Incidental diagnosis of Mounier-Kuhn syndrome during anesthesia: A case report

Patients with Mounier-Kuhn syndrome (MKS), a rare disorder characterized by tracheobronchomegaly (<0.3% prevalence), develop pathological tracheobronchial dilation secondary to elastic fiber atrophy. MKS predisposes patients to recurrent infections and presents significant airway challenges during general anesthesia. Early radiological recognition is critical to prevent perioperative crises. This case report aims to highlight the critical importance of radiologically identifying MKS preoperatively to avoid potentially life-threatening perioperative airway complications-an aspect that can be overlooked when attention is focused solely on the primary surgical diagnosis.

A 57-year-old man with multiple risk factors (40 pack-year smoking history, chronic alcohol consumption of >80 g/d, and 10-year betel quid use) was scheduled for partial glossectomy because of suspected tongue cancer recurrence. The patient denied any preoperative respiratory symptoms, and the written report of preoperative imaging revealed bronchitis without tracheobronchomegaly.

Previously undiagnosed MKS was confirmed intraoperatively and postoperatively. Specifically, postoperative computed tomography revealed tracheobronchomegaly (trachea, 29.3 × 27.3 mm; right main bronchus, 25.5 mm).

Following endotracheal intubation under general anesthesia, significant air leakage was observed. Combined with the preoperative computed tomography findings, this raised suspicion for MKS. Precise measurement of the tracheal diameter guided repositioning of the endotracheal tube cuff to 2 cm below the vocal cords, which resolved the air leak and ensured effective ventilation throughout surgery.

Adjusting the endotracheal tube cuff position under imaging guidance effectively resolved the air leak in this patient with MKS, avoiding the need for tube exchange and preventing barotrauma to the fragile tracheal wall from high cuff pressure.

For patients with undiagnosed MKS, a comprehensive evaluation of preoperative thoracic imaging is crucial. In MKS, both the cuff placement and size of the endotracheal tube significantly influence airway management success. This is particularly critical in patients with oral cancer, in whom difficult airway conditions reduce the likelihood of successful tube exchange. Optimizing endotracheal tube cuff positioning represents a safe and effective approach. Individualised anesthetic airway management is essential to ensure patient safety.