Sexually Transmitted Infections

Sexually Transmitted Infections

Sexually Transmitted Infections

On this page

STI Intro & Epidemiology - Adolescent Hotspots

  • Sexually Transmitted Infections (STIs): Primarily spread via sexual contact; significant global health concern, especially among youth.
  • Common Pathogens in Adolescents:
    • Viral: Human Papillomavirus (HPV), Herpes Simplex Virus (HSV), HIV, Hepatitis B.
    • Bacterial: Chlamydia trachomatis, Neisseria gonorrhoeae, Treponema pallidum (Syphilis).
    • Protozoal: Trichomonas vaginalis.
  • Adolescents (15-24 years) as 'Hotspots': Experience a disproportionate burden of STIs.
    • Key Risk Factors:
      • Biological: Cervical ectopy in females, pubertal immune system changes.
      • Behavioral: Early sexual debut, multiple/concurrent partners, inconsistent condom use, substance abuse influencing risky behavior.
      • Socio-cultural: Limited access to comprehensive sexuality education & youth-friendly health services, stigma, peer pressure.

⭐ Young people aged 15-24 years account for almost half of all new STIs diagnosed each year. STI cases by age and sex

Genital Ulcer STIs - Painful Problems

Key causes: Herpes Genitalis & Chancroid.

  • Herpes Genitalis (HSV)

    • Agent: HSV-2 > HSV-1.
    • Clinical: Grouped vesicles → painful, shallow ulcers. Recurrent. Prodrome common.
    • Dx: PCR (gold std), Tzanck smear (multinucleated giant cells).
    • Rx: Acyclovir, Valacyclovir, Famciclovir. E.g., Acyclovir 400mg TID.
  • Chancroid (H. ducreyi)

    • Agent: Haemophilus ducreyi (Gram-neg coccobacillus).
    • Clinical: Soft, tender ulcer(s); ragged, undermined edges. Painful inguinal bubo (may suppurate). 📌 "Soft chancre, soft bubo".
    • Dx: Gram stain ('school of fish'), culture (difficult), PCR.
    • Rx: Azithromycin 1g PO (single) OR Ceftriaxone 250mg IM (single).

⭐ In Chancroid, auto-inoculation can lead to "kissing ulcers" (ulcers on opposing skin surfaces).

Discharge-Causing STIs - Drip Doctors

📌 Mnemonic: GCT (Gonorrhea, Chlamydia, Trichomoniasis)

  • Gonorrhea ("The Clap"):
    • Agent: N. gonorrhoeae (G- diplococci).
    • Sx: Men (purulent discharge, dysuria), Women (mucopurulent cervicitis, often asymptomatic).
    • Tx: Ceftriaxone 500mg IM + Doxycycline.
  • Chlamydia:
    • Agent: C. trachomatis.
    • Sx: Men (mucoid/watery discharge), Women (asymptomatic cervicitis common).
    • Tx: Doxycycline OR Azithromycin 1g PO single dose.
  • Trichomoniasis ("Trich"):
    • Agent: T. vaginalis (protozoan).
    • Sx: Women (frothy, yellow-green, malodorous discharge; "strawberry cervix"), Men (often asymptomatic).
    • Tx: Metronidazole 2g PO single dose (treat partners).
  • Pelvic Inflammatory Disease (PID):
    • Cause: Ascending GC/CT infection.
    • Sx: Lower abd pain, Cervical Motion Tenderness (CMT), adnexal tenderness.
    • Complications: Infertility, ectopic pregnancy, Fitz-Hugh-Curtis syndrome.

⭐ "Strawberry cervix" (colpitis macularis) is a classic, though not always present, sign of Trichomoniasis.

Neisseria gonorrhoeae Gram Stain

Key Viral STIs & Prophylaxis - Long-Term Lurkers

  • HPV (Human Papillomavirus): Oncogenic (cervical, anogenital, oropharyngeal cancers). Causes condylomata acuminata (genital warts).
    • Prophylaxis: HPV vaccination (e.g., Gardasil 9, Cervarix) ideally before sexual debut (9-14 years).
  • HSV (Herpes Simplex Virus): Recurrent, painful vesicles (oral/genital). Establishes lifelong latency in nerve ganglia.
    • Management: Acyclovir, valacyclovir for acute episodes or suppression. No cure.
  • HIV (Human Immunodeficiency Virus): Retrovirus targeting CD4+ T-lymphocytes, leading to AIDS.
    • Prophylaxis: PrEP (Pre-Exposure Prophylaxis), PEP (Post-Exposure Prophylaxis), safe sex. Lifelong Antiretroviral Therapy (ART) for infected individuals.

    ⭐ Vertical transmission of HIV (mother-to-child) can be significantly reduced to <1% with timely maternal ART and infant prophylaxis.

  • HBV (Hepatitis B Virus): Can cause acute/chronic hepatitis, cirrhosis, and Hepatocellular Carcinoma (HCC).
    • Prophylaxis: HBV vaccination (universal immunization programs). Hepatitis B Immune Globulin (HBIG) + vaccine for post-exposure prophylaxis.

High‑Yield Points - ⚡ Biggest Takeaways

  • Chlamydia trachomatis: Most common bacterial STI; often asymptomatic, screen sexually active females ≤25 yrs annually.
  • Gonorrhea & Chlamydia: Untreated can lead to Pelvic Inflammatory Disease (PID), risking infertility and ectopic pregnancy.
  • Syphilis: Characterized by painless chancre (primary); screen with VDRL/RPR, confirm with TPHA/FTA-ABS.
  • Human Papillomavirus (HPV): Major cause of cervical cancer & genital warts; vaccination is crucial for prevention.
  • Trichomoniasis: Presents with frothy yellow-green discharge, strawberry cervix; treat with Metronidazole (patient and partner).
  • Herpes Simplex Virus (HSV-2 > HSV-1): Causes recurrent, painful genital vesicles/ulcers; managed with Acyclovir.
  • Adolescent consent (usually sufficient for STI testing/treatment) and confidentiality are paramount in STI management; partner notification is key public health measure (e.g., Section 377 IPC decriminalization impact).

Practice Questions: Sexually Transmitted Infections

Test your understanding with these related questions

Which of the following is a risk factor for cervical cancer?

1 of 5

Flashcards: Sexually Transmitted Infections

1/4

What is the first sign of puberty in males?_____

TAP TO REVEAL ANSWER

What is the first sign of puberty in males?_____

increase in testicular volume

browseSpaceflip

Enjoying this lesson?

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

Start Your Free Trial