Pediatric emergency medicine trisk 0681 0681
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Lower Respiratory Tract: Diagnosis
A high clinical index of suspicion is necessary to diagnose foreign-body
aspiration accurately and promptly. Symptoms of foreign-body aspiration are also
seen with common conditions, such as upper respiratory tract infection,
bronchiolitis, pneumonia, and asthma. A history of possible foreign-body
aspiration should be sought in all cases of new-onset respiratory distress, stridor,
wheezing, or cough, especially in young children aged 6 months to 4 years. This
should include questions about recent choking episodes, especially when eating
nuts, seeds, apples, and carrots and what the child was doing when the symptoms
started.
Radiographs serve as important diagnostic aids, but when the clinical suspicion
for foreign-body aspiration is high (suggestive history, acute onset of signs and
symptoms), a lack of confirmatory radiographic findings should not dissuade the
clinician from pursuing bronchoscopy for diagnosis and treatment. Findings on a
chest radiograph suggestive of an aspirated foreign body include air trapping,
atelectasis, mediastinal shift, and consolidation. The more time elapsed after the
aspiration event, the more likely the chest radiograph will be abnormal,
demonstrating findings of consolidation or atelectasis. Inspiratory and expiratory
films comparing the relative deflation of the two lungs may demonstrate
unilateral air trapping indicative of a foreign body producing a ball-valve effect
on the affected side ( Fig. 32.3 ). In the young or uncooperative child in whom
obtaining an adequate expiratory film may be difficult, bilateral lateral decubitus
chest radiographs (both obtained during inspiration) comparing the relative
deflation of the dependent lung may be a useful adjunct. In one study of 1,024
children with foreign-body aspiration, inspiratory and expiratory chest
radiographs were found to be normal in 15% of cases. If available, chest
fluoroscopy may also be useful for diagnosis, demonstrating evidence of focal air
trapping on the side of the foreign body or a mediastinal shift away from the
affected side on expiration. Chest CT is more reliable than either plain
radiography or fluoroscopy in diagnosing aspirated foreign bodies, with a
sensitivity of 91% or higher, though it has increased radiation exposure and is not
routinely used.
The approach to diagnosing foreign-body aspiration is outlined in Figure 32.6 .
When there is concern for a respiratory foreign body, the patient should be given
nothing by mouth until the disposition is determined due to the possible need for
bronchoscopy. The patient should first be evaluated with inspiratory and
expiratory or lateral decubitus chest radiographs. If these studies are normal, the
aspiration history is poor, the material uncommonly aspirated, the patient has
