HIV/AIDS

Epidemiology

• 26800 people with HIV in Australia
• Highest concentration amongst gay men and IVDU
• <0.1% female sex workers

Risk factors

• High viral load for all forms of transmission
• Risky sexual behaviour

Aetiology

• HIV virus acquired through sexual contact, exposure to infected blood or perinatal transmission

Pathophysiology

• Retrovirus
• Binds to CD4+ cells (T-helper lymphocytes, monocytes and macrophages)
• Capsid is released into the cell and reverse transcriptase returns viral RNA to DNA incorporated into the cell genome
• Viral replication by the normal cell mechanisms releases more capsids and increased viral load
• Cytotoxic T cells recognise infected T-cells and cause lysis or induce apoptosis causing reduced CD4+ cells and overall immunity

Classification (CDC)

• Stage 1 - CD4 count >500microL
• Stage 2 - CD4 could 200-499
• Stage 3 - CD4 count <200
• AIDS is the presence of confirmed HIV infection with stage 3 disease and the presence of opportunistic infections

Presentation

• Asymptomatic 10-60%
• Acute retroviral syndrome (seroconversion)
  • Fever, lymphadenopathy, pharyngitis, rash, headache
  • Self-resolving
• Clinical latency period (3-20 years)
• Development of AIDS

Diagnosis

• HIV immunoassay
• HIV PCR (viral load assessment if positive immunoassay)
• Pre and post-test counselling

Management

• Antiretroviral combination therapy for all HIV+ patients regardless of immune status
  • Improves symptoms
  • Improved immune function
  • Reduced transmission risk
• Drug resistance testing can improve regimen selected

Opportunistic infections

• Pneumocystis pneumonia
• Cachexia
• Oesophageal candidiasis
• Encephalitis/meningitis/retinitis
• Kaposi's sarcoma
• Burkitt's lymphoma

Surgical issues

• Upcoming elective surgery
  • Current opportunistic infections
  • Viral load
  • Nutritional status
  • Continue antiretrovirals
• Post-op risks
  • Poor wound healing
  • Sepsis
  • Poor nutrition
• Risk of HIV transmission to the health worker