HIV and STIs

On this page

HIV Pathogenesis - Viral Villainy Unveiled

  • HIV (retrovirus) infects CD4+ T-cells, macrophages, dendritic cells.
  • Entry: gp120 binds CD4, then co-receptor (CCR5/CXCR4).
    • CCR5: Early infection, M-tropic strains.
    • CXCR4: Later infection, T-tropic strains, more cytopathic.
  • Key Viral Enzymes: Reverse Transcriptase, Integrase, Protease.
  • Replication Cycle:
  • Outcome: Progressive ↓CD4 cell count, immune deficiency (AIDS). HIV Life Cycle Diagram

⭐ HIV primarily utilizes the CCR5 co-receptor for entry in early infection (M-tropic), while CXCR4 usage (T-tropic) often emerges later and is associated with faster disease progression.

HIV Clinical & Diagnosis - Spotting The Enemy

  • Acute Retroviral Syndrome (ARS): Flu/mono-like illness, high viral load (2-4 wks post-exposure).
  • Clinical Latency: Asymptomatic, CD4 count gradually ↓.
  • AIDS: CD4 < 200/µL or AIDS-defining illness (e.g., PCP, Kaposi Sarcoma). WHO Stage 4.
  • Diagnosis:
    • Initial: 4th Gen (p24 Ag + HIV Ab) test. Window period: 2-6 weeks.
    • Confirmatory: HIV-1/HIV-2 differentiation assay or NAT.
    • NAT: Detects HIV RNA. Shortest window (1-4 weeks); for acute/neonatal Dx.

⭐ Most common opportunistic infection in HIV patients in India is Tuberculosis.

HIV Management - Fighting Back Smart

  • ART Initiation: Start immediately for all PLHIV, regardless of CD4 count. Goal: viral suppression.
    • Monitoring: VL at 6, 12 months, then annually if suppressed (<50 copies/mL). CD4 if advanced/unsuppressed.
  • PEP: ASAP (<2h ideal, max 72h) post-exposure; TDF + 3TC + DTG for 28 days.
  • PrEP: Daily TDF/FTC or TDF/3TC for high-risk individuals.
  • IRIS: Paradoxical worsening on ART; manage OI, continue ART.

⭐ Preferred first-line ART (NACO): Tenofovir (TDF) + Lamivudine (3TC) + Dolutegravir (DTG) as a fixed-dose combination.

Syphilis Spotlight - The Ancient Foe

  • Agent: Treponema pallidum.
  • Stages:
    • Primary: Painless chancre.
    • Secondary: Rash (palms/soles), condyloma lata. Condyloma Lata: Signs, Background, Cause, Treatment

      ⭐ Jarisch-Herxheimer Reaction: Post-Rx fever, chills, myalgia from treponemal lysis; self-limiting. Usually within 2-12h.

    • Latent: Asymptomatic (early/late).
    • Tertiary: Gummas, neurosyphilis, cardiovascular. Syphilis gumma on arm
  • Diagnosis: Screen: VDRL/RPR. Confirm: TPPA/FTA-ABS.
  • Treatment (Penicillin G):
    • Early (1°, 2°, Early Latent): Benzathine 2.4 MU IM x1.
    • Late Latent/Tertiary: Benzathine 2.4 MU IM weekly x3.
    • Neurosyphilis: Aqueous Crystalline 18-24 MU IV daily x10-14d.

Gonorrhea & Chlamydia - Dual Trouble Duo

  • Co-infection common. Dx: NAAT.
  • Dual Tx for co-infection.
FeatureGonorrhea (GC)Chlamydia (CT)
OrganismGram -ve diplococciObligate intracellular
SymptomsPurulent D/C, PID, DGIOften Asx, PID
Tx (Uncomp.)Ceftriaxone 500mg IM + Azithro 1g POAzithro 1g PO or Doxy 100mg BD x7d

⭐ Fitz-Hugh-Curtis: perihepatitis (RUQ pain, violin-string adhesions) with PID (GC/CT).

Other STIs - Rapid Roundup Reel

  • Trichomoniasis: T. vaginalis; frothy discharge, strawberry cervix. Metronidazole 2g PO single. Trichomoniasis "strawberry cervix" indication
  • HPV (Warts): HPV; condylomata acuminata. Podophyllin, Imiquimod.
  • HSV (Herpes): HSV; painful vesicles. Acyclovir.
  • Chancroid: H. ducreyi; painful ulcer. Azithromycin 1g PO single.
  • LGV: C. trachomatis L1-L3; adenopathy. Doxycycline.

    ⭐ LGV: C. trachomatis L1-L3; pathognomonic "groove sign".

  • Donovanosis: K. granulomatis; beefy-red ulcer, Donovan bodies. Azithromycin.

High‑Yield Points - ⚡ Biggest Takeaways

  • HIV primarily targets CD4+ T-lymphocytes; HAART is crucial for management.
  • Syphilis (Treponema pallidum) presents with a painless chancre; screen with VDRL/RPR, confirm with FTA-ABS/TPHA.
  • Gonorrhea (Neisseria gonorrhoeae) shows Gram-negative diplococci; causes urethritis and cervicitis.
  • Chlamydia (Chlamydia trachomatis) is often asymptomatic; can lead to PID and infertility.
  • Genital Herpes (mainly HSV-2) is characterized by painful vesicular lesions.
  • HPV serotypes 16 & 18 are linked to cervical cancer; 6 & 11 cause genital warts (condyloma acuminata).

Practice Questions: HIV and STIs

Test your understanding with these related questions

Perivascular lymphocytes & microglial nodules are seen in -

1 of 5

Flashcards: HIV and STIs

1/6

_____ syphilis can present with aortitis, particularly of the ascending thoracic aorta

TAP TO REVEAL ANSWER

_____ syphilis can present with aortitis, particularly of the ascending thoracic aorta

Tertiary

browseSpaceflip

Enjoying this lesson?

Get full access to all lessons, practice questions, and more.

Start Your Free Trial