PediAtlas/Respiratory/Lower Airway/Foreign Body Aspiration

Trachea & Bronchi

Foreign Body Aspiration

Aspiration of food or another object into the tracheobronchial tree can cause focal airway obstruction, air trapping, atelectasis, or delayed recurrent pulmonary disease. The initial choking episode may resolve even though the foreign body remains in the lower airway.

Lower AirwayForeign Body AspirationFocal Airway ObstructionBronchoscopy

Clinical Vignette

A toddler with persistent wheezing after a choking episode

A previously healthy 22-month-old boy is brought to the emergency department after suddenly coughing and choking while eating peanuts. His parents report that he briefly became cyanotic but quickly recovered. Since the event, he has continued to cough intermittently. Examination reveals mild tachypnea, decreased breath sounds, and an expiratory wheeze over the right lung field. Oxygen saturation is 97% on room air.

What should you decide first?

Determine whether the choking episode resulted in a retained lower-airway foreign body and whether the child requires further diagnostic evaluation and bronchoscopic removal.

Anatomy & Localization

Airway or esophagus?

After passing through the oropharynx, an object may enter the respiratory tract or pass posteriorly into the esophagus. For an aspirated foreign body that passes below the larynx, the level of tracheobronchial impaction helps determine the clinical pattern.

Airway aspiration

Think cough, wheeze, and focal respiratory findings

• Sudden choking or coughing event
• Persistent cough after apparent recovery
• Unilateral or focal wheezing
• Asymmetric or decreased breath sounds
• Focal air trapping or atelectasis
• Recurrent focal pneumonia with delayed diagnosis

Esophageal ingestion

Think drooling, dysphagia, and feeding refusal

• Drooling or inability to manage secretions
• Dysphagia or odynophagia
• Gagging, vomiting, or feeding refusal
• Retrosternal or neck discomfort
• Object visible within the esophagus on imaging
• Respiratory symptoms may occur from tracheal compression

Localization within the lower airway

Trachea

Cough, noisy breathing, variable wheeze, or symptoms that change as the object moves within the trachea.

Mainstem bronchus

Unilateral wheeze, asymmetric breath sounds, focal air trapping, or atelectasis.

Distal bronchus

Subtle focal findings, persistent cough, segmental atelectasis, or recurrent pneumonia involving the same region.

Pediatric Anatomy Pearl

Do not assume the foreign body is on the right

Young children have less pronounced differences between the right and left mainstem bronchial angles than adults, so an aspirated foreign body may lodge on either side.

Pathophysiology

A retained foreign body changes ventilation distal to the obstruction

The physiologic effect depends on how completely the object obstructs the airway and whether air can move around it during inspiration, expiration, or both.

The foreign body lodges

After passing through the larynx, the object may become lodged within the trachea, mainstem bronchus, or a more distal bronchus.

Airflow becomes mechanically obstructed

The degree and behavior of the obstruction depend on the object's size, shape, position, and interaction with the airway wall.

Distal ventilation becomes abnormal

Ventilation beyond the obstruction becomes asymmetric, producing focal physiologic and examination findings.

Retained objects cause delayed disease

Persistent obstruction can impair secretion clearance and produce local inflammation, post-obstructive infection, recurrent pneumonia, or chronic airway injury when diagnosis is delayed.

Ball-valve obstruction

Air enters around the object more easily during inspiration than it escapes during expiration, progressively trapping air distal to the obstruction.

Imaging clue: unilateral hyperinflation or air trapping.

Fixed or near-complete obstruction

When airflow past the object is markedly limited in both directions, ventilation distal to the obstruction falls and the affected lung segment may lose volume.

Imaging clue: segmental or lobar atelectasis.

Clinical Pearl

The child may look better while the obstruction remains

The initial choking and coughing may improve after the foreign body moves distally. Persistent focal wheeze, asymmetric breath sounds, air trapping, atelectasis, or recurrent focal infection may be the remaining clues to a retained tracheobronchial foreign body.

History & Physical

The choking episode may be over by the time you examine the child

Foreign body aspiration should remain high on the differential when an abrupt choking or coughing event is followed by persistent focal respiratory symptoms, even if the child initially appears to recover.

History clues

• Sudden choking, coughing, or gagging event
• Symptoms beginning while eating or playing with a small object
• Brief cyanosis or respiratory distress during the initial event
• Persistent cough after apparent recovery
• New wheezing without a prior history of recurrent wheeze
• Recurrent pneumonia involving the same region
• A choking event may be unwitnessed or not initially recalled

Physical examination

• Focal or unilateral wheezing
• Asymmetric or decreased breath sounds
• Localized crackles
• Tachypnea or increased work of breathing
• Unequal chest expansion
• Examination may be subtle when obstruction is incomplete
• Normal oxygen saturation does not exclude a retained foreign body

High-Yield Pattern

Sudden onset + persistent unilateral findings = foreign body until evaluated

A previously well child who develops abrupt coughing or choking followed by persistent focal wheeze or asymmetric breath sounds has a classic pattern for retained tracheobronchial foreign body aspiration. The initial choking episode may resolve even though the object remains.

Delayed Presentation

Not every aspiration presents immediately

When the initial event is unwitnessed or forgotten, children may present later with persistent cough, treatment-resistant wheezing, atelectasis, or recurrent pneumonia involving the same region.

Differential Diagnosis

Persistent wheezing is not always asthma

Age, abrupt symptom onset, choking history, and focal examination findings help distinguish foreign body aspiration from more common respiratory illnesses.

Asthma

Recurrent or episodic wheezing is usually more diffuse and often occurs with a prior history of similar episodes, triggers, or atopy. Persistent unilateral findings should prompt consideration of another diagnosis.

Bronchiolitis

Typically occurs in infants with a viral prodrome followed by diffuse crackles, wheezing, and increased work of breathing rather than abrupt focal findings after choking.

Pneumonia

Fever, infectious symptoms, focal crackles, or consolidation may suggest pneumonia, but recurrent pneumonia in the same location can be a clue to an underlying retained foreign body.

Mucus plugging

Airway obstruction from secretions may produce focal atelectasis or asymmetric breath sounds, particularly in children with impaired airway clearance or underlying pulmonary disease.

Airway malacia

Tracheomalacia or bronchomalacia may cause recurrent or persistent noisy breathing and wheezing, but symptoms are generally not linked to a sudden choking event.

Extrinsic airway compression

Vascular or mediastinal structures can compress the airway and produce persistent focal respiratory symptoms, usually without an abrupt choking history.

Diagnostic Clue

Focality matters

Wheezing that remains localized to one lung or one region is less typical of diffuse small-airway diseases such as asthma or bronchiolitis. When focal findings follow a sudden choking event, foreign body aspiration should move high on the differential.

Diagnostic Workup

Normal imaging does not exclude aspiration

Evaluation begins with the clinical history and examination. Imaging can support the diagnosis and localize secondary effects of obstruction, but a normal study cannot reliably exclude a retained tracheobronchial foreign body.

Chest radiographs

Obtain frontal and lateral chest radiographs in a stable child with suspected foreign body aspiration. The foreign body may be directly visible if radiopaque, but many aspirated objects are radiolucent.

Look for unilateral hyperinflation, air trapping, mediastinal shift, atelectasis, or focal consolidation.

Additional radiographic views

Inspiratory-expiratory radiographs may help demonstrate unilateral air trapping when standard radiographs are nondiagnostic. In younger children who cannot cooperate with expiratory imaging, lateral decubitus views may sometimes be used.

Their added diagnostic value is variable, so use depends on patient age, clinical suspicion, and institutional practice.

CT in selected patients

When the diagnosis remains uncertain after radiographs, low-dose noncontrast chest CT may help identify a radiolucent foreign body or secondary airway changes in selected stable patients.

CT should not delay bronchoscopy when clinical suspicion is high.

Bronchoscopy

Persistent clinical concern warrants airway evaluation even when radiographs are normal. Bronchoscopy provides direct visualization of the tracheobronchial tree and allows foreign-body removal during the same procedure.

Key Principle

A normal chest radiograph does not rule out foreign body aspiration

Many aspirated foreign bodies are radiolucent. When the history and examination remain concerning, normal radiographs should not provide false reassurance or prevent further airway evaluation.

Imaging Pearls

Review these classic imaging findings. Study the image first, then reveal the annotations to identify the important features.

Bronchial Foreign Body: Unilateral Air Trapping

Chest radiograph demonstrating unilateral air trapping from bronchial foreign body aspiration

Wikimedia Commons: Foreign Body Aspiration Chest Radiograph (Hellerhoff, 2022) · CC BY-SA 4.0

Clinical Pearl

Most aspirated foreign bodies are radiolucent and are not directly visible on chest radiographs. Diagnosis often relies on indirect findings such as unilateral hyperinflation, air trapping, and mediastinal shift.

Comparison

Esophageal Coin

AP and lateral radiographs demonstrate the typical appearance of an esophageal foreign body. The lateral view confirms that the coin lies posterior to the trachea.

Lateral radiograph demonstrating an esophageal coin

🔍 Click either image to view the full-resolution radiograph.

Radiopaedia Case: Oesophageal Foreign Body – Coin. Licensed under CC BY-NC-SA.

Clinical Pearl

On the AP radiograph, esophageal coins are usually seen en face (round), whereas tracheal coins more commonly appear edge-on.
The lateral radiograph confirms the coin is posterior to the trachea, supporting an esophageal location.
Always distinguish a coin from a button battery, which requires emergent removal because of the risk of caustic injury.

Management

A suspected retained foreign body requires definitive airway evaluation

Once the immediate choking episode has resolved, management focuses on maintaining clinical stability, recognizing when suspicion remains high, and arranging bronchoscopic evaluation and removal.

Initial management

• Keep the child calm and minimize unnecessary agitation
• Assess respiratory status and provide oxygen when indicated
• Maintain appropriate monitoring
• Keep the child NPO when bronchoscopy may be required
• Avoid unnecessary airway manipulation
• Involve the appropriate airway team early

When suspicion remains high

• Witnessed or strongly suspected aspiration event
• Persistent focal wheeze or asymmetric breath sounds
• Unilateral air trapping or focal atelectasis
• Persistent symptoms despite normal radiographs
• Recurrent focal pneumonia without another explanation

Definitive Management

Bronchoscopy allows visualization and removal

A retained tracheobronchial foreign body requires bronchoscopic removal. Rigid bronchoscopy is commonly used because it provides airway control, ventilation, direct visualization, and access for extraction instruments. The procedural team varies by institution and may include otolaryngology, pediatric surgery, pulmonology, and anesthesia.

Disposition

Disposition depends on whether a foreign body remains

Clinical improvement after the choking episode is not enough to determine disposition. Persistent suspicion for a retained tracheobronchial foreign body requires continued evaluation and appropriate airway consultation.

Discharge

• Foreign body successfully removed or aspiration excluded
• Breathing comfortably without respiratory distress
• Normal or reassuring respiratory examination
• No persistent hypoxemia
• No concerning post-procedural complication
• Appropriate follow-up and return precautions arranged

Observe & reassess

• Persistent cough or wheeze after the choking event
• Focal or asymmetric respiratory findings
• Abnormal chest imaging
• Uncertainty that the foreign body was expelled
• Requires further diagnostic or specialty evaluation
• Monitoring after bronchoscopic removal when indicated

Escalate care

• Respiratory distress or hypoxemia
• Worsening or unstable airway symptoms
• Suspected retained tracheobronchial foreign body
• Requires urgent bronchoscopy or operative removal
• Significant atelectasis or post-obstructive infection
• Complication following foreign-body removal

Disposition Pearl

Normal oxygen saturation does not equal a safe discharge

A child with a retained bronchial foreign body may appear comfortable and maintain normal oxygen saturation. Persistent focal findings or a convincing aspiration history should drive further evaluation rather than reassurance from the pulse oximeter alone.

Clinical Pearls

High-yield takeaways

Keep these principles in mind when evaluating a child with possible foreign body aspiration.

The choking may stop while the foreign body remains

Improvement after the initial choking episode does not prove that the object was expelled. A retained foreign body may continue to cause cough, wheeze, or focal respiratory findings.

Focal wheezing deserves an explanation

Persistent unilateral wheeze or asymmetric breath sounds are important clues to focal airway obstruction, particularly when symptoms began abruptly in a previously well child.

A normal radiograph does not rule it out

Many aspirated foreign bodies are radiolucent. When the history and examination remain concerning, normal chest radiographs should not end the evaluation.

Delayed aspiration can mimic common respiratory disease

An unwitnessed or missed aspiration may present later as persistent cough, treatment-resistant wheezing, atelectasis, or recurrent pneumonia involving the same region.

Do not assume the foreign body is on the right

In young children, the differences between the right and left mainstem bronchial angles are less pronounced than in adults, so an aspirated foreign body may lodge on either side.

Bottom Line

Think foreign body when the story is sudden and the findings are focal

A sudden choking or coughing event followed by persistent unilateral wheezing, asymmetric breath sounds, or focal radiographic abnormalities should raise concern for a retained tracheobronchial foreign body—even when the child appears well or the initial radiograph is normal.

Knowledge Check

Test your understanding

Apply the major diagnostic and management principles of pediatric foreign body aspiration.

Question 1

A previously healthy 2-year-old suddenly coughs and chokes while eating peanuts. He later appears comfortable but has persistent unilateral wheezing and decreased breath sounds. What is the most likely diagnosis?

Anki Deck

Foreign Body Aspiration

Reinforce the highest-yield concepts from this module with 16 spaced-repetition cards.

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Evidence Base

Clinical References

Foreign Bodies of the Ear, Nose, Airway, and Esophagus — Pediatric Care Online

American Academy of Pediatrics review covering the presentation, evaluation, and management of pediatric airway and esophageal foreign bodies.

Airway foreign bodies: A critical review for a common pediatric emergency

Clinical review of pediatric airway foreign body presentation, diagnostic evaluation, bronchoscopy, and complications of delayed diagnosis.

Diagnostic Value of Chest Computed Tomography Scan for Identification of Foreign Body Aspiration in Children

Systematic review and meta-analysis evaluating the diagnostic performance of chest CT for suspected pediatric foreign body aspiration.

Imaging of ingested and aspirated foreign bodies in the paediatric population

Pediatric radiology review describing radiographic evaluation, additional views, and advanced imaging of aspirated and ingested foreign bodies.

Secondary Educational Sources

Additional educational synthesis incorporates established pediatric emergency medicine, pulmonology, otolaryngology, and radiology principles. PediAtlas is intended for education and does not replace institution-specific protocols or clinical judgment.

Educational Disclaimer

PediAtlas is intended for medical education and should not replace institutional guidelines, local protocols, patient-specific assessment, or clinical judgment.