Peripheral Neuropathy
Peripheral neuropathy is a disorder of the peripheral nerves, or the nerves that are outside the brain and spinal cord. Peripheral nerves control the sensations and movements of the arms and legs, and some control involuntary functions such as digestion and breathing.
The symptoms of peripheral neuropathy depend on the types of nerves that are damaged. Usually, sensory nerves are affected, and the symptoms typically begin at a point on sensory nerve fibers that are farthest from the center of the body (that is, your fingers/toes and feet) and gradually affect your feet and hands. These symptoms include:
- Numbness and tingling (“pins and needles”)
- Decreased sensation of hot and cold
- Unpleasant sensations when touched
- Muscle weakness and cramping
- Balance problems
- Constipation
Pain may also occur and usually has a burning or electric shock-like feeling. These symptoms may make it difficult to carry out normal daily activities, such as getting dressed (buttoning clothes), picking up small items (such as a coin), or writing. Muscle weakness and balance problems may cause an unsteady gait or problems with walking.
Some chemotherapy drugs are more likely than others to cause peripheral neuropathy. The people who are most likely to get peripheral neuropathy are those who receive chemotherapy with a platinum drug in combination with a taxane drug. Radiation and surgery may also cause peripheral neuropathy, but much less often than chemotherapy.
Peripheral neuropathy is the result of damage to sensory nerves. This damage can be caused by the effects of chemicals within chemotherapy drugs or radiation. Damage to nerves may also occur during surgery.
Peripheral neuropathy caused by chemotherapy can be either acute (short-term) or chronic (long-term). Acute peripheral neuropathy usually begins during or shortly after administration of a platinum-containing drug and most often goes away on its own after several days. In contrast, chronic peripheral neuropathy may arise weeks or months after treatment has ended and is sometimes irreversible. Whether peripheral neuropathy caused by chemotherapy is an acute or a chronic problem depends on many factors, primarily the dose and combinations of drugs and the total dose of a drug given over time. Symptoms of neuropathy related to radiation therapy may not occur until months or years after treatment has ended.
Peripheral neuropathy may be managed in a variety of ways: with substances to protect against damage caused by chemotherapy drugs, with exercises to ease discomfort and strengthen muscles, and with treatments and medications to relieve pain. If these measures fail to relieve your discomfort or if the neuropathy becomes severe, your doctor will most likely change your cancer treatment.
In some cases, a substance known as a chemoprotective agent may be given prior to or with a chemotherapy drug that is most likely to cause peripheral neuropathy. Chemoprotective agents such as glutamine, amifostine, and vitamin E may help to prevent nerve damage in some people but not others; your doctor will help determine what may be appropriate in your individual situation.
Stretching exercises can help decrease pain related to neuropathy, especially in the morning. Moving your hands and feet in all directions before you get out of bed in the morning may be helpful. Strengthening your muscles with isometric exercises (exercises in which you hold a muscle in a flexed position for a period of time) can help you maintain balance and walk normally. Your doctor or nurse may suggest that you see a physical or occupational therapist to help with strengthening exercises and finding ways to carry out everyday tasks with less discomfort.
Other strategies that have helped to relieve pain in some people are massage, acupuncture, and transcutaneous electrical nerve stimulation (TENS). TENS involves a small electrical device with wires attached to the skin with electrodes; the device transmits a gentle current into areas of pain and stimulates the release of endorphins, the body’s natural painkillers. Some medications that have been used to relieve pain include corticosteroids (which must be used only for a short time), topical medications to numb the painful area (such as a lidocaine patch), and opioids for severe pain. Antidepressant drugs (in small doses) such as amitriptyline and nortriptyline (Pamelor) and anticonvulsant drugs such as gabapentin (Neurontin), topiramate (Topamax), pregabalin (Lyrica), carbamazepine (Tegretol), and phenytoin (Dilantin) have also been found to relieve pain related to damaged nerves.
Some simple strategies to help alleviate discomfort are to avoid snug shoes or socks and extreme (hot and cold) temperatures and to take part in regular exercise, such as walking. You should also take some safety precautions, as the decreased sensation in your hands and feet may increase the risk for injury; keep your house well lighted, remove scatter rugs, and watch the floor in front of you as you walk. If you drive, make sure you can feel the pedals with your feet.
You should talk to your doctor about the possibility of neuropathy occurring during your cancer treatment. It is important to call your doctor’s office when you first experience symptoms of peripheral neuropathy, because early treatment offers the best chance of managing the neuropathy.
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