A patient with hyperosmolar hyperglycemic state (HHS) has insufficient activity of which hormone causing the emergency?

In the context of hyperosmolar hyperglycemic state (HHS), the primary issue is related to insufficient insulin activity. HHS is characterized by extremely high blood sugar levels, leading to severe dehydration and an array of metabolic disturbances. Insulin plays a critical role in regulating blood glucose levels by facilitating the uptake of glucose into the cells, especially in muscle and fat tissues.

When there is insufficient insulin, glucose remains in the bloodstream rather than being utilized by the cells, resulting in hyperglycemia. Additionally, this lack of insulin also means that the body cannot suppress the production of glucose by the liver, further exacerbating the condition.

In HHS, even though there may be some insulin present, it is not sufficient to counteract the high levels of glucagon and other counter-regulatory hormones, which leads to ongoing hyperglycemia and dehydration. This highlights the centrality of insulin's role in managing blood sugar levels in this emergency. The other options do not directly contribute to the hyperglycemic state in the same way that insufficient insulin does.