HIV and Acquired Immunodeficiency syndrome _AIDS_ Learning .doc by shenreng9qgrg132


									HIV and Acquired Immunodeficiency syndrome

Learning Objectives
•   The student should know.
     – Classification of HIV infection
     – Correlation between CD4 count and HIV associated diseases.
     – Importance of Viral load monitoring
     – Antiretroviral therapy and its side effects.

•   HIV is a single stranded RNA retrovirus from Lentivirus family.
•   After mucosal exposure, HIV is transported to lymph nodes via. dendritic, CD4
    lymphocytes or Langerhan cells where infection becomes established.
•   Free or cell associated virus is then disseminated widely through the blood with
    seeding of ‘sanctuary’ sites like CNS and latent CD4 cell reservoirs.

Classification of HIV
•   Primary infection
     – It is symptomatic in 70 – 80 % of cases and usually occurs 2-6 weeks after
     – Major clinical manifestations are
            • Fever with rash
            • Pharyngitis with cervical lymphadenopathy
            • Myalgia / Arthralgia
            • Headache
            • Mucosal ulceration
         High plasma HIV-RNA levels and a fall in CD count up to 400 cells/mm 3

•   Asymptomatic infection
     – Category A disease in the Centers for Disease Control (CDC) classification.
     – Follows and lasts for a variable period, during which the infected individual
        remains well with no evidence of disease except for possible presence of
        persistent generalized lymphadenopathy.
     – There is persistent viremia with decline in CD4 cells around 50 to 150 cells
        per year.

•   Mildly symptomatic disease
     – CDC classification category B disease.
     – Develops in many indicating some impairment of cellular immunity but which
          is not AIDS defining.
     –   Clinical manifestations
            • Oral hairy leukoplakia
            • Recurrent oropharyngeal candidiasis.
            • Recurrent vaginal candidiasis
            • Severe pelvic inflammatory disease

           •   Bacillary angiomatosis
           •   Cervical dysplasia
           •   Idiopathic thrombocytopenic purpura
           •   Weight loss
           •   Chronic diarrhea
           •   Herpes zoster

•   Acquired Immunodeficiency Syndrome
     – CDC category C disease is defined by the development of specified
         opportunistic infections and tumors (AIDS defining lesions).
     – AIDS defining diseases
            • Esophgeal candidiasis
            • Cryptococcal meningitis
            • Chronic cryptosporidial diarrhea
            • Cerebral toxoplasmosis
            • CMV retinitis or colitis
            • Pneumocystis jirovecii pneumonia

           •   Disseminated Mycobacterium avium intracellulare
           •   Kaposi sarcoma
           •   Non-Hodgkin lymphoma
           •   Primary cerebral lymphoma
           •   HIV associated dementia
           •   HIV associated wasting

Correlation between CD4 count and HIV associated diseases
•   >500 cells/mm3
            • Acute primary infection
            • Recurrent vaginal candidiasis
            • Persistent generalized lymphadenopathy
    <500 cells/mm3
            • Pulmonary tuberculosis
            • Pneumococcal pneumonia
            • Herpes zoster
            • Oropharyngeal candidiasis
            • Oral hairy leukoplakia
            • ITP
    <200 cells/mm3
            • Pneumocystis jirovecii pneumonia
            • Cryptosporidium
            • Microsporidium
            • Esophageal candidiasis
            • HIV associated wasting
    <100 cells/mm3
            • Cerebral toxoplasmosis
            • Cryptococcal meningitis
            • Non-Hodgkin lymphoma
            • HIV associated dementia

•   <50 cells/mm3
             • CMV retinitis / colitis
             • Primary CNS lymphoma
             • Disseminated MAI

•   CD4 count is also used for determining.
           • When to start prophylactic medication.
           • When to initiate antiretroviral medication.

Viral Load Monitoring
•   Monitoring of viral load is the best method to monitor adequate response to
    therapy when patient is on anti retroviral medications.
•   High viral load indicates a greater risk of complications of the disease.
•   Viral sensitivity is done to determine which antiretroviral medications will be
    effective in an individual patient.

Antiretroviral Therapy
•   Currently available agents and their side effects.
     – Nucleoside Reverse Transcriptase Inhibitors
            • Zidovudine  Leukopenia, anemia, GI distress
            • Tenofovir is a nucleotide analog.

     –    Protease Inhibitors
            • Hyperlipidemia, hyperglycemia and elevated LFTs, abnormal fat loss
               from face and extremities and redistribution in neck and back. These
               side effects are seen with all.
            • Indinavir Nephrolithiasis, hyperbilirubenemia

     –   Non-nucleoside Reverse Transcriptase Inhibitors.
           • These drugs are non competitive inhibitors of reverse transcriptase.
           • Efavirenz  Somnolence, confusion and psychiatric problems

When to start therapy
•   Guidelines for starting are
     – CD4 < 350/microliter
     – Viral load (by PCR-RNA) >55000

What to start
•   Use two nucleosides combined with a protease inhibitor OR
•   Use two nucleosides combined with efavirenz OR
•   Use two nucleosides combined with two protease inhibitors.

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