How diabetes Insipidus differs from diabetes mellitus

Diabetes insipidus and diabetes mellitus are two medical conditions which are often mistakenly put under one umbrella of diabetes. However, these two conditions differ from each other, and this article considers their differences.

Diabetes insipidus

Diabetes insipidus is a rare disorder where dilute urine is excreted from the kidney due to lack of antidiuretic hormone in the body. The antidiuretic hormone (ADH) produced in the hypothalamus is stored in the pituitary gland to help the kidney reabsorb excess water from the filtrate thereby regulating the fluid content of the body. The release of ADH needed for fluid balance in the body can be affected by damage to the pituitary gland or kidney tubules making the body have excess fluid. When the body has excess fluid, excess urine is formed and would be passed out more frequently (polyuria). Diabetes insipidus is of two types, central diabetes caused by the ADH deficiency and nephrogenic diabetes caused by irresponsiveness of the kidney to ADH.

Diabetes mellitus

Diabetes mellitus is a commonly diagnosed medical condition also referred to as sugar diabetes and is caused by the body’s inability to process glucose for storage or consumption. Glucose in the body is processed by insulin a hormone produced in the pancreas. When the body produces insufficient quantities of insulin or is resistant to the insulin produced, the sugar level in the blood rises and the excess sugar leaks into the urine increasing the overall amount of urine produced. Diabetes mellitus is of two types; Type 1 diabetes is a condition where the immune system prevents the production of insulin by destroying the cells which produce it, while Type 2 is the conditions which result from insufficient insulin production and improper use of insulin produced. There is also gestational diabetes which occurs only in pregnant women when there is a rise in blood glucose of a woman who never had diabetes before pregnancy.

Significant Differences between Diabetes Mellitus and Diabetes Insipidus

Diabetes Mellitus and diabetes insipidus are both medical conditions which cause frequent urination and excessive thirst. However, that’s the only similarity between the two types of diabetes. Diabetes mellitus is the most common type of diabetes and is often mistaken as the only type of diabetes in existence, while diabetes insipidus is very rare. The summary of some of the remarkable differences between diabetes insipidus and diabetes mellitus is presented in the table below.


Diabetes Insipidus Diabetes Mellitus
Cause Deficiency in antidiuretic hormone (ADH). deficiency insulin in the body or body’s resistance to insulin
Disorder Hypothalamic disorder Pancreatic disorder
Blood Sugar Normal sugar in the blood High sugar level in blood
Urine Dilution Diluted urine Urine is not diluted
Urine Output Very High High
Types Central Diabetes Insipidus and Nephrogenic Diabetes Insipidus Type 1 Diabetes Mellitus, Type 2 Diabetes Mellitus and Gestational Diabetes Mellitus
Urine Content Urine is not excreted in glucose Urine is excreted with glucose
Prognosis Affects life expectancy; 10 years shorter Does not affect life expectancy
Symptoms Weight loss, headaches Impaired vision
Treatment desmopressin or vasmopressin Insulin and changed lifestyle and diet


Diabetes is an unwanted but manageable medical condition which has two types with different causes and symptoms. Although they both do not have a cure, they can be well managed when properly diagnosed.

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