A large anterior fontanelle in an infant may indicate which condition?

A large anterior fontanelle in an infant can be indicative of several conditions, with the most relevant being hypothyroidism. In infants, hypothyroidism can lead to a range of developmental issues and physical characteristics, one of which may include an enlarged anterior fontanelle. This occurs because thyroid hormones play a crucial role in growth and development, and their deficiency can alter normal head growth patterns.

In the context of other options, dehydration is unlikely to result in an increased anterior fontanelle; rather, it is more often associated with a sunken fontanelle. Hydrocephalus, while also a condition associated with an enlarged fontanelle, is typically characterized by other symptoms such as increased intracranial pressure and abnormal head growth patterns, rather than just the size of the fontanelle alone. Normal development can result in variations in fontanelle size, but typically, the fontanelle would not be described as "large" in that context without other accompanying signs or conditions present. Thus, hypothyroidism aligns well with the finding of a larger anterior fontanelle, warranting further investigation into thyroid function in the infant.