Acquired Immunodeficiency Syndrome (HIV infection)

Acquired immunodeficiency syndrome (AIDS) is defined as the most severe form of a continuum of illnesses associated with human immunodeficiency virus (HIV) infection. HIV belongs to a group of viruses known as retroviruses. These viruses carry their genetic material in the form of ribonucleic acid (RNA) rather than deoxyribonucleic acid (DNA). Infection with HIV occurs when it enters the host CD4 (T) cell and cause this cell to replicate viral RNA and viral proteins, which in turn invade other CD4 cells.

The stage of HIV disease is based on clinical history, physical examination, laboratory evidence of immune dysfunction, signs and symptoms, and infections and malignancies. The stage of primary infection is acute and spans the time from infection to antibody development. Four categories of infected states have been denoted:

  • Primary Infection (A dramatic drop in CD4 T-cell counts from normal level between 500 and 1500 cells/mm3)
  • HIV asymptomatic (more than 500 CD4+ T lymphocytes/mm3)
  • HIV symptomatic (200-499 CD4+ T-lymphocytes/mm3)
  • AIDS (fewer than 200 CD4+ T lymphocytes/mm3)

Risk Factors

HIV is transmitted through bodily fluids by high-risk behaviors such as heterosexual intercourse with an HIV-infected partner, injection drug use, and male homosexual relations.Also at risk are people who received transfusions of blood or blood products contaminated with HIV, children born to mothers with HIV infection, breast-fed infants of HIV-infected mothers, and health care workers exposed to needle-stick injury associated with an infected patient.


Clinical Manifestations:

Symptoms are widespread and may affect any organ system. Manifestations range from mild abnormalities in immune response without overt signs and symptoms to profound immuno-suppression, life-threatening infection, malignancy, and the direct effect of HIV on body tissues.

Respiratory

  • Shortness of breath, dyspnea, cough, chest pain, and fever are associated with opportunistic infections, including Pneumocystis jiroveci pneumonia (PCP), the most common infection, and the immune reconstitution syndromes, such as Mycobacterium avium complex(MAC)/Mycobacterium avium intracellulare (MAI), which is a leading bacterial infection in AIDS patients. Legionella and CMV are other opportunistic organisms.
  • HIV-associated tuberculosis occurs early in the course of HIV infection, often preceding a diagnosis of AIDS.

Gastrointestinal

  • Loss of appetite
  • nausea and vomiting
  • Oral and esophageal candidiasis (white patches, painful swallowing, retrosternal pain, and possibly oral lesions)
  • Chronic diarrhea, possibly with devastating effects (eg, weight loss, fluid and electrolyte imbalances, perianal skin excoriation, weakness, and inability to perform activities of daily living)

Wasting Syndrome (Cachexia)

  • Multifactorial protein-energy malnutrition
  • Profound involuntary weight loss exceeding 10% of baseline body weight
  • Chronic diarrhea, chronic weakness, and documented intermittent or constant fever with no concurrent illness
  • Anorexia, diarrhea, gastrointestinal malabsorption, lack of nutrition, and for some patients a hyper metabolic state.

Neurologic

Neurologic complications involve central, peripheral, and autonomic functions

  • HIV encephalopathy (AIDS dementia complex [ADC]) occurs in two thirds of patients with AIDS. Symptoms include memory deficits, headache, lack of concentration, progressive confusion, psychomotor slowing, apathy and ataxia, and in later stages global cognitive impairments, delayed verbal responses, spastic paraparesis, hyperreflexia, psychosis, seizures, incontinence, mutism, and death.
  • HIV – related peripheral neuropathy is thought to be a demyelinating disorder; it is associated with pain and numbness in the extremities, weakness, diminished deep tendon reflexes, orthostatic hypotension, and impotence.
  • Cryptococcus neoformans, a fungal infection (fever, stiff neck, nausea and vomiting, seizures)
  • Central and peripheral neuropathies, including vascular myelopathy (spastic paraparesis, ataxia, and incontinence)
  • Progressive multifocal leukoencephalopathy (PML), a central nervous system demyelinating disorder, can occur.
  • Other neurologic disorders include Toxoplasma gondii, CMV, and Mycobacterium tuberculosis infection, with symptoms ranging from confusion to blindness, aphasia, paresis, and death.

Integumentary

  • Kaposi’s sarcoma (KS), herpes simplex and herpes zoster viruses, and various forms of dermatitis associated with painful vesicles.
  • Folliculitis, associated with dry flaking skin or atopic dermatitis (eczema or psoriasis)

Reproductive (female)

  • Persistent recurrent vaginal candidiasis may be the first sign of HIV infection
  • Ulcerative sexually transmitted diseases, such as chancroid, syphilis, and herpes, are more severe in women with HIV.
  • Veneral warts and cervical cancer/cervical intraepithelial neoplasia (CIN) may be noted.
  • Women with HIV have a higher incidince of pelvic inflammatory disease (PID) and menstrual abnormalities (amenorrhea or bleeding between periods).

Hematologic / Lymphatic

  • B-cell lymphomas, such as non-Hodgkin’s lymphoma, are the second most common AIDS-related cancer (the first is KS). These lymphomas usually  differ from those in the general population because they develop outside the lymph nodes (mostly in the brain, bone marrow, and GI tract), grow aggressively, affect multiple organs, and exhibit resistance to treatment, which may be complicated by severe hematologic toxicity.

Other: Chronic Illness and Cancers

Early diagnosis and treatment of opportunistic diseases and antiviral therapy have brought HIV infection into the chronic illness category. Additional clinical manifestations follow:

  • Fatigue, headache, profuse night sweats, unexplained weight loss, dry cough, shortness of breath, extreme weakness, diarrhea, decreased endurance, edema, blindness, swallowing difficulties, and possible neurologic involvement resulting in dementia, hemiplegia, spastic paraparesis, painful neuropathies, proximal and distal muscle weakness, and persistent lymphadenopathy.
  • Higher than usual incidence of cancer, including KS, B-cell lymphomas and carcinomas of cervix, skin, stomach, pancreas, rectum, and bladder.
  • Depressive symptoms from multiple causes, including preexisting mental illness, neuropsychiatric disturbances, and psychosocial factors
  • Irrational guilt, loss of self-esteem, helplessness,worthlessness, and suicidal ideation.

Assessment and Diagnostic Methods

Confirmation of HIV antibodies is done using enzyme immunoassay(EIA; formerly enzyme-linked immunosorbent assay [ELISA]), Western blot assay, and viral load tests such as target amplification methods.

Medical Management

Currently there is no cure for HIV or AIDS, although researchers continue to work on developing a vaccine. Treatment decisions for an individual patient are based on three factors: HIV RNA (viral load), CD4 T-cell counts, and the clinical condition of the patient (severity of symptoms and patient’s commitment to participate in lifelong therapy). The goals of treatment are maximal  and durable suppression of viral load, restoration and/or preservation of immunologic function, improvement of quality of life, and reduction of HIV-related morbidity and mortality. To determine and evaluate the treatment plan, viral load testing is recommended at diagnosis and then 3 to 4 months thereafter in the untreated person. CD4+ T-cell counts should be measured at diagnosis and generally every 3 to 6 months thereafter.

Combination therapy is defined as a regimen containing at least two antiretroviral agents; highly active antiretroviral therapy (HAART) includes at least one nucleoside reverse transcriptase inhibitor plus various other drug combination. As new medications are developed, the number of combinations continues to increase. High cost of medications, difficulties with adherence to the regimen, drug resistance, and drug toxicities present problems in drug therapy. Intermittent therapy is under investigation as an alternative regimen.

Pharmacologic Therapy

Antiretroviral Therapy (ART)

  • Nucleoside/nucleotide reverse transcriptase inhibitors (NRTI)
  • Non-nucleoside reverse transcriptase inhibitors (NNRTI)
  • Protease inhibitors (PI)
  • Fusion inhibitors (FI)

Drug Resistance Testing

Helps determine which antiretroviral agents to eliminate from the antiretroviral regimen (rather than which agents should be used)

Treatment Interruption and Reinstitution

Depending on the patient and CD4 cell count, ART may be temporarily discontinued when immune competence recurs and stabilizes (eg, sustained CD4 count between 500 and 800 cells/mm3). Then, when CD4 count fall between 350 and 400 cells/mm3, ART should restart.

Medications for HIV-related Infections

  • PCP: trimethoprim-sulfamethoxazole (TMP-SMZ) and antibacterial agents, such as dapsone, alternatively, pentamidine, an antiprotozoal agent
  • MAC: treatment for MAC infections involves use of either clarithromycin (Biaxin) or azithromycin (Zithromax). The combinaiton of azithromycun with rifabutin (Mycobutin) is more effective but costly, with more adverse effects and interactions.
  • Cryptococcal meningitis:  intravenous amphotericin B with or without antifungal agents, such as fluconazole (Diflucan) or flucytosine (Ancobon).
  • CMV retinitis: ganciclovir, foscarnet, or cidofovir
  • Encephalitis: pyrimethamine (Daraprim) and sulfadiazine or clindamycin (Cleocin)
  • Candidiasis: clotrimazole (Mycelex), ketoconazole, or fluconazole

Anticancer Agents

  • KS: alpha-interferon, surgical excision of lesions, liquid nitrogen to lesions, vinblastine injected into intraoral lesions, interferon;  chemotherapy with doxorubicin (Adriamycin), bleomycin, and vincristine (ABV); radiation
  • Lymphomas: limited successful treatment; chemotherapy and radiation therapy may be used

Immunomodulators

  • Alpha-interferon
  • Other substances under evaluation (interleukin-2, interleukin-12, and other cytokines and lymphokines)

Antidepressants

Psychotherapy is integrated with pharmacology (imipramine [Tofranil]), desipramine [Norpramin], fluoxetine [Prozac], methylphenidate [Ritalin]; electroconvulsive therapy if depression is severe).

Antidiarrheal Agents and Appetite Stimulants

Octreotide acetate (Sandostatin) is given to treat diarrhea and megestrol acetate (Megace) or dronabinol (Marinol) to stimulate appetite.

Reference:

Brunner & Suddath’s

Textbook of Medical-Surgical Nursing 11th edition

Lippincott Williams & Wilkins pp.1-7

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