Shrunken foot muscles signal diabetic nerve damage

The total volume of muscles in the foot is halved in people who have nerve damage resulting from diabetes, compared with diabetics without neuropathy, according to researchers.

Atrophy or shrinkage of foot muscles, they say, is related to the severity of nerve damage and reflects impaired motor function in these patients.

"Diabetic neuropathy is a length-dependent process that leads to reduced muscle strength and atrophy of leg muscles in some patients," Dr. Henning Andersen and colleagues from Aarhus University Hospital, Denmark, write in the medical journal Diabetes Care.

To see if foot muscles are also affected, the team studied 15 long-term diabetics with chronic neuropathy and 8 without nerve damage, along with a comparison group of 23 matched non-diabetic "controls."

The investigators estimated the total volume of the foot muscles from MRI scans of the nondominant foot, and came up with a neuropathy severity score based on clinical examination, nerve conduction studies, and sensory examination.

Participants with nerve damage had a total foot muscle volume of 86 cc's. The diabetic patients without neuropathy and the healthy controls had volumes of 165 and 168 cc's, respectively.

Also, the neuropathy score went up as foot muscle volume declined.

"Our hypothesis that atrophy of intrinsic foot muscles is a measure closely reflecting motor dysfunction in diabetic neuropathy is supported by the close relationship between degree of atrophy and degree of neuropathy," the researchers conclude.

SOURCE: Diabetes Care, October 2004.