A Diabetic Woman With Unilateral Proximal Leg Weakness and Pain

A 70-year-old woman with type II diabetes managed with oral agents had a 3-week history of weakness in the left lower extremity which developed a week after gallbladder surgery. She also had diffuse thigh pain, but no back pain, and was treated with physical therapy without improvement. The condition stabilized, but she continued to have some difficulty walking and had persistent discomfort.

Two months later, she developed progressive pain and weakness in the right lower extremity, and she had some occasional burning paresthesias in both feet. She was unable to walk for 2 weeks.

Past medical history included hypothyroidism treated with thyroid replacement and an L5 laminectomy 10 years previously for chronic back pain, radiating to the right leg; this pain disappeared after surgery.

Neurological examination showed normal mentation and cranial nerves. Upper extremity examination revealed normal strength, reflexes, and sensation bilaterally. She had weakness in the right hip flexors of 3+/5 and knee extensor of 2/5; thigh adductors were 3/5; and other muscles of the hip and leg were normal. In the left lower extremity, hip flexion and knee extension were 4/5 and knee flexion was normal; she also had 3+/5 weakness in adductors. Distal muscles were normal. Reflexes were normal in the upper extremities, absent in the knees, and trace at the ankles. Both adductor reflexes were absent. There were no Babinski signs. Straight leg raising and femoral stretch were negative. She had decreased vibration sense and two-point discrimination in the toes and decreased pain sensation up to the mid-calf level. She also had decreased pain in the anterior and lateral right thigh ( Fig. 58-1 ). Coordination was normal and the rest of the examination was normal.

What is the Most Likely Diagnosis for this Patient?

This patient had diabetes and a peripheral neuropathy. She also had prominent weakness in muscles innervated by L2–L4 roots bilaterally, with a mild distal sensory deficit that corresponds to a peripheral neuropathy, and had decreased pain sensation on the left thigh. The differential diagnosis included a lumbar canal disease such as disk disorder, but the lack of back pain is against this diagnosis. A diabetic lumbosacral radiculoplexus neuropathy, as well as a systemic vasculitis, are considerations. Plexopathy from a tumor should be ruled out. The motor deficit, including muscles innervated not only by the femoral nerve but also by the obturator nerve, is against a femoral neuropathy.

What will be the Next Diagnostic Tests?

Basic blood work was normal, except for an elevated glycosylated hemoglobin of 9.2 ml/dl (normal, <6.4 mm/dL) and blood sugar of 240 mg/dL (normal, 65–120 mg/dL). Erythrocyte sedimentation rate and antineutrophil cytoplasmic antibody and fluorescent antinuclear antibody titers were normal.