What indicates a 5-month-old infant needs an IV for severe dehydration?

An infant's ability to produce tears is an important indicator of hydration status. Generally, if a baby is severely dehydrated, one of the classic signs is the absence of tears when crying. This absence suggests that the body's fluid levels are critically low, which can impair the production of tears. In a 5-month-old infant, the presence of tears is a normal sign of hydration; if this is missing, it can be a concerning indication that the infant may require intravenous (IV) fluid replacement to address severe dehydration effectively.

The other symptoms listed, while concerning and indicative of potential dehydration or other issues, do not specifically signal the need for IV fluids as clearly as the absence of tears. Vomiting for 24 hours may indicate fluid loss but does not, by itself, confirm the severity of dehydration. Excessive sleepiness might suggest a myriad of issues, including dehydration, but does not definitively indicate that IV fluids are necessary. Refusing to eat could be a sign of dehydration or illness too, but it does not provide the direct worsening state of hydration that a lack of tears does. Thus, the absence of tears is a more concrete sign that an infant might be severely dehydrated and in need of more immediate medical intervention through IV fluids.