Numbness in Hands

Compression Neuropathy

Compression neuropathy is pressure on a nerve anywhere along its course (Figure 1). In addition to numbness, compression neuropathy can cause weak or twitchy muscles. The pressure may come from many sources. It can occur after an injury due to bleeding or swelling. A displaced or angled fracture can stretch the nerve. Sometimes tendon lining thickens in an enclosed space, and nerve pressure rises. Fascia is a structure below the fat layer that covers muscles and tendons. Sometimes a thickened edge of fascia or tendon can compress a nerve. An abnormally located muscle can also cause pressure. Soft tissue masses or ganglion cysts can result in nerve compression. Types of nerve compression include:

Ulnar nerve compression at the wrist (Guyon Syndrome)
This causes numbness and tingling typically on the pinky finger side of the hand. The back side of the hand is usually normal. Severe cases can have hand and grip weakness. The weakness is most noticeable when attempting to separate the fingers. The ability to bend the ring and small fingertips remains.

Ulnar nerve compression at the elbow (Cubital Tunnel Syndrome)
This condition typically has the same symptoms as Guyon Syndrome but also numbness on the back of the hand on the pinky side. There can also be pain at the inside portion of the elbow. Severe cases can have hand and grip weakness. The weakness occurs when attempting to separate the fingers, when trying to bend the ring and small fingertips, and when trying to bend the wrist.

Radial nerve compression in the forearm or wrist
The radial nerve could be compressed in either side of the forearm. Proximal compression of the motor branch, called the posterior interosseous nerve, is called radial tunnel syndrome. This condition can cause achiness or vague pain in the backside of the forearm. It may be worsened when straightening the wrist or finger. It can be challenging to diagnose, as nerve conduction studies and imaging may be normal.

When the radial nerve branch is compressed, it typically is a sensory only problem. This nerve can be injured from cuts, placement of an IV for medication or fluids, handcuffs, or during surgeries on the radial bone.

Median nerve compression at the wrist (Carpal Tunnel Syndrome)
This causes numbness and tingling in the thumb, index, and middle fingers. Other fingers and even the whole hand can sometimes feel numb. However, when specifically tested, the small finger should have normal feeling. Severe cases can result in weakness to the thumb lifting away from the hand. Finger bending strength is typically normal. Symptoms are often worse at night. They may also develop from the wrist being bent in a position for a long time.

Median nerve compression at the elbow
The numbness in this condition is similar to carpal tunnel syndrome in the fingers. There is additional numbness in the palm near the thumb that is not present in carpal tunnel. Sometimes there is weakness when bending the index and middle finger and weakness when bending the tip 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 (sometimes even the legs). Pressure on nerves at the neck is more common to have radiating arm pain as part of the symptoms.

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.

Peripheral Neuropathy

In peripheral neuropathy, the very ends of the nerves in the hands and feet are affected. With this condition, there may or may not be pain, and the numbness is often constant. Diabetes, alcoholism, and old age are common known causes of neuropathy. Poisoning from metals and industrial compounds are also possible causes. It typically shows a "stocking-glove" pattern in which the numbness moves up from the toes to the legs. At the time the numbness progresses to the mid-calf, then the fingers and hands become involved. It can happen on both sides of the body and often affects all nerves to the feet or hand in a similar amount.

Fibromyalgia

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 to release pressure in the carpal tunnel. 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.

Myofascial Pain Syndrome

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.

Medications

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.

Other Causes

Other causes of numbness in hands may include:

• Nutritional deficiencies, such as vitamin B1, B6, or B12 deficiency
• Multiple sclerosis
• Stroke
• Disorders of the brain and spinal cord