EVERYTHING! The two conditions are entirely different in cause and effect. The point of similarity is the word “diabetes” because in both cases the patient produces copious amounts of urine and so suffers from Polyuria.
The mechanics of the disease, its cause, effects and the organs affected are different.
Insipidus is the body’s problem with producing an antidiuretic hormone or with the body’s response to it. The kidneys reject the action of this hormone.
Mellitus on the other hand, has to do with the body being unable to produce or rejecting the action of the hormone, Insulin. The various body cells resist the action of insulin and reject the digested sugar; thus, refusing to absorb the fuel required for body activities. Polyuria is therefore caused by the process of “osmatic diuresis”. The concentrated sugars in the blood flow into the urine, carrying away more water from the body than they should normally do.
Polydipsia (for very cold water or even ice) and polyuria (all 24 hours) are symptoms of both diseases. However in diabetes insipidus, the urine does not contain glucose but the body loses potassium, there is rarely a blurring of vision, however, there could be signs of dehydration as the body constantly throws out the water it takes in. Adults with diabetes insipidus will remain healthy for decades if they drink enough water to offset the amounts lost by urination.
Children with diabetes insipidus may suffer from fever, vomiting, or diarrhea and have impaired growth.
E49 – What is the difference between Diabetes Insipidus and Mellitus? – www.diabetic.today