What should you suspect if a one-year-old baby is breathing rapidly, has sunken eyes, and hasn't had wet diapers for a few days?

In the scenario described, the symptoms of rapid breathing, sunken eyes, and a lack of wet diapers over the course of a few days strongly indicate dehydration. A one-year-old who is rapidly breathing may be compensating for a lack of fluid in the body, which can lead to decreased blood volume and lower blood pressure. Sunken eyes are a physical sign of dehydration, reflecting a loss of body fluids, and the absence of wet diapers for several days is a clear indication that the child is not producing adequate urine, suggesting significant fluid loss or insufficient fluid intake.

While an infection could also cause some of these signs, the specific combination of symptoms closely correlates with dehydration rather than solely an infectious process. Respiratory distress might be present in various conditions, but in this case, it is likely a result of the body trying to compensate for dehydration. Congestive heart failure is less common in a one-year-old without other significant underlying health issues and would present differently, often including other symptoms such as poor feeding, lethargy, and increased work of breathing due to fluid overload or congestion.

Considering these clinical signs, dehydration stands out as the most likely diagnosis, necessitating prompt assessment and intervention to address the child's fluid needs.