SESSION TITLE: Bronchology/Interventional Student/Resident Case Report Posters II
SESSION TYPE: Medical Student/Resident Case Report
PRESENTED ON: Tuesday, October 28, 2014 at 01:30 PM - 02:30 PM
INTRODUCTION: Congenital tracheal stenosis as described in the pediatric literature is often a serious and fatal birth defect. Infants with less severe stenosis may manifest later with a symptomatic stridor that leads to diagnosis. Those that escape detection into adulthood are often diagnosed when endotracheal intubation is attempted for general anesthesia1. The case presented here is a rare occurrence of a silent tracheal stenosis diagnosed in a 58 year old female with lifelong symptoms.
CASE PRESENTATION: A 58 year old female presented with longstanding symptoms of dyspnea on exertion despite a regular exercise program. Although dyspneic, she had been active her whole life, had a normal BMI and a normal echocardiogram. On cardiopulmonary exercise testing using a 15 watt ramp protocol she was limited by breathlessness at 6 minutes and 20 seconds. Her A-a gradients before and after testing were 31 and 9 mmHg, respectively. Her maximum oxygen consumption was 1180 cc/min (66% predicted) with an anaerobic threshold of 1040 cc/min (145% predicted). Pulmonary function tests were completed before and after exercise that showed no obstruction (FEV1/FVC 74%) or diffusion defect. The flow-volume loop showed significant flattening of the inspiratory and expiratory flow (Figure 1). A scan of the neck suggested a narrowing of the trachea 3cm below the vocal cords (Figure 2A), and this was confirmed by bronchoscopy (Figure 2B). The patient was referred to a tertiary care center for tracheal stenting.
DISCUSSION: In an un-manipulated airway, the suspicion for tracheal stenosis is low, especially in the absence of stridor. In tracheal stenosis the resistance to flow is exponential, and forms a ceiling to peak flow rate for both inspiration and expiration. The resultant flow is limited on top and bottom showing a flattening which is pathognomonic for fixed airway obstruction.
CONCLUSIONS: This patient illustrates the utility of the flow volume loop in unmasking an unsuspected fixed, airflow limiting stenosis. Normal spirometric values were insufficient for diagnosis as this patient’s flow limitation did not occur until after one second. Examining the shape of the curve is vital to securing the correct diagnosis. This case illustrates a rare congenital abnormality that persisted into adulthood, and until corrected, this patient had never experienced any other baseline for comparison.
Reference #1: Chong Z K, Jawan B, Poon Y Y, Lee J H. Unsuspected difficult intubation caused by a laryngeal web. Br J Anaesth. 1997 Sep;79(3):396-7.
DISCLOSURE: The following authors have nothing to disclose: Brandon Coffey, Frederick Clayton, Thomas Roy, Jayantilal Mehta
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