogenesis of bursal tubercular infection; however, clear evidence is lacking. This possibility could explain why the trochanteric and prepatellar bursae are frequent sites of tubercular infection. The most common site for tubercular bursitis is the trochanteric bursa, which comprises 1–2 percent of all osteo-articular tuberculosis1, 3, 4. Pimm reported that, in sub-deltoid bursa infection, the symptoms develop so insidiously that over a year may pass before patients seek medical advice11. Our patient sought medical attention about 1 year after her first symptoms, when the external swelling had become very conspicuous. Swelling was the most pronounced feature. There was some dull pain associated with it, but no noteworthy stiffness of the shoulder joint. Radiographs and MRI scan are helpful for ruling out joint involvement in such cases. They are also useful in determining the extent of the lesion and differentiating it from other pathologies such as neoplasms. Though periarticular disease does cause formation of some reactionary fluid in the joint, synovial thickening, or signal changes in the bone indicate shoulder joint involvement. Excision of the bursa is the best treatment for massive cysts11. This not only provides tissue for histopathological diagnosis, but also reduces the disease load. Excision of these lesions also decreases the chances of relapse. Large multiloculated abscesses not only make penetration of drugs difficult, but also leave thickened fibrous tissue on healing. Complete excision of the affected bursa is important for preventing postoperative sinus formation. Antitubercular drugs are very effective for treating tubercular soft tissue infections. The conventional duration of treatment for osteo-articular tuberculosis was 18 months14, 15. Recently a shorter duration of treatment, such as 9 or 12 months, has been found to be equally effective13, 16. In cases of osteo-articular tuberculosis, prolonged treatment is important because there is a high risk of persistent infection in the bone due to its poor immune mechanisms. However, the duration of treatment for soft tissue tubercular infection probably does not need be as long. There is no current consensus on how long it should be in these patients. Our patient received 12 months of antitubercular treatment. She had a good clinical response to them, and there was no recurrence after 2 years of follow-up. Tubercular infection of the trochanteric bursa in more prone to recurrences1, 4. This may be because this bursa is closer to the bone in the region of the greater trochanter, making secondary bony involvement more likely. On the other hand, the subdeltoid bursa has good soft tissue coverage. Complete excision of this bursa should reduce the chances of recurrence. Such a large cyst arising from the subdeltoid bursa is extremely unusual. The most likely differential diagnosis is chronic granulomatous infection. Soft tissue tumors generally have large solid components with small, if any, cystic components. Degenerative cysts originating in the shoulder joint or bursa are unlikely to produce such large multiloculated swellings. Excisional biopsy of such lesions is the best surgical treatment. Histological findings of granulomatous inflammation with epithelioid cells and multinucleated giant cells are highly suggestive of tubercular infection. Primary tuberculous infections of periarticular bursae are rare and diagnosis may be difficult. They have a favorable prognosis when treated; unlike skeletal tuberculous infections, they do not lead to extensive destruction. Good results can be achieved with large bursal tuberculous infections by excising the swelling and administering antitubercular medications.