There are four main types of diabetic neuropathy. Learn about the key differences between each, and how the symptoms may differ.
Diabetic neuropathy describes nerve damage occurring in a patient with a case of type I or type II diabetes. This is characterized by numbness, weakness, pain, tingling, and an assortment of neurological deficiencies in the peripheral or autonomic nervous systems.
Nerve damage can and often does occur in cases of diabetes due to long-term excessive blood sugar levels, which causes excess glucose to interfere with the way nerves function, damaging them and disrupting signals from being sent to the brain and vice versa. In fact, diabetic neuropathy is one of the most common causes of peripheral nerve damage in medicine, alongside alcoholic neuropathy.
What is Neuropathy?
Neuropathy is any kind of damage to the nerves. Our nervous system acts as the cable network through which our body and brain interact with one another, as well as process the outside world. Any disruption in the network can lead to a cascade of failures, some isolated, some systemic, depending on which “cable” is disrupted or damaged.
This is why different types of diabetic neuropathy can come in many shapes and sizes and present a long list of potential symptoms. Doctors usually determine diabetic neuropathy through nerve response tests, electrical stimulation, imaging tests (which utilize radiation or magnetic waves to create an image of the inside of the body), and blood tests.
Different types of diabetic neuropathy can occur because of direct physical trauma, poisoning, a hereditary condition, a viral or bacterial infection, or other illnesses. For example, landing hard on your back may damage the nerves surrounding your spine, causing numbness and weakness in one or more limbs. Excessive blood sugar – either because of type I or type II diabetes – can damage the protective myelin sheath of your nerve cells, destroying them in the process.
How Does Diabetes Cause Nerve Damage?
Diabetes is a condition described by high blood sugar. When this occurs, it is often because the body cannot produce enough insulin to process the sugar in the bloodstream. Understanding diabetes relies on understanding insulin.
Insulin is a hormone that the body produces to command cells to take in sugars in the blood as energy. This helps normalize your blood sugar levels. Sugar levels that are too high or too low for a short amount of time can cause hypo or hyperglycemia. Insulin is one of the ways your body regulates those sugar levels, while ensuring that your cells get the fuel they need to produce energy.
Type I diabetes is hereditary and means that a patient’s pancreas is not producing normal levels of insulin. It is an autoimmune disease, because the body’s own immune response is responsible for the pancreas’ underproduction.
Type II diabetes occurs when your cells become insulin resistant. They no longer respond to insulin, forcing your pancreas to compensate by pushing up its production. Eventually the pancreas can’t keep up, and your blood sugar reaches dangerous levels.
In both cases, the end result is very high blood sugar. Once blood sugar is too high, it begins to interfere with several critical functions in the body, including your nerves. Your body will also begin to burn fat in response to its inability to process sugars. This leads to your body releasing an unusual number of ketones into your bloodstream.
This alters the acidity of the blood, rendering it toxic over time. Among other symptoms, your urine begins to become incredibly high in sugar, you begin to feel very thirsty, you begin to develop problems with eyesight as your eyes become damaged.
Eventually, diabetes causes peripheral artery disease, meaning your blood vessels begin to narrow. This can lead to decreased blood flow to key areas of the body, beginning with your extremities (toes and fingers). This can lead to wounds, ulcers, and more nerve damage. If left unchecked, it can cause gangrene, which is why ulcers and tissue damage in the extremities are a common complication for patients with long-term diabetes.
Types of Diabetic Neuropathy
Your symptoms will differ depending on where the nerve damage is setting in. Your body has hundreds of nerves, of which only the major ones are named.
All your nerves and nerve cells are divided between the central nervous system (brain and spinal cord) and the peripheral nervous system (everything else).
The peripheral nervous system is further divided into your motor nerves and sensory nerves. There are nerves that you control consciously (moving your arms and legs). There are also ones that function involuntarily (breathing, swallowing, heartbeat, etc.)
When a nerve or set of nerves is damaged, it is described through one of four different types of neuropathy:
Peripheral neuropathy is the most common and generalized form of diabetic neuropathy and occurs whenever any of your peripheral nerves are affected by high blood sugar. As with most diabetic symptoms, these begin in the hands and feet.
Symptoms include numbness and weakness in the limbs, loss of reflex responses, extreme sensitivity in the skin, and jabbing sensations.
Your autonomic nerves help regulate digestion, heartbeat, breathing, sexual function, sweating, and other involuntary systems. Damage to these nerves will lead to irregularities in any of these functions, including abnormal sweating, bladder problems and incontinence, slowed digestion and nausea, erectile dysfunction or vaginal dryness, and problems with body temperature.
Focal neuropathy or mononeuropathy is damage to a single, specific nerve. For people with diabetes, the most common mononeuropathy is carpal tunnel syndrome. Other examples include Bell’s palsy, and severe pain in a single body part.
Proximal neuropathy describes damage to the peripheral nerves in your buttocks, thighs, and hips, usually in one side of the body. In cases of diabetes, this is also called diabetic amyotrophy, because it often involves shrinking thigh and buttock muscles and severe weakness.
Treating Different Types of Diabetic Neuropathy
Treatments for different types of diabetic neuropathy are split into two major parts: treating the blood sugar and treating the pain.
Blood sugar may be addressed through different medication depending on the type of diabetes the patient is suffering from. Some patients need regular insulin to survive, while others require different medication to ensure that their body responds.
Pain management is a different beast. Physical therapies, non-surgical interventions, and medication all play an important role in managing and reducing acute and long-term pain. Opioid medication is effective for the worst pains, but non-opioid alternatives are usually used for more long-term pain, alongside non-pharmacological options such as electrical nerve stimulation.
Non-opioid medication can include over-the-counter painkillers, as well as non-analgesic drugs, like antidepressants, anticonvulsants, and topical agents like capsaicin, depending on the symptoms and how the patient is responding to treatments.
There is no cure for certain forms of nerve damage, and different types of diabetic neuropathy. Addressing the root of the problem, managing the pain, and helping the body heal the nerves represents the key goals in diabetic neuropathy treatment. Long-term pain management requires pain specialists to work together to identify therapies the patient responds to. This can range from certain medication combinations to non-invasive interventions, and long-term physical therapy.