Which of the following is a late sign of severe dehydration in an infant?

The presence of no tears when crying serves as an indicator of late-stage dehydration in an infant. Tears are produced by the lacrimal glands, which require adequate hydration to function properly. When an infant is dehydrated, the body conserves water, leading to insufficient tear production. This can be particularly concerning since it shows that the infant's hydration status has reached a critical point.

Other signs of severe dehydration, such as sunken eyes, oliguria (decreased urine output), and a dry mouth, can also be observed. Sunken eyes indicate loss of fluid around the eye sockets, and oliguria reflects decreased urine production, often a sign that the kidneys are conserving water due to dehydration. A dry mouth also indicates a significant lack of moisture in the body. However, the absence of tears when crying is often a more striking and specific sign of severe dehydration, giving an immediate visual cue that the infant requires urgent medical attention. Recognizing these signs promptly can help ensure timely intervention and treatment for the infant's dehydration.