Causes of Numbness and Tingling in the Hands
Hand Numbness is Not Always Carpal Tunnel Syndrome
Many people assume numbness, tingling, and pain in the forearm and hand is the result of Carpal Tunnel Syndrome. Although Carpal Tunnel Syndrome is a common cause of this, there are also many other conditions that can cause the same symptoms.
Local pressure on a nerve (“compression neuropathy”) causes numbness in distinct patterns that follow the area supplied by that nerve.
The muscles that are controlled by the compressed nerve may exhibit weakness, wasting, or twitching. The pressure could come from:
Bands of connective tissue
Enlarged blood vessels
Ulnar nerve compression at the wrist may cause you to experience numbness and tingling of:
The little finger
Part of the ring finger
The little finger side (ulnar side) of the palm
If you experience the numbness noted above and/or numbness on the back of the ulnar side of the hand, this could be caused from ulnar nerve compression at the elbow.
Pressure on the radial nerve in the forearm or above the wrist can cause numbness:
Over the back of the thumb
The index finger
The web between these two digits
If the median nerve is compressed at or just below the elbow, numbness is felt not only in the same area as in CTS, but also over the palm at the base of the thumb.
Roots of Nerve Compression
Nerves in the hands and forearm actually have their roots in the neck. Pressure on nerves in the neck (C6-T1) can be caused by numerous conditions. Bone spurs or narrowing of the spinal canal may be caused by arthritis, causing pressure on nerves. Or, degenerating discs may press directly on the nerves at the spinal column or as they leave the spinal column and pass to the upper limbs.
Diseases, infections, tumors, blood vessels abnormalities, and other conditions of the spinal cord itself, in the neck, can also cause pressure on the cord. This may, therefore, result in numbness, tingling, or aching in the arm, forearm or hand. Weakness and/or wasting of muscles supplied by that nerve may be found. Pressure on specific nerves in the neck may also be the cause of decreased reflexes in the arm and forearm. The pattern or zone of the numbness is often very distinct for each nerve root affected.
Sometimes, nerves suffer from pressure at more than one area. For example, a nerve may be compressed in the neck, and then again further down the arm or at the wrist. This is called “double crush”. When a nerve suffers from pressure at one level, it may be more susceptible to problems from pressure at another level.
Diseases of the central nervous system can also cause numbness and tingling. Multiple Sclerosis, stroke, and other disorders of the brain and spinal cord may sometimes cause numbness in the forearm and hand.
Other Causes of Hand Numbness
There are other diseases that can affect the nerves in the upper limb, causing numbness, tingling, and burning.
Neuropathy - If the symptoms are more diffuse, that is, occurring throughout the hands and forearms (and in the legs and feet), the cause may be a condition called “peripheral neuropathy”. The pattern of numbness is not usually that of one nerve, but instead may be generalized, like the pattern of a glove. There may or may not be pain, however, the numbness is often constant. Diabetes, alcoholism, and old age are common known causes of neuropathy.
Poisoning - Poisoning from metals and industrial compounds are also possible causes of numbness.
Chemotherapy - Certain medications used to treat cancer are also known to cause numbness and tingling in the hands. Some of these cause temporary numbness that resolves after completion of the chemotherapy treatment. Some cause permanent numbness.
Vitamin Deficiencies - Nutritional deficiencies, such as vitamin B1 deficiency, may also result in numbness and tingling.
What helps to determine if the source is pressure on a nerve at a particular level (e.g. neck, wrists, elbow), disease, medication, nutritional, or other conditions, is the pattern and distribution of numbness, tingling, burning, dullness, and muscle changes. Depending on the suspected cause, further testing, such as X-ray, MRI, nerve tests (such as EMG), or blood tests may be used to help confirm a diagnosis, and specific treatment recommendations can then be made.
In order to get relief and release pressure on the nerves, some compression neuropathies may require surgery.
For more information about hand numbness and tingling, and the simple, safe, and effective treatments that are available, schedule an appointment with Dr. Sagini by calling 239-337-2003.