Neuropathy - distal median nerve

Carpal tunnel syndrome

Distal median nerve dysfunction occurs when the nerve is injured by trauma, entrapment, or inflammation. Entrapment involves pressure on the nerve where it passes through a narrow structure. Wrist fractures may injure the median nerve directly or may present a risk for entrapment of the nerve later on.

The nerve can also be compressed at the wrist by tendonitis, arthritis, or conditions that affect connective tissue or cause deposits in the tissues (such as multiple myeloma, pregnancy, acromegaly, and hypothyroidism). These mechanical factors may cause nerve disease, blocking blood flow to the area.

In some cases, no detectable cause can be identified.

Carpal tunnel syndrome, a form of median nerve dysfunction, is one of the more common localized peripheral neuropathies. Carpal tunnel syndrome may be associated with entrapment of the nerve following prolonged or repeated pressure on the wrist area (such as may occur with repetitive wrist movements such as those made when typing or using a computer). This is a fairly common occupational or recreational injury.

• Sensation changes of the thumb and first 2 fingers
  • Numbness, decreased sensation
  • Tingling, burning sensation
  • Waking up at night with wrist or hand pain (may be severe)
• Weakness of the hand
  • Dropping things
  • Difficulty grasping objects

• An EMG (a recording of electrical activity in muscles)
• Nerve conduction tests
• A nerve biopsy (rarely needed)

Treatment is aimed at correcting the underlying cause. In most cases, isolated median nerve dysfunction is due to entrapment or injury. In this case, identifying the site of entrapment is best done with EMG or in some cases, X-rays and MRI scans. If an entrapment is confirmed, medications and even surgery may be helpful, depending on the site of entrapment and severity of nerve injury.

If the median nerve is affected by carpal tunnel syndrome, a wrist splint can reduce further injury to the nerve and help alleviate symptoms. In some cases, no treatment is required and recovery is spontaneous. Over-the-counter or prescription analgesics may be needed to control nerve pain (neuralgia).

If other nerves are also affected, it is necessary to look for an underlying medical problem that can affect nerves. Medical conditions like diabetes, kidney disease and others can damage nerves. In these cases, treatment is directed at treating the underlying medical condition.

Physical therapy exercises may be appropriate for some persons to maintain muscle strength. Orthopedic assistance may maximize the ability to use the hand. This may include use of braces, splints, or other appliances. Vocational counseling, occupational therapy, occupational changes, job retraining, or similar interventions may be recommended.

• Partial or complete loss of hand movement
• Partial or complete loss of sensation in the fingers
• Recurrent or unnoticed injury to the hand

Prevention varies depending on the cause. In patients with underlying diabetes, controlling blood sugar may reduce the risk of developing nerve disorders.

In occupations that require repetitive wrist movements, a change in the way the job is performed may be necessary. Frequent breaks in activity, "wrist rests" on keyboards, and other measures may reduce the risk of distal median nerve dysfunction. When possible, avoid prolonged repetitive movement of the wrist.