Human immunodeficiency virus

General

• Single stranded RNA virus
• Infects CD4 T lymphocytes primarily
• Transmission - sexual, blood, vertical
• CD4 T lymphocyte count = <200 or at any level with an AIDS defining condition or opportunistic infection (e,g, pneumocystis jirovicii) = AIDS
• AIDS defining cancers
  • Kaposi sarcoma
  • NHL
  • Cervical cancer
  • Multiple others

Pathophysiology

• Single stranded RNA virus
• Mechanism
  • Viral entry into CD4+ T cells
  • HIV release its RNA Genome into the cytoplasm as well as viral enzyme reverse transcriptase
  • Replication generating a DNA copy (reverse transcriptase)
  • Incorporating into host DNA via integrase
  • The host cell machinery transcribes the proviral DNA into RNA and the virus is assembled and then buds off the host cell acquiring an envelope from the host membrane
• Co receptors needed for binding
• Primarily affect CD4 T lymphocytes
  • Cell death - apoptosis
  • Cell destruction - architectures and cellular composition of lymphoid tissue
• Also affects macrophages, monocytes and dendritic cells

Clinical

• Acute - viral type illness e.g. fever, sore throat, LN, aches, resolves within 2-4 wks
• Chronic - ongoing viral replication in lymphoid tissue
• Clinical features
  • Opportunistic infections
    • Pneumocystis carinii
    • Candida incl thrush
    • CMV - retinitis
    • Mycobacterial - TB
    • Cryptococcus neoformans - diarrhoea, meningitis
    • Toxoplasma gondii
    • Crypto
    • HSV
    • Salmonella
  • AIDS neoplasia
    • Kaposi sarcoma
    • NHL
    • Cervical cancer
    • Anal cancer

Progression to AIDS

1. Acute infection: High viral load, transient symptoms, and initial CD4+ T cell depletion.
2. Clinical latency: Slow, ongoing loss of CD4+ T cells with minimal symptoms.
3. AIDS: Severe immunosuppression, characterized by opportunistic infections, malignancies, and CD4+ T cell counts below 200 cells/μL.

Tracked by

• CD4 count - expressed as percentage of lymphocytes

Bloods

• ELISA = enzyme linked immunosorbent assay - detect HIV AB
• PCR test to confirm
• Monitor
  • CD4 count - <200 = AIDS, monitor antiretroviral therapy response
  • HIV viral load
  • CD4:CD8 ratio - lower = increased frailty and mortality

Indicate the role for medical imaging where indicated To identify complications if indicated

Universal precautions

• Universal precautions are a set of infection control practices designed to prevent the transmission of bloodborne pathogens (e.g., HIV, hepatitis B, and hepatitis C) and other infectious agents through exposure to blood, bodily fluids, and other potentially infectious materials (OPIM)
• Include
  • Barrier protection
  • Googles, gloves, masks, shields, gowns/PPE
  • Hand hygiene

Operative precautions

• Normal pre op screening
• Have higher rates of morbidity and mortality
  • Marginally
  • Worse for AIDS pts
  • Review meds preop
  • If oral absorption concerning for antiretrovirals that are needed - give IV option
  • Most post op infection in HIV pt is usual ones
    • But if low CD4 count have high suspicion for opportunistic infection
  • Low risk of transmission to healthcare workers

Other surgical implications

• Lower threshold for defunctioning
• Higher incidence of wound complications
• Higher risk of infection for oral and anal surgery