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