What are the signs of diabetic neuropathy?
Some people with diabetic neuropathy have no signs at all. Depending on the type of peripheral or autonomic involvement, the presentations and signs will vary widely.
Damage to the peripheral nerves can take many forms: “polyneuropathy” (damage to all the nerves in a limb) or “mononeuropathy” (damage to a single nerve).
– Diabetic polyneuropathy (“polyneuritis”) usually affects the nerves of the lower extremities. It affects the legs quite symmetrically, starting at the distal end of the longest nerves, i.e. in the feet, and going up the legs.
This symmetrical diabetic polyneuropathy can manifest itself by a tingling and unpleasant sensation (paresthesia) or numbness in the feet, sometimes by a burning pain or a sensation of electric current and without an obvious cause.
These signs appear gradually, over several months or even years.
Finally, polyneuropathy can lead to a decrease or loss of sensation in the feet, which favors the appearance of ulcers. The motor functions are affected much later because the nerves responsible are better protected and more resistant.
Diabetic mononeuropathy is a condition in which only one peripheral nerve is affected. If several peripheral nerves in different parts of the body are affected, it is called multiple mononeuropathies.
In most cases of a mononeuropathy, it is the nervus cruralis in the thigh (cruralgia) or the nervus medianus in the wrist (carpal tunnel syndrome) that are concerned.
This mononeuropathy usually leads to extreme skin sensitivity (allodynia) and intense burning pain or current sensation with weakness and difficulties in motor control in the affected extremity. Most of the time these signs are sudden.
Autonomic diabetic neuropathy may involve various automatic bodily functions, which may lead to the coexistence of signs that are normally unrelated:
- dizziness, vertigo or malaise that can lead to a fall, especially when patients suddenly get up from a bed or chair. These are signs of blood pressure that do not adapt quickly enough to get up (orthostatic hypotension).
- An accelerated heartbeat (tachycardia).
- A heavy stomach or bloating after meals, with nausea and vomiting associated with reduced stomach motility (gastroparesis).
- Alternating nocturnal motor diarrhea and constipation associated with a disturbance in the coordination of peristaltic bowel movements.
- Too much or too little sweating, with skin changes.
- Difficulties urinating, such as a delayed urge to urinate (loss of sensation in the bladder) or a bladder that does not empty properly (insufficient wall contraction).
- Erectile dysfunction or vaginal dryness.