Sunday, April 1, 2012

HIV and Aids



·         Acquired Immune Deficiency Syndrome (AIDS) is a chronic, life threatening condition caused by Human Immunodeficiency Virus (HIV).
·         Characterized by generalized dysfunction of the immune system making individuals susceptible to opportunistic infections & tumors.
·         Pneumocystis carinii pneumonia: most common opportunistic infection. 
·         Incubation period estimates range from 6 months to 9 years.

Pathophysiology:

·         HIV binds with CD4+T cells and replicates by generating a DNA copy by reverse transcriptase.
·         HIV causes AIDS by destroying CD4+T cells which leads to a weak immune system allowing opportunistic infections.

Epidemiology:

·         5th leading cause of death among ages 25-44 years in the US
·         In the US, it is common among African American, Hispanics and Caucasians. (CDC)
·         Most HIV infections occur in men due to homosexual contact but the incident is already increasing among women who engage in unprotected sexual activities.

Mode of Transmission:

·         Horizontal transmission: Sexual contact (oral, vaginal, anal sex); parenteral exposure to blood or body fluid containing visible blood.
·         Vertical (perinatal) transmission: HIV infected pregnant woman passes the infection to fetus during pregnancy, delivery or breastfeeding.

      Clinicl Stages of HIV/AIDS
Signs & Symptoms
         Stage I.
        Asymptomatic/Primary    HIV infection
       Flu-like symptoms
ü  Fever
ü  Myalgia
ü  Persistent generalized lymphadenopathy
ü  Headache
       Stage II.

ü  Person may experience outbreak of herpes zoster
ü  Recurrent respiratory tract infection
ü  Chronic diarrhea for longer than 1 month
       Stage III.

ü  Integumentary problems
ü  Gynecological problems
       Stage IV.

ü  HIV wasting syndrome
ü  Development of opportunistic infections



Diagnostic Exams:

§  AIDS is present if there is 2 positive results of ELISA confirmed with positive result on Western blot assay.
§  Enzyme –linked immunosorbent assay (ELISA)/ Enzyme immunoassay (EIA)
o Identifies antibodies directed specifically to HIV.
o Useful in children older than 18 months.
§  Western blot assay
o Confirm HIV infection
                        Useful in children older than 18 months

§  Viral load tests: Reverse Transcriptase- Polymerase Chain Reaction (RT-PCR) & Nucleic Acid Sequence-Based Amplification (NASBA)
o < 10,000 copies/mL = low risk AIDS
o > 100,000 copies/mL = High risk for AIDS. (+) viral activity
o Measures HIV RNA in the plasma.
o Measures response to treatment.
o RT-PCR detects HIV in high risk seronegative people before antibodies are measurable, screen neonates, & confirm + EIA result.
§  CD4/CD8 Ratio
o Helper/ suppressor ratio = degree of immune suppression.
o CD4 count of <200/mm3: indicates AIDS
o Normal values depend on age (ratio 0.9 to 3.7 in adults).
§  p24 antigen
o 2 or more positive results are diagnostic for HIV infection
o Used o detect HIV antigen in children younger than 18 months.
§  Nonspecific markers of disease progression: blood counts, albumin levels & ESR
§  Skin biopsy, serum chemistries and imaging studies are indicated depending on organ/system involvement & disease progression.

Treatment:

·         There is no cure; prevention is the only key to control.
·         Highly Active Antiretroviral Therapy (HAART): reduces the number of HIV particles in the blood stream as measured by viral load test.
-    Combination of three (3) drugs belonging to 2 types of antiretroviral agents.
-    Side effects include: lipodystrophy, dyslipidaemia, diarrhea, insulin resistance, an increase in cardiovascular risks and birth defects.
-    n.b: Patient problem with HAART: non-adherence with complex administration leads to drug resistance development.
·         Antiretroviral drugs: inhibit the growth and replication of HIV at various stages of its life cycle.

Types/Classes:

1.        Nucleotide reverse transcriptase inhibitors/NtRTIs & Nucleoside analogue reverse transcriptase inhibitors/NRTIs (“nukes”): inhibit the replication of an HIV enzyme called reverse transcriptase.
E.g.  idovudine (Retrovir®) [formerly called AZT azidothymidine], lamivudine (Epivir®) didanosine (Videx®), zalcitabine (Hivid®), stavudine (Zerit®) and abacavir (Ziagen®)

2.        Protease inhibitors (PIs): interfere with an enzyme known as HIV protease. This causes HIV particles in your body to become structurally disorganized and noninfectious.
e.g atazanavir/ATV (Reyataz®), darunavir/DRV (Prezista®), Fosamprenavir/FPV (Lexiva®), lopinavir + ritonavir (Kaletra®), saquinavir/SQV (Invirase®), tipranavir/TPV (Aptivus®)

3.        Non-nucleoside reverse transcriptase inhibitors (NNRTIs): bind directly to the enzyme reverse transcriptase. E.g efavirenz (Sustiva®, Stocrin®);  nevirapine (Viramune®); delavirdine (Rescriptor®); etravirine (Intelence®)
1.        Fusion inhibitors (entry inhibitors): suppress resistant strains of HIV. e.g maraviroc (Selzentry®), enfuvirtide (Fuzeon®)

2.        Integrase inhibitors: aims to treat those who become resistant to other treatments. e.g raltegravir (Isentress®)

·         CCR5 antagonists: new class of drugs used to treat a particular type of HIV infection called CCR5-tropic HIV-1
E.g. maraviroc (Selzentry®)

Side effects: liver problems, postural hypotension, inflammation response.

·         Oral Progesterone (Megace®, Winstrol®): stimulate appetite thereby assisting with the treatment of weight loss (HIV Wasting Syndrome)& loss of taste perception

·         For disease progression: Antibiotic therapy, chemotherapy, analgesic, antiemetic, antifungal & appetite stimulants.

·         Supportive care for chronic illness associated with HIV infection: O2 therapy, IV fluid, electrolyte replacement and mechanical ventilation (end stage AIDS).

Prevention:

If HIV negative:
·         Know the HIV status of your partner.
·         Provide client education regarding safe & protected sex:
o Latex condom: vaginal or anal intercourse
o Dental dam: used for oral contact with the vagina or rectum
o Avoid sexual contact with multiple partners.
·         Consider male circumcision
·         Use sterile needle & avoid needle sharing.
·         Be cautious about blood products.
·         Get routine HIV testing

If HIV positive:
·         Follow safe sex practices.
·         Tell your sexual partner that you have HIV.
·         Don’t share needles or syringes.
·         Don’t donate blood or organ.
·         Don’t share razors, toothbrush, sex toys or blood contaminated articles.
·         Drug users interested in drug treatment programs must be referred.
·         Get immediate medical care if pregnant.
·         Don’t breastfeed the infant.
·         TB testing 

For health workers:
·         Standard precautions: apply to blood, body secretions & excretions.



Nursing Interventions:

·         Use of universal precautions for all clients regardless of diagnosis.
·         Provide ongoing coordination of health care team to afford client the best possible assistance.
·         Provide emotional support, counseling and referral to support group.
·         Protect the client from secondary infections; assess for early signs and report for treatment.
·         Maintain client advocacy and confidentiality.
·         Refer to dietician to analyze nutritional requirements & make recommendations to maintain ideal body weight.
·         Provide high-caloric, high protein diet to prevent weight loss.
·         Encourage intake of foods rich in vitamins A, C & E.
·         Educate on:
o    Importance of compliance to long-term treatment regimen.
o    Stress the need for follow-up check-up & diagnostic tests to monitor response to treatment & disease progression.
Discuss life issues with the client & support system members as disease progresses & prognosis worsens





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