A 64-year-old woman comes to the physician because she has had bilateral foot numbness and burning for the past three months. The symptoms are especially bothersome at night. She has a history of hypertension, coronary artery disease, and type 2 diabetes mellitus. She had an anterior wall myocardial infarction two years ago, which was treated with angioplasty and stenting of the left anterior descending artery. An echocardiogram obtained one year ago revealed an ejection fraction of 40%. She does not use tobacco, alcohol, or drugs. Her medications include metoprolol, furosemide, glyburide, atorvastatin, aspirin, and enalapril. She has been on oral hypoglycemic medications for the last ten years. Her blood pressure is 142/82 mmHg and her heart rate is 63/min. Her BMI is 34 kg/m². Physical examination shows intact skin over both feet and 2+ peripheral pulses.
Which of the following is the most appropriate next step in managing this patient?

Question

Quizplus · Accepted Answer

Explanation: This patient's history and symptoms suggest a diagnosis of diabetic neuropathy. We are not provided her HbA1c level, but based on her elevated BMI and recent myocardial infarction, it is a reasonable deduction that her diabetes has been poorly controlled. Diabetic neuropathy tends to affect longer nerve axons first, therefore patients typically first present with symptoms in the feet. The symptoms that this patient describes are secondary to changes in the nerve fibers controlling pain sensation. However, the nerve fibers controlling vibration and proprioception are commonly affected as well. While there are several complicated screening mechanisms for diabetic neuropathy using questionnaires and physical exam findings, the most commonly used screening test is the tuning fork test which takes advantage of loss of vibratory sense. The test is easy to perform and inexpensive. Aggressive glycemic control is mandatory in patients with diabetic neuropathy since the problem predisposes to foot ulceration, which can be complicated by infection and may even necessitate amputation in extreme cases. (Choice A) A duplex lower extremity ultrasound is used to diagnose lower extremity venous disease, including deep venous thrombosis. However, this patient has no edema or ulceration in the lower extremity to suggest venous disease. (Choice B) A spine MRI would be used to evaluate for causes of lumbar radiculopathy. The bilateral nature of this patient's symptoms along with the worsening of symptoms at night make a lumbar radiculopathy less likely. (Choice C) Nerve conduction studies can be used to confirm a diagnosis of diabetic neuropathy. However, most clinicians use a combination of clinical symptoms and the tuning fork test given its ease and low cost. (Choice D) Peripheral neuropathy can occur in patients with multiple myeloma, usually secondary to amyloid deposition. However, this patient's history of diabetes makes diabetic neuropathy far more likely. Educational objective: Diabetic neuropathy should be suspected in patients with diabetes who have symmetric sensory changes in the feet that consist of injury to nerve fibers controlling pain, temperature, vibratory, and proprioception sense. The tuning fork test is an easy and inexpensive way to assess for the loss of vibratory sense in patients with diabetic neuropathy.

A 64-Year-Old Woman Comes to the Physician Because She Has