Polyneuropathy - sensorimotor
Sensorimotor polyneuropathy is a decrease in movement or sensation associated with nerve damage.
Causes, incidence, and risk factors
Sensorimotor polyneuropathy is a form of peripheral neuropathy (damage to nerves other than the brain or spinal cord). It is not a disorder itself but occurs with disorders involving damage to multiple peripheral nerves (polyneuropathy).
Sensorimotor polyneuropathy involves a systemic (widespread) process that damages nerves. This damage may include loss of the myelin sheath (the covering of the nerve cell), which slows conduction through the nerve. Likewise, the axon (nerve fiber) or the nerve cell itself may be damaged.
Causes of damage to nerves include any condition that results in pressure on nerves, inflammation, decreased blood flow, connective tissue disorders, and similar conditions.
The disorders that can cause sensorimotor polyneuropathy vary greatly, ranging from acute or chronic conditions to unknown causes. Possible causes of sensorimotor polyneuropathy are alcoholic neuropathy, diabetic neuropathy, chronic inflammatory neuropathy, Guillain-Barre syndrome, and neuropathy caused by drugs.
- Weakness of any area of the body, facial weakness, or weakness of the arms or legs
- Difficulty walking
- Difficulty using the legs or feet
- Difficulty using the arms or hands (legs and feet usually affected first)
- Difficulty swallowing
- Decreased sensation of any area of the body
- Pain, burning, tingling, or abnormal sensation of any area of the body
- Numbness, loss of sensation in the arms or legs
Symptoms of sensorimotor neuropathy may develop gradually over weeks to years and usually occur on both sides of the body. They may progress from distal (far from the center) areas to proximal (close to the center) portions of the body.
Signs and tests
A neuromuscular examination shows sensory and movement abnormalities. There is a pattern of slow progression of weakness or sensation changes. Sensation deficits usually occur in a symmetrical pattern and progress from distal areas to proximal locations.
Reflexes may be decreased or absent. Muscle weakness or paralysis of the affected area may be present. A muscle twitch (fasciculations) or muscle atrophy may be apparent.
An EMG (a test of electrical activity in muscles) may indicate the type and degree of peripheral nerve injury. Nerve conduction tests may indicate the loss of the myelin sheath (slow conduction rate) or degeneration of the axon of the nerve cell (normal conduction rate).
Other tests are guided by the suspected cause of the disorder and may include X-rays, scans, blood tests, or other tests and procedures.
The goals of treatment include finding the cause, maximizing self-care ability and independence, and controlling symptoms.
The cause should be identified and treated whenever possible. This may include such things as controlling blood sugar levels for diabetics, abstaining from alcohol, and taking daily nutritional supplements. If medications (such as some treatments for HIV) are causing the problem, these should be identified and changed, if possible.
MAXIMIZE SELF-CARE AND INDEPENDENCE
Physical therapy, vocational therapy, occupational therapy, and orthopedic interventions may be recommended to promote self-care ability and independence.
For example, exercises and retraining may increase muscle strength and control. Appliances such as wheelchairs, braces, or splints may provide mobility or help support an extremity so that it can be used.
CONTROL OF SYMPTOMS
Safety is an important consideration for people with neuropathy. Lack of muscle control may increase the risk of falls or other injuries. Also, decreased sensation may increase the risk of falls and injuries because the person is unable to perceive a potential source of harm.
Safety measures for people with difficulty in movement may include the use of railings, removal of obstacles (such as loose rugs that may slip on the floor), and other measures as appropriate.
Safety measures for people experiencing difficulty with sensation include awareness of the lack of sensation and compensation through other measures. Specific measures may include the use of adequate lighting (including lights left on at night), testing of water temperature before bathing, use of protective shoes (such as those with closed toes and low heels), and similar measures.
People with decreased sensation should check their feet (or other affected area) frequently for bruises, open skin areas, or other injury, which may go unnoticed and become severely infected.
Shoes should be checked inside frequently for grit or rough spots that may injure the feet. Patients with sensorimotor neuropathy should be evaluated by a podiatrist to reduce the risk of injury to the feet.
People with neuropathy are prone to new nerve injury at pressure points (such as knees and elbows). They should avoid prolonged pressure on these areas from leaning on the elbows, crossing the knees, or being in similar positions.
Over-the-counter analgesics or prescription analgesics may be needed to control pain (neuralgia). Various other medications may be used to reduce the stabbing pains that some people experience, including anticonvulsants (phenytoin, carbamazepine, neurontin) or tricyclic antidepressants. Whenever possible, medication use should be avoided or minimized to reduce the risk of side effects.
Positioning, keeping bedclothes off a tender body part, or other measures may be helpful to control pain.
If the cause of the sensorimotor polyneuropathy can be identified and successfully treated, and if the damage is limited to the axon or myelin sheath - leaving the cell body intact - there is a possibility of full recovery from peripheral neuropathy.
The extent of the disability varies (from no disability to partial or complete loss of movement, function, or sensation). Nerve pain may be quite uncomfortable and may persist for a prolonged period. Occasionally the disorder causes severe, life-threatening symptoms.
- Partial or complete loss of movement
- Partial or complete loss of control of movement
- Partial or complete loss of sensation
- Difficulty swallowing
- Recurrent or unnoticed injury to any part of the body
Calling your health care provider
Call your health care provider if loss of movement or sensation of a part of the body occurs. Early diagnosis and treatment increase the chance of controlling the symptoms.
Prevention varies depending on the cause.
by David A. Scott, M.D.
All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.