By Jonathan S. Katz, MD, and Michelle Greer, RN, MBA
Neuropathy means disease or abnormality of the nervous system. Neuropathies can be sensory, motor or autonomic. Sensory nerves give us information about the position of our joints, pain and temperature. Motor nerves stimulate muscle contraction and movement. Autonomic nerves control functions that our bodies don't consciously regulate such as sweating, certain bowel and bladder functions, and heart rate.
Symptoms of neuropathy depend on both the type of nerves affected and the mechanism that causes damage to the nerves. The most common presenting symptom is the combination of numbness and tingling in the toes and feet. Less-common neuropathies can cause weakness or clumsiness, and it may be difficult to perform certain activities such as raising an arm over the head, getting up from a seated position or walking up stairs.
Symptoms can be similar in different types of neuropathies, which can make diagnosis challenging. This is why a thorough workup is so important. Here is handy checklist to discuss with your neurologist:
- Complete Health History: This includes questions about your symptoms, including type, onset, duration and location. Specific details about what brings on the symptoms, what relieves them and the types of sensations that occur serve as clues to the diagnosis. A complete list of medications should also be provided in case the medication itself is the cause of the neuropathy.
- Neurological Evaluation: In addition to the history of symptoms, the neurologist will examine reflexes, strength and the ability to feel various sensations. Again, this aids in an overall diagnosis.
- Blood Tests: Certain lab tests can help determine the cause of the neuropathy. This may include tests for vitamin deficiencies, immune responses, blood sugar levels and the presence of toxins or infections.
- EMG: An EMG, or electromyography, electronically measures and records muscle activity. This tells the neurologist the location of any muscle, nerve or neuromuscular junction damage, as well as its cause.
- Nerve Conduction Studies: This test measures the size and speed of electrical signals as they pass along the nerves. It tells the neurologist of any abnormality of the nerves. EMG and nerve conduction studies usually go hand in hand.
- MRI: An MRI (magnetic resonance imaging) may be performed to rule out any other causes of the neuropathy such as trauma or nerve entrapment, and sometimes to show inflammation along the nerves.
- Lumbar Puncture: A spinal tap or lumbar puncture can determine the presence of protein and cells in the spinal fluid. This test is usually performed if the doctor thinks the nerves are affected by inflammation.
- Nerve, Muscle or Skin Biopsy: A small piece of nerve, muscle or skin can help determine the cause of the damage. These tests are only done if the doctor suspects very specific conditions.
Neuropathy may also be caused by certain vitamin or mineral deficiencies, medication toxicity such as chemotherapy, alcohol abuse, certain infections, and as a symptom of other systemic illnesses. For an accurate diagnosis, be sure to discuss all your concerns and risk factors with your doctor.