Abnormal Glucose Metabolism May Contribute To Chronic Nerve Disorder

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Abnormal Glucose Metabolism May Contribute To Chronic Nerve Disorder

http://www.medicalnewstoday.com/medicalnews.php?newsid=45102

Abnormal glucose metabolism, which occurs when the body has

difficulty processing sugar (glucose) into energy, is twice as common

among patients with chronic nerve dysfunction of unknown cause than

among the general population and may be a risk factor for the

condition, according to a study posted online that will appear in the

August 2006 print issue of Archives of Neurology, one of the

JAMA/Archives journals.

Many older adults experience nerve disorders known as neuropathy,

some of which are characterized by symptoms of " burning feet " and

other unpleasant sensations in the lower leg, according to background

information in the article. Diabetes, genetic disorders, exposure to

toxic substances and a condition called amyloidosis in which extra

protein-based substances accumulate in the body tissues can all cause

neuropathy, but many cases do not have an easily identifiable

underlying cause. When laboratory tests cannot determine the cause,

the condition is known as chronic idiopathic axonal polyneuropathy; a

cause is eventually found in only 7 to 30 percent of these cases.

Charlene Hoffman-Snyder, M.S.N., N.P.-B.C., Mayo Clinic, Arizona, and

colleagues identified 100 consecutive patients (60 women and 40 men)

with chronic idiopathic axonal polyneuropathy who were evaluated

between January 2003 and January 2005. Patients underwent a complete

neurological evaluation and had a fasting plasma glucose test, which

measures the levels of glucose in the blood after eight hours of not

eating, and a two-hour oral glucose tolerance test, which determines

how well the body processes glucose by drawing blood two hours after

fasting patients ingest a dose of glucose. " The fasting plasma

glucose level alone does not always identify patients with impaired

glucose tolerance and neither does the two-hour oral glucose

tolerance test always detect patients with impaired glucose

metabolism, " the authors write. " Both tests are, however, useful to

detect hyperglycemia [high blood sugar] and the consequences of

disordered glucose metabolism. "

According to the two-hour oral glucose tolerance test, 62 patients

(62 percent) with neuropathy had abnormal fasting glucose metabolism,

including 24 with undiagnosed diabetes. (This compares with 33

percent of patients of similar ages in the general population with

abnormal glucose metabolism as previously estimated by the Centers

for Disease Control and Prevention in other published reports.) The

results of the current study suggest that abnormal glucose metabolism

may be a risk factor for neuropathy.

" Conventional thinking among diabetologists is that diabetic

polyneuropathies are the result of prolonged hyperglycemia, " the

authors write. " Like previous studies, this investigation supports

the hypothesis that distal axonal polyneuropathies may occur in much

earlier stages of abnormal glucose metabolism than previously

thought. Recent studies suggest that the neuropathy associated with

impaired glucose tolerance may be milder than neuropathies

traditionally associated with diabetes mellitus and may be the

earliest detectable sign of abnormal glucose metabolism. "

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(Arch Neurol. 2006; 63: (doi: 10.1001/archneur.63.8.noc50336).)