Which molecule accumulates in the blood and causes symptoms of a diabetic coma?

The correct answer is ketones, which are produced when the body begins to break down fat for energy due to insufficient insulin availability. In individuals with diabetes, especially type 1 diabetes, the lack of insulin prevents glucose from entering the cells, leading the body to utilize fat stores instead. This process results in the production of ketones as a byproduct, which can accumulate in the bloodstream.

High levels of ketones can lead to a condition known as diabetic ketoacidosis (DKA). In DKA, the accumulation of ketones causes the blood to become more acidic, leading to various symptoms, including confusion, difficulty breathing, and potentially a diabetic coma if not treated promptly. The presence of ketones, along with elevated glucose levels, is critical in the diagnosis of DKA.

While glucose is also elevated in diabetics and contributes to the overall metabolic derangement in DKA, it is the accumulation of ketones specifically that leads to the acidosis and severe complications associated with diabetic coma. Sodium bicarbonate and nitrogen do not play a direct role in the mechanism that leads to diabetic coma from ketone accumulation. Therefore, ketones are the primary molecules involved in this serious state.