Diabetic neuropathy is nerve damage caused by diabetes.
It is the most common diabetic complication, affecting at least 50% of all patients.
Chronic high blood sugar levels cause progressive injury to neurons.
Sensory neurons are usually the first to be affected, followed by autonomic neurons that
control internal organs.
Rarely, motor neurons that activate voluntary movements may also be impaired later in the
disease, albeit to a lesser extent.
There are several types of diabetic neuropathy.
A patient may develop more than one type at a time.
The most common is peripheral neuropathy.
It’s also called “distal symmetric polyneuropathy” because it typically involves multiple peripheral
nerves, on both sides of the body, and affects the longest sensory axons that convey sensations
from the feet, legs, and hands.
Symptoms develop on the body in that order and include numbness, tingling, or burning
sensation, which usually worsen at night.
Sensitivity to pain can either be exaggerated, or, on the contrary, lost.
Loss of sensation leads to increased risk of painless injuries, which often go unnoticed
and therefore untreated.
This, together with slow healing caused by diabetes, can turn minor cuts or blisters
into serious infections.
Autonomic neuropathy affects nerves that control activities of internal organs.
In cardiac autonomic neuropathy, nerves that regulate heart rate and blood pressure are
damaged.
As a result, the body reacts more slowly to change of position, and patients may feel
lightheadedness when standing up.
Other signs include rapid heart rates, or sudden, unexplained changes in heart rate.
In the digestive system, nerve damage may cause nausea, vomiting, loss of appetite,
difficulty swallowing, slow stomach emptying, and bowel problems.
Neuropathy in the urinary and reproductive systems may lead to urinary retention, hesitancy,
urinary incontinence, and sexual dysfunctions.
Nerve damage in the eyes can cause slower adjustment to changes in light and darkness.
Nerve damage in sweat glands may result in either absence of sweat or heavy sweating,
especially at night; different parts of the body may also produce sweat differently.
Another effect of autonomic neuropathy is hypoglycemia unawareness, meaning the body
is unaware when blood sugar levels are low.
Warning signs such as hunger or dizziness cannot be felt, and patients may pass out
before taking steps to increase their blood sugar.
Mononeuropathy, or focal neuropathy, is dysfunction of a single nerve, typically due to entrapment.
A common example is carpal tunnel syndrome, in which the median nerve is compressed as
it passes through a narrow tunnel in the wrist, causing pain, numbness, and tingling in the
hand.
Damage to a cranial nerve can cause problems with vision or loss of control of facial muscles.
Proximal neuropathy is a rare type of nerve damage affecting the thighs, hip, buttock,
and occasionally, the abdomen or chest, typically on one side of the body.
Symptoms include severe pain in the affected areas, and thigh muscle weakness and wasting.
Diabetic neuropathy can be prevented by effectively controlling blood sugar levels.
Managing diabetes also helps slow the progression of damage.
Treatments aim to relieve pain and symptoms, to restore functions and prevent further complications.
Treatments vary depending on the affected organs.