Discussion
Foreign body aspiration (FBA) demands timely diagnosis and treatment, diagnostic evaluation of suspected FBA is based on a history of choking, cough, dyspnea, and decrease breathe sound, wheeze and stridor and among these signs and symptoms choking event is the most specific one.3 Most of the time history of choking or witness of the event is absent leading to delayed diagnosis and increasing the risk of complications. Study done by Karakoc et. al. revealed that inorganic foreign bodies are more common in adolescents. Due to radiopaque nature and positive history of aspiration these kind of foreign bodies are diagnosed promptly. On the other hand, organic FBA is associated with a longer elapsed time from aspiration to diagnosis with increased risk of complication like pneumonia and bronchiectasis, bronchial fistula, and it can even get secondarily dislodged and cause acute respiratory deterioration.4,5
Our case was unique as the patient developed the shortness of breath after an attempt of partial hanging and intubation and tracheostomy to follow. This history compelled us to make the provisional diagnosis of subglottic stenosis without a second thought. Furthermore, CT scan findings also supported our diagnosis. The sensitivity of CT scan for the detection of bronchial FB is close to 100% with specificity between 66.7 and 100% and very few false-negative. Qiu et. al. found false negative rate of about 7% and it depended upon endobronchial inflammatory exudate, tracheobronchial stenosis or obstruction, which may cover up the sign of intrabronchial foreign body. When they were aspirated into the trachea or bronchus, they often located in parallel with the bronchial lumen, so the layer images of CT may miss the signs of FBs.6,7 In our case also the granulation tissue might have obscured the CT finding.
Airway stenosis due to long standing foreign body is underrated in the literature as only pneumonia, bronchiectesis and fistulas are described in most of the literatures. Any impacted FB causes mucosal trauma to airway lumen and initiate the granulation around it which then leads to cicatrization and airway stenosis. The process of stenosis may progress even after removing the foreign body signifying the need of periodic post-operative bronchoscopic evaluation.8
Patients suspected with sub glottis stenosis need accurate assessment for proper planning of the treatment and to prognosticate the future outcome. Though imaging is a simple, noninvasive and easily accessible tool for the assessment, rigid bronchoscopy is the basic assessment tool for precise pre-operative assessment of the site, grade and length of laryngotracheal stenosis.9 Similarly rigid bronchoscopy under general anesthesia is standard of care to diagnose and remove the air way foreign body.10