One of the commonest complications of diabetes is the development of neuropathy. A neuropathy is a problem with the nerves of the body. This can have an effect on all of the nerves of the body, including the sensory, motor, and autonomic nervous systems.
Symptoms and types of neuropathy - The symptoms of diabetic neuropathy are dependent on the nerves involved. The sensory system relays signals from the external environment to the brain. If there is a problem with this division of the nervous system, one may experience numbness or tingling in the extremities, pain in the hands and feet, or a loss of balance.
The motor system allows us to move our muscles, and to keep the proper tone required for healthy limbs. Neuropathy to the motor system may cause muscle weakness and loss of tone to the muscles.
Sensorimotor neuropathy is commonly seen in a “glove and stocking” pattern. This means that the areas affected first are the hands and feet, and the symptoms will travel towards the body from the distal most point in each. Symptoms include pain, burning, tingling, prickly, achy, or dull sensations of the extremities.
Diabetic patients are at an elevated risk for infections of the feet in particular, due to ulcerations of the skin. The loss of feeling in the feet leads to a loss of protective sensation. This means that a diabetic patient with sensorimotor neuropathy in the feet (often referred to as peripheral neuropathy) will never feel that their shoes are too tight or that they have walking on a pebble inside their shoe all day, causing an irritation and perhaps a break in the skin. Compounded with a weakened immune system, the diabetic neuropathic patient is a prime target for infections of the foot.
Loss of motor control in the diabetic neuropathic patient can also lead to a loss of muscle mass and strength in the foot. This may be seen as contractures of the extensor muscles of the toes, which will result in the formation of hammer toes.
Perhaps the piece of the diabetic neuropathy puzzle that is of greatest value mentioning is autonomic neuropathy. The autonomic (or involuntary) nervous system controls all of the functions that we don’t have to think about. This includes controlling the heart rate, tension/tone of the blood vessels, gastrointestinal control, and control of the urinary system, to mention a few. Autonomic neuropathy can result in a loss of control over any one of these systems, and in many patients it results in a loss of control of several.
Manifestations of autonomic neuropathy are seen with ease in the feet of a patient. Signs and symptoms include a loss of hair on the foot, ankle, and lower leg over time, increased prevalence of fungal nail infections and superficial fungal infections of the feet (tinea pedis, or athlete’s foot), feet that are cold to touch, and a general decrease in blood flow to the feet. The development of peripheral neuropathy in the feet of a diabetic patient is one of the first noticeable signs of diabetic complications.
How diabetic peripheral neuropathy develops – Evidence exists for several different mechanism of how the problem develops, all of which are related to each other.
Microvascular disease is a popular idea of how peripheral neuropathy develops. Interdependence of the vascular and nervous systems is a common theme in many disease processes of each system. As vasoconstriction (the tightening of a blood vessel) is one of the first functions lost, microvascular disease to the vessels that supply the long nerves (vasa nervorum) fits as an explanation.
Other explanations include advanced glycated end products altering the function of proteins and enzymes in the body, an increased level of protein kinase C that may alter the function of intercellular proteins, and the polyol pathway (sorbitol/aldose reductase pathway), which helps explain the microvascular component of peripheral neuropathy. Further explanations of these processes are beyond the scope of this article, but much more can be found about these biochemical processes online.
Treatment of peripheral neuropathy – Assessing and evaluating peripheral neuropathy is perhaps the simplest method of tracking the progression of the problem. This is done with very simple clinical tests that your doctor may perform in the office. These tests also aid in the diagnosis of peripheral neuropathy.
Simply put, each type of nerve in the legs and feet has a clinical test that evaluates the function of a particular nerve. The different types of nerve fibers include sensory fibers that conduct vibration, proprioception (the way your brain knows where your foot is in space), deep touch, light touch, cold/heat sensation, pain, and protective sensation.
Several medications may be prescribed by your doctor to treat painful peripheral neuropathy. These include agents such as tricyclic antidepressants, serotonin reuptake inhibitors, anticonvulsant medications, and other pharmaceuticals. Experimental treatments include the use of topirimate and carbemazepine, both of which are also used to treat epilepsy and other disease processes of the nervous system. It should be noted that the vast majority of products used to treat peripheral neuropathy are used off-label, meaning that they have not been FDA-approved to treat such conditions.
Other treatments include the use of transcutaneous electric nerve stimulation (TENS) and injection of methylcobalamin (activated vitamin B12). These have both been shown to be an effective method of treatment in patients with diabetic neuropathy.
Prevention and Epidemiology – The most effective method of treating diabetic neuropathy is a tight control on blood glucose levels. High blood sugar levels, or hyperglycemia, is the characteristic trait of diabetes mellitus and high levels of blood glucose correlate with an increase in complications. An aggressive approach to glycemic control us of utmost importance, and includes diet modification, regular and appropriate exercise, and medications to help control blood glucose and insulin levels.
The prevalence of diabetic neuropathy ranges in populations from 20-50%. There are numerous studies evaluating the prevalence in different populations, all with different averages. However, what remains consistent in these studies is that Type II diabetics are more likely to develop complications that Type I diabetics (insulin-dependent). To see how the Dellon Procedure can help curb neuropathy pain click HERE.
