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Definition:
A common complication of diabetes mellitus in which nerves are
damaged as a result of hyperglycemia (high blood sugar levels).
Alternative Names: Nerve damage - diabetic
Causes, incidence, and risk factors:
People with diabetes commonly develop temporary or permanent damage
to nerve tissue. Nerve injuries are caused by decreased blood flow
and high blood-sugar levels, and are more likely to develop if
blood-glucose levels are poorly controlled. Some diabetics will not
develop nerve damage, while others may develop this condition
relatively early. On average, the onset of symptoms occurs 10 to 20
years after diabetes has been diagnosed. Approximately 50% of people
with diabetes will eventually develop nerve damage.
Peripheral nerve injuries may affect cranial
nerves or nerves from the spinal column and their branches. This
type of neuropathy (nerve injury) tends to
develop in stages. Early on, intermittent pain and tingling is noted
in the extremities, particularly the feet. In later stages, the pain
is more intense
and constant. Finally, a painless neuropathy develops when pain
sensation is lost to an area. This greatly increases the risk of
severe tissue injury because
pain no longer alerts the person to injury.
Autonomic neuropathies affect the nerves that regulate involuntary
vital functions, including the heart muscle, smooth muscles and
glands. Low blood pressure, diarrhea, constipation, sexual
impotence, and other symptoms can be caused by autonomic
neuropathies.
Symptoms:
Numbness
Tingling
Decreased sensation to a body part
Loss of sensation to a body part or area
Diarrhea
Constipation
Loss of bladder control
Impotence
Facial drooping eyelid
Drooping mouth
Vision changes
Dizziness
Weakness
Swallowing difficulty
Speech impairment
Muscle contractions
Note: Symptoms vary depending on the nerve(s) affected and may
include symptoms other than those listed. Symptoms usually develop
gradually over years.
Signs and tests:
Physical examination, including neurological and sensory tests, may
reveal many neuropathies. A common early finding is the absence of
ankle reflexes.
Treatment:
The goals of treating diabetic neuropathy are
to prevent progression and reduce the symptoms of the disease. Tight
control of glucose is important to prevent progression. To reduce
the symptoms, topical treatment with Capsaicin or oral medication
like amitriptyline, gabapentin, and carbamazepine have been used
successfully. Analgesics (pain medications) are rarely of much
benefit in the treatment of painful neuropathy.
Regular foot exams are important to identify small infections and
prevent progression. If foot injuries go unnoticed for too long,
amputation may be required.
Expectations (prognosis):
The mechanisms of diabetic neuropathy are poorly understood. At
present, treatment alleviates pain and can control some associated
symptoms, but the process is generally progressive.
Complications:
There is an increased risk of injury to the
feet because of loss of sensation. Small infections can progress to
ulceration (skin and soft tissue breakdown)
and require amputation. In addition, motor nerve damage can lead to
muscle breakdown and imbalance.
Calling your health care provider:
Call your health care provider if signs and symptoms of diabetic
neuropathy develop.
Prevention:
It is clear now that tight control of blood sugar level (Hemoglobin
A1C < 7.0) prevents the development of neuropathy in 60% of type 1
diabetics and decreases the severity of symptoms. In addition,
regular foot care can prevent a small infection from progressing.
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