Diabetic Neuropathy

Symptoms depend on the type of neuropathy and which nerves are affected and can range from mild to painful and disabling. 

As symptoms usually develop gradually, considerable nerve damage may have occurred before diabetic neuropathy is detected.

There are four main types of diabetic neuropathy, and it is possible to have more than one type at the same time.

Depending on the affected nerves, diabetic neuropathy symptoms can range from pain and numbness in your legs and feet to problems with your digestive system, urinary tract, blood vessels and heart. 

Peripheral neuropathy is the most common type. It affects the feet and legs first, followed by the hands and arms. Signs and symptoms of peripheral neuropathy are often worse at night, and may include:

• Numbness or reduced ability to feel pain or temperature changes
• Tingling or burning sensation
• Sharp pains or cramps
• Increased sensitivity to touch — for some people, even a bedsheet’s weight can be painful
• Serious foot problems, such as ulcers, infections, and bone and joint pain

Autonomic neuropathy affects the autonomic nervous system which controls your heart, bladder, stomach, intestines, sex organs and eyes. Diabetes can affect nerves in any of these areas, possibly causing:

• A lack of awareness that blood sugar levels are low (hypoglycaemia unawareness)
• Bladder or bowel problems
• Slow stomach emptying (gastroparesis), causing nausea, vomiting and loss of appetite
• Changes in the way your eyes adjust from light to dark
• Decreased sexual response

Proximal neuropathy often affects nerves in the thighs, hips, buttocks or legs. It can also affect the abdominal and chest area. Symptoms, which usually affect one side of the body but may spread to the other side, include:

• Severe pain in a hip and thigh or buttock
• Weakening and shrinking of thigh muscles
• Difficulty rising from a sitting position
• Severe stomach pain

Mononeuropathy (focal neuropathy) refers to damage to a specific nerve. There are two types of mononeuropathy — cranial and peripheral. Depending on the nerve affected, symptoms may include:

• Double vision or difficulty focusing
• Aching behind one eye
• Paralysis on one side of your face (Bell’s palsy)
• Numbness or tingling in your hand or fingers, except the smallest finger
• Weakness in your hand that may cause you to drop things

See a doctor if you have:

• A cut or sore on your foot that is infected or will not heal
• Burning, tingling, weakness or pain in your hands or feet that interferes with daily activities or sleep
• Changes in digestion, urination or sexual function
• Dizziness and fainting.

The exact cause of each type of neuropathy is unknown. It is thought that over time, uncontrolled high blood sugar damages nerves and interferes with their ability to send signals. High blood sugar also weakens the walls of the small blood vessels (capillaries) that supply the nerves with oxygen and nutrients.

Anyone who has diabetes can develop neuropathy. The amount of time you have diabetes, poor blood sugar control, kidney disease, being overweight and smoking can increase the risk of nerve damage:

Complications

If left untreated, diabetic neuropathy can lead to serious complications, including:

• Failure to notice warning signs of low blood sugar (hypoglycaemia unawareness)
• Loss of a toe, foot or leg as sores, ulcers or infection which develop and progress without pain 
• Urinary tract infections and urinary incontinence if the nerves that control your bladder are damaged
• Dizziness and fainting due to sharp drops in blood pressure if the nerves that control blood flow are damaged.
• Digestive problems if the nerves that control digestion are affected.
• Sexual dysfunction when autonomic neuropathy damages the nerves that affect the sex organs
• Increased or decreased sweating if nerves which control sweat glands are affected.

Review of medical history and symptoms

Physical examination including testing overall muscle strength and tone, tendon reflexes and sensitivity to touch and vibration.

Further tests may be requested, including:

• Nerve conduction testing
• Muscle response testing (electromyography)
• Autonomic testing – special tests to determine control of blood pressure or sweat glands

Diabetic patients should be screened at intervals for diabetic neuropathy.

As there is no known cure for diabetic neuropathy, treatment aims to slow progression of the disease, relieve pain, manage complications and restore function.

Consistent blood sugar control is the key to preventing or delaying nerve damage. Your doctor will advise you on your target blood sugar levels and methods for control. Good blood pressure control, maintaining a healthy weight and getting regular physical activity can also help.

Pain-relieving medications may be prescribed. The benefits and possible side-effects should be discussed with your doctor.

Various specialists can help with management of complications:

• Blood sugar management
• Regular foot examinations (at least once a year) and home foot care.