Porth's Essentials of Pathophysiology, 4e

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Disorders of the Immune Response

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Gynecologic examination with cervical cytologic analysis for HPV should be part of the routine eval- uation of HIV-infected women. Since HPV can also cause anal dysplasia, a precursor of anal carcinoma, cytologic evaluations of the anal canal are also rec- ommended for both HIV-infected men and women. A quadrivalent vaccine to prevent HPV infection became available in 2007. The safety and immunogenicity of this vaccine among HIV-infected men and women are being studied. 69 Wasting Syndrome. The wasting syndrome, which is an AIDS-defining illness, is characterized by invol- untary weight loss of at least 10% of baseline body weight in the presence of diarrhea, more than two stools per day, or chronic weakness and a fever. 70 This diagnosis is made when no other opportunistic infections or neoplasms can be identified as causing these symptoms. Factors that contribute to wasting are anorexia, metabolic abnormalities, endocrine dys- function, malabsorption, and cytokine dysregulation. Treatment for wasting includes nutritional interven- tions such as oral supplements or enteral or parenteral nutrition, as well as pharmacologic agents, includ- ing appetite stimulants, cannabinoids, and megestrol acetate. Metabolic Disorders. A wide range of metabolic and morphologic disorders are associated with HIV infec- tion, including insulin resistance and diabetes, lipodys- trophy, hyperlipidemia, and mitochondrial disorders. 71 It is not known why insulin resistance appears to be increased in people with HIV infection; however, most experts believe it is secondary to dysregulation of meta- bolic pathways or to indirect effects through mitochon- drial toxicity linked to adipocyte toxicity. 72 Moreover, metabolic complications among people with HIV infec- tion have been increasing since the introduction of potent HAART. The term lipodystrophy is frequently used to describe the body composition changes with or without the other metabolic derangements. Lipodystrophy related to HIV infection includes symptoms that fall into two categories: changes in body composition and metabolic changes. 73 The alterations in body appearance are an increase in abdominal girth, buffalo hump develop- ment (abnormal distribution of fat in the dorsoclavical area), wasting of fat from the face and extremities, and breast enlargement in men and women. Most individu- als experience either lipohypertrophy or lipoatrophy. Mixed patterns of fat changes are less common. 74 The metabolic changes include elevated serum cholesterol, low HDL cholesterol, elevated triglyceride levels, and insulin resistance. Originally attributed solely to the use of protease inhibitors, the pathogenesis of these metabolic derangements is complex and there may be multiple confounding factors. 75 Wasting Syndrome and Metabolic Disorders

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FIGURE 16-11. Kaposi sarcoma. (A) Intraoral Kaposi sarcoma of the hard palate secondary to HIV infection. (B) Cutaneous brown Kaposi sarcoma lesions located over the medial left ankle and foot. (From the Centers for Disease Control and Prevention Public Health Image Library. Nos. 6070, 5515. A courtesy of Sol Silverman, Jr; B courtesy of Steve Kraus.)

Pulmonary KS usually is a late development of the disease and causes dyspnea, cough, and hemoptysis (coughing up blood). 68 With prolonged survival, the number of persons with AIDS who develop non-Hodgkin lymphoma has increased steadily. 2 The clinical features are nonspecific and include fever, night sweats, and weight loss (see Chapter 11). Because the manifestations of non-Hodgkin lymphoma are similar to those of other opportunistic infections, diagnosis often is difficult. Diagnosis can be made by biopsy of the affected tissue. The high prevalence of human papillomavirus (HPV) infection in persons with AIDS has been linked to the development of cervical carcinoma and anal carcinoma in both HIV-positive men and women. 2