Michael, who stands at 5 feet 11 inches and 165 pounds, is a 35-year-old real estate agent from Queens who works out 4 or 5 times per week and practices very healthy eating habits. Except for the occasional flu, Michael has enjoyed good health, so he was at a loss to explain why suddenly, after each work day his leg muscles felt progressively weaker.
At first Michael thought he had suffered an injury during weight training but even after changing his work-out routine, the lost of sensation and pain in his lower extremities caused him to miss two days of work. Michael was forced to seek medical help and reluctantly went to his primary care physician.
After undergoing thorough physical and neurological examinations and a battery of diagnostic tests, Michael was shocked to learn he was positive for human immunodeficiency virus (HIV) and his neurological symptoms were due to acute inflammatory demyelinating polyneuropathy (IDP). IDP, a form of peripheral neuropathy, is a clinical complication of HIV disease and is sometimes the first clinical manifestation that a person is HIV-infected. Peripheral neuropathy is the most frequent neurological complication associated with HIV infection.
Understanding the Nervous System
Within the peripheral nervous system, there are three kinds of nerves: motor nerves, sensory nerves, and autonomic nerves. The motor nerves are responsible for voluntary movements such as picking up an object or jogging. Sensory nerves allow us to feel pain, vibrations and touch by transmitting signals from sensory receptors in the skin and other organs to the central nervous system. The autonomic nerves control involuntary functions like breathing, heartbeat, and digestion and they work automatically whether we are awake or asleep.
Most neuropathies affect all three types of nerves. Peripheral neuropathy describes disorders which occur from injury to the peripheral nerves These disorders can impair functional status, limit physical activity, and diminish quality of life.
There are at least six forms of HIV-associated peripheral neuropathy. Besides IDP, which Michael developed, a person with HIV disease may be diagnosed with distal symmetrical polyneuropathy (DSPN); progressive polyradiculopathy (PP); mononeuritis multiplex (MM); diffuse infiltrative lymphocytosis syndrome (DILS); or autonomic neuropathy.
Some Causes of Peripheral Neuropathy
Although Michael developed IDP, the most common form of peripheral neuropathy in people with HIV infection is DSPN. Unlike IDP which can occur at anytime during the course of HIV disease, DSPN occurs mainly with advanced immunosuppression and may also be secondary to the neurotoxic effects of antiretroviral medications such as didanosine (ddI), zalcitabine (ddC), and stavudine (d4T). Other medications which are considered neurotoxins and can cause DSPN include vincristine and cisplatinum used to treat HIV-related lymphoma or Kaposi's sarcoma; and isoniazid used in the treatment of tuberculosis, especially when the person takes this drug without pyridoxine (vitamin B6) supplementation.
Besides medications, certain toxins such as lead, arsenic, mercury, thalium, organic solvents, and insecticides can cause peripheral neuropathy in persons infected with HIV.
Additionally, alcohol is directly toxic to nerves and alcohol abuse can be a major cause of peripheral neuropathy in someone with HIV. Unfortunately, some people increase their consumption of alcohol because of depression associated with the illness. These people could join support groups which can be helpful with management of alcoholism and depression related to HIV.
Peripheral neuropathy can also be caused by nutritional imbalance such as deficiencies of vitamins B12, B1 (thiamine), B6 (pyridoxine), or E. In people infected with HIV, this vitamin deficiency can be due to poor diet or to inability to absorb nutrients from the stomach. Other reasons include poor appetite, diarrhea, pain and depression. Megadoses of vitamin B6 can also cause peripheral neuropathy.
Also considered at increased risk for developing peripheral neuropathy are those with HIV infection as well as other medical conditions. These conditions include diabetes, which is the most common known cause of peripheral neuropathy; some conditions where the immune system turns against the body causing autoimmune diseases such as Guillian-Barre syndrome, lupus, and rheumatoid arthritis; lung cancer; chronic renal failure; and hypothyroidism.
Symptoms of Peripheral Neuropathy
The symptoms experienced by those with HIV-related peripheral neuropathy depend on the types of nerves affected and their location, but the problem usually starts with weakness, numbness or pain.
For example, damage to the motor nerves can cause leg symptoms such as difficulty walking, running, tiring easily or stumbling. Sensory nerve damage can cause paresthesias such as numbness, tingling, pins and needles, burning, cold, sharp, deep stabs, or electric shocks. Or instead, one can also develop anesthesia, a lessening or absence of sensation, which can cause a person to burn or cut oneself and not know it.
Sensory nerve damage can also cause absence of position sense where a person is not sure just where his or her feet are and so may be uncoordinated and unsteady when walking. Damage to the autonomic nerves can cause dizziness when standing up, bowel and/or bladder dysfunction, and sexual dysfunction.
How to Minimize or Alleviate Symptoms
If symptoms of peripheral neuropathy develop while taking one of the neurotoxic drugs mentioned, or any other prescribed medication, you should consult your healthcare provider before making any changes in your drug therapy.
Futhermore, people who develop HIV-associated peripheral neuropathy may experience a variety of signs and symptoms at different particular stages of HIV infection. It is therefore very important to consult your healthcare provider as soon as these symptoms develop so the appropriate treatment can be offered, thus preventing further neurological damage. It is important to note that as the disease progresses, severe pain can be debilitating to some and management of pain medication becomes an important issue. For severe pain caused by peripheral neuropathy, pain medication is most effective when a fixed dose is taken at a fixed time schedule.
Non-medical therapeutic approaches include relaxation training which can reduce anxiety and stress, and subsequently reduce pain and/or promote sleep. Imagery, meditation and visualization techniques can be used for desensitization to anxiety producing stimuli and improve coping with the illness.
Massage therapy can reduce pain and improve sense of well-being. Furthermore, massage therapy promotes arterial and venous blood flow and lymphatic drainage is stimulated, increasing the supply of oxygen and nutrients to sites of pain. Also massage therapy results in passive stretching and elongation of connective and muscular tissue which causes a reduction in muscular tightness and tension. With massage therapy there is systemic release of endorphins and opiates, resulting in pain reduction and a greater sense of well-being.
A diet high in fiber that includes vegetables and fruits, the use of vitamins, especially vitamin B complex, and liberal daily fluid intake are important. Regular daily exercise like walking and stretching exercises to keep muscles flexible should be done as tolerated.
Protective footwear must be worn at all times and should not apply pressure. Shoes and slippers should go over the instep of the foot. Also, it is important to wear warm socks during cold weather. Other safety measures include using a thermometer to test bath temperature; use skid-free shower and bathroom mats; clear walkways of clutter and wipe spills on the floor immediately. Pay close attention to driving skills, particularly the ability to feel gas and brake pedals and changes in your reaction time. If these changes occur, refrain from driving immediately and discuss this with your healthcare provider.
Finally, HIV-infected people with symptomatic peripheral neuropathy should consider participation in one of the many clinical trials of treatments for the associated discomfort from this disease. Your healthcare provider can assist you with enrollment in clinical trials.
References and Further Reading
Berger, J.R. and Nath, A. (2000). "Remedies for HIV-associated peripheral neuropathy." Neurology, 54 (1), 2037-2038.
Kelleher, T., Cross, A., and Dunkle, L. (1999). "Relation of peripheral neuropathy to HIV treatment in four randomized clinical trials including didanosine." Clinical Therapy, 21(7), 1182-1192.
McArthur, J.H. (1998). "The reliability and validity of the subjective peripheral neuropathy screen." Journal of the Association of Nurses in AIDS Care, 9 (4), 84-94.
Holzemer, W L., Henry, S.B., and Reilly, C. . (1998). "Assessing and managing pain in AIDS care: The patient perspective." Journal of the Association of Nurses in AIDS Care, 9 (1), 22-30.
"Physiological aspects of nursing care" by the National Institute of Nursing Research. (2000) Retrieved November 16, 2001, from www.nih.gov/ninr/research/vol2/Chapter2.htm.
Scherer, P. (1990). "How HIV attacks the periperal nervous system." American Journal of Nursing, 6 (3), 66-70.
Swanson, B., Zeller, J.M., and Paice, J.A. (1998). "HIV-associated distal symmetrical polyneuropathy: Clinical features and nursing management." Journal of the Association of Nurses in AIDS Care, 9 (2), 77-80.
"What is peripheral neuropathy?" By the Neuropathy Association. (2000). Retrieved November 8, 2001, from www.neuropathy.org.
Wulff, E.A., Simpson, D.M. (1998). "HIV-associated neuropathy: Recent advances in management. HIV: Advances in research and therapy." Retrieved November 9, 2001, from www.iapac.org.
Wulff, E.A., Wang, A.K., and Simpson, D.M. (2000). "HIV-associated peripheral neuropathy." Drugs, 59 (6), 1251-1260.
Debra Boucaud-Obali R.N., B.S.N. is a graduate student at Hunter College, City University of New York.