This article includes discussion of diabetic amyotrophy, Bruns-Garland syndrome, diabetic lumbosacral radiculoplexus neuropathy, diabetic mononeuritis multiplex, diabetic polyradiculopathy, and proximal diabetic neuropathy. The foregoing terms may include synonyms, similar disorders, variations in usage, and abbreviations.
Diabetic amyotrophy is predominantly a motor condition that involves various elements of the lumbosacral plexus, particularly those related to the femoral nerve. It usually presents acutely as unilateral thigh pain followed by weakness and later wasting in the anterior thigh muscles. Diabetic amyotrophy typically occurs in older patients with type 2 diabetes. An immune-mediated epineurial microvasculitis has been demonstrated in nerve biopsies. When severe and progressive, predominantly motor polyneuropathy develops in diabetic patients, one must also consider chronic inflammatory demyelinating polyradiculoneuropathy. In this article, the authors discuss studies that have provided novel insights into the pathogenesis of diabetic amyotrophy, leading to the establishment of formal clinical trials of mechanistically relevant therapies like immunoglobulin and methylprednisolone.
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• Diabetic amyotrophy, which presents usually as unilateral thigh pain followed by weakness, can be painless.
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• The diabetic amyotrophy mechanism is ischemic injury possibly secondary to microvasculitis.
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• It is important, and sometimes difficult, to differentiate diabetic amyotrophy from chronic inflammatory demyelinating polyradiculoneuropathy.
Historical note and terminology
The syndrome of wasting and weakness of the pelvifemoral muscles associated with diabetes mellitus was originally described by Ludwig Bruns in 1890 (07). Many years later, Garland and Taverner expanded the description (20) and later coined the term “diabetic amyotrophy” (19). Since the inception of the term, its nomenclature has been controversial based on its variable presentations (proximal vs. proximal and distal; asymmetric vs. symmetric), onset (abrupt vs. insidious), and different electrophysiological and biopsy findings described. Skeptics have challenged the term “diabetic amyotrophy” because it erroneously implies a primary muscle disorder as well as the term “proximal diabetic neuropathy” because distal weakness is often present as well. Disagreements regarding pathogenesis (metabolic vs. ischemia) have prompted some authors to suggest that the process is a clinical continuum of diabetic neuropathy rather than a distinct clinical entity (02). Similarities to other symptom complexes have produced newer and more descriptive terms such as “diabetic lumbosacral radiculoplexus neuropathy” and “diabetic mononeuritis multiplex.” Considerable evidence that diabetic amyotrophy is a distinct clinical entity with a defined clinical spectrum and pathophysiology has emerged over the last several years.