2025 – PAGE 427 – PULMONOLOGY

STRIDOR

PEARL: Some of these topics will definitely be on your exam, and they are very quick and easy points.

Inspiratory stridor suggests obstruction above the glottis.

LARYNGOMALACIA: The soft, floppy, immature cartilage of the larynx collapses and causes airway obstruction. This is the most common cause of stridor in infants. Look for a child with onset of stridor around 4–6 weeks of age. Stridor is more prominent, or noted, when the child is SUPINE or AGITATED. The patient may have retractions. Laryngoscopy may reveal a rolled, omega-shaped epiglottis. Usually resolves by 12 months of age.
- IMAGE: www.pbrlinks.com/INSPIRATORYSTRIDOR1 (omega shape)
- IMAGE: www.pbrlinks.com/INSPIRATORYSTRIDOR2 (omega shape)
- MNEMONIC: larINgomalacia = INspiratory stridor presenting in INfancy
VOCAL CORD PARALYSIS: Look for a child with a high-pitched stridor but weak cry since birth. The stridor is usually inspiratory and is less likely to be present at rest. Children seem uncomfortable when crying.
- PEARL: The patient may have a hoarse cry. This can present later in life with a hoarse voice. Also, do not rule this out if the patient has a biphasic stridor (inspiratory and expiratory).
- MNEMONIC: If I were a baby and wanted to make a bunch of noise when I’m crying to get my parents’ attention, but couldn’t, I would be uncomfortable too!
PERTUSSIS: Look for the single whoop and “paroxysmal” cough.
CROUP: Look for the barky cough and the steeple sign on X-ray (see ID).
MASSES: Pharyngeal masses, hypertrophic tonsils or adenoids.

Expiratory stridor suggests obstruction in the lower trachea.

TRACHEOMALACIA: Like laryngomalacia, this usually presents around 4–6 weeks of age and may also be worse when supine. The differences are that it’s usually an expiratory stridor, or wheeze, and located in the trachea. This CAN sometimes also have an inspiratory stridor, but expiratory is much more common.
- MNEMONICS: tracheOUTmalacia = Stridor when breathing OUT. Also, note that both of the “–malacias” present around 4–6 weeks!
VASCULAR RING: Look for a neonate having trouble feeding and expiratory stridor since birth.
- PEARL: Evaluate this with a barium swallow, not a scope! Diagnose with either CT angiography or MRA. If you have to choose between the two on the boards, pick CT angiography because it’s cheaper, quicker, and would not require any sedation.