Cold abscess – a rare entity in the present era of anti-tubercular treatment
A 25-year-old student presented to the pulmonary medicine outpatient department with a low-grade fever, cough, and weight loss of 3kg in the preceding three months. He had no background atopy or usage of tobacco products. He had no shortness of breath, wheezing, skin, or joint disease. He denied a history of thyroid disease or high-risk sexual behavior. Enzyme-linked immunosorbent assay for HIV was negative. Sputum examination for acid-fast bacilli (AFB) sputum was positive for M. tuberculosis with no rifampicin resistance. He was started on standard four drugs anti-TB treatment with the symptomatic improvement of cough and weight gain.
He presented 2 months later with acute pain and swelling of the right axilla, of sudden onset. The swelling progressively increased over 7 days. On inspection, there was swelling of the right axilla. On palpation, the swelling was soft and fluctuant; there were no skin changes. Diagnosis of the tubercular cold abscess was made. Blood counts and liver functions were normal. Suspicion of irregular drug intake and drug-resistant TB was entertained. However, the patient denied irregular drug intake. He was referred to us for further management.
After stabilizing the patient, base line investigations were done. CT thorax showed multiple fluid collections with thick rim enhancing wall seen along the right posterolateral chest wall involving predominantly the right serratus anterior muscle and chest wall muscle. Largest pocket extended for about 12 cm in cranial caudal direction with width of 2.7cm. Superiorly fluid pocket/abscess pocket was seen to extend to the level of apex of lung. Anteromedially this abscess pocket was seen to extend along the extrapleural space on the medial aspect of the right 3rd rib. No obvious erosion/lytic area was noted in the surrounding bones.
The patient was taken to operation room and under general anesthesia. The patient was put in right lateral position. Using a large spinal needle, aspiration was done and a sample of the abscess was taken for microbiological investigations. The abscess site was opened and drained. The abscess extended in the posterolateral aspect of the thoracic wall from axilla to lateral scapular border. The wound was closed over drains. He made an uneventful postoperative recovery and was discharged on the 6th postoperative day.
The development of cold abscess is an important cause for poor clinical response or worsening in a patient on anti-tubercular treatment. It is seen in about 0.1% of musculoskeletal tuberculosis. Tubercular abscess of the chest wall is usually seen at the sternal margins or along the ribs. Mechanisms described include hematogenous dissemination, direct extension from lymphadenitis of the chest wall or suboptimal management of tubercular abscess of the chest wall and osteomyelitis of the ribs. Surgical excision of the affected tissue, under cover of anti-tubercular treatment, is believed to be the ideal strategy to prevent recurrence.