Pediatric ATI Practice Exam

What indicates moderate to severe dehydration in a 3-month-old with rotavirus?

1. Heart rate 124/min.

2. Increased tear production.

3. Sunken anterior fontanel.

4. Capillary refill 2 seconds.

The correct answer is: Sunken anterior fontanel.

A sunken anterior fontanelle is a significant indicator of moderate to severe dehydration in a young infant, such as a 3-month-old. The anterior fontanelle, which is the soft spot on the baby's head, can become sunken due to a decrease in intracranial pressure as a result of fluid loss. In cases of moderate to severe dehydration, the body loses fluids and subsequently may fail to maintain adequate hydration levels, leading to a noticeable change in the fontanelle's appearance. In contrast, a heart rate of 124 beats per minute can be normal for an infant and does not specifically indicate dehydration. Increased tear production typically suggests that the child is well-hydrated, as dehydration often results in decreased tear production. A capillary refill time of 2 seconds is generally considered within normal limits for an infant and does not reflect significant dehydration, as longer refill times would be more indicative of circulatory issues related to dehydration. Therefore, the sunken anterior fontanel serves as a clear clinical sign of serious dehydration in this age group, necessitating prompt assessment and intervention.