What conditions cause symptoms in HIV patients?
How are opportunistic infections diagnosed and treated?
What noninfectious problems are common in HIV patients?
When should antiretroviral therapy be started?
More than 1 million people are HIV seropositive in the United States. As survival with HIV has increased because of antiretroviral therapy (ART), the spectrum of illness affecting this population has expanded. Opportunistic infections still occur in untreated patients and patients who do not adhere to therapy. However, in patients whose HIV infection is controlled by ART, noninfectious problems such as coronary artery disease, pulmonary hypertension, and malignancy are increasing in prevalence. This chapter uses a symptom-based approach to guide differential diagnosis in HIV, and outlines the presentation, diagnosis, and treatment of common opportunistic infections. Other aspects of HIV therapy important to the hospitalist are discussed, including medication interactions and side effects.
Most patients with acute HIV infection develop symptoms from two to four weeks after exposure. Some patients are asymptomatic, but many report an acute febrile illness resembling mononucleosis. Features may include rash, anorexia, mucocutaneous ulcerations, pharyngitis, lymphadenopathy, diarrhea, myalgias, and rarely meningoencephalitis. As HIV antibody does not appear until three to four weeks after the symptoms of acute HIV syndrome develop, both HIV RNA (viral load) testing and HIV antibody should be obtained. Clinicians should bear in mind that patients with acute HIV infection may also have acquired other infections, such as viral hepatitis, syphilis, or cytomegalovirus (CMV), at the time of their HIV exposure.
HIV depletes CD4+ lymphocytes, also known as T-helper cells, leading to opportunistic infections (OIs). In acute HIV infection, CD4+ cells decline sharply, generally followed by a modest rebound, as HIV replication is brought under partial control. Over time, viremia rises, CD4+ cells are gradually depleted, and AIDS develops.
The tempo for progression to AIDS has great individual variability. Illnesses such as seborrheic dermatitis, cutaneous zoster, bacterial pneumonia, and cytopenias, while not specific to HIV, occur with increased frequency in patients with waning CD4+ cells and may be a clue to undiagnosed HIV.
Admission of the patient with CD4+ count > 500 cells/mm3, suppressed viral load, and admission for a non–HIV-related reason does not necessarily require infectious diseases consultation. By contrast, newly diagnosed HIV, acute opportunistic infections, undifferentiated illness in patients with more advanced HIV, or possible modification of ART warrant review with a specialist familiar with HIV disease and its management.
The most recent CD4+ cell count is critical in determining the likelihood of an HIV-related complication (Table 195-1). If recent CD4+ counts are unavailable, there is controversy about the usefulness of CD4+ testing in the context of acute illness, which depresses the CD4+ below the patient's true baseline. Despite this caveat, we recommend measuring CD4+ cell count during hospital admissions, as markedly low values (eg, < 100 cells/mm3) almost invariably indicate severe HIV-related immunosuppression. Conversely, OIs are unusual in patients with ...