HIV INFECTIONS AND AIDS / MedUrgent
HIV INFECTIONS AND AIDS
Human immunodeficiency viruses HIV 1 and HIV 2 cause AIDS.
In the year 2006, more than 25 million African adults and children were
estimated to be living with HIV. The routes of transmission of the infection
include unprotected sexual intercourse, mother to child transmission,
transfusion of infected blood products, unsterile needles and surgical
instruments.
The virus attacks
mainly the CD4-T lymphocytes where it replicates and gradually destroys these
cells and as their number decreases immunosuppression state prevails (when CD4
is<200 cells/mm3). This predisposes the patient to some opportunistic
infections and virus related tumors e.g. lymphoma and Kaposi sarcoma.
CLINICAL PRESENTATION
1- Acute retroviral
illness: Occurs 2-5 weeks after infection and lasts for 3-21 days. It is
characterized by malaise, fever, anorexia, sore throat, myalgia, arthralgia,
headache, diarrhea, maculopapular rash and generalized lymphadenopathy, a
picture similar to Infectious Mononucleosis.
2- Asymptomatic HIV:
After seroconversion, the virus and the body immune system are in balance for a
variable period while the virus continues to replicate. The only positive
finding during this stage is the generalized lymphadenopathy.
3- Symptomatic HIV infection: When the immune system becomes compromised, opportunistic infections appear. Weight loss, weakness and loss of functional capacity follow.
WHO clinical staging system (adults)
STAGE 1
Asymptomatic or appearance of generalized lymphadenopathy
STAGE 2
Includes: weight loss (<10%), minor mucocutaneous lesions, herpes zoster or recurrent URTI.
STAGE 3
Includes: weight loss >10%, unexplained diarrhea for>1 month, unexplained fever for >1 month, oral and vaginal candidiasis, oral hairy leukoplakia and unexplained anemia, leucopenia and thrombocytopenia.
Infections
including: pulmonary TB, severe bacterial infections and acute necrotizing oral
disease.
STAGE 4
HIV wasting syndrome
Infections including:
peumocystis jiroveci pneumonia, CNS toxoplasmosis, chronic cryptosporidiosis,
chronic isosporiasis, cryptococcosis, CMV infection and Chronic HSV infection
>1 month.
Other infections are
Candidiasis of the oesophagus, trachea, bronchi or lungs, disseminated
non-tuberculous mycobacterial infection, recurrent septicemia, recurrent severe
bacterial pneumonia, extrapulmonary tuberculosis and atypical disseminated
leishmaniasis.
CNS involvement
includes: progressive multifocal leukoencephalopathy and HIV encephalopathy
Cancer disease including: lymphoma, Kaposi sarcoma and Invasive cervical cancer.
System diseases: including disseminated mycosis, symptomatic HIV nephropathy or cardiomyopathy.
CLINICAL STAGING SYSTEM FOR CHILDREN
The same staging
applies to children except for the degree of loss of weight which is included
in: STAGE 3 Unexplained moderate malnutrition, which is not responding to
adequate nutritional treatment.
STAGE 4
Unexplained severe wasting/ malnutrition not responding to therapy
INVESTIGATIONS
• HIV viral RNA PCR
• Integrated HIV viral
DNA
• P24 antigen ELISA
• Viral antibodies
• 1st, 2nd, 3rd
generation ELISA
• Rapid tests
• Western Blot
• 4th Generation
combo-ELISA
• CD4 (to start prophylaxis or ART)
MANAGEMENT
Criteria to start Antiretroviral Therapy (ART) includes CD count <200/ mm3,
and WHO clinical stage 3 and stage4.
Prophylactic treatment
includes vaccination and prevention of opportunistic infections:
• Pneumocystis:
Co-trimoxazole
• ТВ: INH
• Cryptococcus:
Fluconazole
• Toxoplasmosis: Co-trimoxazole
Prevention of mother to child transmission includes elective
Cesarean section; prohibit breast feeding and the use of single dose nevirapine
to mother in labor and single dose to the infant within 72 hours of delivery.
For post-exposure prophylaxis, three drugs of ART should be used for 4 weeks..
Antiretroviral Therapy (ART) Three classes of ART are in use now:
1. Neucleoside reverse transcriptase inhibitors (NRTIs) e.g.abacavir (ABC), .Zidovudin(AZT), Didanosine (DDI), Lamivudine (3TC).
2. Non-nucleoside
reverse transcriptase inhibitors e.g. Efavirenz (EFZ), Nevirapine (NVP),
Delaviridine (DLV).
3. Protease Inhibitors
(PI) e.g. Amprenavir (APV), Atazanvir (ATZ), Ritonavir (RTV), and Lopinavir
(LPV). Combined preparations in use include Combivir, Truvada, and Kivexa. For
first-line therapy, three drugs are selected and used e.g. AZT. 3TC and NVP. For
second-line therapy, a protease inhibitor and two NRTIs regimen is preferred.
The decision regarding use of drugs is governed by availability, national
program and the drugs used as first-line therapy.
Comments
Post a Comment