Although carpal tunnel syndrome is a common condition associated with numbness in hands, it is not the only cause. Other potential causes are listed below.
Compression neuropathy is pressure on a nerve and a potential cause of numbness in hands. This image shows the sensory distribution of nerves.
The nerves in the neck (roots) feed the arms and hands. Pressure on these nerves can cause numbness in hands.
Interconnections of nerves originating in the neck
n addition to numbness, compression neuropathy can cause weak or twitchy muscles. Compression neuropathy is pressure on a nerve (Figure 1). The pressure may come from an injury, thickened muscles, enlarged blood vessels, ganglion cysts, etc. Types include:
- Ulnar nerve compression at the wrist: This causes numbness and tingling of the little finger, part of the ring finger, and in the palm on the little finger side.
- Ulnar nerve compression at the elbow: This causes not only the numbness noted above but also numbness on the back of the hand on the pinky side.
- Pressure on the radial nerve in the forearm or above the wrist: This can cause numbness over the back of the thumb, the index finger, and the web between these two fingers.
- Median nerve compression at the elbow: This can cause numbness not only in the same area as in carpal tunnel syndrome but also in the palm at the base of the thumb.
- Pressure on nerves in the neck (Figures 2-3): This can be caused by arthritis, diseases, infections, tumors, blood vessel abnormalities and other conditions of the spinal cord. In addition to numbness, symptoms include weak muscles and decreased reflexes in the arm and forearm, and even the legs.
Sometimes, a nerve may suffer from pressure at more than one area. This is called “double crush.” Pressure on a nerve may require surgery to get relief.
With this condition, there may or may not be pain, and the numbness is often constant and very general in location. Diabetes, alcoholism, and old age are common known causes of neuropathy. Poisoning from metals and industrial compounds are also possible causes.
Millions of Americans suffer from this condition, which can last for years or indefinitely. People with fibromyalgia have been shown to be more likely than others to develop carpal tunnel syndrome and may seek surgical treatment, which can only help carpal tunnel syndrome if it exists with fibromyalgia.
People with this condition have persistent pain, frequently in many areas throughout the body, as well as fatigue, headaches, bowel problems, depression, sleep problems and other generalized symptoms.
Certain medications, such as cancer treatment drugs, are known to cause tingling and numbness in hands. Some of these cause temporary numbness that goes away after completion of the chemotherapy treatment. Others may cause permanent numbness.
Myofascial Pain SyndromeH
This is another condition known to cause numbness in hands. It has some symptoms similar to fibromyalgia, specifically numb hands and numb forearms, often with aches and pain. Although the symptoms may be felt in the hands, the muscles causing the problems are usually those in the neck and shoulder region. The symptoms are usually stiffness and may be associated with frequent headaches.
There is no hand surgery to correct or improve symptoms with this condition.
Other causes of numb hands may include:
- Nutritional deficiencies, such as vitamin B1 deficiency
- Multiple sclerosis
- Disorders of the brain and spinal cord
The pattern and distribution of symptoms can help determine if the cause is pressure on a nerve, a disease, medications, nutritional or another condition. Depending on the suspected cause, further tests such as an x-ray, an MRI, nerve tests (such as EMG), blood tests, or a spinal tap may be used to help confirm a diagnosis. Specific treatment recommendations can then be made by your specialist. You may also be referred to other specialists such as a neurologist, rheumatologist, pain management specialist, or other.