HESI Health Assessment Practice Test 2026 – All-in-One Study Guide for Exam Success!

In assessing an infant with depressed and sunken fontanels, the most likely condition to suspect is dehydration. The fontanels are the soft spots on an infant's skull where the bones have not yet fused. In a well-hydrated infant, these fontanels should be flat and firm. However, when dehydration occurs, fluid loss can lead to decreased intracranial and cerebrospinal fluid volume, resulting in a sunken appearance of the fontanels.

Dehydration in infants can arise from various causes, including diarrhea, vomiting, or inadequate fluid intake, and it can present with other clinical signs such as dry mouth, decreased urinary output, and lethargy. Prompt recognition of dehydration is crucial since it can quickly lead to more severe complications if not addressed.

In contrast, conditions like rickets, mental retardation, or increased intracranial pressure do not typically cause sunken fontanels. Rickets is characterized by bone weakness due to vitamin D deficiency, which would not directly influence the appearance of fontanels. Mental retardation, a developmental condition, does not manifest with specific signs related to the fontanels. Increased intracranial pressure, on the other hand, usually causes the fontanels to