Rare Bilateral Invasive Pulmonary Mucormycosis with Tracheo-Esophageal Fistula and Left Mainstem Bronchus Disruption

ABSTRACT

Introduction: Mucormycosis is a rare invasive opportunistic fungal infection caused by Zygomycetes. [1,2] It is associated with worse outcomes in immunocompromised patients.[3,4] Invasive pulmonary infections can lead to bronchial necrosis from angioinvasion.[1,3] Here, we present a case of invasive pulmonary mucormycosis (IPM) caused by Rhizopus spp, resulting in tracheo-esophageal fistula. Case An 18-year-old male with uncontrolled type 1 diabetes was admitted to the intensive care unit for diabetic ketoacidosis (DKA) and acute hypoxia due to COVID 19 pneumonia requiring ventilatory support. Chest imaging showed bilateral opacities. He was treated with dexamethasone for COVID 19 and broad-spectrum antibiotics for superimposed bacterial pneumonia. Clinical course was complicated by acute respiratory distress syndrome and pneumomediastinum. Computed tomography of the chest showed large pneumomediastinum with air leak within the distal thoracic trachea. Bronchoscopy revealed a disfigured main carina with erosions (figure 1), a tracheo-esophageal fistula, necrotic blood-tinged left mainstem bronchus tissue, and a necrotic pus-filled superior segment of the right lower lobe. Left mainstem bronchial tissue specimen culture grew Rhizopus and Klebsiella spp. Liposomal amphotericin was initiated. Given his poor prognosis, the patient's family refused aggressive thoracic surgical intervention and pursued palliative care. Discussion: Rhizopus spp is the most common cause of mucormycosis in immunocompromised populations.[6] IPM is the second most common clinical form reported after the central nervous system.[3,6] Typically, IPM lesions are localized, and invasive presentations are infrequent. Rarely, IPM can cause invasive disease by angioinvasion, obstructing blood flow, and ischemic tissue necrosis.[6] Airway tissue necrosis can lead to fistulas between the airway and adjacent structures, including pleura, pericardium, and mediastinum.[2,3,4,5] Published clinical literature review revealed only a few cases due to IPM. Common predisposing factors include diabetes, DKA, and immunosuppressive medications, as observed in our patient.[3] Lobar bronchi are the usual locations of endobronchial erosions, with a predilection for the upper lobes.[3] In contrast, the left mainstem bronchus and right lower lobe were involved in the case presented here. In addition to antifungal treatment, surgical debridement is the mainstay of therapy due to necrosis.[7] The survival rate is between 35-46% in medically managed compared to 51-90% in surgically treated patients.[3]Conclusion: IPM is a life-threatening invasive disease associated with high mortality rates. Clinicians should suspect it in immunocompromised patients, including diabetes. The clinical history may include uncontrolled diabetes, recent DKA, and infections predisposing patients to develop superimposed fungal infections. The concurrent use of systemic steroids may also contribute to worse outcomes. (Figure Presented).