Diabetic neuropathy is a nerve disorder caused by diabetes. The Diabetes Control and Complications Trial (DCCT) studied two groups of …
Diabetic Neuropathy
The Nerve Damage of Diabetes
What Is Diabetic Neuropathy?
Diabetic neuropathy is a nerve disorder caused by diabetes Symptoms of
neuropathy include numbness and sometimes pain in the hands, feet, or
legs Nerve damage caused by diabetes can also lead to problems with
internal organs such as the digestive tract, heart, and sexual organs,
causing indigestion, diarrhea or constipation,, dizziness,
bladder infections, and impotence In some cases, neuropathy can start
up suddenly, causing weakness, weight loss, and sometimes depression
While some treatments are available, a great deal of research is still
needed to understand how diabetes affects the nerves and to find more
effective treatments
DCCT: Can Diabetic Neuropathy Be Prevented?
A 10-year clinical study that involved 1,441 volunteers with insulin-
dependent diabetes mellitus IDDM was recently completed by the
National Institute of Diabetes and Digestive and Kidney Diseases The
study proved that keeping blood sugar levels as close to the normal
range as possible slows the onset and progression of nerve
disease
caused by diabetes The Diabetes Control and Complications Trial DCCT
studied two groups of volunteers: those who followed a standard diabetes
management routine and those who intensively managed their diabetes
Persons in the intensive management group took multiple injections of
insulin daily or used an insulin pump and monitored their blood glucose
at least four times a day to try to lower their blood glucose levels to
the normal range After 5 five years, tests of neurological function
showed that the risk of nerve damage was reduced by 60 percent in the
intensively managed group People in the standard treatment group, whose
average blood glucose levels were higher, had higher rates of
neuropathy Although the DCCT included only patients with IDDM,
researchers believe that people with noninsulin-dependent diabetes would
also benefit from maintaining lower levels of blood glucose
How Common Is Diabetic Neuropathy?
People with diabetes can develop nerve problems at any time Significant
clinical neuropathy can develop within the first 10 years after
diagnosis of diabetes,
and the risk of developing neuropathy increases
the longer a person has diabetes Some recent studies have reported
that:
60 percent of patients with diabetes have some form of neuropathy,
but in most cases 30 to 40 percent, there are no symptoms
30 to 40 percent of patients with diabetes have symptoms
suggesting neuropathy, compared with 10 percent of people without
diabetes
Diabetic neuropathy appears to be more common in smokers, people
over 40 years of age, and those who have had problems controlling
their blood glucose levels
What Causes Diabetic Neuropathy?
Scientists do not know what causes diabetic neuropathy, but several
factors are likely to contribute to the disorder High blood glucose, a
condition associated with diabetes, causes chemical changes in nerves
that impair the nerves ability to transmit signals High blood glucose
also damages blood vessels that carry oxygen and nutrients to the
nerves In addition, inherited factors probably unrelated to diabetes
may make some people more susceptible to nerve disease than others
The
precise mechanism by which high blood glucose leads to nerve damage is
unknown and is a subject of intense research Researchers have
discovered that high glucose levels affect many metabolic pathways in
the nerves, leading to an accumulation of a sugar called sorbitol and
depletion of a substance called myoinositol However, studies in humans
have not credibly shown that these changes are the mechanism that causes
nerve damage More recently, researchers have focused on the effects of
excessive glucose metabolism on the amount of nitric oxide in nerves
Nitric oxide dilates blood vessels In a person with diabetes, low
levels of nitric oxide may lead to constriction of blood vessels
supplying the nerve, causing nerve damage Another promising area of
research focuses on the effect of high glucose attaching to proteins,
altering the structure and function of the proteins and affecting
vascular function Scientists are studying how these changes occur, how
they are connected, how they cause nerve damage, and how to prevent and
treat damage
What Are the Symptoms of Diabetic
Neuropathy?
The symptoms of diabetic neuropathy vary Numbness and tingling in feet
are often the first sign Some people notice no symptoms, while others
are severely disabled Neuropathy may cause both pain and insensitivity
to pain in the same person Often, symptoms are slight at first, and
since most nerve damage occurs over a period of years, mild cases may go
unnoticed for a long time In some people, mainly those afflicted by
focal neuropathy, the onset of pain may be sudden and severe
What Are the Major Types of Neuropathy?
The symptoms of neuropathy also depend on which nerves and what part of
the body is affected Neuropathy may be diffuse, affecting many parts of
the body, or focal, affecting a single, specific nerve and part of the
body
Diffuse Neuropathy
The two categories of diffuse neuropathy are peripheral neuropathy
affecting the feet and hands and autonomic neuropathy affecting the
internal organs
Peripheral Neuropathy
The most common type of peripheral neuropathy damages the nerves of the
limbs, especially the feet Nerves on both sides of the body are
affected Common symptoms of this kind of neuropathy are:
Numbness or insensitivity to pain or temperature
Tingling, burning, or prickling
Sharp pains or cramps
Extreme sensitivity to touch, even light touch
Loss of balance and coordination
SThese symptoms are often worse at night
The damage to nerves often results in loss of reflexes and muscle
weakening The foot often becomes wider and shorter, the step changes,
and foot ulcers appear as pressure is put on parts of the foot that are
less protected Because of the loss of sensation, injuries may go
unnoticed and often become infected If ulcers or foot injuries are not
treated in time, the infection may involve the bone and require
amputation However, problems caused by minor injuries can usually be
controlled if they are caught in time Avoiding foot injury by wearing
well-fitted shoes and examining the feet daily can help prevent
amputations
Autonomic Neuropathy Also Called Visceral Neuropathy
Autonomic neuropathy is another form of diffuse neuropathy It affects
the nerves that serve the heart and
internal organs and produces changes
in many processes and systems
Urination and Sexual Response
Autonomic neuropathy most often affects the organs that control
urination and sexual function Nerve damage can prevent the bladder from
emptying completely, so bacteria grow more easily in the urinary tract
bladder and kidneys When the nerves of the bladder are damaged, a
person may have difficulty knowing when the bladder is full or
controlling it, resulting in urinary incontinence The nerve damage and
circulatory problems of diabetes can also lead to a gradual loss of
sexual response in both men and women, although sex drive is unchanged
A man may be unable to have erections or may reach sexual climax without
ejaculating normally
Digestion
Autonomic neuropathy can affect digestion Nerve damage can cause the
stomach to empty too slowly, a disorder called gastric stasis When the
condition is severe gastroparesis, a person can suffer from persistent
nausea and vomiting, bloating, and loss of appetite Blood glucose
levels tend to fluctuate greatly with this condition If nerves in
the
esophagus are involved, swallowing may be difficult Nerve damage to the
bowels can cause constipation or frequent diarrhea, especially at night
Problems with the digestive system often lead to weight loss
Cardiovascular system System
Autonomic neuropathy can affect the cardiovascular system, which
controls the circulation of blood throughout the body Damage to this
system interferes with the nerve impulses from various parts of the body
that signal the need for blood and regulate blood pressure and heart
rate As a result, blood pressure may drop sharply after sitting or
standing, causing a person to feel dizzy or light-headed, or even to
faint orthostatic hypotension Neuropathy that affects the
cardiovascular system may also affect the perception of pain from heart
disease People may not experience angina as a warning sign of heart
disease or may suffer painless heart attacks It may also raise the risk
of a heart attack during general anesthesia
Hypoglycemia
Autonomic neuropathy can hinder the bodys normal response to low blood
sugar or hypoglycemia, which makes it
difficult to recognize and treat
an insulin reaction
Sweating
Autonomic neuropathy can affect the nerves that control sweating
Sometimes, nerve damage interferes with the activity of the sweat
glands, making it difficult for the body to regulate its temperature
Other times, the result can be profuse sweating at night or while eating
gustatory sweating
Focal Neuropathy Including Multiplex Neuropathy
Occasionally, diabetic neuropathy appears suddenly and affects specific
nerves, most often in the torso, leg, or head Focal neuropathy may
cause:
Pain in the front of a thigh
Severe pain in the lower back or pelvis
Pain in the chest, stomach, or flank
Chest or abdominal pain sometimes mistaken for angina, heart attack
or appendicitis
Aching behind an eye
Inability to focus the eye
Double vision
Paralysis on one side of the face Bells Bells palsy
Problems with hearing
This kind of neuropathy is unpredictable and occurs most often in older
people who have mild diabetes Although focal neuropathy can be painful,
it tends to improve by itself
after a period of weeks or months without
causing long-term damage
People with diabetes are also prone to developing compression
neuropathies The most common form of compression neuropathy is carpal
tunnel syndrome Asymptomatic carpal tunnel syndrome occurs in 20 to 30
percent of people with diabetes, and symptomatic carpal tunnel syndrome
occurs in 6 to 11 percent Numbness and tingling of the hand are the
most common symptoms Muscle weakness may also develop
Diabetic Neuropathy Can Affect Virtually Every Part of the Body
Diffuse Peripheral Neuropathy:
Legs
Feet
Arms
Hands
Diffuse Autonomic Neuropathy:
Heart
Digestive System system
Sexual organs
Urinary tract
Sweat glands
Focal Neuropathy:
Eyes
Facial muscles
Hearing
Pelvis and lower back
Thigh
Abdomen
How Do Doctors Diagnose Diabetic Neuropathy?
A doctor diagnoses neuropathy based on symptoms and a physical exam
During the exam, the doctor may check muscle strength, reflexes, and
sensitivity to position, vibration, temperature, and light touch
Sometimes special tests are also used to
help determine the cause of
symptoms and to suggest treatment A simple screening test to check
point sensation in the feet can be done in the doctors office The
test uses a nylon filament mounted on a small wand The filament
delivers a standardized 10-gram force when touched to areas of the foot
Patients who cannot sense pressure from the filament have lost
protective sensation and are at risk for developing neuropathic foot
ulcers Physicians may order the filament with instructions for use
free from the Lower Extremity Amputation Prevention Program, LEAP,
Bureau of Primary Health Care, Division of Programs for Special
Populations, 4350 East West Highway, 9th floor, Bethesda, MD 20814;
telephone 301 -594-4424
Nerve conduction studies check the flow of electrical current through a
nerve With this test, an image of the nerve impulse is projected on a
screen as it transmits an electrical signal Impulses that seem slower
or weaker than usual indicate possible damage to the nerve This test
allows the doctor to assess the condition of all the nerves in the arms
and
legs
Electromyography EMG is used to see how well muscles respond to
electrical impulses transmitted by nearby nerves The electrical
activity of the muscle is displayed on a screen A response that is
slower or weaker than usual suggests damage to the nerve or muscle This
test is often done at the same time as nerve conduction studies
Ultrasound employs sound waves The sound waves are too high to hear,
but they produce an image showing how well the bladder and other parts
of the urinary tract are functioning
Nerve biopsy involves removing a sample of nerve tissue for examination
This test is most often used in research settings
If your doctor suspects autonomic neuropathy, you may also be referred
to a physician who specializes in digestive disorders
gastroenterologist for additional tests
How Is Diabetic Neuropathy Usually Treated?
Treatment aims to relieve discomfort and prevent further tissue damage
The first step is to bring blood sugar under control by diet and oral
drugs or insulin injections, if needed, and by careful monitoring of
blood sugar levels
Although symptoms can sometimes worsen at first as
blood sugar is brought under control, maintaining lower blood sugar
levels helps reverse the pain or loss of sensation that neuropathy can
cause Good control of blood sugar may also help prevent or delay the
onset of further problems
Another important part of treatment involves special care of the feet,
which are prone to problems
A number of medications and other approaches are used to relieve the
symptoms of diabetic neuropathy
Relief of Pain
For, burning, tingling, or numbness, the doctor may suggest an analgesic
such as aspirin or acetaminophen or anti-inflammatory drugs containing
ibuprofen Nonsteroidal anti-inflammatory drugs should be used with
caution in people with renal disease Antidepressant medications such as
amitriptyline sometimes used with fluphenazine or nerve medications
such as carbamazepine or phenytoin sodium may be helpful Codeine is
sometimes prescribed for short-term use to relieve severe pain In
addition, a topical cream, capsaicin, is now available to help relieve
the pain of neuropathy
The doctor
may also prescribe a therapy known as transcutaneous
electronic nerve stimulations TENS In this treatment, small amounts
of electricity block pain signals as they pass through a patients skin
Other treatments include hypnosis, relaxation training, biofeedback, and
acupuncture Some people find that walking regularly or using elastic
stockings helps relieve leg pain Warm not hot baths, massage, or an
analgesic ointment such as Beng Gay may also help
Gastrointestinal Problems
Indigestion, belching, nausea, or vomiting are symptoms of
gastroparesis For patients with mild symptoms of slow stomach emptying,
doctors suggest eating small, frequent meals and avoiding fats Eating
less fiber may also relieve symptoms For patients with severe
gastroparesis, the doctor may prescribe metoclopramide, which speeds
digestion and helps relieve nausea Other drugs that help regulate
digestion or reduce stomach acid secretion may also be used or
erythromycin may be prescribed In each case, the potential benefits of
these drugs need to be weighed against their side effects To relieve
diarrhea or other bowel problems, antibiotics or clonidine HCIHCl, a
drug used to treat high blood pressure, are sometimes prescribed The
antibiotic tetracycline may be prescribed A wheat-free diet may also
bring relief since the gluten in flour sometimes causes diarrhea
Neurological problems affecting the urinary tract can result in
infections or incontinence The doctor may prescribe an antibiotic to
clear up an infection and suggest drinking more fluids to prevent
further infections If incontinence is a problem, patients may be
advised to urinate at regular times every 3 three hours, for example
since they may not be able to tell when the bladder is full
Dizziness, Weakness
Sitting or standing slowly may help prevent light-headedness, dizziness,
or fainting, which are symptoms that may be associated with some forms
of autonomic neuropathy Raising the head of the bed and wearing elastic
stockings may also help Increased salt in the diet and treatment with
salt-retaining hormones such as fludrocortisone are other possible
approaches In certain patients, drugs used to treat
hypertension can
instead raise blood pressure, although predicting which patients will
have this paradoxical reaction is difficult Muscle weakness or loss of
coordination caused by diabetic neuropathy can often be helped by
physical therapy
Urinary and Sexual Problems
Nerve and circulatory problems of diabetes can disrupt normal male
sexual function, resulting in impotence After ruling out a hormonal
cause of impotence, the doctor can provide information about methods
available to treat impotence caused by neuropathy Short-term solutions
involve using a mechanical vacuum device or injecting a drug called a
vasodilator into the penis before sex Both methods raise blood flow to
the penis, making it easier to have and maintain an erection Surgical
procedures, in which an inflatable or semi-rigid device is implanted in
the penis, offer a more permanent solution For some people, counseling
may help relieve the stress caused by neuropathy and thereby help
restore sexual function In women who feel their sexual life is not
satisfactory, the role of diabetic neuropathy is less clear
Illness,
vaginal or urinary tract infections, and anxiety about pregnancy
complicated by diabetes can interfere with a womans ability to enjoy
intimacy Infections can be reduced by good blood glucose control
Counseling may also help a woman identify and cope with sexual concerns
Why Is Good Foot Care Important for People with Diabetic Neuropathy?
People with diabetes need to take special care of their feet Neuropathy
and blood vessel disease both increase the risk of foot ulcers The
nerves to the feet are the longest in the body, and are most often
affected by neuropathy Because of the loss of sensation caused by
neuropathy, sores or injuries to the feet may not be noticed and may
become ulcerated At least 15 percent of all people with diabetes
eventually have a foot ulcer, and 6 out of every 1,000 people with
diabetes have an amputation However, doctors estimate that nearly three
three-quarters of all amputations caused by neuropathy and poor
circulation could be prevented with careful foot care To prevent foot
problems from developing, people with diabetes should
follow these rules
for foot care:
Check your feet and toes daily for any cuts, sores, bruises, bumps,
or infections– - using a mirror if necessary
Wash your feet daily, using warm not hot water and a mild soap
If you have neuropathy, you should test the water temperature with
your wrist before putting your feet in the water Doctors do not
advise soaking your feet for long periods, since you may lose
protective calluses Dry your feet carefully with a soft towel,
especially between the toes
Cover your feet except for the skin between the toes with
petroleum jelly, a lotion containing lanolin, or cold cream before
putting on shoes and socks In people with diabetes, the feet tend
to sweat less than normal Using a moisturizer helps prevent dry,
cracked skin
Wear thick, soft socks and avoid wearing slippery stockings, mended
stockings, or stockings with seams
Wear shoes that fit your feet well and allow your toes to move
Break in new shoes gradually, wearing them for only an hour at a
time at first After years
of neuropathy, as reflexes are lost, the
feet are likely to become wider and flatter If you have difficulty
finding shoes that fit, ask your doctor to refer you to a
specialist, called a pedorthist, who can provide you with
corrective shoes or inserts
Examine your shoes before putting them on to make sure they have no
tears, sharp edges, or objects in them that might injure your feet
Never go barefoot, especially on the beach, hot sand, or rocks
Cut your toenails straight across, but be careful not to leave any
sharp corners that could cut the next toe
Use an emery board or pumice stone to file away dead skin, but do
not remove calluses, which act as protective padding Do not try to
cut off any growths yourself, and avoid using harsh chemicals such
as wart remover on your feet
Test the water temperature with your elbow before stepping in a
bath
If your feet are cold at night wear socks Do not use heating pads
or hot water bottles
Avoid sitting with your legs crossed Crossing your legs can reduce
the flow of
blood to the feet
Ask your doctor to check your feet at every visit, and call your
doctor if you notice that a sore is not healing well
If you are not able to take care of your own feet, ask your doctor
to recommend a podiatrist specialist in the care and treatment of
feet who can help
Are There Any Experimental Treatments for Diabetic Neuropathy?
Several new drugs under study may eventually prevent or reverse diabetic
neuropathy However, extensive testing is required by the US Food and
Drug Administration to establish the safety and efficacy of drugs before
they are approved for widespread use
Researchers are exploring treatment with a compound called myoinositol
Early findings have shown that nerves in diabetic animals and humans
have less than normal amounts of this substance Myoinositol supplements
increase the levels of this substance in tissues of diabetic animals,
but research is still needed to show any concrete lasting benefits from
this treatment
Another area of research concerns the drug aminoguanidine In animals,
this drug blocks cross-linking of proteins that occurs
more quickly than
normal in tissues exposed to high levels of glucose Early clinical
tests are under way to determine the effects of aminoguanidine in
humans
One approach that appeared promising involved the use of aldose
reductase inhibitors ARlsARIs ARls ARIs are a class of drugs that
block the formation of the sugar alcohol sorbitol, which is thought to
damage nerves Scientists hoped these drugs would prevent and might even
repair nerve damage But so far, clinical trials have shown that these
drugs have major side effects and, consequently, they are not available
for clinical use
Some General Hints
Ask your doctor to suggest an exercise routine that is right for
you Many people who exercise regularly find the pain of
neuropathy less severe Aside from helping you reach and maintain
a healthy weight, exercise also improves the bodys use of
insulin, helps improve circulation, and strengthens muscles Check
with your doctor before starting exercise that can be hard on your
feet, such as running or aerobics
If you
smoke, try to stop because smoking makes circulatory
problems worse and increases the risk of neuropathy and heart
disease
Reduce the amount of alcohol you drink Recent research has
indicated that as few
as four drinks per week can worsen neuropathy
Take special care of your feet
The Neuropathy Association Inc does not endorse any treatments,
medications, articles, abstracts or products that may be discussed
herein You should consult a neurologist with any questions you have
about your condition
———————–
By Mail: The Neuropathy Association 60 E 42nd Street, Suite 942, New York,
NY 10165 Online: wwwneuropathyorg
Source:neuropathy.org
