A 7-year-old male exhibits decreased mental status after several days of fatigue and vomiting. What is the most likely cause?

In this scenario, the most likely cause of the 7-year-old male's decreased mental status, following several days of fatigue and vomiting, is diabetic ketoacidosis (DKA). DKA is a serious condition that can occur in children, particularly those with undiagnosed type 1 diabetes. The combination of fatigue, vomiting, and altered mental status suggests a significant metabolic disturbance, often associated with electrolyte imbalances and acidosis.

Dehydration can certainly result from prolonged vomiting and could contribute to altered mental status as well. However, dehydration in itself is generally not the primary cause of decreased mental status unless it is severe enough to lead to shock or other critical states, which is less common than DKA presenting with similar symptoms.

Gastroenteritis, while it can cause vomiting and potentially lead to dehydration, would not typically explain the profound change in mental status unless the child became severely dehydrated. Intussusception is a surgical emergency that usually presents with abdominal pain, and while it can lead to vomiting, it is less likely to directly cause decreased mental status without other accompanying symptoms such as severe abdominal pain or a palpable mass.

Therefore, considering the progression of symptoms and their seriousness, DKA aligns best with the clinical picture and is a