- Constant urge to urinate (polyuria)
- Weight loss
- Blurred vision
- Frequent urinary tract infections
- Unusual thirst
Although these symptoms seem familiar to diabetics, these patients usually don’t know why they occur. Let’s start with Polyuria, which is the increased production and excretion of urine leading to an increase in the frequency of urination. In the case of hyperglycemia, the body will find a way to reduce these high blood sugar levels. The main mechanism by which the body gets rid of this excess of glucose is through the urine. Now, to better understand why Polyuria occurs, one must know how the kidneys work.
The functional unit of the kidney responsible for the production of urine is the nephron, which is formed by two mayor components: the first one is the Bowman’s capsule whose functions is to filtrate water and other substances such as glucose, amino acids, and ions (e.g. sodium) out of the blood entering the kidneys. The second functional components are the renal tubules or vasa recta that are responsible for the reabsorption and secretion of those particles useful to the body such as amino acids and glucose. The remaining substances (e.g. urea) and water will continue through the kidney to form the urine. The key point to be emphasized here is that normally there is no glucose in urine.
In the case of hyperglycemia, as happens in diabetics, the kidney eventually fails to filter the excess of glucose, which passes through the renal tubules and exceeds the capacity of reabsorption. The excess of non-reabsorbed glucose will be excreted through the urine producing glycosuria, a condition characterized by an excess of sugar in the urine, typically associated with diabetes.
The presence of excessive glucose in the kidneys will produce a diuretic effect causing an increase in the amount of fluid (water) to be excreted as urine. In summarizing, this is how polyuria is produced. Typically, 3 or more liters of water is excreted daily from the body. Such urine is so diluted that it looks colorless.
Polyuria can occur not only during the day but also at night in which case is called nycturia.
Polyuria is a symptom that should be taken into consideration not only for the diagnosis of Diabetes, but also as a warning sign for diabetics as it hints the presence of hyperglycemia.
Therefore, if you are a diabetic and suspect that you have Polyuria, check your blood sugar and then keep track of how often you go to the bathroom, and how much water you are drinking. Take this information to your Doctor as soon as possible so kidney complications from your diabetes can be avoided.