Diabetic Neuropathy

Definition

High blood sugar can injure the nerve fibres throughout the body but in diabetics it mainly involves the legs and feet. There can be pain and numbness in the extremities to problems with the digestive, urinary tracts, blood vessels and the heart.

The symptoms range from pain to disabling to being fatal.

The disease can be prevented or slowed by life style changes and blood sugar control.

Symptoms

This effects feet and legs before hands and arms. The symptoms are worse at night and include:

• Tingling or burning sensation.
• Sharp pain or cramps.
• Increased sensitivity to touch – weight of bed sheet can be agonising.
• Muscle weakness.
• Loss of ankle reflexes.
• Loss of balance and coordination.
• Serious foot problems like ulcers, infections and deformities, bone and joint pain.

Autonomic Neuropathy

The autonomic nerves control the heart, bladder, lungs, intestines, stomach, sex organs and eyes. They may cause:

• Lack of awareness that the blood sugar levels are low (hypoglycemia awareness).
• Bladder problems like urinary tract infection, urinary retention or incontinence.
• Constipation, uncontrolled diarrhoea or a combination of both.
• Slow stomach emptying (gastroparesis) causing nausea, vomiting and loss of appetite.
• Difficulty swallowing.
• Erectile dysfunction in men.
• Vaginal dryness and other difficulties in females.
• Increased or decreased sweating.
• Inability to adjust to blood pressure and heart rate with sharp drop in blood pressure on standing or sitting that may cause you to faint and feel light headed.
• Problems regulating your body temperature.
• Changes in the way your eyes adjust from light to dark.
• Increased heart rate when you are at rest.

Rediculoplexus Neuropathy (diabetic amyotrophy)

Affects nerves in the thigh, hips, buttock and the legs. It is commoner in people with type 2 diabetes and older people. Mostly it is unilateral though it maybe bilateral. The symptoms are:

• Sudden severe pain in hip, buttock or thigh.
• Eventual weak and atrophic thigh muscles.
• Difficult to rise from a sitting position.
• Abdominal swelling if abdomen is affected.
• Weight loss.

Mononeuropathy

It is damage to specific nerves and is sudden in onset and affects elderly males. It may cause severe pain but disappears over a few weeks. Symptoms depend on which nerve is affected:

• Difficulty in focusing eyes, double vision or aching behind eyes.
• Paralysis on one side of face (Bell’s palsy).
• Pain on shin or foot.
• Pain lower back or pelvis.
• Pain in front of thigh.
• Pain in chest of abdomen.

It may occur when the nerve is compressed as in carpel tunnel syndrome. The symptoms include:

• Numbness or tingling in your fingers and hand especially thumb, index, middle and ring fingers.
• Sense of weakness in your hand and tendency to drop things.
• When to see your doctor.
• See your doctor if there is a sore on your foot which is not healing, getting infected or worse.
• Burning, tingling, weakness or pain in hands or feet that interferes with your daily routine or sleep.
• Dizziness.
• Changes in your urination, digestion or sexual function.

These symptoms are not always due to nerve damage but signal other problems needing medical care. Early diagnosis and treatment offer the best chance for controlling symptoms and preventing more severe problems.

Minor sores if neglected can lead to ulcers which if not treated may become infected or gangrenous needing surgery or amputation. Early treatment can prevent this from happening.

Causes

• Damage to the blood vessels : Exposure to high blood sugars damages the delicate nerves causing neuropathy. Why this happens is not very clear but there is a combination of factors like complex interaction between nerve and blood vessels.
• Poor blood supply below the knee and in the foot.
• Poor blood supply below the knee and in the foot.
• High blood sugar interferes with the ability of the nerve to transmit signals. It also weakens the walls of the capillaries that supply the nerves with oxygen and nutrients.

Other factors

• Inflammation in the nerves caused by autoimmune response. In this the immune system by mistake attacks part of your own body taking it to be a foreign organism.
• Genetic factors unrelated to diabetes making people more susceptible to nerve damage.
• Smoking and alcohol abuse which damage both nerves and blood vessels.

Risk Factors

Anyone with diabetes may develop neuropathy but factors make you more susceptible to nerve damage:

• Poor blood sugar control – this is the greatest risk factor for every complication of diabetes including nerve damage. Keeping sugar levels under control protects your nerves and blood vessels.
• Length of time you have diabetes – The risk of diabetic neuropathy increases the longer you have diabetes and especially if it is poorly controlled.
• Kidney disease – diabetes damages kidneys and as a consequence the increase in blood toxins contribute to nerve damage.
• Being overweight – Body mass index over 24 increases the risk of diabetic neuropathy.
• Smoking – damages the blood vessels reducing the flow to your legs and feet. This delays wound healing and damages nerves.

Complications

Diabetic neuropathy can cause:

Loss of limb – due to the lack of sensation the patient does not notice cuts and bruises and infections. These therefore worsen leading to infected ulcers. Added to this is the poor blood supply to the limb. The infection may spread to the bone and cause gangrene. This may result in loss of limb.

Charcot joint – This is the deterioration of the joint due to nerve damage leading to swelling, loss of sensation, joint instability and deformity. Early treatment promotes healing and prevents further damage.

Urinary tract infection and urinary incontinence – damage to the nerves that control your bladder can prevent it from emptying completely which leads to colonisation of the bacteria in the bladder causing UTI. Nerve damage can also reduce your ability to know when to pass urine and you can lose control over the release of urine.

Hypoglycemia unawareness – Normally when your blood sugar falls below 70 gm% you develop sweating, fast heart beat and shakiness. Autonomic neuropathy can interfere with the ability to notice this.

Low blood pressure – damage to the nerves that control circulation can effect the control of blood pressure. This can bring about a sharp fall in BP when you stand or sit (orthostatic hypotension) which could cause dizziness and fainting.

Digestive problems – nerve damage to the digestive system can cause constipation or diarrhoea along with bloating, nausea, vomiting and loss of appetite. This is due to gastroperesis where the stomach empties too slowly or not at all. This can severely affect blood sugar levels and nutrition.

Sexual dysfunction – autonomic neuropathy damages the nerves affecting sexual function. It leads to erectile dysfunction is men and problems with lubrication and arousal in women.

Increased and decreased sweating – when sweat glands do not function properly your body cannot regulate temperature properly. A reduction or complete absence of sweating (anhydrosis) can be life threatening. Autonomic neuropathy can also cause excessive sweating at night or while eating.

Tests and Diagnosis

Diabetic neuropathy is diagnosed based on history and physical examination. The muscle strength and tone is checked along with tendon reflexes, sensitivity to touch, temperature and vibration.The other tests that maybe needed are:

Filament test – sensitivity to touch may be tested with a soft nylon fibre called monofilament.
Monofilament test for neuropathy
Monofilament test for neuropathy

Nerve conduction studies – this tells how quickly the nerves in your body can conduct electrical signals. It is used to diagnose carpel tunnel syndrome.

Electromyography (EMG) - this measures the electrical discharges produced in your muscles.

Quantitative sensory testing – it tests how your nerves respond to vibration and temperature changes.

Autonomic testing – if you have symptoms of autonomic neuropathy your blood pressure would be tested in various positions and your ability to sweat.

A comprehensive foot examination should be done once a year and feet checked at every visit for cracks, sores, ulcers, calluses and bone and joint abnormalities. A diabetic foot may not even feel the pin pricks.

Treatment and Drugs

Diabetic neuropathy has no cure. Treatment focuses on:

• Slowing progression of disease
• Reliving pain
• Managing complications and restoring function
• Slowing progression of disease

Keeping blood sugar under check prevents or delays progression of diabetic neuropathy and may even improve some symptoms. The target sugar levels recommended are:

• 80 – 120 mg% or 4.4 – 6.7 mmol/L for patients below 60 years
• 100 – 140 mg% or 5.6 – 7.8 mmol/L for patients over 60 years or those with other medical ailments like heart, lung or kidney disease.

To help slow nerve damage the following is recommended:

• Regular foot care
• BP under control
• Healthy diet
• Plenty of physical activity
• Maintain healthy weight
• Stop smoking
• Avoid alcohol or drink in moderation

Relieving Pain

Most drugs are not very helpful and some have more side-effects than benefits. One should try:
1. Capsaicin cream ( from chili pepper)
2. Acupuncture or physical therapy

Pain relieving medications used include:

Anti-seizure medications –

These include gabapentine (neurontin, grablise), pregabalin (lyrica), and carbamazepine (carbatrol, tegretol). These drugs treat epilepsy and also used for nerve pain relief. Side effects include drowsiness, dizziness and swelling.

Antidepressants –

Tricyclic antidepressant medications like amitriptyline, desipramine (norpramine) and imipramine (Torfanil) may case relief for mild to moderate symptoms by interfering with the chemical processes in your brain that cause you to feel pain but they may also have many side-effects like dry mouth. sweating, weight gain, constipation and dizziness. for some antidepressants like serotonin and nor-epinephrine reuptake inhibitors (SNRIs) like duloxetine can relieve pain with a few side effects like nausea, sleepiness, dizziness, reduced appetite and constipation.

Managing complications and restoring function

Urinary tract problems –

Antispasmodic medications (anticholenergics), behavioural techniques like times urination, devices like pessaries (rings inserted into the vagina to prevent urine leak) could be helpful in treating loss of bladder control. A combination of therapies could be most helpful.

Digestive problems –

This is due to gastroperesis – indigestion, belching, nausea vomiting. this is treated by eating smaller frequent meals, reducing fibre and fat in diet and eating soups and mashed foods. dietary changes and medication may help treating nausea, vomoting, diarrhoea and constipation.

Low blood pressure on standing (orthostatic hypotension) -

This is helped by simple measures like avoiding alcohol, drinking a lot of water and sitting or standing slowly. Abdominal binder and compression stocking may help. Several medications may be used.

Sexual dysfunction –

Sildenafil (viagra), tadalafil (cialis) and vardenafil (Levitra) may improve sexual function in men but they are not safe or effective for everyone. Mechanical vacuum devices may improve the blood supply to the penis. Women may find relief with vaginal creams.

Life-style and Home Remedies

These measures help reduce risk of diabetic neuropathy:

Keep your blood pressure under control –

This increases the risk to your blood vessels and should be kept under check.

Make healthy food choices –

Eat fruits, vegetables and whole grain and limit portions to maintain healthy weight.

Be active daily –

This protects your heart and improves blood flow. It also keeps your blood sugar and blood pressure under control. Exercise for 30 mins, 5 times a week is recommended. In severe neuropathy and reduced sensations in the legs one must do non-weight bearing activities like swimming and bicycling. Daily walks

Stop smoking –

Do not smoke or have tobacco with diabetes because you have a high chance of dying of heart attack or stroke. You are also likely to have circulatory problems in your feet. Talk to your doctors about the waist quit.
Give up smoking totally.

Alternative Medicine

There are alternative ways to relieve symptoms from this problem:

• Capsaicin – this is a cream which can reduce pain sensation in some. Side effects are skin irritation and burining.
• Alpha-lipoic acid - this powerful antioxidant is found in some foods and may relieve symptoms of peripheral neuropathy.
• Transcutaneous Electrical Nerve Stimulation (TENS) – this helps pain signals fro m reaching your brain. TENS delivers tiny electrical impulses to specific nerve pathways through small electrodes placed on your skin. Though safe it does not work for everyone.
• Acupuncture – It may relieve pain of neuropathy and has no side effects. More than one session may be needed.

Coping and support

Living with diabetic neuropathy could be frustrating and difficult and may need counselling.

Prevention

This could be achieved by:

• Blood sugar control – closely monitor your blood sugar and keep it in the range prescribed by your doctor. This is the best way to prevent or delay neuropathy and other diabetic complications. Consistency is important because variations in blood sugar levels can accelerate nerve damage. All diabetics must have A1C test done every 6 months to see the average blood sugar level during the past 2-3 months. If it is not well controlled change the medication or get the test more often.
• Foot Care – non-healing ulcers and amputations are common in diabetic neuropathy. Get your doctor to check your feet at every visit and you must examine them daily. To protect the health of your feet
• Check your feet every day – look for cuts, bruises, peeling skin, redness and swelling. Use a handle mirror to see the sole of the foot.

Check your feet daily and look at the sole with hand mirror

• Keep the feet clean and dry – wash with lukewarm water and mild soap. Do not soak your feet. Dry between the toes with soft towel. Moisturise your feet to prevent cracking but avoid lotion between toes as this encourages fungal growth.
• Trim toe nails carefully – Cut your toe nails straight across and file them carefully so that there are no sharp edges.
• Wear clean dry socks – wear cotton socks without tight bands.
• Wear padded shoes that fit well – Always wear shoes of slippers to protect your feet from injury. Your shoes must fit properly and allow your toes to move.

Even tiny sores can get infected and become major problems. So be careful.