[의학신문·일간보사=김현기 기자] Numbness in the hands and feet is a relatively common symptom for many people. However, if you ignore it, it can become so severe that you can’t even sleep and interfere with your daily life.
Numbness in the limbs, where early treatment is especially important, as it can be difficult to treat if it leads to chronic pain. From causes and treatments to frequently asked questions, we have compiled a list with Professor Shin Je-young of the Department of Neurology at Seoul National University Hospital.
The most common cause of numbness in the hands and feet is peripheral neuropathy. The brain and spinal cord are called central nerves, and the thin nerves that branch out from the spinal cord are called peripheral nerves. Peripheral nerves come out of the bones through small holes between the vertebrae called ‘neural holes’ and are widely distributed throughout the body, including arms, legs, and trunk. It is divided into three types of motor, sensory, and autonomic nerves according to their functions, and when each nerve is damaged, different symptoms appear.
Numbness in the hands and feet occurs when sensory nerves are damaged. If the motor nerves are damaged, the strength may be lost and the muscles may become dry. If the autonomic nerves are damaged, sweat secretion may become abnormal, bowel and urine functions may be impaired, and dizziness may occur.
There are many causes of peripheral neuropathy, but damage to the peripheral nerves in the neck and back is most common. Since the neck and lower back move frequently, the cervical and lumbar vertebrae are also continuously moved through the connected joints. This is called ‘neural root disease’ and is one of the most common causes of numbness in the hands and feet.
◆How to diagnose peripheral neuropathy, the cause of numbness in the hands and feet?=In order to diagnose peripheral neuropathy, it is necessary to first determine whether the patient’s symptoms and medical history match the neurological symptoms. In addition, through physical examination, other diseases such as nerve diseases and joint or muscle diseases are differentiated. As a result, if a nerve abnormality is suspected, the cause is examined. Through blood test, blood sugar measurement, liver function test, kidney function test, hormone test, etc. can be performed, and imaging tests such as spine MRI can be performed.
In addition, electrophysiological tests such as ‘neural conduction test’ and ‘electromyography test’ are performed. These tests record the response after giving an electrical stimulation, or record the signal stimulation generated by the muscle by inserting a needle into the muscle. am. This helps to accurately determine whether the nerve is damaged and the extent of the damage.
Nerve conduction testing is very useful when nerves are compressed in certain sections, such as carpal tunnel syndrome. In addition, in the case of ‘Guillain-Barré syndrome’ or hereditary neuropathy, which is a peripheral neuropathy that causes acute generalized paralysis, this test can play an important role not only in diagnosis but also in setting future treatment policies.
◆What is the difference between numbness in limbs and numbness?=Both numbness and tingling can be caused by peripheral neuropathy, and there are many cases where they have it at the same time, but in that case, the pathogenesis is the same. However, when complaining mainly of soreness, it is necessary to differentiate it from other diseases such as peripheral blood circulation disorders. In general, when both hands and feet are sore and numb, ‘polyneuropathy’ involving multiple nerves and ‘polyneuropathy’ involving both cervical and lumbar vertebrae should be considered among peripheral neuropathy.
◆Can there be any symptoms but no abnormalities in the test results?=Yes. In this case, it is possible to suspect that it is an early stage of peripheral neuropathy with mild symptoms, or ‘small fiber neuropathy’ in which only very thin nerve fibers are selectively damaged. Small fiber neuropathy is a type of peripheral neuropathy that may appear temporarily in the early stages of neuropathy, but the condition may persist. Recently, a diagnostic test for small fiber neuropathy has been developed, but in many cases, diagnosis alone is sufficient in many cases.
This ‘symptom diagnosis’ can be made in many neurological diseases. If neurological symptoms such as numbness in the hands and feet continue to cause discomfort, it is recommended to make a presumptive diagnosis of neuropathy and start appropriate treatment early, even if the test results are normal.
◆What is the treatment for numbness in the hands and feet?A typical example is drug treatment, but most of the drugs used at this time were not originally developed for the purpose of treating numbness in the hands and feet. Drugs developed for the purpose of controlling convulsions or depression are later known to be effective in numbness in the hands and feet, and as the mechanism is gradually revealed, it is now mostly used as a treatment for numbness in the hands and feet.
Since numbness in the hands and feet is caused by abnormal electrical signals from peripheral nerves, it can be effectively controlled by anticonvulsants that block the transmission of these electrical signals. In addition, since depression-related neurotransmitters secreted from the brain play an important role in the transmission and suppression of pain, some antidepressant drugs can also be used as a treatment for numbness in the hands and feet.
Non-pharmacological treatments include surgical treatment such as nerve block, physical therapy, and other symptomatic treatments. If a structural abnormality is evident, such as a case in which the nerve is significantly compressed in the wrist, as in the case of carpal tunnel syndrome, surgical treatment should also be considered.
◆Is it possible to cure numbness in limbs due to peripheral neuropathy?=In general, ‘cure’ means a state in which a certain disease is cured without sequelae and treatment is completely discontinued. However, the cause of the symptoms of numbness in the hands and feet, duration of illness, and response to treatment vary from patient to patient, so the possibility of a complete cure cannot be said uniformly. It is important to make an appropriate diagnostic evaluation and customized treatment for each patient before making a decision.
However, if an appropriate diagnosis is made at an early stage and an optimal treatment is assumed, it is clear that a significant number of patients think that they can improve to the extent that there is no significant inconvenience in their daily life. Neurological symptoms such as numbness in the hands and feet can be difficult to control in the future if they are not treated properly in the beginning and progress to chronic symptoms.
Q1. If peripheral neuropathy is suspected, which hospital should I go to?
– A neurologist is recommended to receive an appropriate treatment after a detailed cause examination. However, if a detailed examination is unnecessary or only symptom control is required, it is irrelevant to see a doctor with related treatment experience, orthopedic surgery, neurosurgery, pain medicine, or rehabilitation medicine.
Q2) I have numbness in my hands and feet after starting chemotherapy, how should I treat it?
– Peripheral neuropathy induced by chemotherapy is a neuropathy commonly seen in cancer patients. Symptoms may worsen depending on the type of anticancer drug used, the dose of the anticancer drug, and the duration of the anticancer drug administration.
– In this case, in principle, neuropathy can be fundamentally cured only when cancer treatment is successful and chemotherapy can be stopped. However, even if anticancer drugs are being used, starting to control symptoms with drugs is helpful, so it is recommended to administer drugs similar to neuropathic pain.
Q3) If a diabetic patient has numbness in his limbs, should he suspect peripheral neuropathy?
– The prevalence of diabetes is increasing year by year due to Western diet, etc., and peripheral neuropathy is one of the major complications of diabetes.
– Polyneuropathy is the most common peripheral neuropathy caused by diabetes. It is typical that numbness or numbness develops from the toes, gradually ascends, spreads to the developing body and calves, and later begins to numb the hands. If a diabetic patient has these symptoms, it is important to start controlling the numbness of the limbs as well as the glucose control early.