HIV/AIDS and Immunity: Study Notes for Personal Health Students

Immunity and HIV/AIDS

Overview of HIV/AIDS

HIV/AIDS is a major infectious disease that impacts the immune system, leading to increased susceptibility to opportunistic infections and certain cancers. Understanding its pathophysiology, risk factors, prevention, and management is essential for personal health and public health awareness.

• Acquired Immunodeficiency Syndrome (AIDS) was first identified in 1981, with HIV isolated in 1984.

• Combination antiretroviral therapy (ART) has slowed disease progression and changed monitoring practices.

Pathophysiology of HIV/AIDS

HIV-1 is the primary virus responsible for AIDS, destroying the body's ability to fight infection by targeting CD4 cells.

• Transmission: Sexual contact, sharing needles, transfusions (before 1985), and vertical transmission from mother to child.

• HIV infects cells with CD4 antigen, uses reverse transcriptase to convert viral RNA to DNA, which integrates into host DNA.

• Helper T cells (CD4 cells) are the main target, leading to immunodeficiency.

Etiology and Epidemiology

HIV/AIDS affects diverse populations, with certain groups at higher risk due to behavioral and demographic factors.

• Men account for >80% of cases; rapid increases among young, gay or bisexual men.

• Women, especially Black and Hispanic injection drug users, are increasingly affected.

• Improved perinatal interventions have reduced infection rates in children under 13.

Risk Factors

Behavioral and occupational factors contribute to HIV transmission risk.

• Unprotected sexual intercourse, sharing drug equipment, hemophilia, blood transfusions.

• Healthcare workers face low but present risk (needlestick injuries).

Prevention Strategies

Prevention focuses on education, safe practices, and medical prophylaxis.

• No vaccine exists; education and safe sex are primary tools.

• Standard precautions treat all patients and fluids as potentially infectious.

• Pre-exposure prophylaxis (PrEP) and post-exposure prophylaxis (PEP) are effective for at-risk individuals.

Clinical Manifestations

Symptoms range from none to severe immunodeficiency, with progression from acute illness to AIDS over years.

• Acute mononucleosis-like illness may occur soon after infection.

• Long asymptomatic period (mean 8–10 years), followed by symptomatic AIDS (10–15 years after infection).

• Classification systems (CDC, WHO) use CD4 counts and clinical conditions to stage disease.

Neurological Manifestations

HIV/AIDS can affect both central and peripheral nervous systems.

• AIDS dementia complex: Memory loss, confusion, motor disturbances.

• CNS: Toxoplasmosis, non-Hodgkin lymphoma, cryptococcal meningitis, cytomegalovirus.

• PNS: Numbness, tingling, pain, progressive weakness.

Opportunistic Infections

Immunodeficiency leads to increased risk of opportunistic infections.

• Pneumocystis jiroveci pneumonia (PJP): Most common, often fatal.

• Tuberculosis: Rapid progression, disseminated disease.

• Candidiasis: Oral thrush, esophagitis, vaginal infections.

• Other: Mycobacterium avium complex, herpes, CMV, parasitic and bacterial infections.

Secondary Cancers

HIV/AIDS increases risk for certain cancers.

• Kaposi sarcoma (KS): Most common, indicator of late-stage HIV.

• Non-Hodgkin lymphoma: More frequent, aggressive.

• Cervical cancer: Common in women with HIV, requires frequent screening and aggressive treatment.

Diagnostic Tests

Diagnosis and monitoring involve multiple laboratory tests.

• Rapid screening tests, ELISA, combination antigen/antibody tests.

• Confirmatory tests: HIV-1/HIV-2 immunoassay, Western blot (no longer preferred), nucleic acid tests (NAT).

• Monitoring: HIV viral load, CD4 cell count, resistance testing.

• Other: CBC, tuberculin skin test, MRI, Pap smears.

Pharmacologic Therapy

ART is the cornerstone of HIV/AIDS management, with multiple drug classes targeting different stages of viral replication.

• Six classes: NRTIs, NNRTIs, PIs, EIs, INSTIs, cytochrome P-450 inhibitors.

• Combination therapy reduces viral load, but adherence is challenging due to complexity and side effects.

• Prophylaxis for opportunistic infections and malignancies is essential.

Nonpharmacologic and Complementary Therapies

Collaboration among healthcare providers and use of complementary therapies can improve quality of life.

• Limit exposure to infectious diseases, especially in children.

• Some complementary therapies may interact with ART; physician consultation is necessary.

Lifespan Considerations

HIV/AIDS affects individuals across the lifespan, with unique considerations for pregnant women, newborns, children, adolescents, and older adults.

• Pregnant women: ART reduces risk of vertical transmission; cesarean delivery recommended.

• Newborns: Prophylactic AZT, PJP prevention, early identification.

• Children: Early symptoms, failure to thrive, opportunistic infections, developmental delays.

• Adolescents: Risk behaviors, adherence challenges, misinformation.

• Older adults: Delayed diagnosis, drug interactions, overlooked symptoms.

Nursing Process in HIV/AIDS Care

Nursing care focuses on promoting knowledge, self-care, comfort, and quality of life, adapting to changing needs over the course of the disease.

• Assessment: Comprehensive interview, psychosocial and physical examination.

• Diagnosis: Address coping, skin integrity, nutrition, infection risk, anxiety, sexual activity, knowledge deficits.

• Planning: Prevention education, testing, follow-up, psychosocial support.

• Implementation: Prevent infections, promote medication adherence, effective coping, skin integrity, nutrition, sexuality, knowledge.

• Evaluation: Monitor outcomes, prevent spread, control progression, opportunistic infection prevention.

Key Terms and Concepts

• CD4 cell count: Indicator of immune function; used to stage HIV/AIDS.

• Viral load: Amount of HIV RNA in blood; used to monitor treatment effectiveness.

• Opportunistic infection: Infection occurring due to weakened immune system.

• Antiretroviral therapy (ART): Combination of drugs to suppress HIV replication.

Example Table: HIV/AIDS Drug Classes

Drug Class	Mechanism	Example
NRTIs	Inhibit reverse transcriptase	Zidovudine (AZT)
NNRTIs	Non-competitive inhibition of reverse transcriptase	Nevirapine, Efavirenz
PIs	Block viral protease	Ritonavir
EIs	Prevent viral entry	Enfuvirtide
INSTIs	Block integration of viral DNA	Raltegravir
Cytochrome P-450 inhibitors	Enhance ART effectiveness	Cobicistat

Relevant Equations

CD4 cell count and viral load are key laboratory values:

• CD4 cell count: $\text{CD4 cells/\mu L}$

• Viral load: $\text{HIV RNA copies/mL}$

Summary

HIV/AIDS is a complex disease requiring multidisciplinary care, prevention strategies, and ongoing education. Understanding its impact on immunity, clinical manifestations, and management is crucial for personal health students.