Using botulinum toxin to treat diabetic foot pain

Abstract

Botulinum toxin type A (BoNT/A) is made naturally by certain bacteria. BoNT/A works by paralyzing specific kinds of nerve cells. BoNT/A can be used to treat many illnesses that affect either nerves or the muscles with which they communicate. In the article “Botulinum Toxin for Diabetic Neuropathic Pain: A Randomized Double-Blind Crossover Trial,” Dr. Yuan and associates describe how BoNT/A might be used to treat the kind of nerve pain that develops in some people who have diabetes.1 The study compares whether injecting BoNT/A into the skin is better at reducing neuropathic pain than injecting a placebo (saline, salt water) into the skin. Dr. Yuan and colleagues looked carefully at 20 people who had neuropathic pain due to type 2 diabetes. Each person had been diagnosed with diabetes for at least 3 years. Patients with neuropathy experienced either paresthesias (prickling, tingling, or numbness) or a specific kind of pain (burning, itchy, shooting, etc.) in both of their feet up to the ankle or mid-shin. Doctors assessed the pain by 1) physical examination, 2) a specific questionnaire for pain, and 3) a specific test of nerve function. The nerve test is called a nerve conduction velocity test. It is designed to see how well patients’ nerves can transmit electrical signals. If the nerve is damaged, as happens in diabetes, the signals carried by the nerves are either slower or weaker than normal. As in all studies, there are reasons to include specific participants. This makes sure that the group is alike and that the results are solid. For instance, only people with proven polyneuropathy due to diabetes were included. Since a specific treatment was being studied, only people who had not changed …