Final Answer:
The signs of dehydration in a 5-month-old infant who has had vomiting and diarrhea for 3 days include Sunken fontanelles (Option 1).
Step-by-step explanation:
Dehydration is a critical concern in infants with prolonged vomiting and diarrhea. Sunken fontanelles, the soft spots on an infant's head, are a reliable indicator of dehydration. When a child is dehydrated, there is a decrease in fluid volume, leading to a sunken appearance of the fontanelles.
The fontanelles normally have a slight depression, but excessive sunkenness can indicate a significant fluid deficit. This occurs because as the body loses more fluids than it takes in, there is a decrease in the intravascular volume, causing the fontanelles to appear sunken.
Assessing dehydration in infants involves considering various clinical signs. Sunken fontanelles are particularly valuable because they provide a visual cue to the healthcare provider regarding the extent of dehydration. Other signs, such as increased urine output (Option 2), moist mucous membranes (Option 3), and normal capillary refill time (Option 4), are generally not consistent with dehydration.
Increased urine output may suggest adequate hydration, moist mucous membranes are expected in a well-hydrated state, and a normal capillary refill time is also indicative of adequate perfusion.
In conclusion, recognizing sunken fontanelles as a sign of dehydration is crucial for prompt intervention and fluid resuscitation in a 5-month-old infant with vomiting and diarrhea. Other options are not reliable indicators of dehydration in this context. It is essential to act swiftly in such cases to prevent complications associated with dehydration, such as electrolyte imbalances and organ dysfunction.