One of the commonest and easily detectable symptoms of diabetes is frequent urination. It is a symptom that is present in all types of diabetes mellitus. Also, it is a symptom of diabetes insipidus even though both diabetes mellitus and diabetes insipidus have different causes and are two different conditions.
In diabetes mellitus, there is a lot of glucose in the blood known as hyperglycemia. This excess glucose in the blood is due to the inability of the body to make use of the glucose. This inability of the body to utilise glucose may be due to the lack of insulin in the body or the unresponsiveness of the cells to the glucose that is present.
This characterizes diabetes mellitus into two main types, namely; type 1 diabetes mellitus and type 2 diabetes mellitus.
Type 1 diabetes mellitus is when there is total absence of the insulin or there is only a minimal amount of it being produced. This therefore has to do with the pancreas which is the site of insulin synthesis and release. Some cells known as beta cells of the pancreas are responsible for release of the stored insulin and may be destroyed, and are mostly due to an autoimmune disorder or a genetic disorder.
In type 2 diabetes mellitus, the body is able to produce insulin but the cells are insensitive to insulin, thus it is as if there isn’t any insulin at all. This is usually as a result of poor lifestyle practices including ‘bad diets’.
Why do people with diabetes mellitus urinate a lot?
Since insulin is not working well or absent, glucose accumulates in the blood. Glucose in itself is osmotic in nature meaning, it is able to draw water to itself wherever it finds itself.
With the principle of osmosis, there is movement of water from a region of low concentration to one with higher concentration. Therefore as the amount of glucose in the blood keeps increasing, it begins to draw in more water into the blood.
Also, in a normal person, only a small amount of glucose passes through the urine. The kidneys detect this and reabsorbs the glucose. However, there is a threshold beyond which this reabsorption is not possible. Once the renal glucose threshold is exceeded, a lot more glucose will be excreted without reabsorption.
Following the principle of osmosis as explained above, the glucose draws with it a lot of water. As such the volume of urine as well as the frequency of urination increases drastically in such patients.
Why do people with diabetes insipidus urinate a lot?
With diabetes insipidus the passage of urine has nothing to do with the presence or accumulation of glucose. In these kinds of patients, they usually will have no problems with insulin.
A different hormone is responsible for the frequent and copious urination seen with diabetes insipidus. This hormone is known as the antidiuretic hormone (vasopressin). This hormone is responsible for maintaining fluid balance in the body. It works by reabsorbing excess water from urine.
However, in diabetes insipidus, the hormone is also either not produced or the body becomes insensitive and does not respond to its actions. In a normal person without this disease, any time the urine gets to the collecting duct of the kidneys, this hormone causes a reabsorption of water based on the need of the individual.
But for those who have this condition, fluid regulation rarely happens and hence all the water filtered through the kidney gets urinated out and this happens all the time in them. That is why they keep passing out copious amounts of urine frequently.
WRITTEN AND EDITED RESPECTIVELY BY:
Dr. Ehoneah Obed is a registered pharmacist and a member of the Pharmaceutical Society of Ghana. He has a Doctor of Pharmacy degree from Kwame Nkrumah University of Science and Technology and has experience working in a Tertiary hospital as well as various community pharmacies. He is also a software engineer interested in healthcare technologies.
His love for helping others motivates him to create content on an array of topics mostly relating to the health of people and also software engineering content.
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