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Acquired Immunodeficiency Syndrome (AIDS)


Microscopic pathology image showing a medium power view of histoplasma fungus in a AIDS patient on a silver stain.

What are the other Names for this Condition? (Also known as/Synonyms)

  • Acquired Immune Deficiency Syndrome
  • AIDS (Acquired Immunodeficiency Syndrome)

What is Acquired Immunodeficiency Syndrome? (Definition/Background Information)

  • Acquired Immunodeficiency Syndrome, or AIDS, is a chronic infectious condition caused by the human immunodeficiency virus (HIV), especially HIV-1. The primary mechanism by which the virus causes AIDS is by damaging the immune system.
  • HIV is transmitted by sexual contact, needles, surgical or nonsurgical procedures (parenteral), and it may also be transmitted from a mother to her child.
  • As per the U.S. Centers for Disease Control and Prevention (CDC), AIDS is defined as the presence of HIV positivity including one or more of the following factors:

    • Opportunistic infections that unusually occur in individuals with immunity
    • Cancers that uncommonly occur in individuals with immunity
    • Association with conditions such as dementia
    • CD4 lymphocyte cells below 200 or below 14%
  • The prognosis has considerably improved in the past 20 years ever since the treatment therapy, known as HAART (highly active anti-retroviral therapy), was introduced

Who gets Acquired Immunodeficiency Syndrome? (Age and Sex Distribution)

  • Any individual who is infected with human immunodeficiency virus may develop Acquired Immunodeficiency Syndrome (AIDS)
  • AIDS is more common in younger adults than other age groups due to their risky behaviors such as multiple partners, usage of injectable drugs, etc.
  • Children are usually infected from an infected mother, during pregnancy or after childbirth
  • In the developed countries such as the United States and Europe, men are more commonly infected than women
  • In the developing countries, there is an equal prevalence of HIV/AIDS in both genders
  • More than 30 million worldwide are affected with HIV infection. The condition is slightly more common in sub-Saharan Africa than the rest of the world

What are the Risk Factors for Acquired Immunodeficiency Syndrome? (Predisposing Factors)

Any individual who has contact with another infected individual (leading to a transmission) through one of the following methods are at risk of HIV infection or Acquired Immunodeficiency Syndrome.

  • Blood, semen, vaginal secretions, and breast milk may transmit the HIV virus to others, though HIV is present in almost all body fluids such as saliva, tears, and spinal fluid
  • Unprotected sexual contact (such as not wearing a condom) including oral, vaginal, and anal sexual practices
    • Among the different sexual practices, men having sex with men anally have the highest risk of HIV/AIDS. In this group, receiving men are at a higher risk than the dominant men
    • Men receiving men anally, anal sex with women, women having vaginal sex, women receiving ejaculate orally, and men having vaginal sex are those at risk, in decreasing order of risk
    • Additional factors that may place an individual at risk include having ulcers in the genital areas, presence of other sexually transmitted diseases (STDs), menses, uncircumcised penis, and other factors
  • Individuals receiving HIV-contaminated blood via blood transfusions are at risk. However, this is extremely rare (1 in 1 million chance), since blood is normally screened before a transfusion
  • Needle-sharing, especially among intravenous drug abusers
  • An infected pregnant mother can transmit the virus to her child
  • A nursing mother can transmit the virus to her child through breast milk
  • Healthcare workers are at risk if they are accidentally exposed to infected medical instruments such as needles
  • Individuals getting infected organ transplants are also at risk

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Acquired Immunodeficiency Syndrome? (Etiology)

The causes of Acquired Immunodeficiency Syndrome include:

  • The human immunodeficiency virus type 1 (HIV-1) causes AIDS. HIV-2 does not cause infection in humans
  • Individuals get HIV/AIDS when they come in contact with HIV-infected individuals either through sexual contact, sharing needles, from an infected mother, or through other factors
  • HIV causes AIDS (syndrome) by attacking the immune system and making the individual immune deficient. This leaves the body vulnerable to a variety of life-threatening infections and cancers
  • When the immunity becomes deficient, these individuals are affected by infections from common pathogens that usually do not cause disease in those with a healthy immune system. The immune deficient individuals are also more prone to severe and life-threatening infections than others
  • Other less common mechanisms by which HIV causes the AIDS syndrome are autoimmune, hypersensitivity, and allergic reactions

What are the Signs and Symptoms of Acquired Immunodeficiency Syndrome?

The signs and symptoms of Acquired Immune Deficiency Syndrome or HIV infection include:

  • When the HIV enters for the very first time in an individual, it causes a flu-like illness with symptoms such as fever, sore throat, enlarged glands, headaches, and muscle and body aches. This is the acute, infectious, or primary HIV infection stage
  • Following this, many HIV-infected individuals may not have symptoms on an average for up to 10 years. This is known as the clinical latency stage. Nevertheless, asymptomatic individuals (infected individuals without symptoms) can still transmit the disease to others during this period
  • Over time, the asymptomatic individuals develop the AIDS syndrome when their immune system gradually fails. The HIV/AIDS infection can affect almost any organ in the body. At this point, the affected individuals may have:
    • Non-specific symptoms (symptoms that are observed with other diseases too) such as anorexia, nausea, vomiting, chills, fever, rash, sweats (particularly at night), swollen lymph glands, weakness, and weight loss among many others
    • The signs and symptoms can also be due to common community infections such as pneumonia, sinusitis, and Staphylococcus skin infection that may be seen in increasing frequency compared to the normal population
    • Signs and symptoms that are specific to HIV infection such as Kaposi’s sarcoma
    • Signs and symptoms due to treatment therapy (antiretroviral therapy)
  • As per the U.S. CDC, AIDS is defined as the presence of HIV positivity (tests positive for the presence of human immunodeficiency virus) with one or more of the following factors:
    • Opportunistic infections that are not commonly seen in individuals with immunity
    • Cancers that are unusual in individuals with immunity
    • Association with conditions such as dementia
    • CD4 lymphocyte cells (a type of white blood cell) below 200 cells/mm3 (normal count is 500-1200 cells/mm3), or a percentage below 14
  • The signs and symptoms in an AIDS affected individual depends upon the HIV infection itself and the presence of other opportunistic infections (infections caused by germs that normally do not cause infection in immunocompetent individuals) and cancers
  • HIV infection can cause wasting syndrome that results due to nausea and loss of appetite, leading to a disproportionate loss of strength in different muscles in the body
  • The CD4 lymphocyte count predicts the type of opportunistic infections and cancers an HIV-infected individual can develop as the count decreases
  • Sometimes, an individual is considered to have AIDS even if laboratory values are normal, but has diseases such as Candida fungal infection of the esophagus or trachea, Cryptosporidium diarrhea, pneumocystis jirovecii pneumonia, Kaposi’s sarcoma, and atypical mycobacteria infection

The following signs and symptoms are seen due to diseases or infections when the CD4 count drops below 350 cells/mm3:

  • Herpes simplex/herpes zoster ulcers and blisters of the skin and oral mucosa
  • Kaposi’s sarcoma due to herpes virus (HHV 8): It is more common in men who have sex with men. Purplish or brownish raised patches of the skin characterize this condition. It can also occur in the lungs and the gastrointestinal tract
  • Tuberculosis is a lung infection caused by Mycobacterium tuberculosis and is seen in an increasing frequency in the infected individuals than among the general population. Such individuals present with weight loss, fever, night sweats, cough, sputum production, coughing-up blood, etc. Tuberculosis can also affect other organs such as the bowel, brain, lining of central nervous system (brain and spinal cord), etc.
  • Thrush (yeast infection caused by Candida albicans fungus): White discharge/layer seen in the mouth or vagina

The following signs and symptoms are seen due to diseases or infections when the CD4 count drops below 200 cells/mm3:

  • Pneumocystis jiroveci pneumonia with fever, cough, and shortness of breath
  • Toxoplasma gondii infection of the brain can occur due to handling cat litter. Common presentations include headache, fits, altered mental status, or paralysis
  • Cryptosporidium diarrhea, which is marked by the presence of extreme watery-diarrhea and caused by the parasite Cryptosporidium. Although it can affect normal individuals, if it persists beyond a month, it may be due to HIV/AIDS
  • Candida esophagitis: A painful fungal infection of the esophagus (tube through which food travels)
  • Cryptococcus meningitis (fungal infection of the brain lining) that presents with headache, vomiting, and neck stiffness
  • Progressive multifocal leukoencephalopathy (a viral infection) seen in advanced stages of HIV infection. They present with difficulty in speech, paralysis, and other symptoms

The following signs and symptoms are seen due to diseases or infections when CD4 count drops below 50 cells/mm3:

  • Cytomegalovirus infection (a viral infection) can affect almost any organ system, but more commonly it involves the eyes (retinitis) causing visual changes, large bowel causing diarrhea, etc.
  • Mycobacterium avium complex (MAC): These bacteria are related to tuberculosis and usually do not cause illness in immunocompetent individuals. When the CD4 drops below 50, a widespread body infection may occur causing symptoms such as fever, night sweats, diarrhea, anemia, hepatitis, and sepsis
  • Non-Hodgkin’s lymphoma (a type of cancer involving white blood cell lymphocytes and the lymph node) involving the brain, liver, gastrointestinal tract, lungs, or other regions of the body. It may be present with region-specific symptoms
  • Histoplasmosis fungal infections of the lung

Other signs and symptoms and diseases observed in HIV/AIDS affected individuals include:

  • Arthritis (inflammation of the joints)
  • Hepatitis (inflammation of liver) due to hepatitis B, hepatitis C, CMV, or lymphoma
  • HIV/AIDS dementia: These individuals may have problems with memory, attention, and emotions
  • Peripheral neuropathy that could cause symptoms such as tingling, numbness, or pain in the lower extremities
  • Hairy leukoplakia characterized by the presence of parallel hairy lines (projections) on the tongue, which is very specific to HIV/AIDS
  • Gum disease (gingivitis), due to the overgrowth of germs is very common in HIV/AIDS individuals
  • Enterocolitis (infection of the small and large intestine), which may occur due to many germs such as salmonella, shigella, CMV, isospora, Cryptosporidium, etc. Severe symptoms such as severe diarrhea, high fever, and abdominal pain due to the infection occur in HIV/AIDS individuals when compared to immunocompetent individuals
  • Hypogonadism, a condition characterized by decreased functioning capacity of the gonads, especially in men, may cause inadequate male hormone production
  • Bacillary angiomatosis is an infection of the skin which is commonly seen in individuals having pet cats. This condition is characterized by reddish skin patches, fever, and the involvement of other organs
  • Seborrheic dermatitis, if widespread, raises the suspicion of HIV/AIDS. These are characterized by yellow greasy skin patches in the scalp, forehead, etc.
  • Cancers: The four types of cancers that are included in the definition of AIDS are Kaposi’s sarcoma, primary lymphoma brain, non-Hodgkin’s lymphoma, and cervical cancer. Other types of cancers, such as Hodgkin’s lymphoma and squamous cell carcinoma of the skin, may also occur
  • Immune reconstitution inflammatory syndromes (IRIS), occurs when the HIV-infected individual is started on antiretroviral therapy. Individuals with IRIS may present with fever, malaise, and signs of opportunistic infections

How is Acquired Immunodeficiency Syndrome Diagnosed?

The following procedures may be used to diagnose Acquired Immunodeficiency Syndrome:

  • Thorough evaluation of the individual’s medical history and a thorough physical examination
  • During history taking, the physician may want to know the following:
    • When the symptoms began and whether they become worse
    • List of prescription and over-the-counter medications currently being taken
    • About the individual’s sexual history, intravenous drug abuse history, childbirth history, blood transfusion history, etc.
  • Consultation with an infectious disease specialist is often necessary, as they are the experts in dealing with infections including HIV

An HIV infection is usually diagnosed through blood tests that may include:

  • HIV ELISA (enzyme-linked  immunosorbent assay): This is the first test (screening test) done to check if there is an HIV infection
  • Western blot test: If ELISA is positive, then this test is done to confirm the diagnosis
  • CD4 lymphocyte (helper cell) count: It is usually done to monitor the disease progression. A CD4 count of less than 200 cells/mm3 indicates that the HIV-infected individual is having AIDS
    • AIDS can also be diagnosed without a CD4 count or viral load test, if the individual has uncommon infections/diseases such as Kaposi’s sarcoma, toxoplasmosis of the brain, etc.
    • CD4 lymphocyte percentage is a more reliable test than CD4 count
  • HIV RNA level (viral load test): This test measures viral replication (multiplication) and is useful for monitoring disease progression and response to treatment
  • Home access express test (sold in pharmacies): This test can be done at home or at the clinic. It is done by swabbing the gums of the mouth. If this test is positive, it should be confirmed with an ELISA or Western blot test

Other related tests include:

  • Genotype and phenotype tests for antiretroviral resistance: These tests are usually done before initiation and/or after treatment. They help in finding if an individual may develop or has developed resistance to antiretroviral medications, so that appropriate treatment regimen can be planned
  • Tests for monitoring toxicity: They are done periodically once an individual is started on antiretroviral medications
  • Other tests that may be done in HIV/AIDS individuals are complete blood count, lipid profile, liver function tests, renal function tests, etc., as required
  • Other tests for diagnosing opportunistic infections and cancers may be done, depending on the clinical situation

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Acquired Immunodeficiency Syndrome?

The complications due to HIV infection or Acquired Immunodeficiency Syndrome may include:

  • Dementia, wasting syndrome, polyneuropathy, and many other conditions
  • Coronary artery disease (cause of heart attacks), stroke, hepatitis (inflammation of the liver), opportunistic infections, cancer, etc.

The complications due to antiretroviral treatment may include:

  • Polyneuropathy, myopathy, Cushing’s disease, metabolic syndrome (abnormal levels of glucose, insulin, obesity), anemia, lipodystrophy (abnormal fat deposits), and many other conditions

How is Acquired Immunodeficiency Syndrome (AIDS) Treated?

Although there is no complete cure for an HIV infection, the new antiretroviral drugs have revolutionized the management of individuals with HIV infections and Acquired Immunodeficiency Syndrome (AIDS). Individuals undergoing treatment can have a life expectancy comparable to normal individuals.

  • The main principle in treating these individuals is to keep the viral load to the minimal possible level. Research has shown that when viral load is controlled, the infected individuals live near normal lives. Scientists believe that starting antiretroviral therapy soon after a diagnosis is established helps in achieving this goal
  • Antiretroviral therapy suppresses the multiplication of the virus in the body through different mechanisms
  • Currently, a regimen called highly active antiretroviral therapy (HAART), which is a combination of two different classes of 3 anti-retroviral medications, is being employed. There are no drug-free holidays once antiretroviral therapy is started
  • HAART has shown to be very effective in reducing the viral load. When the viral load is controlled, the CD4 count and the immunity of an individual improves
  • The different classes (different mechanism of action) of anti-retroviral therapy include:
    • Nucleoside reverse transcriptase inhibitors, e.g. emtricitabine and stavudine
    • Nucleotide reverse transcriptase inhibitors, e.g. tenofovir
    • Nonnucleoside reverse transcriptase inhibitors (NNRTIs), e.g. efavirenz
    • Protease inhibitors, e.g. indinavir
    • Entry inhibitors, e.g. enfuvirtide
    • Integrase inhibitors, e.g. raltegravir
  • The choice of antiretroviral medications depends on many factors such as tolerance, toxicity, pregnancy, simple dosing regimen, compliance, resistance to medications, current health status of the individual, drug interactions, the presence or absence of associated opportunistic infections and cancers, etc.
  • The popular combinations currently used are tenofovir + emtricitabine + efavirenz and tenofovir+ emtricitabine + raltegravir. These combinations may vary from one individual to another depending on various factors, as determined by a healthcare provider
  • Apart from antiretroviral therapy, appropriate treatment may be given if an individual develops opportunistic infections or cancers
  • When the CD4 count drops below 200 cells/mm3, preventative treatment for different opportunistic infections may be started depending on the actual CD4 count

How can Acquired Immunodeficiency Syndrome be Prevented?

Providing education about avoiding high-risk behavior, which puts individuals at a higher risk of getting infected, remains the foremost and primary step to prevention of HIV infections and Acquired Immunodeficiency Syndrome (AIDS).

  • Currently, there are no vaccines available for the condition
  • Safe sex practices include the use of latex condoms with a water-soluble lubricants, every time during sex
  • Maintaining long-term monogamous relationships and avoiding multiple sexual partners
  • Avoiding needle sharing practices in individuals who have a habit of intravenous drug abuse. There are many programs in the community that exchange used syringes for sterile ones and offer referral to individuals for addiction treatment
  • Routine HIV testing and counselling should be offered to all individuals between the ages of 15 and 65 years. This will help infected individuals know about their HIV-status and thus avoid further transmission to uninfected individuals
  • Routine HIV testing in the mother: If the expectant mother is tested positive, preventative measures, such as antiretroviral therapy and planned elective cesarean section, may be performed
  • Those caring for ‘at-risk’ individuals must wear protective clothing, masks, and goggles, to avoid contact with body fluids
  • Routine screening of blood and organ donors, transfusion products, etc.
  • Male circumcision: The transmission of HIV is decreased in circumcised men in comparison to uncircumcised men
  • Post-exposure prophylaxis with antiretroviral therapy may be given in cases of accidental needle stick injury or sexual contact with an infected individual
  • HIV-positive individuals should be encouraged to talk about their status to their partners
  • HIV-positive mothers should avoid breastfeeding their baby to prevent transmission
  • HIV-positive individuals can decrease the transmission to uninfected partners if they are on antiretroviral therapy

HIV infection cannot be transmitted by activities such as hugging, through mosquito bites, participation in sports, touching items that were touched by an infected individual, etc.

What is the Prognosis of Acquired Immunodeficiency Syndrome? (Outcomes/Resolutions)

  • The prognosis of HIV-infected individual without any associated conditions is excellent when diagnosed early and antiretroviral therapy is started, very early in the course of the illness
  • The prognosis of individuals who have developed Acquired Immunodeficiency Syndrome (AIDS) is not favorable. But, their quality of life can be improved with proper and aggressive treatment of opportunistic infections and cancers

Additional and Relevant Useful Information for Acquired Immunodeficiency Syndrome:

  • The HIV is a virus belonging to the retrovirus group of viruses. AIDS causing HIV was discovered in the early 1980s
  • In the US, it is more commonly seen in African-Americans and Hispanic Americans than other races

Information about confidential home testing kit for HIV infection is available at http://www.oraquick.com/FAQs

What are some Useful Resources for Additional Information?

Website: http://www.aids.org 

World Health Organization (WHO)
Avenue Appia 20, 1211 Geneva 27, Switzerland
Phone: + 41 22 791 21 11
Fax: + 41 22 791 31 11
Website: http://www.who.int 

Centers for Disease Control and Prevention (CDC)
1600 Clifton Rd. Atlanta, GA 30333, USA
Phone: (404) 639-3534
Toll-Free: 800-CDC-INFO (800-232-4636)
TTY: (888) 232-6348
Email: cdcinfo@cdc.gov
Website: http://www.cdc.gov

Sexually Transmitted Diseases Diagnostics Initiative (SDI)
World Health Organization, TDR/PRD, 20 Avenue Appia, CH 1211 Geneva 27, Switzerland
Email: peelingr@who.int
Website: http://www.who.int/tdr/publications/documents/sdi.pdf

References and Information Sources used for the Article:

Aids.gov. What Is HIV/AIDS?. 2015. Available at: https://www.aids.gov/hiv-aids-basics/hiv-aids-101/what-is-hiv-aids/. (accessed 05/01/2015)

Cdc.gov. CDC - HIV/AIDS Home. 2015. Available at: http://www.cdc.gov/hiv/. (accessed 05/01/2015)

Nlm.nih.gov. HIV/AIDS: MedlinePlus. 2015. Available at: http://www.nlm.nih.gov/medlineplus/hivaids.html. (accessed 05/01/2015)

Helpful Peer-Reviewed Medical Articles:

Sui Y, Gordon S, Franchini G, Berzofsky J. Nonhuman Primate Models for HIV/AIDS Vaccine Development. Current Protocols in Immunology. 2001:12.14.1-12.14.30. doi:10.1002/0471142735.im1214s102.

Cobucci R, Lima P, de Souza P et al. Assessing the impact of HAART on the incidence of defining and non-defining AIDS cancers among patients with HIV/AIDS: A systematic review. Journal of Infection and Public Health. 2015;8(1):1-10. doi:10.1016/j.jiph.2014.08.003.

Shytaj I, Savarino A. A cure for AIDS: a matter of timing?. Retrovirology. 2013;10(1):145. doi:10.1186/1742-4690-10-145

Kranick, S. M., Goncalves, P. H., Stetler-Stevenson, M., Aleman, K., Polizzotto, M. N., Little, R. F., ... & Uldrick, T. S. (2015). Paradoxical central nervous system immune reconstitution syndrome in acquired immunodeficiency syndrome-related primary central nervous system lymphoma. haematologica, 100(1), e21.

Ferreira, N. R., Vicente, P., Costa, R., Gouveia, C., & Mateus, S. (2015). Gastric and Peritoneal Involvement of Human Herpes Virus 8 Related Kaposi Sarcoma in a Patient with Acquired Immunodeficiency Syndrome. European Journal of Case Reports in Internal Medicine, 2(5).

Jabs, D. A., Van Natta, M. L., Sezgin, E., Pak, J. W., Danis, R., & Studies of the Ocular Complications of AIDS Research Group. (2015). Prevalence of Intermediate-Stage Age-Related Macular Degeneration in Patients With Acquired Immunodeficiency Syndrome. American journal of ophthalmology, 159(6), 1115-1122.

Kamath, R., Robin, S., & Chandrasekaran, V. (2015). Common mental disorders: A challenge among people living with human immunodeficiency virus infection/acquired immunodeficiency syndrome in Udupi, India. Annals of medical and health sciences research, 4(2), 242-247.

ElKalmi, R. M., Al-Shami, A. K., Alkoudmani, R. M., Al-Syed, T., Al-Lela, O. Q. B., & Patel, I. (2015). Knowledge, Attitudes and Risk Perceptions towards Human Immunodeficiency Virus and Acquired Immunodeficiency Syndrome (HIV/AIDS) Among Health Sciences Students in a Public University, Malaysia. Nursing, 18, 7-6.

Byun, E., Gay, C., & Lee, K. (2015). Sleep quality and fatigue are associated with cognitive function in adults living with human immunodeficiency virus/acquired immunodeficiency syndrome. Sleep Medicine, 16, S234.

García-García, C., Castillo-Álvarez, F., Azcona-Gutiérrez, J. M., Herraiz, M. J., Ibarra, V., & Oteo, J. A. (2015). Spinal cord toxoplasmosis in human immunodeficiency virus infection/acquired immunodeficiency syndrome. Infectious Diseases, 47(5), 277-282.