HIV & AIDS

HIV and AIDS: Overview, Diagnosis, and Management

HIV (Human Immunodeficiency Virus)

Definition
HIV is a retrovirus that targets and destroys CD4 cells, which are essential components of the immune system. The progressive loss of these cells leads to a severe weakening of the immune system, making the body highly susceptible to infections and certain cancers. If left untreated, HIV can lead to AIDS (Acquired Immunodeficiency Syndrome), the most advanced and severe stage of HIV infection.

Causative Agent
HIV is caused by two main types of viruses:

• HIV-1: The most common and globally widespread type, responsible for the majority of HIV infections worldwide.
• HIV-2: Less common and primarily found in West Africa, though it can also be found in other regions. It generally leads to a slower progression of the disease compared to HIV-1.

Transmission
HIV is transmitted through contact with specific body fluids from a person who is infected with the virus, including:

• Blood: Via sharing needles or syringes, or through transfusions of contaminated blood products.
• Sexual fluids: Through unprotected vaginal, anal, or oral sex.
• Breast milk: From an infected mother to her infant during breastfeeding.
• Mother-to-child transmission: During childbirth or pregnancy if the mother is not receiving proper medical treatment.

Etiopathogenesis
After entering the body, HIV binds to and penetrates CD4+ T lymphocytes (a type of white blood cell) using the viral spike proteins. Once inside the cell, HIV uses the host cell's machinery to replicate, eventually causing the cell to burst and release new viral particles into the bloodstream. This continuous cycle of viral replication and cell destruction leads to a gradual decline in the number of CD4+ T cells, which impairs the immune system's ability to fight off infections and diseases.

Manifestations

• Acute HIV Infection (Primary HIV): Occurs 2-4 weeks post-exposure and is marked by flu-like symptoms including fever, rash, sore throat, and swollen lymph nodes. This initial stage is highly infectious and the virus is rapidly multiplying.
• Chronic HIV Infection (Clinical Latency): This stage may last for years, during which the virus continues to replicate but often with mild or no symptoms. The immune system is progressively weakened.
• AIDS: The final stage of HIV infection, characterized by a significantly compromised immune system. Individuals with AIDS are highly susceptible to opportunistic infections and cancers, including:
• Pneumocystis jirovecii pneumonia (PCP)
• Candidiasis (thrush)
• Kaposi's sarcoma
• Cytomegalovirus (CMV) infection

AIDS (Acquired Immunodeficiency Syndrome)

Definition
AIDS is the most advanced stage of HIV infection, defined by a severely weakened immune system and the occurrence of specific opportunistic infections or certain cancers. The diagnosis of AIDS is made based on:

• A CD4 count below 200 cells/mm³ (normal range is about 500-1600 cells/mm³).
• The presence of specific opportunistic infections or cancers related to immune system failure.

Diagnostic Criteria for AIDS

• CD4 Cell Count: A count of fewer than 200 CD4+ T cells per cubic millimeter of blood.
• Opportunistic Infections: The occurrence of infections such as PCP, candidiasis, or tuberculosis that are indicative of severely impaired immune function.
• AIDS-Defining Cancers: Such as Kaposi’s sarcoma or non-Hodgkin lymphoma.

Treatment
While there is no cure for HIV or AIDS, effective treatment can manage the disease and improve quality of life. The primary treatment is:

• Antiretroviral Therapy (ART): ART involves a combination of drugs that inhibit various stages of the HIV life cycle. Common classes of ART include:
• Nucleoside Reverse Transcriptase Inhibitors (NRTIs)
• Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTIs)
• Protease Inhibitors (PIs)
• Integrase Strand Transfer Inhibitors (INSTIs)
• Fusion Inhibitors

ART reduces the viral load in the body, helping to restore and maintain CD4 counts, thereby slowing disease progression and reducing the risk of opportunistic infections.

Non-Pharmacological Measures:

• Adherence to ART: Consistent and correct use of ART is crucial for controlling HIV and preventing progression to AIDS.
• Regular Monitoring: Regular check-ups to monitor viral load, CD4 count, and the potential emergence of opportunistic infections or ART side effects.
• Healthy Lifestyle: Maintaining a balanced diet, regular exercise, and avoiding substances that can further compromise the immune system.

Prevention Tips:

• Safe Sex Practices: Use condoms and engage in safer sex practices to reduce the risk of HIV transmission.
• Pre-Exposure Prophylaxis (PrEP): For individuals at high risk of HIV, PrEP can significantly reduce the risk of infection when taken consistently.
• Needle Exchange Programs: Provide clean needles to people who inject drugs to prevent the spread of HIV.
• HIV Testing and Early Treatment: Regular testing for HIV and early initiation of ART can prevent the progression to AIDS and reduce transmission to others.

Opportunistic Infections

Definition
Opportunistic infections are infections caused by pathogens that do not typically cause disease in individuals with a healthy immune system but can be severe or life-threatening in those with a compromised immune system, such as individuals with AIDS.

Common Opportunistic Infections:

• Pneumocystis jirovecii Pneumonia (PCP): A fungal infection that affects the lungs and can be life-threatening if not treated promptly.
• Candidiasis: Fungal infections affecting the mouth (oral thrush), throat, or genital area.
• Tuberculosis (TB): A bacterial infection that can cause severe disease in people with HIV.
• Cryptococcus: A fungal infection that can lead to meningitis.
• Toxoplasmosis: A parasitic infection that primarily affects the brain and can cause severe neurological symptoms.
• Cytomegalovirus (CMV): A viral infection that can lead to retinitis, potentially resulting in vision loss.

Diagnosis:

• Clinical Evaluation: Identifying symptoms and conducting physical examinations.
• Laboratory Tests: Blood tests, cultures, imaging studies, and other diagnostic procedures to identify specific pathogens and assess the extent of the infection.

Treatment:

• Antibiotics and Antifungals: Depending on the specific infection, targeted treatment is used.
• Antiviral Medications: For infections caused by viruses, such as CMV.
• Antiparasitic Drugs: For parasitic infections like toxoplasmosis.

Non-Pharmacological Measures:

• Regular Screening and Prophylaxis: For individuals with HIV, especially those with low CD4 counts, to prevent opportunistic infections.
• Vaccinations: To protect against preventable diseases such as pneumococcal pneumonia and influenza.

Prevention Tips:

• Adherence to ART: Essential for maintaining immune system function and preventing opportunistic infections.
• Preventive Medications: Prophylactic drugs may be prescribed to prevent specific infections in individuals with advanced HIV.
• Healthy Living: Maintaining good hygiene, a balanced diet, and avoiding exposure to infections can help manage health and reduce risks.

Conclusion

HIV and AIDS represent a significant challenge to global health, but with effective antiretroviral treatment and preventive measures, the progression of the disease can be managed and the quality of life improved. Early diagnosis, adherence to ART, and preventive strategies are crucial in managing HIV and preventing the development of AIDS and opportunistic infections.

FAQs on HIV/AIDS

1. What is HIV and how does it differ from AIDS?
HIV (Human Immunodeficiency Virus) is a virus that attacks the immune system, while AIDS (Acquired Immunodeficiency Syndrome) is the most severe stage of HIV infection, where the immune system is critically damaged.

2. How is HIV transmitted?
HIV is transmitted through contact with infected body fluids, such as blood, semen, vaginal fluids, or breast milk, most commonly via unprotected sex, sharing needles, or from mother to baby during childbirth or breastfeeding.

3. What are the early symptoms of HIV?
Early symptoms of HIV, often called acute HIV infection, include flu-like symptoms such as fever, sore throat, swollen glands, and fatigue, but many may have no symptoms initially.

4. How is HIV diagnosed?
HIV is diagnosed through blood tests that detect the virus or the antibodies the body produces in response to it, including rapid tests, ELISA, or polymerase chain reaction (PCR) tests.

5. How is HIV treated?
HIV is treated with antiretroviral therapy (ART), a combination of medications that helps reduce the virus in the body and slows the progression to AIDS, improving the quality of life.

6. Can HIV be prevented?
HIV can be prevented by using condoms, taking pre-exposure prophylaxis (PrEP) for those at high risk, avoiding sharing needles, and undergoing regular HIV testing, especially if sexually active with multiple partners.

7. What happens if HIV progresses to AIDS?
If HIV progresses to AIDS, the immune system becomes severely weakened, making the body vulnerable to opportunistic infections and certain cancers, which can be life-threatening without treatment.