Which condition is characterized by excess glucose excretion in urine?

The condition characterized by excess glucose excretion in urine is glycosuria. Glycosuria occurs when the renal threshold for glucose is exceeded, leading to glucose spilling into the urine. This generally happens when blood glucose levels are abnormally high, such as in uncontrolled diabetes mellitus. The kidneys are unable to reabsorb all the glucose filtered through the glomeruli, causing glucose to be present in the urine.

In a normal physiological state, the kidneys efficiently reabsorb most of the glucose, leading to very little or no glucose in the urine. However, when there's an excess of circulating glucose—typically noted in cases of hyperglycemia—it results in glycosuria. Consequently, monitoring urine for glucose is an important diagnostic tool in managing diabetes.

The other conditions listed do not pertain specifically to glucose excretion. Acidosis refers to an increase in acidity in the body fluids, which is unrelated to glucose levels. Proteinuria involves the presence of excess proteins in the urine, indicating kidney damage or disease rather than an issue with glucose. Ketonuria, the presence of ketones in the urine, is generally seen in metabolic conditions like diabetic ketoacidosis but also does not relate to glucose excretion. Thus, glycosuria is the condition