Pediatric Stridor - Notes

BMJ article notes.
Reference:
Majumdar S., et al. Pediatric Stridor. BMJ 2006; 91-4:101-105.

Notes:

Definition: High pitched noised due to turbulent airflow through a partially obstructed airway

Types of stridors:

• Obstruction at the level of the glottis or subglottis = inspiratory stridor
• Obstruction at the level of the supraglottis = stertor, low pitched sound
• Obstruction at the extrathoracic trachea = biphasic stridor
• Obstruction at the intrathoracic trachea = expiratory stridor.

Once a case comes in with the presentation of stridor; assess and secure the airway so that the airway is not lost. History and lab investigations to determine pathology.

Mechanism of stridor:

• Pediatric airway: epiglottis at level of atlas, cricoid cartilage at the level of C4.
• Apposition of the epiglottis and the soft palate= suckling and nasal breathing
• Thyroid cartilage is partly contained causing the laryngeal skeleton to be compact.
• With age, larynx grows, epiglottis increases faster than the rest of the larynx.
• Sub-glottis = 4-5cms and rich in mucus glands.
• Aspiration and laryngospasm due to inefficient closing and opening laryngeal reflex.
• Trachea tends to collapse more readily due to increased negative intrathoracic pressure.

Important physical sign in management of the stridor:

1. If the airway is flexible causes the wall to collapse due to the linear flow of air rather than the lateral.
2. Airway resistance is inversely proportional to the fourth power of the radius, hence, if the radius decrease by 0.5 will cause a 16 times increase in resistance.

Therefore, the narrowest lumen, the sub-glottis, can present a life threatening situation when obstructed by inflammatory edema, smooth muscle spasm, stenosis (cong., or acquired), foreign body.

Diagnosis and Initial Management:

• H/o of time; mode of onset of stridor
• Pyrexia, hypoxia
• Respiratory distress
• Severity of stridor during sleeping, wakefulness
• Feeding behavior

Tachypnea, Tracheal tug, Sternal and Subcostal recession, restlessness, reduced response, exhaustion, bradycardia, cyanosis.
Child can stop making stridor noises due to difficulty to move enough air to generate a sound or because there is a soft lesion like laryngeal papillomata à do not exclude diagnosis.
Radiographs: Metallic foreign bodies that narrow airway; Ultrasound: used to check masses or vocal cord function, Contrast swallow for trachea-esophageal fistula or laryngo-tracheal clefts.
MRI/CT: vascular abnormalities
Endoscopy and Laryngoscopy.

Conclusion:

Identify cause, secure airway, restore normal respiratory function. Thorough history required for diagnosis.


No plagiarism was intended, just notes from the article. All credits to the author.