Burning Foot Pain May Signal Microvascular Lesions in T2DM

At 68 years old, Mr Thomas has osteoarthritis, hypertension, and a 10-year history of type 2 diabetes mellitus (T2DM). He presents to your office complaining of limited exercise tolerance. When questioned further, he reports that he is limited mostly by pain in his right foot, which he describes as a burning sensation that improves when he rests. His medications include aspirin, rosuvastatin, hydrochlorothaizide, lisinopril, diclofenac, and metformin. Cardiac examination demonstrates a regular rhythm with a II/VI midsystolic murmur heard best at the left sternal border. ECG today demonstrates normal sinus rhythm.

Which of the following is/are appropriate to order at this time (select all that apply):

A. Urine microalbumin

B. ECG-treadmill stress test

C. Ankle-brachial Index

D. Transthoracic echocardiogram

E. CT angiography and coronary calcium score

F. Referral to a podiatrist for comprehensive examination

Answers: A, C, and F

Vascular diseases, particularly atherosclerosis, are major causes of disability and death in patients with T2DM. Therefore, there should be a low threshold to screen for microvascular and macrovascular complications in these patients. 

Microvascular complications, such as retinopathy, nephropathy, and neuropathy, should be screened for annually with regular ophthalmologic exams, measurement of urine microalbumin (A), and podiatric examinations (F).

Macrovascular complications caused by T2DM include coronary, cerebrovascular, and peripheral arterial disease. The threshold also should be low for ordering screening tests for signs of these. 

Mr Thomas is complaining of foot pain, which could be a result of diabetic peripheral neuropathy or a manifestation of peripheral vascular disease. Therefore, it is appropriate to both order an ankle-brachial index (C) and make a referral to podiatry (F) for a comprehensive foot examination with advanced neurologic testing, such as filament testing to assess for peripheral neuropathy. 

It is not appropriate to order a screening stress test or CT angiography (E) at this time, because the limitations in exercise tolerance are clearly the result of foot pain. Either of these tests would be appropriate choices if he was endorsing symptoms consistent with angina, especially since his baseline ECG is normal.   

A transthoracic echocardiogram (D) is also not indicated because grade I/II murmurs, which are otherwise asymptomatic, are most likely physiologic in nature and do not warrant costly imaging.  

Of note, Mr Thomas should be counseled at this visit about the risks of NSAID use, which have been linked to an increased risk of heart failure, kidney disease, hypertension, and atrial fibrillation.