Zygomycosis is an opportunistic fungal infection primarily affecting immunocompromised hosts: patients with diabetes, metabolic acidosis, hematologic malignancies, iron overload states, and transplant patients. Pulmonary zygomycosis is a relatively rare entity, usually manifesting as parenchymal infiltrates or cavities, and is a diagnosis often made at autopsy. We present a case of zygomycosis isolated to the trachea, presenting as an airway emergency.
A 52 y/o man with poorly controlled diabetes mellitus presented with stridor for one day, and blood-tinged sputum associated with progressive dyspnea for 6 weeks. He had no fevers, chills, or weight loss. For the past five years, he had been taking prednisone 5 mg per day for rheumatoid arthritis. On examination, he was afebrile, stridorus, and using accessory muscles to breathe. His chest examination revealed transmitted sounds from his upper airway. Notable laboratory studies include a WBC count of 10,100, a serum bicarbonate level of 19 without an elevated anion gap, and a glucose of 239. CT of the chest showed a thickened trachea with mediastinal lymphadenopathy, without parenchymal lesions. The patient underwent emergent tracheostomy for acute upper airway obstruction. Bronchoscopy showed circumferential gray white membranes with necrotic debris extending from the fourth tracheal ring down to 2 cm above the carina (Graphic 1). Tracheal biospies revealed broad, nonseptate hyphae consistent with mucor (Graphic 2). The patient was not a candidate for surgical resection due to the extensive tracheal involvement. He underwent multiple tracheal debridements and was treated with liposomal amphotericin B. He received tight glycemic control and was titrated off prednisone. He was also treated with eleven sessions of hyperbaric oxygen, each consisting of 100% oxygen at two atmospheres for 90 minutes. Seven months after his initial presentation, the patient is off of amphotericin B, and is doing well with a tracheostomy tube which bypasses an area of tracheal stenosis resulting from tracheal fibrosis. Follow up chest CT shows improvement of his mediastinal adenopathy.
Pulmonary zygomycosis has a very poor prognosis. It carries a 55 percent mortality rate with medical treatment alone, and a 27 percent mortality rate with combined surgical and medical treatment. Only two case reports of tracheal zygomycosis exist in the literature. Both patients presented in diabetic ketoacidosis. One patient was treated with tracheal resection with primary reanastamosis and survived (1), while the other died of overwhelming infection before surgery was contemplated (2). Unfortunately, our patient was not a surgical candidate due to the extensive length of trachea involved. He was given maximal medical therapy including tight glycemic control, tapering off steroids, as well as amphotericin B. Hyperbaric oxygen has been studied and used in rhinocerebral and cutaneous zygomycosis. It is believed to increase oxygen tension in tissues, to enhance cidal action of PMN’s, and to promote angiogenesis. There is no data on its utility in pulmonary zygomycosis. Due to the favorable risk benefit profile, we decided to try hyperbaric oxygen treatment on our patient. It is uncertain to what extent it has helped in our patient’s recovery.
Tracheal zygomycosis is a rare cause of acute upper airway obstruction. This is the first report of successful treatment of tracheal zygomycosis with medical therapy alone. This is also the first reported use of hyperbaric oxygen in treating pulmonary zygomycosis.
V.Y. Kwan, None.