I am leaking wee and suspect our old friend diabetes;what's the mechanism;nerve damage?

You will leak if you are older and have diabetes (and especially if a diabetic smokes, since nicotine stimulates the kidneys). Kidney threshold is about 160 mg/dl on a glucometer...at that point, the kidney tries to work like mad, pulling water from the body to flush sugar out of the bladder (and usually dehydrating the person).

The mechanism of nerve damage is usually demylination of the nerve fibers (the nerves lose their protective outer coating called the myelin sheath). Therefore, signals traveling the nerves can be skewed, so you don't "feel" when the bladder is releasing pressure from urine...or you do feel it, but can't stop it because the nerve supplying the "message" to the muscles that control the bladder opening have been damaged.

It's the same mechanism that causes neuropathy in the extremeties. A nerve's myelin in an area has been damaged...the nerve is therefore not protected from errant signals. So you're in bed and suddenly you feel like a bug with huge jaws has just taken a bite of your big toe. You look...there's nothing there...it was just the nerve misfiring and causing severe, localized pain. Source(s): BS Biology and also been Type I for 40 years.

It may be, but are you male or female? If your female than just happens after you get older (from having babies or being overweight).