In which situation might a child present with altered mental status and seizures?

Hypoglycemia is a leading cause of altered mental status and seizures in children due to the brain's dependence on glucose for energy. When blood sugar levels drop significantly, neurological functions can be impaired, manifesting as confusion, irritability, lethargy, or loss of consciousness. Additionally, hypoglycemia can trigger seizures because the brain is not receiving the necessary energy to function properly.

In contrast, while anaphylactic reactions can lead to altered mental status due to decreased oxygenation or shock, they are more typically associated with respiratory distress or skin reactions rather than seizures as a primary manifestation. Pulmonary embolism is rare in pediatric patients and typically presents with respiratory distress rather than altered mental state or seizures. Severe constipation may cause abdominal pain or distension but is unlikely to directly result in altered mental status or seizures. Thus, hypoglycemia stands out as the most likely cause in this scenario.