A 3-year-old child has a sudden onset of respiratory distress with no recent illnesses. What should you suspect?

In a scenario where a 3-year-old child experiences sudden onset respiratory distress without any recent illnesses, the most likely concern is foreign body airway obstruction. This situation often occurs when a child accidentally inhales a small object or food item, leading to an acute airway blockage. Such an event can result in immediate respiratory difficulties, wheezing, coughing, or stridor, depending on the location and extent of the obstruction.

The sudden nature of the symptoms and the lack of prior indications of illness strongly point towards a foreign body obstruction rather than conditions like croup or epiglottitis, which typically have a different onset and include accompanying symptoms such as a preceding respiratory illness or fever. While lower respiratory infections could also cause respiratory distress, they generally develop over time and are not characterized by a sudden onset without previous signs. Therefore, the acute presentation of respiratory distress in this case supports the suspicion of foreign body airway obstruction as the most likely cause.