Part One: Neuropathy
Neuropathy is the loss of function of the nerves. There are three types of nerves that are affected in diabetic peripheral neuropathy: motor, sensory, and autonomic. Each lead to different symptoms and different outcomes, but all can be the result of high blood glucose levels sustained over a long period of time.
Just as the name implies, motor neuropathy affects the motor functions of the muscles in the feet. Motor neuropathy can lead to weakness and atrophy. With the muscles inside the foot being the first to be affected, deformity of the feet can arise due to the imbalance of the muscles. With this deformity, abnormal stress arises leading to higher than normal pressures on the bottom of the feet. The body responds to abnormal pressure by forming callous or thickening the skin. When this callous builds up, it creates more pressure which can lead to further breakdown of the skin and ulceration
Sensory neuropathy indicates a loss of protective sensation. When the podiatrist examines your feet, a monofilament wire is used to test this sensation (see image). Without this protection, you stand the greater chance of doing harm without even knowing it. Knowing that there is pain in the feet is a good thing, for, without this knowledge you can’t protect yourself from further damage.
An example that I have heard on multiple occasions is the patient that couldn’t feel their feet due to neuropathy. They step on a beer bottle cap without realizing it and it sticks to their foot. This wouldn’t last long on the foot if they had feeling, but, without that protective sensation, the cap could stay their without their knowing it, causing a major ulceration in days. This is also another reason why it is important to check your feet daily.
Autonomic neuropathy involves damage to the part of the nervous system that manages every day body functions such as blood pressure, heart rate, sweating, bowel and bladder emptying, and digestion. For diabetics, this will manifest itself in the feet with dry skin, and lack of sweating. Autonomic neuropathy can also lead to altered blood flow regulation. Autonomic neuropathy and diabetes may lead to a condition called “Charcot neuropathy,” which is a complex topic for another time.
What can you do?
In the fight against diabetic neuropathy you can help. Controlling your diabetes and following the recommendations of your primary care doctor that is managing the disease, along with yearly visits to the podiatrist, can greatly improve your outcomes if you get this condition.