Mycobacterium Chelonae Lung Disease in a Child with a Tracheostomy

Introduction: Mycobacterium chelonae is a nontuberculous mycobacterium (NTM) that is ubiquitous in the environment and is commonly associated with infections of the skin and soft tissues, surgical sites, and central venous catheters, most often in immunosuppressed people. Pulmonary infection with M. chelonae is rare compared to other NTMs. We present a case of an adolescent female with a rare presentation of M. chelonae pulmonary disease. Case description: The patient is an 11-year-old female with Aicardi syndrome, history of Wilms tumor in long-term remission, neuromuscular scoliosis, severe GI dysmotility with diverting ileostomy, and tracheostomy dependence for upper airway obstruction due to craniofacial abnormalities since 1.5 years of age. She did not require positive pressure support routinely until 3 years ago, when nighttime positive pressure ventilation was initiated for progressive restrictive lung disease from scoliosis and worsening central sleep apnea. Two years ago, her respiratory health continued to decline with recurrent pneumonias and tracheitis, requiring frequent antibiotics and one 3-day course of oral corticosteroids. Over the last year, she progressed to requiring continuous ventilator support. Due to concern that chronic gut dysfunction, including dysmotility, gastroesophageal reflux, persistent Clostridium difficile infection requiring multiple fecal transplants, and ascending aspiration contributed to her respiratory decline, an ileostomy was placed 10 months prior to diagnosis. Her respiratory health did not improve. Four months prior to diagnosis, an abdominal CT to evaluate for renal stones incidentally identified pulmonary nodules, confirmed on chest CT with associated bilateral ground glass opacities and mediastinal adenopathy. These findings were concerning for chronic aspiration, Wilms tumor recurrence, or infection. Follow-up chest CT 4 months later demonstrated increased number and size of pulmonary nodules, and bronchoalveolar-lavage samples were smear-positive for acid-fast bacilli. Culture of these samples and tracheal aspirate samples one month later identified persistent M. chelonae. Discussion: Although M. chelonae is a well-described cause of opportunistic infections of immunocompromised patients and patients with bronchiectasis, it is an uncommon cause of lung disease in other settings. Our patient's infection may be attributable to her multifactorial airway clearance impairment. Perhaps her risk was increased by GI dysmotility, tracheostomy dependence possibly serving as a reservoir for infection, and chronic aspiration. While these risk factors may have predisposed her to NTM infection, reports of M. chelonae infection are exceedingly rare among medically-complex children. In this case, a broad infectious workup was instrumental in identifying the likely cause of sustained clinical decline in this vulnerable child.