Peripheral Neuropathy Testing
Peripheral neuropathy, a result of damage to the nerves located outside of the brain and spinal cord (peripheral nerves), often causes weakness, numbness and pain, usually in the hands and feet. It can also affect other areas and body functions including digestion, urination and circulation.
Your peripheral nervous system sends information from your brain and spinal cord (central nervous system) to the rest of your body. The peripheral nerves also send sensory information to the central nervous system.
Peripheral neuropathy can result from traumatic injuries, infections, metabolic problems, inherited causes and exposure to toxins. One of the most common causes is diabetes.
People with peripheral neuropathy generally describe the pain as stabbing, burning or tingling. In many cases, symptoms improve, especially if caused by a treatable condition. Medications can reduce the pain of peripheral neuropathy.
Seek medical care right away if you notice unusual tingling, weakness or pain in your hands or feet. Early diagnosis and treatment offer the best chance for controlling your symptoms and preventing further damage to your peripheral nerves.
Peripheral neuropathy has many potential causes. Besides a physical exam, which may include blood tests, diagnosis usually requires:
A full medical history. Your doctor will review your medical history, including your symptoms, lifestyle, exposure to toxins, drinking habits and a family history of nervous system (neurological) diseases.
Neurological examination. Your doctor might check your tendon reflexes, your muscle strength and tone, your ability to feel certain sensations, and your posture and coordination.
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Your doctor may order tests, including:
Blood tests. These can detect vitamin deficiencies, diabetes, abnormal immune function and other indications of conditions that can cause peripheral neuropathy.
Imaging tests. CT or MRI scans can look for herniated disks, pinched (compressed) nerves, tumors or other abnormalities affecting the blood vessels and bones.
Nerve function tests. Electromyography (EMG) records electrical activity in your muscles to detect nerve damage. A thin needle (electrode) is inserted into the muscle to measure electrical activity as you contract the muscle.
At the same time your doctor or an EMG technician obtains an electromyogram, he or she typically performs a nerve conduction study. Flat electrodes are placed on the skin and a low electric current stimulates the nerves. Your doctor will record your nerves' responses to the electric current.
Other nerve function tests. These might include an autonomic reflex screen that records how the autonomic nerve fibers work, a sweat test that measures your body's ability to sweat, and sensory tests that record how you feel touch, vibration, cooling and heat.
Nerve biopsy. This involves removing a small portion of a nerve, usually a sensory nerve, to look for abnormalities.
Skin biopsy. Your doctor removes a small portion of skin to look for a reduction in nerve endings.