Mr. O is a 29-year-old white man with a history of unprotected anal intercourse with multiple partners. He has noticed some oral lesions and weight loss. He is quite worried and wants to know if he is infected with HIV.
Prioritizing the Differential Diagnosis
Mr. O presents with weight loss and significant HIV risk factors. Men who have sex with men (MSM) are at very high risk for acquiring HIV infection, especially if they have multiple partners and do not use condoms consistently. Mr. O is well aware of his high-risk behavior and is rightly concerned that his weight loss and oral lesions may suggest HIV infection. He comes to your office to be tested for HIV.
This discussion will focus on his chief concern: whether he has acquired HIV infection.
Mr. O's past medical history is remarkable for a history of syphilis and gonorrhea. Physical exam reveals a thin white man. He is 6' tall and weighs 140 pounds. HEENT exam reveals white coating on the palate consistent with thrush. Cardiac and pulmonary exam are unremarkable.
|Is the clinical information sufficient to make a diagnosis? If not, what other information do you need?|
Leading Hypothesis: HIV Infection
Chronic HIV infection may present in a myriad of ways. Many patients are asymptomatic in spite of long-standing HIV infection and even advanced immune deficiency. Other patients have conditions that suggest possible HIV infection but are frequently encountered in non–HIV-infected persons (eg, tuberculosis (TB), idiopathic thrombocytopenic purpura, nephropathy, cardiomyopathy, unexplained chronic diarrhea, herpes zoster, non-Hodgkin lymphoma). HIV infection may be diagnosed only after a patient seeks medical attention for an opportunistic infection or malignancy that is highly suggestive of severe T-cell immunodeficiency (eg, oral candidiasis, pneumocystosis, cryptococcosis, Kaposi sarcoma, primary CNS lymphoma). Nonspecific skin findings, such as severe or refractory seborrheic dermatitis, psoriasis, and prurigo nodularis (see below for skin findings in HIV infected patients), may suggest the diagnosis.
In December 2007, about 33.2 [30.6–36.1] million people were reported living with HIV worldwide (Table 5–1).
Rates vary dramatically by gender and ethnicity (Figure 5–1).
The Center for Disease Control and Prevention (CDC) estimates that at the end of 2003 the total number of persons in the United States living with HIV was > 1 million (1,039,000–1,185,000). Approximately 25% are unaware that they are infected.
HIV is a retrovirus. The viral enzyme reverse transcriptase uses the viral RNA genome as a template for production of DNA that is integrated into the cell genome.
The HIV virus carries 3 enzymes: reverse transcriptase, integrase, and protease; all 3 enzymes are targets of highly effective inhibitors....