A 3 month old child presents with intermittent stridor which reduces on lying prone. The most likely diagnosis is:
**Core Concept**
The question is testing the understanding of laryngomalacia, a congenital condition characterized by the softening of the laryngeal cartilages, leading to partial airway obstruction. This condition is most commonly seen in infants and often presents with inspiratory stridor that worsens with crying or agitation.
**Why the Correct Answer is Right**
The correct answer is likely **C. Laryngomalacia**. This condition is caused by the floppy epiglottis and supraglottic tissues, which collapse into the airway during inspiration, leading to partial airway obstruction. The stridor is typically inspiratory and worsens with agitation or crying. The fact that the stridor improves when the child is lying prone is a classic clinical finding in laryngomalacia, as this position helps to reduce the severity of the airway obstruction.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is not relevant to the clinical presentation described. **Option B:** This option is incorrect as laryngomalacia typically presents in the first few weeks of life, whereas this child is 3 months old. **Option D:** This option is incorrect as laryngomalacia is not caused by a foreign body or an infectious process.
**Clinical Pearl / High-Yield Fact**
A key clinical feature of laryngomalacia is that the stridor is typically inspiratory and worsens with agitation or crying. The stridor often improves when the child is lying prone, which can help to differentiate this condition from other causes of stridor.
**Correct Answer: C. Laryngomalacia**