Hello, (moved from the diabetes type II forum)
I have always drunk more water than others and have become curious as to whether I have partial diabetes insipidus.
Recently I have been monitoring my daily water intake. It is usually around 3.5 litres, though if I exercise more it will be around 4 litres or even above; the temperature here is moderate so I do not believe I am sweating excessively.
I urinate 7 or 8 times a day; occasionally, though not too often, I wake up in the night and need to urinate.
My mouth becomes thirsty often so I always try to have a glass or bottle of water near; when I don't have water I become a bit dehydrated though, with the exception of one time when hiking, never seriously. When playing strenuous sport for 1 hour I would consume 1.5 litres and still be thirsty while others would consume less than 600 ml.
It is true that my mouth dries out when nervous.
I have had blood tests and urine analysis.
Specific gravity in the morning (after waking, without drinking) was 1.012
Specific gravity in the evening (with drinking) was 1.008
On the same paper as these results, the normal range for specific gravity is noted as 1.005 - 1.030. As on both occasions I was within this range my Dr is sceptical about the existence of a problem.
Sodium, Potassium, Chloride are all squarely in the center of the noted normal range. Bicarbonate (tested a few days ago) was 30 (in the range of 20-32); the last three blood tests (over several years) show bicarbonate to have been 33,31,34, while the other electrolytes remain in the centre of their range.
Thyroid is 1.10 (range 0.5-5.0)
In addition, in the blood test that was taken concurrently with the 'morning' urine sample (specific gravity 1.012), both UREA and CREAT readings were reported as below the norm (2.9L mmol (range 3.0-7.5), 56L umol (range 60-110) respectively).
My Doctor has suggested I measure the level of fluid urinated over a 24 hour period. I feel certain that my level will be above 2l, but I can't understand how this would distinguish insipidus from polydipsia. I started to measure volume of urination but I came down with a slight fever last night (bad food) which threw things off (urination much higher than intake).
If I want to test my levels of osmolality I need to go to hospital; given my symptoms I am not sure whether this is warranted.
I have had many other tests; I do not have diabetes mellitus, and my general health is quite good, though I don't feel energetic and I have chronic eye strain. I do not eat meat.
I am not seriously worried about this and my symptoms are quite manageable though sometimes frustrating, but I would like to know if I do have an issue. What do you think? And are there any other things I can do to test?