The metabolic response to opportunistic infections in AIDS

Objective : The metabolic response to AIDS-defining opportunistic infections was examined to provide a logical basis for the management of associated weight loss. Design : A prospective study of metabolism in AIDS. Setting : HIV outpatients' department and wards at the Chelsea and Westminster Hospital, London. Patients : Ten asymptomatic Centers for Disease Control and Prevention stage II HIV-seropositive control subjects and 36 HIV-seropositive patients with a single newly diagnosed and untreated opportunistic infection [10 with microsporidial or cryptosporidial diarrhoea, 10 with Pneumocystis carinii pneumonia, nine with cytomegalovirus enteritis and seven with systemic Mycobacterium avium-intracellulare]. Main outcome measurements : Subjects had measurements of resting energy expenditure using indirect calorimetry and of body composition using dual energy X-ray absorptiometry. Results : Subjects with protozoal diarrhoea had a decreased resting energy expenditure (P < 0.05) and decreased body fat (P < 0.01). Subjects with P. carinii pneumonia had an elevated resting energy expenditure (P< 0.05). Subjects with systemic M. avium-intracellulare had an elevated resting energy expenditure (P< 0.05) and decreased skeletal muscle mass (P< 0.05). Subjects with cytomegalovirus enteritis had a non-significant elevation of resting energy expenditure with a non-significant loss of both fat and lean tissue. Conclusion : Subjects with protozoal diarrhoea show a starvation response to infection and subjects with systemic M. avium-intracellulare show a cachectic response. Since there is a variation in the metabolic response to opportunistic infection in AIDS patients, nutritional management should be directed according to the specific cause.