Diabetes mellitus types 1 and 2 are often accompanied by increased thirst and a frequent need to urinate. In both conditions, the amount of sugar in the blood rises to a point where the kidneys are not able to prevent "spillage" of sugar out of the body via the urine. As sugar exits your body, it takes water with it; the net result of a chronically elevated blood sugar level is dehydration and ensuing thirst.Diabetes insipidus is also typically accompanied by excessive thirst and frequent urination. But the cause isn't related to having a high blood sugar level. Diabetes insipidus is an autoimmune illness that results in a deficiency of or resistance to antidiuretic hormone (ADH). The net effect of diabetes insipidus is loss of excessive water via your urine, which leads to low blood volume and chronic thirst.
Other Causes of Thirst: Any factor that results in a significant decrease in blood volume can cause thirst; examples include diarrhea, vomiting, severe infections, congestive heart failure, kidney failure, and severe liver dysfunction.
Steps to prevent excessive dehydration: Besides drinking adequate amount of water,minimize intake of salty foods,eat water-rich foods and drink healthy liquids whenever your thirst calls for them. Water-rich foods include all fruits, vegetables, and most other plant foods like legumes and whole grains that have been properly soaked and cooked.Healthy liquids include water, freshly pressed juices that aren't too sugary, and smoothies made with whole fruits and vegetables
One of my friends has the symptoms of excessive thirst and urination since last few weeks. He is a little fat at the waist level. He has recently started taking .5mg tablet for his high BP problem. Though BP is under ccontrol I wonder whether the problem is due to BP medicine or Diabetes? If I can have a quick answer on my mail. He has not yet got himself checked for diabetes.