Diabetic nerve damage (neuropathy)
Diabetic neuropathy is nerve damage caused by years of high blood glucose. It most often begins in the toes and feet on both sides, causing burning, tingling, electric-shock pains or numbness that is characteristically worse at night. The danger is not the pain but the numbness: a foot that cannot feel injury gets injured. Existing nerve damage rarely reverses, but tightening glucose control slows or halts progression, and medicines such as amitriptyline, duloxetine, pregabalin and gabapentin genuinely reduce the pain. Nerve damage can also affect the stomach, bladder, heart rate and sexual function.
Diabetologist & General Physician · MBBS
High glucose damages the smallest blood vessels that supply nerves, and the longest nerves suffer first. That is why symptoms start in the toes rather than the hands, and why they spread upward in a pattern often described as a stocking distribution.
What it feels like
- Burning, as if the feet are too close to a fire
- Pins and needles, or a crawling sensation
- Sudden electric-shock or stabbing pains
- Numbness — sometimes described as walking on cotton wool
- Pain from things that should not hurt, such as the weight of a bedsheet
- Symptoms worse at night, which is the most characteristic feature
The other kinds of neuropathy
| Type | What it affects | Typical symptoms |
|---|---|---|
| Peripheral | Feet, legs, later hands | Burning, numbness, tingling |
| Autonomic — stomach | Stomach emptying (gastroparesis) | Fullness after small meals, nausea, erratic glucose after eating |
| Autonomic — heart | Heart rate and blood pressure control | Dizziness on standing, absent chest pain during a heart attack |
| Autonomic — bladder | Bladder emptying | Poor stream, incomplete emptying, repeated urine infections |
| Autonomic — sexual | Erectile and sexual function | Erectile dysfunction, vaginal dryness |
| Focal | A single nerve | Sudden wrist drop, foot drop, or double vision |
How it is diagnosed
Usually by examination rather than by scans. A 10 gram monofilament tests protective sensation, a 128 Hz tuning fork tests vibration sense, and reflexes and pinprick sensation complete the picture. Nerve conduction studies are reserved for unclear cases. Blood tests are often done to exclude other causes — vitamin B12 deficiency, thyroid disease, kidney failure and excess alcohol all damage nerves and are all treatable.
Treating the pain
These medicines do not repair nerves; they reduce the pain signal. They are started at a low dose and increased slowly, and they usually take two to four weeks to show their effect — stopping after three days because nothing happened is the commonest reason they appear not to work.
| Medicine | Notes |
|---|---|
| Amitriptyline | Taken at night; helps sleep; causes dry mouth and drowsiness; used cautiously in older people |
| Duloxetine | Often first choice in diabetes; may cause nausea initially |
| Pregabalin | Effective; can cause dizziness, drowsiness and weight gain |
| Gabapentin | Similar to pregabalin; needs dose adjustment in kidney disease |
| Capsaicin cream | Applied locally; burns initially before it helps |
What slows it down
Living with it
- Keep the bedsheet off sensitive feet with a cradle or a rolled blanket at the foot of the bed.
- Cool — not cold — water can ease burning; never use heat on a numb foot.
- Well-cushioned shoes that fit, worn indoors as well as out.
- Treat sleep seriously; pain worsens with poor sleep and poor sleep worsens pain.
- Tell your doctor about erectile dysfunction or bladder symptoms — both are common, both are treatable, and neither is something to be embarrassed about.
Common questions
Still not sure what to do?
Reading about a symptom only goes so far. A doctor who can ask you questions and examine you will get further in ten minutes than any article can.
