Human Immunodeficiency Virus (HIV)

Definition | Aetiology | Pathophysiology | Risk Factors | Signs and Symptoms | Investigations | Management | References

Definition

Human Immunodeficiency Virus (HIV) is a virus that attacks the body's immune system, specifically the CD4 cells (T cells), which help the immune system fight off infections. If untreated, HIV reduces the number of CD4 cells in the body, making the person more likely to get infections or infection-related cancers. Over time, HIV can destroy so many of these cells that the body can't fight off infections and diseases. This infection can lead to Acquired Immunodeficiency Syndrome (AIDS).

Aetiology

HIV is caused by the human immunodeficiency virus, which is transmitted through:

• Unprotected sexual contact with an infected person
• Sharing needles or syringes with someone who has HIV
• Transfusion of contaminated blood products
• From mother to child during childbirth or breastfeeding

Pathophysiology

The pathophysiology of HIV involves:

• The virus enters the body and targets CD4 cells (T cells), which play a crucial role in the immune response.
• HIV uses the CD4 cells to replicate and produce more virus particles.
• As the virus replicates, it destroys the CD4 cells, weakening the immune system.
• Over time, the loss of CD4 cells leads to immunodeficiency, making the body more susceptible to opportunistic infections and certain cancers.

Risk Factors

• Unprotected sex (vaginal, anal, or oral) with an infected person
• Multiple sexual partners
• Sharing needles or syringes
• Having another sexually transmitted infection (STI)
• Receiving unsafe injections, blood transfusions, or tissue transplants
• Mother-to-child transmission during childbirth or breastfeeding

Signs and Symptoms

The signs and symptoms of HIV infection can vary, including:

• Acute HIV infection: Flu-like symptoms such as fever, headache, rash, and sore throat.
• Clinical latency stage: The virus is still active but reproduces at very low levels. People may not have any symptoms or only mild ones.
• Progression to AIDS: Rapid weight loss, recurring fever or profuse night sweats, extreme and unexplained tiredness, prolonged swelling of the lymph glands, diarrhoea that lasts for more than a week, sores of the mouth, anus, or genitals, pneumonia, red, brown, pink, or purplish blotches on or under the skin or inside the mouth, nose, or eyelids, and memory loss, depression, and other neurologic disorders.

Investigations

Specific investigations to diagnose HIV include:

• Antibody/Antigen tests: Detect antibodies and antigens to HIV in the blood.
• HIV RNA tests (PCR): Detect the virus directly by measuring the amount of HIV in the blood (viral load).
• CD4 count: Measures the number of CD4 cells in the blood to assess the immune system's health.
• Viral load test: Measures the amount of HIV RNA in the blood.

Management

Primary Care Management

• Antiretroviral therapy (ART): The main treatment for HIV, involving a combination of HIV medicines to reduce the viral load and maintain immune function.
• Regular monitoring: Regular blood tests to monitor CD4 count and viral load.
• Prevention and education: Providing information on safe sex practices, needle exchange programmes, and prevention of mother-to-child transmission.
• Vaccinations: Ensuring patients receive vaccines to prevent opportunistic infections, such as pneumococcal and influenza vaccines.

Specialist Management

• Management of opportunistic infections: Treatment of infections like tuberculosis, pneumonia, and fungal infections that occur due to weakened immunity.
• Specialist referrals: Referral to infectious disease specialists, hepatologists (for co-infection with hepatitis), or oncologists (for HIV-related cancers).
• Mental health support: Providing counselling and support for mental health issues related to living with HIV.

References

1. NHS (2024) HIV and AIDS. Available at: https://www.nhs.uk/conditions/hiv-and-aids/ (Accessed: 24 June 2024).
2. Centers for Disease Control and Prevention (2024) HIV Basics. Available at: https://www.cdc.gov/hiv/basics/index.html (Accessed: 24 June 2024).
3. World Health Organization (2024) HIV/AIDS. Available at: https://www.who.int/news-room/fact-sheets/detail/hiv-aids (Accessed: 24 June 2024).
4. British Medical Journal (2024) HIV: clinical features, diagnosis, and management. Available at: https://www.bmj.com/content/350/bmj.h1718 (Accessed: 24 June 2024).

Back to Top