Neuropathy, or nerve damage, is a serious and common
complication of diabetes. Studies estimate that 50% of people with diabetes will develop neuropathy. Even if you lack symptoms—which is very likely, considering
that many diabetics develop nerve damage one or two decades after diagnosis—you
should maintain close control over blood glucose levels to keep your risk of
nerve damage as low as possible.
In addition to keeping glucose levels in a healthy range,
studies now show that controlling blood pressure to ward off complications from
diabetes is just as important. In 2010, the British
Medical Journal reported, “In patients with type 2 diabetes the risk of
diabetic complications was strongly associated with raised blood pressure.” Any
reduction in blood pressure is likely to reduce the risk of complications, with
the lowest risk being in those with systolic blood pressure less than 120
Diabetic neuropathy is often caused by years of high,
unregulated blood glucose, largely due to lack of awareness. Long periods of
elevated blood glucose can injure the vessels that supply the body’s nerves
with adequate nutrition and oxygen. After years of deprivation due to poor
blood replenishment, the nerves become numb. Some people with neuropathy
experience pain, but as the disorder progresses, that pain often disappears; the
nerves are too damaged to feel anything.
Four Types of Neuropathy
Neuropathy is an umbrella term for several types of nerve
damage. Peripheral neuropathy is
nerve damage that affects the feet, toes, legs, hands, and arms. Autonomic neuropathy relates to damage
of the nerves that regulate digestive, bladder, and bowel functions as well as
heart and sexual function. Proximal
neuropathy causes nerve damage in the thighs, hips, and buttocks. Focal neuropathy is the sudden weakness
of one or more groups of nerves anywhere in the body.
In type 2 diabetics, nerve damage due to peripheral
neuropathy usually affects the feet and legs before the arms or hands. Symptoms
are varied and can be mild to severe. They include numbness, tingling or
burning sensations, extreme sensitivity to touch, insensitivity to hot and cold
temperatures, and pain or cramping. Some people with neuropathy are affected by
their symptoms largely at night.
Peripheral neuropathy can cause muscle weakness and the loss
of reflexes, which often leads to changes in a person’s mobility, gait, and
balance. Changes in walking sometimes causes foot deformities and foot
injuries. Risks from foot injuries are especially dangerous to diabetics since
the combination of neuropathy and poor blood circulation makes wounds tougher
to heal. Longer healing times can leave injuries prone to infection. In extreme
cases, infection can lead to amputation.
In this type of nerve damage, the “automatic” nerve responses
of the body’s internal organs are affected. Type 2 diabetics with autonomic
neuropathy may have problems digesting food, breathing, trouble urinating or
with incontinence, and/or sexual problems, such as impotence. Even the sweat
glands and eyes can be weakened. Symptoms are varied and also range from mild
Problems with autonomic neuropathy may make it difficult to
determine when your blood glucose levels are too low. Normally, symptoms
associated with hypoglycemia like sweating and heart palpitations are obvious,
but those symptoms may be masked by nerve damage. Because autonomic neuropathy
often obscures the normally painful symptoms of a heart attack, those with the
condition are urged to know the other warning signs, such as profuse sweating,
pain in the arm, back, neck, jaw, or stomach, shortness of breath, nausea, and
Nerve damage to the digestive system may cause constipation,
trouble swallowing, or gastroparesis, a disorder that causes a delay in
digestion. Gastroparesis may worsen over time until a person is debilitated by
frequent nausea and vomiting. Delayed digestion often makes keeping track of
glucose levels more difficult. In severe instances of gastroparesis, a person
may subsist on a liquid diet or be fed via feeding tube.
Nerve damage to the cardiovascular system can cause changes
in a person’s heart rate and blood pressure. For instance, type 2 diabetics
with autonomic neuropathy may experience a drop in blood pressure after sitting
or standing, causing them to feel dizzy and light-headed.
Nerve damage to the urinary tract and sex organs can cause
difficulty controlling urination and sexual function. For instance, neuropathy
in the bladder may cause incontinence or make it more difficult to fully empty.
Autonomic neuropathy may also decrease sexual function, leaving men without the
ability to become erect or ejaculate normally, and women with vaginal dryness
and difficulty achieving orgasm.
This type of neuropathy commonly affects type 2 diabetics,
especially older adults. It predominantly affects the hips, thighs, buttocks,
or legs and typically begins on one side of the body. Proximal neuropathy can
weaken the legs, and in severe cases, a person may lose enough muscle tone to
no longer have the ability to go from a sitting to a standing position without
assistance. Nerve damage of this type is often painful.
The head, upper body, or legs may be affected by focal
neuropathy, which appears suddenly and is usually painful. Unlike the other
forms of neuropathy, this type usually goes away in a few weeks or months and
leaves no lasting damage.
Symptoms of focal neuropathy include an inability to focus,
double vision, aching behind the eyes, one-sided facial paralysis (Bell’s
palsy), carpal tunnel syndrome, and pain in isolated areas, like the front of
the thigh, lower back, pelvic region, chest, stomach, inside the foot, and the
According to Nancy Klobassa Davidson, R.N. and diabetic
educator for the Mayo Clinic, “Pain relief (for focal neuropathy] can be among
the most difficult aspects of managing the disorder. Often several treatments
or a combination of treatments are tried before adequate relief can be found.
For some people, the pain never goes away completely.”