Chronic Tubercular Mediastinitis: A Rare Case Presentation With Subcutaneous Emphysema

Abstract

Tuberculosis, histoplasmosis, various fungal infections, malignancy, and sarcoidosis are the most common causes of chronic or slowly progressing mediastinitis. Chronic mediastinitis of tubercular origin with subcutaneous emphysema is exceptionally uncommon, and the majority of cases are caused by trauma. Here we report the case of a 35-year-old chronic alcoholic male who presented to the Outpatient Department (OPD) with complaints of cough, chest pain, loss of weight, and intermittent low-grade fever for three months with no significant past medical history or family history for any respiratory diseases. He was admitted and all routine investigations were performed, which were normal including his chest X-ray, except erythrocyte sedimentation rate (ESR) which was raised. The patient's high-resolution Computed Tomography (HRCT) of the thorax was done which showed multiple pleural-based nodular lesions with few showing central cavitary nodules along with ground glass appearance. It also showed two fistulous tracks of 3.4-millimeter diameter, arising from the trachea at the T1 - T2 vertebral level and at the carina which led to the presence of air in the subcutaneous plane extending from the neck up to visualized abdomen suggestive of chronic mediastinitis with tracheal fistula, along with subcutaneous emphysema. This fistula was confirmed by video bronchoscopy as well as three-dimensional (3D) virtual bronchoscopy. A biopsy was taken, which was positive for acid-fast bacilli (AFB) stain, polymerase chain reaction (PCR) for tuberculosis, and positive tuberculin skin test. The patient was started on anti-tubercular treatment and on a follow-up visit upon completion of the intensive phase, his HRCT and video bronchoscopy showed fibrosing scarring with fistula closure.

Keywords: mediastinitis; subcutaneos emphysema; tracheal fistula; tuberculosis; virtual bronchoscopy.

Figure 1. High-resolution computed tomography (HRCT) of the thorax (coronal view) showing the presence of tracheoesophageal fistula (red arrow) and subcutaneous emphysema (blue arrow)

Figure 2. Mediastinal window showing tracheoesophageal fistula (blue arrow) and subcutaneous emphysema (red arrow)

Figure 3. A three-dimensional (3D) virtual bronchoscopy image showing the presence of a tracheal fistula (red arrow)

Figure 4. Histopathological examination (HPE) of the tracheal biopsy revealing the presence of caseous necrosis (red arrow) with acid-fast bacilli (AFB) (blue arrow)

Figure 5. High-resolution computed tomography (HRCT) of the thorax showing healing of the tracheal fistula (red arrow) with complete resolution of the subcutaneous emphysema (blue arrow)