In a case involving a high school girl found with cool and clammy skin and a blood glucose level of 20, what condition is most likely?

The scenario presented describes a high school girl with cool and clammy skin and a significantly low blood glucose level of 20 mg/dL. This combination of symptoms is indicative of hypoglycemia, which occurs when blood glucose levels fall below normal ranges, usually under 70 mg/dL.

Cool and clammy skin suggests the body is undergoing stress due to low glucose levels, which can activate the sympathetic nervous system—resulting in symptoms such as sweating and paleness. These signs are typical in hypoglycemic events, as the body tries to compensate for the low sugar by releasing stress hormones like adrenaline.

In contrast, hyperglycemia, diabetic ketoacidosis, and dehydration present with different symptoms and are characterized by high blood sugar levels or other metabolic disturbances. Hyperglycemia would not align with a blood glucose level of 20, and diabetic ketoacidosis typically presents with signs of dehydration, fruity breath, and an elevated glucose level. Dehydration, while it can accompany various conditions, does not directly cause the specific symptoms seen in hypoglycemia. Therefore, the symptoms and blood glucose level together strongly point towards hypoglycemia as the most likely condition in this case.