Your peripheral nervous system connects the nerves from your brain and spinal cord, or central nervous system, to the rest of your body. This includes your:
- arms and hands
- legs and feet
- face and mouth
- internal organs
The job of these nerves is to deliver signals about physical sensations back to your brain. They also make sure your body’s internal functions, like blood circulation and food digestion, work as they should.
Peripheral neuropathy occurs when these nerves don’t work properly because they’re damaged or destroyed. This disrupts the nerves’ normal functioning. They might send signals of pain when there’s nothing causing pain, or they might not send a pain signal even if something is harming you. This can be due to:
- systemic illness
- hormonal imbalance
- certain medications
- vitamin deficiency
- an inherited disorder
The causes are therefore vast, as are the types of the condition. More than 100 Trusted Source different types of peripheral neuropathy exist. Each type has unique symptoms and specific treatment options.
Medical researchers also classify peripheral neuropathies further classified by the type of nerve damage involved. Mononeuropathy occurs when only one nerve is damaged. Polyneuropathies, which are more common, happen when multiple nerves are damaged.
The disorder is uncomfortable, but treatments can be very helpful. The most important thing to determine is whether the neuropathy is the result of a serious underlying condition.
What are the symptoms of peripheral neuropathy?
There are three types of nerves in the body. Since there are so many types of peripheral neuropathy, doctors will diagnose your type by the group of nerves it affects. The three groups are:
- Motor. These nerves are responsible for muscle movement, like walking, talking, or using your hands or arms.
- Sensory. These are responsible for sensory information, like hot or cold, pain, or touch.
- Autonomic. These are responsible for body processes you don’t see, like breathing, heartbeat, and digestion.
Peripheral neuropathy can affect one nerve group, two groups, or all three. Sometimes it will affect one nerve only, and that’s called mononeuropathy.
The symptoms of peripheral neuropathy depend on the kind of neuropathy.
Motor neuropathy symptoms include:
- muscle cramps
- muscle weakness
- foot drop
- muscle wasting
Sensory neuropathy symptoms include:
- prickling and tingling sensation, or “pins and needles”
- reduced sensations of pain or hot and cold
- increased pain from things that shouldn’t cause pain, like light touch
- burning or sharp pain
- loss of balance or coordination
Autonomic neuropathy symptoms include:
- constipation or diarrhoea
- bloating, belching, or feeling of sickness
- faint or dizziness upon standing from low blood pressure
- rapid heart rate
- sweating too much or too little
- problems with sexual function
- loss of bowel control
- difficulty emptying bladder completely
Symptoms can cause challenges in daily life, like trouble walking or sleeping because of pain in the feet and legs.
These symptoms can also indicate other conditions. Make sure you tell your doctor about all of your symptoms so they can find the right diagnosis and the best treatment.
What are the causes of peripheral neuropathy?
- Amyloidosis: Amyloidosis is a condition in which abnormal protein fibers are deposited in tissues and organs. These protein deposits can lead to varying degrees of organ damage and may be a cause of neuropathy.
- Poorly Managed Diabetes The most common type of neuropathy is diabetic peripheral neuropathy, which affects people managing diabetes with poorly controlled blood sugar and accounts for about 60 percent of the total people with neuropathy.
- Idiopathic Neuropathy The second-largest group of neuropathy sufferers are those for which no cause has been identified — 23 percent — and therefore their condition is known as idiopathic peripheral neuropathy.
- Cancer Specifically, chemotherapy-induced peripheral neuropathy afflicts 10 percent of Americans with neuropathy.
- Tumors: Benign or malignant tumors of the nerves or nearby structures may damage the nerves directly, by invading the nerves, or cause neuropathy due to pressure on the nerves.
- Toxins and poisons can damage nerves. Examples include gold compounds, lead, arsenic, mercury, some industrial solvents, nitrous oxide, and organophosphate pesticides.
- Trauma/Injury: Trauma or injury to nerves, including prolonged pressure on a nerve or group of nerves, is a common cause of neuropathy. Decreased blood flow (ischemia) to the nerves can also lead to long-term damage.
- Abnormal vitamin levels and alcoholism: Proper levels of vitamins E, B1, B6, B12, and niacin are important for healthy nerve function. Chronic alcoholism, which typically results in lack of a well-rounded diet, robs the body of thiamine and other essential nutrients needed for nerve function.
- Vascular disorders: Neuropathy can occur when blood flow to the arms and legs is decreased or slowed by inflammation, blood clots, or other blood vessel disorders. Decreased blood flow deprives the nerve cells of oxygen, causing nerve damage or nerve cell death. Vascular problems can be caused by vasculitis, smoking and diabetes.
Certain medications may also cause nerve damage. These include:
- anticonvulsants, which people take to treat seizures
- drugs to fight bacterial infections
- some blood pressure medications
- medications used to treat cancer
A 2020 study found that although there’s no direct evidence that statins, a class of drugs used to lower cholesterol and prevent cardiovascular disease, cause neuropathy, statins may increase the risk of neuropathy from other causes.