– Why does untreated diabetes cause parts of limbs to die?
In: Biology
As with most things it’s multifaceted. But the two most fundamental factors are damage to blood vessels and nerves.
Elevated levels of blood sugar causes, to summarize it, a low grade inflammation which over time damage said structures. Blood vessels thicken and nerves can no longer properly send their signals. Thickening blood vessels decreases blood flow and deprive tissues of vital nutrients. Therefore these tissues will, eventually, become necrotic (die). Also; If you get wounds these will not heal effectively and will more easily get infected (since immune cells can’t reach the tissues). The nerve damage also make so you lose your sensation. Therefore you can go a long time without noticing that you have a wound. So when you finally notice it the wound will be large, infected and is unable to heal because of reduced blood flow. The only option left then is to amputate.
An effect of long-term high blood glucose is a condition called diabetic neuropathy, or peripheral neuropathy. This goes hand in hand with a lot of the other answers, but neuropathy is, as far as I can tell, the leading cause of eventual amputation with diabetes.
Nerve endings get damaged and the patient loses sensation in their extremities. This often leads to wounds or ulcers that go unnoticed. When these wounds are on the lower extremity they can go unnoticed because the patient just plain doesnt feel it! Since the wound is unnoticed they can become infected, become necrotic, and eventually require amputation. A big part of the care for diabetic patients involves education on the importance of inspecting their feet – but this can become difficult if the patient is very obese, elderly, or afflicted with any co-morbidities limiting range of motion.
When shadowing a family medicine physician I spent time with the Dietician who handled the the detailed cases for the clinic’s diabetic patients. Every patient would have a foot exam done, which consisted of us looking for any wounds, testing for sensory impairment (google neuropathy monofilament), and continued patient education on inspecting their feet daily.
side note: when you find out someone has diabetes, the next thing you SHOULDNT say is “oh my ________ had that and lost his leg and then died”
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