Clinical Categories of HIV Infection

9.5 Clinical Categories of HIV Infection

9.5.1 Primary infection or Acute Retroviral Syndrome:

Primary infection refers to the time when HIV first enters the body. At the time of primary infection with HIV, a person's blood carries a high viral load, meaning that there are many individual viruses in the blood. The number of copies of virus per milliliter of plasma or blood can exceed 1 million. Newly infected adults often experience an acute retroviral syndrome. Signs and symptoms of acute retroviral syndrome include fever, myalgia (muscle pain), headache, nausea, vomiting, diarrhea, night sweats, weight loss, and rash. These signs and symptoms usually occur 2-4 weeks after infection, subside after a few days, and often are misdiagnosed as influenza. An important differentiating symptom that is often absent is the presence of a runny nose or nasal congestion.

During primary infection, the CD4+ count in the blood decreases remarkably but rarely drops to less than 200 cells/μL. The virus targets CD4+ cells in the lymph nodes and the thymus during this time, making the HIV-infected person vulnerable to opportunistic infections and limiting the thymus's ability to produce T lymphocytes. HIV antibody testing using an enzyme-linked immunosorbent assay (ELISA) may yield positive or negative results depending on the time of seroconversion. The average time to seroconversion is 25 days.

Clinical Latency/Asymptomatic Disease (Clinical Stage 1)

Although patients recently infected with HIV usually experience a "clinically latent" period of years between HIV infection and clinical signs and symptoms of AIDS, evidence of HIV replication and host immune system destruction exists from the onset of infection. During latency, HIV-infected patients may or may not have signs and symptoms of HIV infection though persistent lymphadenopathy is common. In HIV-infected adults, this phase may last 8-10 years. The HIV ELISA and Western blot will be positive.

Mild Signs and Symptoms of HIV (Clinical Stage 2)

HIV-infected people may appear to be healthy for years, and then minor signs and symptoms of HIV infection begin to appear. They may develop candidiasis, lymphadenopathy, molluscom contagiosum, persistent hepatosplenomegaly, popular pruritic eruptions, herpes zoster, and/or peripheral neuropathy. The viral load increases, and the CD4+ count falls.

Advanced Signs and Symptoms of HIV (Clinical Stage 3)

HIV-infected patients with weakened immune systems can develop life-threatening infections. The development of cryptosporidiosis, pulmonary and lymph node tuberculosis, wasting, persistent fever (longer than one month), persistent candidiasis, recurrent bacterial pneumonia, and other opportunistic infections is common. These patients may be wasting, or losing weight. Their viral load continues to increase, and the CD4+ count falls.

Clinical Stage 4

Patients with advanced HIV disease, or AIDS, can continue to develop new opportunistic infections, such as Pneumocystis jirovecii pneumonia (formerly Pneumocystis carinii pneumonia), cytomegalovirus infection, toxoplasmosis, Mycobacterium avium complex, cryptococcal meningitis, progressive multifocal leukoencephalopathy, Kaposi sarcoma and other infections that commonly occur with a severely depressed immune system. The viral load is very high, and the CD4+ count is less than 200 cells/μL. At this point in the disease course death can be imminent.