The neuropathies associated with diabetes mellitus

Abstract

A total of 103 unselected diabetic patients were studied independently in the electromyographic laboratory and by clinical neurologic examination. In 43 of these patients, the lindings of neuropathy were unequivocal. A comparison of the electromyographic and clinical findings arrived at independently revealed a most complete agreement between the 2 when a diagnosis of polyneuropathy was made. The discrepancies observed in the diagnosis of mononeuropathy were related to the occasional failure to select the involved nerve or muscle for test by the electromyographer, who is this study worked without a preliminary neurologic examination, and to the greater sensitivity of the electromyographic examination in the nerves and muscles which were tested. The advantages of the electromyogram included its greater sensitivity to nerve changes and its ability to measure alterations of nerve function in a reproducible manner. The neuropathies encountered included both mononeuropathy and polyneuropathy. The former included those neuropathies which we have previously called "autogenous" and which are amenable to specific therapy, and femoral neuropathy, which in our experience is a self-limiting disturbance. The polyneuropathies were found most commonly in patients with long-standing and severe diabetes. However, polyneuropathy occasionally was seen in patients with newly discovered mild diabetes, and it may not be present in patients with severe, poorly controlled diabetes of long duration. Studies of nerve conduction revealed slowing of conduction in most of these patients as measured by the tests used. These studies suggest that there may be alteration in the peripheral nerves of diabetic patients without overt neuropathy as well as in those with neuropathy. It is suggested that this alteration of peripheral nerves may be accompanied by an increased vulnerability of the nerves, which in some patients is expressed by polyneuropathy and in others, when the stress is local, by mononeuropathy.