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.

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