Diabetes Over View

Diabetic Neuropathy

Patients with diabetes mellitus should know that they are at risk of developing neuropathy, or damaged nerves. When nerves are damaged, both sensation and muscle are impaired. Neuropathy occurs in 50 percent of those who have had diabetes for more than 25 years. Twelve percent of those with type 2 diabetes have neuropathy at the time of diagnosis.

Diabetic Distal Polyneuropathy

The most common form of diabetic neuropathy is distal symmetric polyneuropathy. It is called distal because it typically begins in the lower legs with painful paresthesias, or tingling, which progresses over time to numbness. It is called symmetric because both sides of the body are affected equally. And it is called polyneuropathy because feet, calves, and then hands are affected in a stocking-glove distribution. In other words, tingling occurs in an area of the hands and feet as if you were wearing gloves and stockings.

Diabetes is the most common cause of stocking-glove neuropathy, but there are other causes that your doctor will need to rule out, such as excessive alcohol use, hypothyroidism, renal failure, and folic acid or vitamin B12 deficiencies.

Complications of Distal Polyneuropathy

Pain

The first complication of distal neuropathy is pain, which can be debilitating, making it difficult to walk or sleep. Although some patients develop chronic pain, for most people, the pain remits within 16 to 24 months. Neuropathy also weakens the small muscles of the foot, causing the toes to curl. This condition is called a claw-foot deformity. As your weight shifts to the ball of the foot, abnormal calluses can form.

Numbness

Another complication is numbness. It is less noticeable than pain, but often more dangerous, as unnoticed numbness can lead to unnoticed injuries that can progress to skin ulceration. Acute ulcerations caused by silent trauma and chronic ulcerations caused by foot deformities can become infected. If not treated promptly, further tissue damage can follow.

Amputation

Because of the underlying neuropathy and sometimes poor vascular supply, infections can be slow to heal, and in some cases, they may not heal at all. Amputation then becomes the sad outcome of diabetic neuropathy. Half of all amputations in the United States result from diabetic complications.

Risk Factors and Treatment of Diabetic Neuropathy

Two major factors determine your risk for neuropathy:

• The level of your average blood sugar
• The length of time you have had diabetes

Your doctor can determine your average blood sugar by checking a hemoglobin A1C, which allows the doctor to see if your blood sugars have been controlled during the last several weeks. This test is more accurate than a random blood sugar. The Diabetes Control and Complications trial demonstrated that tight blood-glucose control can decrease the risk of developing neuropathy by 60 percent and can delay the progression of it. Neuropathy equally affects patients with type 1 and type 2 diabetes.

The most important means of preventing and treating neuropathy is to control your sugar level. Tight glucose control is attained when the blood-sugar level after fasting is less than 120 mg/dl; two hours after eating, it is less than 160 mg/dl; the average blood-sugar level is less than 150mg/dl; and hemoglobin A1C is less than seven percent.

In addition to tight glucose control, there are two other components in the treatment of diabetic polyneuropathy: good foot hygiene and attention to neuropathic pain.

Sometimes, no matter how well you control your blood sugar, neuropathy still develops. It becomes a team effort between you and your doctor to prevent the complications of neuropathy, which are mainly ulceration, infection, and amputation. Good foot hygiene is an essential component of management of the diabetic foot. If you can prevent trauma to your feet, many of the complications can be prevented.

Fundamentals of good foot hygiene include:

• Examining your feet every night for signs of trauma or redness.
• Calling your physician for the first sign of redness or skin breakdown.
• Taking care of your calluses.
• Use a pumice stone to gently rub calluses away.
• Lubricate calluses with lotion.
• Never shave a callus; do not use corn medications.
• See a podiatrist for thick calluses so that they can be removed safely.

Taking care of your nails; trim nails straight across, well above the quick.Have a healthcare professional trim your nails if:

• your nails are thick and hard.
• you are unable to see exactly what you are cutting.
• you are unable to bend to cut them yourself.
• you have a history of foot infection.

Taking care of your skin.

• Use lotion.
• Do not let skin become cracked or dry.
• Test warm water with hands before putting feet in bath.
• Do not use a heating pad.

Wearing proper footwear.

• Do not wear ill-fitting or broken shoes.
• Do not go barefoot.
• Consider orthopedic shoes if you have a foot deformity.

Treating infections promptly

• Cellulitis should be treated promptly with antibiotics.
• Fungal skin infections should be treated with anti-fungal cream.
• Fungal nail infections are difficult to eradicate and should be treated by a doctor.
• Foot examination

In a routine physical, your physician may examine your feet in several ways. Sensation can be assessed by using a tool called a 5.07 monofilament. Impaired sensation from this small nylon fiber indicates sensation loss to the degree that silent trauma could go unnoticed by the patient. Absent heel reflexes can also be a sign of neuropathy.

Your physician will look for signs of infection. Fungal skin infections can cause dry and cracked skin. These fissures can then lead to a more serious infection. Your physician will check the vascular supply by feeling for pulses.

If your doctor notices a severe foot deformity, a referral to a podiatrist may be necessary to fit orthopedic shoes. Your physician may consider an x-ray if there is evidence of trauma.

Cellulitis, or infection of the skin, should be treated promptly with antibiotics. Fungal skin infection, also known as athlete’s foot, should be treated with anti-fungal cream because the dry, flaky irritation can be a portal of entry for more dangerous bacteria. Nail fungal infection, also called onychomycosis, is very difficult to eradicate and often returns.

Medical Treatment for Painful Distal Neuropathy

Although most painful neuropathy diminishes in 16 to 24 months, the intervening months of distress can be debilitating. Fortunately, there are several medicines that can decrease and abolish pain.

Tricyclic antidepressants

Tricyclic antidepressants such as Amitryptiline, Desipramine, and Nortriptiline, are traditionally used for treating depression. In lower doses, however, they are quite effective in treating different types of pain, including diabetic neuropathic pain. The main side effects of triclyclics are dry mouth, dry eyes, and drowsiness. Drowsiness can be tackled by taking the medication at bedtime; the dry mouth and eye symptoms usually improve within two to three weeks. Sour candies can stimulate saliva production.

Patients should be advised that the drugs do not work immediately. If not informed that it takes the drug between three to six weeks to change the central perception of pain, patients will often stop taking the medication erroneously thinking it isn’t working.

Capsaicin cream

Capsaicin cream, derived from hot peppers, can be an important addition to tricyclic therapy. The cream works by depleting the nerves of substance P, which enhances nerve conduction. Without substance P, the nerves transmit the sensation of pain poorly. Capsaicin cream can cause burning of the skin when applied; this burning sensation improves over days or weeks of use. When there is no relief from tricyclic antidepressants, Capsaicin cream is a valuable second agent to try.

Antiseizure medications

Neurontin, Carbamazepine, and Dilantin, all antiseizure medications, have also been used to decrease pain from neuropathy. It may seem strange that these medications are used to control pain in the lower legs when they were designed to control seizures that are caused by an abnormal firing of neurons in the brain. These medications stabilize irritated nerves, whether the nerves are in the feet or in the head. Drowsiness is the most common side effect, but often diminishes with time. None of these drugs should be taken if you have kidney failure, abnormal liver function, or cirrhosis. They are also contraindicated in pregnancy, women who are breast-feeding, or in alcoholics.

Both Dilantin and Carbamazepine interact with a long list of other medications, including estrogens, oral contraceptive pills, certain antibiotics, certain antidepressants, and certain asthma medications. Before prescribing either of these two medications, your doctor should look at your entire medication list. Neurontin has fewer drug interaction, and in that sense, it is easier to take if you are on other medications.

Non-steroidal anti-inflammatory drugs (NSAIDS)

Over-the-counter analgesics such as acetaminophen (Tylenol) and non-steroidal anti-inflammatory drugs (also known as NSAIDS: Motrin, Advil, Relafen, Alleve) may help when taken alone or in conjunction with the other drugs mentioned above.

If you have kidney disease or have been told that you have protein in your urine, you should not take NSAIDS without talking to your doctor. NSAIDS are like aspirin and can cause intestinal and stomach ulcers. The newer NSAIDS, Vioxx and Celebrex, are not supposed to cause stomach ulceration and may be an option for patients who were unable to tolerate this class of medications in the past.

Narcotic drugs

Because of their highly addictive nature, drugs that contain narcotics, such as morphine or codeine, do not play a role in treating the chronic pain of diabetic neuropathy. If you continue to have pain on one regimen, take heart; it does not mean all drug regimens will fail. If you are on a tricyclic, your doctor may want to add Capsaicin, change to Neurontin, or maximize over-the-counter analgesics.

For unremitting pain, ask your doctor about a referral to a pain specialist. Pain specialists are anesthesiologists who can recommend other drug regimens or perform nerve blocks to decrease the sensation of pain at the level of the nerve root. Alternative medical options, including acupuncture or meditation, can help reduce pain, by decreasing perception and increasing tolerance of pain.

Other Neuropathies Associated with Diabetes Mellitus

There are other neuropathies associated with diabetes mellitus. These include autonomic neuropathy, entrapment neuropathy, and cranial neuropathies. These are explained briefly below.

Autonomic Neuropathy

Autonomic nerves control the function of internal organs such as the heart or intestinal tract. We are not aware when these nerves work well; symptoms of autonomic neuropathy are manifested by malfunctioning of the organs and tissues the nerves supply. Autonomic neuropathy is a late complication of diabetes and usually occurs once distal polyneuropathy is present. Treatment is based on two things:

• Controlling the other conditions that exacerbate diabetes, such as hypertension, high cholesterol, and high glucose.
• Treatment of the underlying symptoms.

Cardiovascular autonomic neuropathy

Cardiovascular autonomic neuropathy causes postural or orthostatic hypotension, which is a drop in blood pressure while standing that causes light-headedness. Treatment for postural hypotension includes stopping aggravating medication such as tranquilizers, antidepressants, and diuretics (“water pills”). If you are suffering from orthostatic hypotension, you will want to change position slowly. You may want to consider elevating the head of your bed, crossing your legs while standing, and doing muscle exercises before standing. Body stockings, may or may not be helpful. Theoretically, body stockings increase the pressure in the lower extremities such that blood cannot pool to cause low blood pressure. Practically, however, body stockings can be hot to wear and do not work in every case.

If you do not have co-existent hypertension—high blood pressure—your doctor may consider medical therapy with fludrocortisone, a mineralocorticoid that enhances sodium and water retention.

Gastrointestinal autonomic neuropathy

Gastrointestinal autonomic neuropathy causes gastroparesis and enteropathy (intestinal problems). Gastroparesis literally means paralyzed stomach. The main symptoms are anorexia, nausea, vomiting, and feeling full after eating only a little amount of food. If you have symptoms of gastroparesis, you know that it complicates the management of diabetes. Often, you do not know if you will be able to eat a full meal or whether you will vomit after eating.

Taking a full dose of insulin and not being able to eat can cause dangerous hypoglycemia. Unfortunately, many patients find themselves in a catch-22. Not only does long-term hyperglycemia contribute to developing gastroparesis; short-term hyperglycemia exacerbates gastroparesis. It is imperative that blood sugars are brought down to a somewhat normal range without causing low blood sugars. If you find yourself in this predicament, ask your doctor about using humulog (fast-acting insulin) after meals. Small, frequent meals can help. Medications that can be helpful are Reglan, and erythromycin.

As a last resort, a feeding tube may be placed. Intestinal neuropathy can be manifest as diarrhea, constipation, or fecal incontinence (inability to hold bowel movements). Treatment is centered around symptomatic relief. Because diarrhea can be worsened by bacterial overgrowth, antibiotics are often useful. Antimotility agents such as Loperamide can be tried. Stool softeners are used for constipation. Biofeedback, a type of psychological therapy that works by teaching patients to mentally retrain certain body habits, can aid in treating incontinence.

Genitourinary neuropathy

Genitourinary neuropathy includes urinary incontinence from overflow and bladder distention. If nerves to the bladder are damaged, a person might not be able to sense when his or her bladder is full. This leads to stretching of the bladder wall, or distention, and overflow incontinence. People with overflow incontinence are at greater risk for developing urinary tract infections.

Impotence is often multifactorial; neuropathy is often a part of the problem. Impotence or erectile dysfunction (ED) occurs more frequently in patients with diabetes. In fact, 12 percent of men whose presenting complaint is ED are diagnosed with diabetes. The cause of erectile dysfunction in a patient with diabetes is often multifactorial and includes poor vascular supply, low testosterone, certain medications used to treat high blood pressure, as well as neuropathy. There are new treatments for ED, including Viagra and penile prostheses.

Entrapment Neuropathies

Entrapment neuropathies are so called because the nerve is trapped in a tight space, causing pressure to the nerve, damaging the tissue it supplies. Carpal tunnel is the most common entrapment neuropathy and is characterized by pain and tingling of the thumb, first two fingers, and ring finger. The pain can radiate to the forearm.

Treatment involves stopping repetitive motions of the wrist, such as typing, assembly-line work, hand-involved hobbies. You should splint the wrist in a position that causes the least pressure to the median nerve. NSAIDS can improve inflammation. Corticosteroid injections should be used judiciously. If muscle weakness is present, referral to surgery should be made immediately.

Cranial Neuropathies

Cranial nerves are the nerves that supply the muscles and sensation of the face, eyes, and neck. Elderly people with diabetes are predisposed to cranial nerve palsies or weaknesses, believed to be caused by infarction, or death of the small vessels that feed the nerves. The symptoms depend on which nerve is involved. Often affected is the third nerve that normally lifts the eyelid; when the third nerve is damaged, the eyelid droops. There is no specific treatment; often the nerve palsy improves over months.

Diabetic neuropathy can lead to pain, numbness, and infection. Amputation can be the outcome of a non-healing foot ulcer. Tight glucose control can decrease your risk for developing neuropathy and can delay the progression of neuropathy if you already have it. Attention to good foot care has been shown to decrease your risk for foot ulceration and infection. Advances in pain management have helped people with painful neuropathy cope.