Human Papillomavirus Infections

Human Papillomavirus Infections

Human Papillomavirus Infections

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Human Papillomavirus Infections - Viral Villain Intro

  • Virus: Human Papillomavirus (HPV)
    • Structure: Double-stranded DNA (dsDNA), non-enveloped.
  • Transmission:
    • Direct contact (skin-to-skin).
    • Indirect contact (fomites).
    • Sexual contact.
  • Key HPV Types & Associations:
    • Low-risk (cutaneous & genital warts/condyloma acuminata): e.g., 6, 11.
    • High-risk (cancers: cervical, anogenital, oropharyngeal): e.g., 16, 18, 31, 33.
  • Pathogenesis:
    • Infects basal keratinocytes of stratified squamous epithelium.
    • Oncogenic potential (high-risk types) linked to viral proteins E6 and E7.

      ⭐ High-risk HPV E6 protein targets p53 (tumor suppressor protein) for degradation, and E7 protein inactivates retinoblastoma protein (pRb).

Human Papillomavirus Infections - Common Wart Parade

  • Common cutaneous manifestations of HPV infection, varying by type and location.
Wart TypeLocationMorphologyHPV TypesKey Features
Verruca vulgarisHands, fingers, kneesHyperkeratotic papules, rough surface2, 4Common warts
Verruca plantarisSoles of feetDeep, painful; black dots (thrombosed capillaries)1, 2, 4Plantar warts
Verruca planaFace, hands, shinsSmooth, flat-topped, skin-colored papules3, 10Flat warts
Filiform wartsFace, neck, eyelidsSlender, finger-like projections1, 2Often around mouth, nose

⭐ The presence of thrombosed capillaries (black dots) is a characteristic feature of plantar warts (Verruca plantaris).

Human Papillomavirus Infections - Risky Regions

  • Anogenital Warts (Condyloma Acuminata)
    • Cauliflower-like lesions.
    • Commonly HPV 6, 11.
    • Histopathology of Condyloma Acuminata
  • Koilocytes
    • Pathognomonic cytological feature: perinuclear halo, nuclear atypia (raisinoid nucleus).
  • Oncogenic Potential
    • Cancers: Cervical (most common), vulvar, vaginal, penile, anal, oropharyngeal.
    • Primarily HPV 16, 18; also 31, 33, 45.
    • E6 gene product → p53 degradation.
    • E7 gene product → pRb inactivation.
  • Laryngeal Papillomatosis
    • Benign tumors in larynx.
    • HPV 6, 11.
    • Common in children (vertical transmission during birth).

⭐ Koilocytic atypia, characterized by a perinuclear vacuole and an irregular, enlarged nucleus, is a histological hallmark of HPV infection.

📌 Mnemonic (Oncogenic HPV types): 16 and 18 can cause Cancer (Cervical).

Human Papillomavirus Infections - Warding Off Warts

  • Diagnosis: Primarily clinical.
    • Acetic acid test: Acetowhitening (subclinical genital lesions).
    • Biopsy: If uncertain, unresponsive, or malignancy suspected.
    • HPV DNA tests: Cervical cancer screening, high-risk type ID.
  • Treatment Modalities: Choice depends on wart type, location, size, number, patient preference, and immune status.
  • Prevention:
    • HPV Vaccines (e.g., Gardasil 9: types 6, 11, 16, 18, 31, 33, 45, 52, 58). Recommended ages for vaccination.
    • Cervical cancer screening (Pap smear, HPV testing).

⭐ Imiquimod is an immunomodulator that acts as a Toll-like receptor 7 (TLR-7) agonist, stimulating innate and cell-mediated immune responses against HPV.

High‑Yield Points - ⚡ Biggest Takeaways

  • HPV types 6 & 11 primarily cause anogenital warts (condyloma acuminata).
  • HPV types 16 & 18 are high-risk oncogenic types, linked to cervical and other SCCs.
  • Koilocytes on microscopy (perinuclear halo, wrinkled nucleus) are pathognomonic.
  • Common warts (verruca vulgaris) frequent on hands; plantar warts on soles; flat warts on face.
  • Treatment options include topical podophyllin/imiquimod, cryotherapy, and salicylic acid.
  • Prophylactic HPV vaccination is crucial for preventing infections with major oncogenic types_

Practice Questions: Human Papillomavirus Infections

Test your understanding with these related questions

Which quadivalent HPV vaccine protects against both cervical cancer and genital warts?

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Flashcards: Human Papillomavirus Infections

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Buschke Lwenstein tumor is caused by HPV _____

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Buschke Lwenstein tumor is caused by HPV _____

6 and 11

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