Case Presentation: An 80-year-old man with a history of Type 2 diabetes and chronic lumbar radiculopathy presented to the emergency room after four days of left thigh pain radiating from the groin and progressive left leg weakness, now needing a wheelchair. On exam of his left leg, he had decreased strength in hip flexion and knee extension, decreased sensation to touch along his medial calf, and a muted patellar reflex. He also had decreased vibrational sense in the toes bilaterally. Labs revealed a hemoglobin A1C of 9.8%. An MRI showed diffuse, extensive degenerative disease in the lumbar-sacral spine but no focal structural lesions such as epidural abscess or osteomyelitis. Electromyography showed evidence for diabetic amyotrophy as well as moderate polyneuropathy. After two months of strict glycemic control and physical therapy, the patient recovered some function and was ambulatory with a cane.
Discussion: Diabetic amyotrophy is also known as diabetic femoral neuropathy, diabetic proximal neuropathy, diabetic lumbosacral radiculoplexopathy, and Bruns-Gardland syndrome. Patients with this entity typically present with acute or subacute, severe unilateral pain and weakness in the proximal lower extremity, and may often have muscle wasting. While distal polyneuropathy is the most common type of diabetes-induced neuropathy that can affect more than 20% of all diabetic patients, diabetic amyotrophy is much rarer and affect less than 1% of patients. Because of its low prevalence, it is often misdiagnosed as lumbosacral radiculopathy. In this case, our patient’s neurologic symptoms were initially assumed to be due to known lumbar radiculopathy. However, a thorough exam localized the lesion to the left femoral nerve, which did not correlate with the imaging finding and prompted further work up. The diagnosis of diabetic amyotrophy depended on a high level of suspicion, recognition of poorly controlled diabetes, and confirmatory testing with electromyography. Treatment mainly consists of pain management and glycemic control, but studies on steroids and immunoglobulin are on-going. The majority of patients spontaneously improve over months.
Conclusions: Diabetic amyotrophy is a rare yet debilitating complication of diabetes. Because diagnosis reply heavily on clinical recognition, it is important for hospitalists to keep a high level of suspicion when diabetic patients present with asymmetric proximal neuropathy.