Mononeuritis multiplex

Mononeuritis multiplex is a nervous system disorder that involves damage to at least two separate nerve areas.

Causes

Mononeuritis multiplex is a form of damage to one or more peripheral nerves -- the nerves outside the brain and spinal cord. It is a group of symptoms (syndrome), not a disease.

However, certain diseases can cause the injury or nerve damage that leads to the symptoms of mononeuritis multiplex.

Common conditions include:

• Blood vessel diseases such as polyarteritis nodosa


• Connective tissue diseases such as rheumatoid arthritis or systemic lupus erythematosus (the most common cause in children)


• Diabetes mellitus

Less common causes include:

• Amyloidosis


• Blood disorders (such as hypereosinophilia and cryoglobulinemia)


• Infections such as Lyme disease


• Leprosy


• Sarcoidosis


• Sjogren syndrome


• Wegener's granulomatosis

Symptoms

Symptoms will depend on the specific nerves involved, and may include:

• Loss of bladder or bowel control


• Loss of sensation in one or more areas of the body


• Paralysis in one or more areas of the body


• Tingling, burning, pain, or other abnormal sensations in one or more areas of the body


• Weakness in one or more areas of the body

Exams and Tests

A detailed history is needed to determine the possible cause of the disorder. Examination and neuromuscular testing may show a loss of feeling and movement due to problems with specific nerves. Reflexes may be abnormal.

To diagnose mononeuritis multiplex, there usually needs to be problems with two or more unrelated nerve areas. Common nerves affected are the:

• Axillary nerve in either arm and shoulder


• Common peroneal nerve in the lower leg


• Distal median nerve to the hand


• Femoral nerve in the thigh


• Radial nerve in the arm


• Sciatic nerve in the back of the leg


• Ulnar nerve in the arm

Tests may include:

• Electromyogram (EMG, a recording of electrical activity in the muscles)


• Nerve biopsy to examine the nerve under a microscope


• Nerve conduction tests to measure how fast nerve impulses move along the nerve

Other tests may include:

• Antinuclear antibody panel (ANA)


• Blood chemistry tests


• C-reactive protein


• Imaging scans


• Pregnancy test


• Rheumatoid factor


• Sedimentation rate


• Thyroid tests


• X-rays

Treatment

The goals of treatment are to:

• Treat the illness that is causing the problem, if possible


• Provide supportive care to maximize independence


• Control symptoms (this may include controlling blood sugar levels for diabetics, nutritional supplementation, or medically treating conditions)

To improve independence, treatments may include:

• Occupational therapy


• Orthopedic help (for example, appliances such as wheelchairs, braces, and splints)


• Physical therapy (for example, exercises and retraining to increase muscle strength)


• Vocational therapy

Safety is an important consideration for people with sensation or movement difficulties. Lack of muscle control and decreased sensation may increase the risk of falls or injuries. Safety measures for people with movement difficulty include:

• Adequate lighting (including leaving lights on at night)


• Railings


• Removing obstacles (such as loose rugs that may slip on the floor)


• Testing water temperature before bathing


• Wearing protective shoes (no open toes or high heels)

Check shoes often for grit or rough spots that may injure the feet.

People with decreased sensation should check their feet (or other affected area) often for bruises, open skin areas, or other injuries that may go unnoticed. These injuries may become severely infected because the pain nerves of the area are not signaling the injury.

People with mononeuropathy multiplex are prone to new nerve injuries at pressure points such as knees and elbows. They should avoid putting pressure on these areas, for example by not leaning on the elbows, crossing the knees, or holding similar positions.

Medications that may help include:

• Over-the-counter pain medicines (ibuprofen or acetaminophen) or prescription pain medications may be needed to control pain (neuralgia).


• Anticonvulsants (gabapentin, phenytoin, carbamazepine, or pregabalin) or antidepressants (amitriptyline, nortriptyline, or duloxetine), may be used to reduce stabbing pains.

Whenever possible, avoid or minimize the use of medications to reduce the risk of side effects.

Positioning (the use of frames to keep bedclothes off of a tender body part) and other measures may help control pain. Autonomic symptoms can be difficult to treat or respond poorly to treatment.

Outlook (Prognosis)

A full recovery is possible if the cause is found and treated, especially if the nerve damage is limited. Some people have no type of disability. Others have a partial or complete loss of movement, function, or sensation.

Nerve pain may be quite uncomfortable and can last for a long time. If this occurs, see a pain specialist to discuss all pain treatment options available to you.

Possible Complications

• Deformity, loss of tissue or muscle mass


• Disturbances of organ functions


• Medication side effects


• Repeated or unnoticed injury to the affected area due to lack of sensation


• Relationship problems due to impotence

When to Contact a Medical Professional

Call your health care provider if you notice signs of mononeuritis multiplex.

Prevention

Preventive measures vary depending on the specific disorder. Eating a proper diet and taking medication for diabetes may help prevent mononeuritis multiplex from developing.