HIV Flashcards
Human Immunodeficiency Virus
HIV infects and destroys cells of the immune system especially T-Helper cells that are CD4+
HIV: Virology
- Viral surface glycoprotein (gp120) binds to CD4 glycoprotein on host cell
- Virus penetrates host cell and releases RNA
- Reverse transcriptase converts RNA to DNA
- DNA incorporated into host genome
HIV diversity
Mutations during RNA transcription
HIV progression influenced by
- Age
- HLA type
- History of seroconversion
Chemokine receptor 5
- Co-factor for viral attachment
- Mutation of allele: resistance
- Single mutant: slow progression
HIV Epidemiology
- Sexual transmission
- IVDU
- Blood products
- Vertical transmission
- Organ transplant
- Needle-stick injury
Symptoms of HIV
- Weight loss
- Lymphadenopathy
- Thrush
- Skin/oral disease
Primary HIV/seroconversion symptoms
Similar to EDV
- Flu-like
- Fever
- Malaise/lethargy
- Pharyngitis
- Lymphadenopathy
- Toxic exanthema (rash)
- Diarrhoea, meningitis, neuropathy
HIV Skin manifestations
- Seborrhoeic dermatitis
- Molluscum contagiosum
- Shingles
- Recurrent varicella zoster
- Recurrent genital, peranal, oral herpes
HIV Mouth manifestations
- Oral hairy leukoplakia
- Oral candidiasis
HIV Tumours
- Kaposi’s sarcoma
- B-cell lymphoma
HIV Clinical Staging
- Asymptomatic, normal activity, persistent lymphadenopathy
- Symptomatic, normal activity, weight loss (<10%), skin changes, URTI
- Bedridden <50%/day
- Bedridden >50%/day
HIV Primary Infection Investigations
- Acute phase serum
- Convalescent phase serum
HIV Investigations
- CD4 lymphocyte
- HIV viral load
CD4 lymphocyte
Normal = 500-1500 cells/mm3
Symptomatic <200 cells/mm3
- Measures disease progression
HIV viral load
- Quantification: PCR assay (RNA copies/ml blood)
- Measures ART effect
HIV Resistance (to ART) testing
- Specific nucleic acid mutations
- Optimal therapy
HIV Management
Lifelong antiretroviral therapy
- <350 cells/mm3
- Different classes inhibit different stages
- Combination: 3 drugs, 2 groups
- Side effects: metabolic, lipodystrophy
Reverse transcription inhibitors
Inhibit viral RNA conversion to DNA
Nucleoside: marrow toxicity, neuropathy, lipodystrophy
Non-nucleoside: rashes, hypersensitivity, interactions, psychiatric
Integrase inhibitor
- Prevent integration into host genome
- Side effects: rashes, disturbed sleep
Protease inhibitor
- Prevent maturation of virus
- Side effects: interactions, diarrhoea, lipodystrophy, hyperlipidaemia
Fusion inhibitor
Block attachment (GP41)
CCR-5 receptor antagonists
Prevent viral attachment
Prevention of HIV
- Behaviour change and condoms
- Circumcision
- Treatment as prevention
- Pre-exposure prophylaxis
- Post-exposure prophylaxis for sexual exposure
Needlestick injury: transmittable infections
- HIV
- Hep B
- Hep C
Needlestick injury: recommended procedure
- Wash off splashes on skin, eyes, nose, mouth
- Encourage bleeding
- Assessment of risk
- HIV: combination ART
- Hep B: vaccine
- Hep C: no vaccine, immunoglobulin, ART for post-exposure - Report incidence
