noun, plural: glycosuria
The presence of atypically high sugar level in urine
Glycosuria is a condition wherein glucose is excreted into the urine. Under normal condition, glucose should not be present in the urine. The kidneys should be able to filter glucose back into the bloodstream. However, due to the presence of elevated sugar level in the bloodstream the kidneys fail to reabsorb all glucose and therefore glucose is excreted into the urine. This condition commonly occurs in individuals with untreated diabetes. The inability to synthesize insulin to remove excess sugar (glucose) in the bloodstream and convert it into its storable form, glycogen, results in increased sugar circulating in the bloodstream.
Glycosuria also results from problems in the kidney itself, such as when the kidney fails to reabsorb glucose. The latter is referred to as renal glycosuria. Glucose is supposed to be reabsorbed from the filtrate through the proximal tubule of the kidney across the tubular epithelium and back into the bloodstream. The proximal tubule, though, can reabsorb a limited amount of glucose. If the sugar level exceeds the renal threshold of glucose, about 160 – 180 mg/dL, the proximal tubule becomes overwhelmed by the high amount of glucose and begins excreting glucose into the urine.1
Glycosuria may also lead to dehydration. The presence of sugar in the urine results in the excessive water loss in a process called osmotic diuresis.
1 AIDA on-line’ Explanations. Retrieved from http://www.mendosa.com/www-2aida-org/explain.htm#10.