The signs and symptoms of HIV infection vary across the three stages of infection: acute infection, latency, and AIDS. Acute infection (also known as primary infection) begins soon after exposure and typically lasts 2–4 weeks and may include symptoms such as fever, swollen lymph nodes, inflammation of the throat, rash, muscle pain, malaise, and mouth and esophageal sores. This is followed by the latency stage, which involves few or no symptoms, and can last anywhere from two weeks to twenty years or more. The final stage, AIDS, is defined by low CD4+ T cell counts (fewer than 200 per μL), various opportunistic infections, cancers, and other conditions.
Acute infection
Acute HIV infection (also called primary HIV infection, HIV prodrome, or acute seroconversion syndrome) is the first stage of HIV infection. It presents in 50–90% of infected individuals in the immediate days and weeks post-exposure. The duration of symptoms varies; they normally last at least one week, but average between 14-28 days, and can last for several months. During this period, individuals may develop an influenza or mononucleosis-like illness. The most common symptoms include fever, fatigue, lymphadenopathy, pharyngitis, rash, myalgia, malaise, mouth and esophageal sores, and may also include, but less commonly, headache, nausea and vomiting, ulcers in the mouth or on the genitals, enlarged liver/spleen, weight loss, thrush, night sweats and diarrhea and neurological symptoms. Infected individuals may experience all, some, or none of these symptoms. Because of the nonspecific nature of these symptoms, they are often not recognized as signs of HIV infection. Even if patients see a healthcare provider, they will often be misdiagnosed as having a more common infectious disease with similar symptoms. As a consequence, these primary symptoms are not used to diagnose HIV infection. However, recognizing the infection can be important because the patient is much more infectious during this period.
Some of those symptoms (nasal congestion, sore throat) have a sensitivity that is less than 1 − specificity {\displaystyle 1-{\text{specificity}}} (meaning that they are more likely without HIV than with it), and are therefore slight evidence against rather than for HIV, per Bayes' theorem.
Latency A strong immune defense reduces the number of viral particles in the bloodstream, marking the start of secondary or chronic HIV infection. The secondary stage of HIV infection can vary between two weeks and 10 years. During the secondary phase of infection, HIV is active within lymph nodes, which typically become persistently swollen, in response to large amounts of virus that become trapped in the follicular dendritic cells (FDC) network. The surrounding tissues that are rich in CD4+ T cells may also become infected, and viral particles accumulate both in infected cells and as free virus. Individuals who are in this phase are still infectious. During this time, CD4+ CD45RO+ T cells carry most of the proviral load. A small percentage of HIV-1 infected individuals retain high levels of CD4+ T-cells without antiretroviral therapy. However, most have detectable viral loads and will eventually progress to AIDS without treatment. The former are classified as HIV controllers or long-term nonprogressors (LTNP). People who maintain CD4+ T cell counts and also have low or clinically undetectable viral load without antiretroviral treatment are known as elite controllers or elite suppressors (ES).
AIDS
The symptoms of AIDS are primarily the result of conditions that do not normally develop in individuals with healthy immune systems. Most of these conditions are opportunistic infections caused by bacteria, viruses, fungi, and parasites that are normally controlled by the elements of the immune system that HIV damages. These infections affect nearly every organ system. A declining CD4+/CD8+ ratio is predictive of the progression of HIV to AIDS. People with AIDS also have an increased risk of developing various cancers such as Kaposi's sarcoma, cervical cancer, and cancers of the immune system known as lymphomas. Additionally, people with AIDS often have systemic symptoms of infection like fevers, sweats (particularly at night), swollen glands, chills, weakness, and weight loss. The specific opportunistic infections that AIDS patients develop depend in part on the prevalence of these infections in the geographic area in which the patient lives.
Pulmonary Pneumocystis pneumonia (PCP) (originally known as Pneumocystis carinii pneumonia) is relatively rare in healthy, immunocompetent people, but common among HIV-infected individuals. It is caused by Pneumocystis jirovecii. Before the advent of effective diagnosis, treatment, and routine prophylaxis in Western countries, it was a common immediate cause of death. In developing countries, it is still one of the first indications of AIDS in untested individuals, although it does not generally occur unless the CD4 count is less than 200 cells per μL of blood. Tuberculosis (TB) is unique among infections associated with HIV because it is transmissible to immunocompetent people via the respiratory route, and it is not easily treatable once identified. Multidrug resistance is a serious problem. Tuberculosis with HIV co-infection (TB/HIV) is a major world health problem according to the World Health Organization: in 2007, 456,000 deaths among incident TB cases were HIV-positive, a third of all TB deaths and nearly a quarter of the estimated 2 million HIV deaths in that year. Even though its incidence has declined because of the use of directly observed therapy and other improved practices in Western countries, this is not the case in developing countries where HIV is most prevalent. In early-stage HIV infection (CD4 count >300 cells per μL), TB typically presents as a pulmonary disease. In advanced HIV infection, TB often presents atypically with extrapulmonary (systemic) disease a common feature. Symptoms are usually constitutional and are not localized to one particular site, often affecting bone marrow, bone, urinary and gastrointestinal tracts, liver, regional lymph nodes, and the central nervous system.
… excerpt ends here. Continue reading the full article.
