A common cause of shock in an infant is:

Dehydration from vomiting and diarrhea is a common cause of shock in infants due to their smaller body size and greater susceptibility to fluid loss. Infants have a higher percentage of body water compared to adults, and when they experience significant fluid loss from gastrointestinal issues, they can quickly become dehydrated. This dehydration can lead to hypovolemic shock, where the volume of circulating blood is insufficient to maintain adequate circulation and oxygen delivery to vital organs.

When infants lose fluids, it can affect their heart rate and blood pressure, ultimately leading to a decrease in perfusion. Since they cannot compensate for this fluid loss as effectively as older children or adults, recognition of dehydration as a potential cause of shock is crucial for timely intervention.

In contrast, while excessive tachycardia, cardiovascular disease, and cardiac arrhythmias may also contribute to clinical instability or shock, they are less common causes in infants compared to the immediate effects of dehydration from vomiting and diarrhea. Understanding the physiological differences in infants, including their fluid balance and responses to illness, is key in recognizing why dehydration is the more prevalent cause of shock in this age group.