                        CARPAL TUNNEL SYNDROME



Neuropathy, Peripheral 

Synonyms --------------------------------

Peripheral Neuritis 
Mononeuropathy 
Mononeuritis 
Mononeuritis Multiplex 
Polyneuropathy 
Polyneuritis 
Multiple Peripheral Neuritis 
Ulnar Nerve Palsy 
Tardy Ulnar Palsy 
Carpal Tunnel Syndrome 
Peroneal Nerve Palsy 
Radial Nerve Palsy, also known as Saturday Night Palsy 



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General Discussion
--------------------------------

** REMINDER ** 
The information contained in the Rare Disease Database is provided for
educational purposes only.  It should not be used for diagnostic or treatment
purposes.  If you wish to obtain more information about this disorder, please
contact your personal physician and/or the agencies listed in the "Resources"
section of this report. 

Peripheral Neuropathy is a syndrome characterized by sensory, motor, reflex and
blood vessel (vasomotor) symptoms.  These symptoms can occur singly or in any
combination.  



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Symptomatology
--------------------------------

The symptoms of Peripheral neuropathy are produced by disease of a single nerve
(mononeuropathy, mononeuritis), several nerves in asymmetric areas of the body
(mononeuritis multiplex), or many nerves simultaneously (polyneuropathy,
polyneuritis, multiple peripheral neuritis). These symptoms may involve sensory,
motor, reflex, or blood vessel (vasomotor) function.  Lesions, usually
degenerative and rarely accompanied by signs of inflammation, may occur in the
nerve roots or peripheral nerves.  

Mononeuritis or mononeuropathy is characterized by pain, weakness, and abnormal
sensations (paresthesias) in the area that is innervated by the affected nerve. 
In mononeuritis multiplex all the affected nerves may be involved from the
outset or become involved progressively.  Extensive involvement of many nerves
often resembles the symptoms of polyneuropathy.  

Compression and entrapment neuropathies result from malfunction of a nerve
caused by mechanical means. Paralysis around the elbow (ulnar nerve palsy) is
caused by trauma or pressure on the nerve in the ulnar groove of the elbow. 
This can occur as the result of repeated leaning on the elbow or by abnormal
bone growth after a childhood fracture ("tardy ulnar palsy").  Unusual
sensations and sensory deficits in the 4th and 5th fingers can be accompanied by
weakness and atrophy of: 

1) the muscle that pulls the thumb to the hand (adductor) 
2) a muscle on the lateral side of the 5th finger (abductor) 
3) muscles between the bones in the hand adjacent to 4th and 5th fingers.  

The carpal tunnel syndrome results from compression of the median nerve in the
wrist between the tendons of forearm muscles and the carpal ligament in the
hand.  This compression can produce abnormal sensations in the hand plus pain in
the wrist, the palm, or sometimes proximal to the compression site in the
forearm.  Commonly, patients feel that their hand "falls asleep" often.  Carpal
tunnel syndrome is relatively common.  It may occur in one or both hands and it
is seen more often in women.  It often occurs in patients with acromegaly,
myxedema, rheumatoid arthritis and also in people with occupations that require
repeated forceful wrist flexion (e.g. carpenters).  
Peroneal nerve palsy is caused by compression of the nerve against the lateral
side of the fibula in the leg.  It is most common in emaciated nonambulatory
patients and in thin people who habitually cross their legs.  Weakness when
bending the foot upward (dorsiflexion) and foot drop may occur.  Occasionally, a
sensory deficit is found on the dorsal side of the web between the first and
second long bones in the foot (metatarsals).  

Radial nerve palsy ("Saturday night palsy") is caused by compression of the
radial nerve in the upper arm (e.g. when the arm is draped over the back of a
chair for long periods of time).  Symptoms include weakness of wrist and finger
stretching (extensor) muscles , wrist drop, and occasionally a sensory loss on
the dorsal web between 1st and 2nd metatarsals.  

The site of local nerve damage can be identified by Tinel's sign, a distal
abnormal sensation in the area that is innervated by the nerve when the region
over the nerve is tapped.  Electrical nerve conduction studies also help to
identify the location of the nerve damage.  Polyneuropathy is usually
bilaterally symmetric, and all nerves (sensory, motor, vasomotor, or a
combination) are involved at the same time.  
There are several forms of polyneuropathy.  The most common form is seen with
metabolic diseases, diabetes mellitus or malnutrition.  This form develops
slowly, often over months or years, and often begins with sensory abnormalities
in the legs.  Peripheral tingling, numbness, burning pain, or deficiencies in
perception of joints and vibratory sensation are often prominent.  Pain is often
worse at night and may be aggravated by touching the affected area or by
temperature changes.  In severe cases, signs of sensory loss can be
demonstrated, characteristically in the area that would be covered by stockings
and gloves.  The Achilles and other deep tendon reflexes are diminished or
absent.  Painless ulcers on the fingers and toes or Charcot's joints may be seen
when sensory loss is profound.  Sensory or joint perception deficits may lead to
abnormal posture or gait that simulate a kind of clubfoot.  Weakness and atrophy
of distal limb muscles and flaccid tone characterize involvement of motor nerve
fibers.  

The autonomic nervous system may be additionally involved, leading to diarrhea
at night, bladder and bowel incontinence, impotence, or postural low blood
pressure. 

An exclusively sensory polyneuropathy is sometimes seen in lung cancer
originating in the bronchi.  This often begins with pain and abnormal sensations
and progresses to a loss of all forms of sensation.  



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Etiology
--------------------------------

Peripheral Neuropathy may have many different causes.  These include: 

1.  Mechanical stress such as compression, direct trauma, penetrating injuries,
contusions, tearing away of a nerve by fracture, or dislocation of bones can
cause mononeuritis and sometimes mononeuritis multiplex.  

2.  Pressure paralysis usually affects superficial nerves such as ulnar, radial
or peroneal, when they are adjacent to bony prominences (e.g. during sound sleep
or anesthesia in thin or weakened persons and frequently in alcoholics).  It may
affect nerves in narrow canals such as in the entrapment neuropathies (e.g., the
median nerve in the carpal tunnel syndrome).  Pressure paralysis may also result
from tumors, bony hyperostosis, use of casts, crutches, or prolonged cramped
postures (e.g. while gardening).  

3.  Violent muscular activity or forcible overextension of a nerve may produce a
mechanical neuritis, as may small traumas such as those encountered by engravers
through tight gripping of small tools, or by air- hammer operators through
excessive vibration.  

4.  Hemorrhage into a nerve and exposure to cold or to radiation may also cause
neuropathy.  

5.  Vascular or collagen disorders such as polyarteritis nodosa,
atherosclerosis, systemic lupus erythematosus, scleroderma, sarcoidosis and
rheumatoid arthritis can cause mononeuritis multiplex (for information on these
disorders, see those articles in the Rare Disease Database).  

6.  Volkmann's ischemic paralysis occurs when closing off (occlusion) of a major
artery affects nerves with a common blood supply in one limb.  



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Related Disorders
--------------------------------

Guillain-Barre syndrome (acute idiopathic polyneuritis) occurs when the body's
immune system attacks the nerves, damaging the nerves' myelin sheath and
sometimes the axon.  Nerve signals are delayed and altered, causing weakness and
paralysis of the muscles of the legs, arms and other parts of the body along
with abnormal sensations.  (For more information on Guillain- Barre syndrome,
choose Guillain-Barre as your search term in the Rare Disease Database.) 

Carpal tunnel syndrome resembles the symptoms of cervical nerve 6 root
compression due to cervical osteoarthropathy.  



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Therapies:  Standard
--------------------------------

Recovery may be complete or incomplete with sensory, motor or vasomotor residual
and, in severe cases, chronic muscular atrophy as well.  

Specific therapy is directed at the cause such as control of diabetes,
administration of vitamins or proper diet, avoiding further mechanical trauma or
surgery when tumors or ruptured intervertebral disks are involved. 

 
Stitching a nerve together, surgically breaking up adhesions around a nerve
(neurolysis), or nerve transplant may be advisable in some traumatic lesions. 

 
In peripheral nerve entrapment or compression neuropathy (i.e. carpal tunnel
syndrome), splinting or surgical decompression of the ulnar or median nerves is
often beneficial.  

Peroneal and radial compression neuropathies are treated by avoiding pressure on
the areas.  Recovery is often slow, and physical therapy or splints may help to
avoid contractures.  



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Therapies:  Investigational
--------------------------------

This disease entry is based upon medical information available through March
1987.  Since NORD's resources are limited, it is not possible to keep every
entry in the Rare Disease Database completely current and accurate.  Please
check with the agencies listed in the Resources section for the most current
information about this disorder. 



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Resources
--------------------------------

For more information on Peripheral Neuropathy, please contact: 

National Organization for Rare Disorders 
P.O. Box 8923 
New Fairfield, CT  06812 
(203) 746-6518 

NIH/National Institute of Neurological and Communicative Disorders and Stroke 
9000 Rockville Pike 
Bethesda, MD  20892 
(301) 496-5751 
============================================================================
Stonehenge BBS [415] 479-8328
