A 17 month old male presents to the ED in the 
evening with a one-hour history of noisy and abnormal 
breathing after a choking episode while he was eating a 
chocolate and almond bar.  He was able to speak and 
drink fluids without difficulty.
     Exam:  VS T36.8, P200 (crying), R28 (crying), 
oxygen saturation 99% in room air.  He appeared alert, 
with no signs of respiratory distress.  He was able to 
speak, had no cyanosis, no drooling, and no dyspnea.  
His lung sounds showed mild wheezing with possible 
mild inspiratory stridor.  An albuterol aerosol was 
administered but no improvement was noted.  A 
chest radiograph was ordered.

View CXR.


Questions:
     1.  Are any foreign bodies visible on this radiograph?
     2.  Are there any subtle findings on this radiograph 
to suggest a foreign body?
     3.  Are there other radiologic procedures that can be 
done to try to identify a foreign body?
     4.  Is an invasive procedure necessary or indicated 
at this point, i.e., bronchoscopy?

     This CXR is within normal limits; however, when a
clinical suspicion of an airway foreign body is present, 
a standard PA and lateral CXR are an insufficient 
evaluation.  A lateral neck film should be obtained to 
examine the upper airway for evidence of swelling or 
foreign body.  Decubitus films and/or expiratory films 
should also be obtained to look for evidence of air 
trapping.

View supplementary radiographs.

Lateral neck.


Expiratory Chest.


Left lateral decubitus.


Right lateral decubitus.


     The lateral neck radiograph is within normal limits.  
The black dots in the upper right are pointing to a 
metallic object in the holder's watch band.
     These other radiographs were interpreted as 
possible bilateral air trapping.
     The expiratory view is fairly symmetric in this 
instance.  A foreign body in a bronchus is expected to 
show air trapping with some hyperexpansion visible in 
that lung.  In the expiratory view, both lung volumes 
should normally be decreased.  If one side is still 
expanded during expiration, this indicates air trapping 
and a possible foreign body on that side.
     An expiratory CXR that shows symmetry of both 
lung volumes does not rule out a foreign body.  Such a 
CXR is often assumed to be consistent with asthma.  
Although this is often true, this is occasionally a pitfall 
that should be avoided by considering such a CXR to 
also be consistent with a tracheal foreign body.  
Examine the expiratory CXR again.  It shows that both 
lungs empty poorly, indicating bilateral air trapping.  
This could be consistent with asthma or with a tracheal 
foreign body.
     The left lateral decubitus view (left side down) shows 
the left lung volume to be somewhat smaller than the 
right lung volume.  However, one might expect the left 
lung to be even smaller in the dependent position, so 
perhaps it isn't as small as it should be.  This suggests 
some degree of air trapping on the left.
     The right lateral decubitus view (right side down)
is of poor quality.  The original film was very dark so 
the scanned image is very grainy.  This shows the right 
lung to be clearly expanded even though it is 
dependent.  This suggests air trapping since a normal 
lung should appear smaller in the dependent position.
     The patient was taken to the operating room for
bronchoscopy.  At bronchoscopy, about 15-20 pieces of 
nut particles in the lower trachea and in both major
bronchi were found.  They were somewhat difficult to
remove because of their small size.  Most were 
removed with grasping forceps and suction.  He did well
postoperatively.

Discussion and Teaching Points:
     Approximately 75% of all cases of foreign body
aspiration occur in children less than 3 years of age.
Organic debris is most frequently retrieved on
bronchoscopy.  Peanuts are the most common 
offending agent.  Unfortunately, only 6-17% of airway 
foreign bodies are radio-opaque.  Respiratory 
symptoms may be produced by an object lodged 
anywhere in the airway, from the hypopharynx to a 
segmental bronchus.  
     Children who ingest or aspirate foreign bodies may 
present in acute respiratory distress days or months 
after the aspiration episode.  Between 50% and 90% of 
children have a suggestive history, most commonly of 
an acute episode of paroxysmal cough.  Other common 
signs are cyanosis, choking, and dyspnea.  However, 
delays in presentation for care are common, and 
concern about aspiration as a cause of the child's 
symptoms may diminish as the primary event becomes 
more distant.  Only half of all children are diagnosed 
correctly in the first 24 hours after an aspiration event.  
An additional 30% receive the correct diagnosis in the 
following week, while the remainder may have delays in 
diagnosis of weeks to years.  One-fourth of children 
may be asymptomatic at the time of presentation, and 
up to 38% may have no helpful physical exam findings.  
     The complete triad of coughing, wheezing, and 
decreased or absent breath sounds is present in only 
about 40% of cases.  Other suggestive physical exam 
findings are stridor, tachypnea, retractions, rales, and 
fever.  They are often misdiagnosed as croup, asthma, 
pneumonia, or bronchitis.  This is a diagnostic pitfall 
that should be avoided.  Thus, the diagnosis of foreign 
body aspiration must be considered in any previously 
well, child who has a history of acute onset of choking, 
coughing, or wheezing, as well as any child who has a 
poorly defined, chronic respiratory complaint.  

Remember this general principle:

Nuts + Choking = Bronchoscopy
     (regardless of radiographic results)

     Roughly 85% of foreign bodies are bronchial, while 
15% are laryngotracheal.  Laryngotracheal foreign 
bodies are more difficult to diagnose and they have a 
higher mortality rate.  Differential findings, clinically or 
radiographically, may only be present in unilateral 
bronchial foreign bodies.  Differential findings are often 
absent in bilateral bronchial foreign bodies or 
laryngotracheal foreign bodies.  Additionally, foreign 
bodies may shift in position.  Thus, a previously 
suspicious radiographic study may be negative if it is 
repeated.  One cannot assume that such a patient is 
now normal since a more likely explanation is that the 
foreign body has moved.  Avoid this pitfall.
     Although appropriate radiologic studies may localize 
the site of the foreign body, a significant number of 
children with retained airway foreign bodies have 
non-diagnostic films.  Radiologic evaluation should start 
with AP and lateral views of the chest and neck.  
Although plain films may be interpreted as normal, 
differential inflation of the affected lung, the most 
common abnormality identified, may be documented by 
fluoroscopy, lateral decubitus views, or an assisted 
expiratory film (the examiner compresses the patient's 
abdomen during expiration).  Other indirect signs of an 
airway foreign body include reabsorption atelectasis 
beyond the site of bronchial obstruction, and the 
presence of pulmonary infiltrates reflecting an 
inflammatory reaction.  One source (Esclamado) 
reported positive findings on chest radiographs in only 
42% of children with laryngotracheal (as opposed to 
bronchial) foreign bodies, but a higher rate of positive 
findings on lateral neck films in the same series.  This 
emphasizes the need to direct the examination to the 
neck (ie., lateral neck view) when signs of upper airway 
obstruction are present.  Esophageal foreign bodies 
may also cause predominantly respiratory symptoms.
     Although CT scan, xeroradiography, and 
ultrasonography have been advocated for foreign body
imaging, their utility is not well defined at this time.
CT scanning may be non diagnostic because of 
respiratory motion (resulting in poor images) and such 
patients usually require sedation which can be risky in 
the presence of airway compromise.  Given the high 
morbidity associated with delay in the diagnosis of an 
airway foreign body, and the limited sensitivity of 
radiographic studies in identifying this condition, clinical 
judgment must dictate whether the child should be 
scheduled for diagnostic bronchoscopy in the absence 
of radiographic findings.

References
     Schunk JE.  Foreign Body-Ingestion/Aspiration.  In:
Fleisher GR, Ludwig S (eds).  Textbook of Pediatric
Emergency Medicine, third edition.  Baltimore, Williams
& Wilkins, 1993, pp. 210-217.
     Brownstein D.  Foreign Bodies of the 
Gastrointestinal Tract and Airway.  In:  Barkin R (ed).  
Pediatric Emergency Medicine Concepts and Clinical 
Practice.  Chicago, Mosby Year Book, 1992, pp. 
311-314.
     Hamilton AH, Carswell F, Wisheart JD.  The Bristol 
Children's Experience of Tracheobronchial Foreign 
Bodies 1977-87.  Bristol Med Chir Journal 1989;104:72.
     Esclamado RM, Richardson MA.  Laryngotracheal 
Foreign Bodies in Children.  American Journal of 
Diseases in Children 1987;141:259.