Foreign Body in Tracheobronchial tree

I. Introduction & Epidemiology

• Definition: Inhalation of an object into the tracheobronchial tree.
• Age: Peak incidence 1–3 years (oral exploration phase, lack of molars).
• Site: Right Bronchus (60%) > Left Bronchus.
  • Reason: Right main bronchus is wider, shorter, and more vertical.
• Nature of Object:
  • Organic (Most common): Peanuts (Vegetable bronchitis), seeds.
    • Risk: Cause severe chemical pneumonitis due to oils (arachidonic acid).
  • Inorganic: Beads, pins, plastic parts.

II. Pathophysiology: Mechanisms of Obstruction

Jackson described 4 types of bronchial obstruction based on the fit of the foreign body (FB):

1. Bypass Valve:
   • FB causes partial obstruction.
   • Air passes in and out.
   • Sign: Localized wheeze.
2. Check-Valve (Ball-Valve):
   • Air enters during inspiration (airway dilation).
   • Air cannot exit during expiration (airway collapse).
   • Result: Obstructive Emphysema (Air trapping/Hyperinflation) distal to obstruction.
3. Stop-Valve:
   • Complete obstruction. No air enters or exits.
   • Result: Atelectasis (Collapse) of the lung segment.
4. Ball-Valve (Reverse): Rare; air exits but cannot enter.

III. Clinical Features: The 3 Stages

Triad: Sudden onset Cough, Wheeze, Decreased Air Entry.

1. Stage 1: Initial Event (Choking Crisis)

   • Sudden onset of violent coughing, gagging, and choking.
   • Cyanosis and stridor may occur.
   • often witnessed by parents.

2. Stage 2: Asymptomatic Interval (The "Latent" Phase)

   • The FB lodges in a bronchus; reflexes fatigue.
   • Child appears fine.
   • Danger: Often leads to delayed diagnosis or misdiagnosis as asthma.

3. Stage 3: Complications

   • Obstruction, erosion, or infection leads to pneumonia, lung abscess, or bronchiectasis.
   • Fever, productive cough, hemoptysis.

IV. Diagnosis

1. History (Most Important)

• A positive history of choking is highly specific (Sensitivity >90%).
• "A choking child is a foreign body until proven otherwise."

2. Physical Examination

• Classic Signs:
  • Unilateral decreased air entry.
  • Localized wheeze (monophonic).
  • Tracheal shift (away from air trapping, towards collapse).

3. Radiology (Chest X-ray)

• Standard: PA View (Inspiration and Expiration).
• Findings:
  • Radio-opaque FB: Visible (coins, metal) - only 10-15% of cases.
  • Radio-lucent FB (Vegetative): Indirect signs are key.
    • Obstructive Emphysema: Hyperlucency on the affected side.
    • Mediastinal Shift:
      • Inspiration: Normal or slight shift to affected side.
      • Expiration: Mediastinum shifts to the NORMAL side (Holzknecht sign) because the obstructed lung cannot deflate.
    • Atelectasis: Opacity/collapse (late sign).

V. Management

1. Emergency (If Choking/Apneic)

• <1 year: Back blows and Chest thrusts.
• >1 year: Heimlich Maneuver (Abdominal thrusts).
• Unresponsive: CPR.

2. Definitive Management

Rigid Bronchoscopy is the Gold Standard for both diagnosis and removal.

• Procedure: Under General Anesthesia (spontaneous ventilation preferred).
• Why Rigid?
  • Better control of the airway.
  • Ability to use optical forceps for grasping.
  • Better suctioning of secretions/blood.
• Flexible Bronchoscopy: Used primarily for diagnosis in doubtful cases or distal FBs.

3. Post-Procedure

• Observation for laryngeal edema.
• Antibiotics (if chemical pneumonitis or secondary infection is present).
• Steroids (short course) for edema.

VI. Complications

• Acute: Laryngeal edema, Hypoxic brain injury, Pneumothorax.
• Chronic (Delayed Diagnosis):
  • Recurrent Pneumonia (same lobe).
  • Lung Abscess.
  • Bronchiectasis (irreversible damage).