I was on a train commuting to London and got the need-to-go-nothing-happening thing, too many years before T2DM for it to be related. I figured that if I chugged some liquid it might help so I downed a litre of Aqua Libre, then kept sipping water and cranberry juice drink and the sensation lessened and eventually I was able to pee normally so I assumed that I was dehydrated. I had the same thing several years later but not as badly, and since then I have made a real effort to keep hydrated.
I've read that flying is dehydrating and that by the time you feel thirsty, in any situation, you're already dehydrated. With diabetes, it easy to get dehydrated, because the kidneys force you to pee to expel high blood glucose. This removes water that your body would use for other purposes.
Sometimes when we think we're hungry, we're actually thirsty. The majority of people don't take on enough hydrating fluid. Coffee for example, is a diuretic i.e. encourages fluid loss.
I usually drink at least 4 x 500ml bottles of Evian a day and might have 4 quarter pint mugs of tea without milk as well. In hot weather I may have a whole pack of Evian a day.Water hydrates better than anything else and we need it - especially when feeling under the weather or after episodes of nausea or diarrhoea - the nurses bugged me constantly to drink more water when I had food poisoning.
If your blood glucose isn't high and you don't have prostate or kidney problems, the NHS website says the best thing you can do for kidney health is to drink plenty of fluids, especially water.
Whether you have diabetes or not, it can be a difficult thing to adjust to upping your water intake, but the body does adjust quickly and you may well find that you feel better and can see a difference in your skin.
Sorry to hear about your knee.
