Wasting Syndrome
Wasting syndrome is involuntary weight loss greater than 10% of body weight, accompanied by more than 30 days of diarrhea, weakness, or fever. This condition was one of the first noted HIV-related systemic conditions and, before antiretrovirals, was one of the most common HIV-related conditions.
Patients with wasting are more likely to develop an HIV-related infection or cancer and are more likely to die from AIDS. In particular, weight loss of 3% in one month, 5% in 6 months, or 10% in 12 months often indicates the development of HIV related illnesses.
HIV infection affects the body in many ways. An increased demand for calories compounded by a poor intake of calories, results in weight loss and poor nutrition:
- Altered metabolism—Baseline metabolism is the rate at which the body burns calories. HIV infection (without illness) increases the baseline metabolism by 10%, meaning that a patient with HIV needs more calories to maintain body weight. In an HIV-infected patient who has an infection or cancer, the baseline metabolism increases by about 30%, requiring even more calories to maintain a normal body weight.
- Low food intake—Many patients with HIV, especially those who have an HIV-related infection or cancer, do not eat enough food to maintain body weight. They may have a poor appetite or may not eat when they are hungry because so many AIDS drugs must be taken on an empty stomach. In addition, opportunistic infections in the mouth may make it difficult to eat, infections in the intestines may make eating unpleasant, or patients may not have the energy to prepare food.
- Poor nutrient absorption—In healthy people, nutrients are absorbed from food in the small intestine. In patients who have HIV, nutrients are not well absorbed because of intestinal infections, diarrhea, and perhaps, the virus itself.
- Hormonal and biochemical changes—Most of the weight lost in HIV wasting is lean body mass, the body's working tissue of the body (e.g., muscle). Normally, a person with poor nutrition and a high metabolism burns off fat first and then muscle. Due to hormonal and biochemical changes, patients with HIV tend to burn off muscle first and then fat. For example, patients with HIV have low levels of testosterone, which is a hormone that helps maintain lean body mass.
Antiretroviral therapy and treatment for HIV-related infections or cancers decreases the metabolism. A decreased metabolic rate means that calories are not used up as quickly and weight loss is slowed. Good nutrition is essential. Patients who experience wasting may benefit from a nutritionist.
Several medications are used to treat wasting by increasing the patient's appetite, lean body mass, or body fat, either singly, or in combination. Medications include the following:
- Megesterol acetate was the first medication approved by the Food and Drug Administration (FDA) to treat wasting. This drug is a powerful appetite stimulant. It reduces testosterone levels in men and women and the weight gained is primarily fat.
- Dronabinol, an active ingredient in marijuana, is an appetite stimulant and does not have a direct effect on fat or muscle.
- Human growth hormone (HGH) increases appetite and lean body mass.
- Thalidomide increases appetite, lean body mass, and fat.
- Steroids (e.g., oxandralone, nandralone, testosterone) increase appetite and a sense of well-being. Weight gained is predominantly lean body mass.
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