STI- Discharge

Sexually Transmitted Infections (STIs)

Introduction

  • Definition: Sexually transmitted infections are communicable diseases transmitted through sexual contact.

    • Pathogens: Caused by a variety of pathogens: bacteria, viruses, fungi, and parasites.

  • Common Symptoms:

    • Vaginal discharge

    • Urethral discharge or burning in men

    • Genital ulcers

    • Abdominal pain

  • Management Approach:

    • Syndromic Management: A method that simplifies treatment by providing rapid, same-day treatment without the need for expensive or sometimes unavailable diagnostic tests.

Objectives

  1. Understand the importance of STIs in women's health.

  2. Classify STIs using a syndromic approach.

  3. List the risk factors for STIs.

  4. Understand the etiology of common STIs.

  5. Discuss transmission, pathogenesis, and pathology of STIs.

  6. Identify common presentations of STIs.

  7. Laboratory diagnosis of common STIs.

  8. Management and prevention strategies for common STIs.

Vaginal Environment

  • Overview: The vagina acts as a dynamic ecosystem primarily inhabited by a large population of bacteria (approximately 10910^9 bacterial colony-forming units per gram of vaginal fluid).

  • Normal Vaginal Discharge: Clear to white, odorless, and viscous.

  • Bacterial Flora: Predominantly lactobacilli, which:

    • Convert glycogen to lactic acid, maintaining a vaginal pH of 3.5 to 4.5.

    • Some lactobacilli produce hydrogen peroxide (H$2$O$2$), serving as a host defense mechanism against pathogens.

Categories of STIs

  • STIs with Discharge:

    • Chlamydia: Chlamydia trachomatis

    • Gonorrhea: Neisseria gonorrhoeae

    • Candidiasis: Candida species

    • Trichomoniasis: Trichomonas vaginalis

  • STIs with Ulcers:

    • Herpes: HSV-1 and HSV-2

    • Syphilis: Treponema pallidum

    • Lymphogranuloma Venereum (LGV): Chlamydia trachomatis

    • Granuloma Inguinale: Klebsiella granulomatis

    • Chancroid: Haemophilus ducreyi ( painful and non compulsive disorder

Epidemiology of STIs

  • Global Statistics:

    • Over 1 million STIs acquired daily worldwide.

    • Approximately 375 million new infections yearly for the STIs: chlamydia, gonorrhea, syphilis, and trichomoniasis.

    • Over 300 million women have a human papillomavirus (HPV) infection.

    • Majority of STIs may be asymptomatic or present mild symptoms that go unrecognized.

Risk Factors for STIs

  • Demographics: Being young, having multiple sexual partners, or having a new sexual partner.

  • Behavioral Factors: Exchange of sex for money or drugs.

Gonococcal Infection

  • Pathogen: Neisseria gonorrhoeae, a Gram-negative diplococcus.

  • Virulence Factors:

    • Pili and outer membrane proteins that aid adherence to epithelial cells in the genitourinary tract, rectum, pharynx, and conjunctiva.

  • Cultural Growth: Grows on chocolate agar in the presence of carbon dioxide; best isolated on Thayer-Martin agar enriched with antibiotics (vancomycin, colistin, nystatin, and TMP-SMX).

Clinical Presentation

  • Common Infections: Conjunctivitis, pharyngitis, proctitis, urethritis, prostatitis, orchitis.

  • Symptoms in Men:

    • Urethritis: Incubation of 1-14 days (typically 2-5 days).

    • Purulent or mucopurulent urethral discharge and dysuria, over 90% symptomatic.

  • Symptoms in Women:

    • At least 50% asymptomatic.

    • Possible cervicitis and urethritis with dysuria and abnormal vaginal discharge.

Complications of Gonorrhea

  • Disseminated Gonococcal Infection: Can lead to gonococcal arthritis, which is the most common acute septic arthritis in young adults. Exhibits a classic triad of dermatitis, tenosynovitis, and migratory polyarthritis.

  • Fitz-Hugh-Curtis Syndrome: Associated perihepatitis tragedy.

  • Ophthalmia Neonatorum: Infection acquired during birth causes eye infection in newborns.

Diagnostic Methods for Gonorrhea

  • Tests:

    • Culture, Gram stain (for males), and nucleic acid detection tests (NAATs).

    • Culture considered the historical standard, suitable for various specimen sites.

    • NAATs are highly sensitive but cannot determine antimicrobial susceptibility.

Treatment Recommendations

  • If chlamydial infection is not excluded:

    • Add Doxycycline 100 mg orally twice daily for 7 days.

    • Uncomplicated Gonococcal Infections:

      • Ceftriaxone 500 mg IM in a single dose.

Partner Management

  • Recent sexual partners within the last 60 days of diagnosis should be evaluated and treated to prevent reinfection.

Non-Gonococcal Urethritis (NGU)

  • Causes: Chlamydia trachomatis (serovar D-K), Mycoplasma spp. (Ureaplasma urealyticum, Mycoplasma genitalium).

  • Clinical Presentation: Longer incubation period, dysuria, mucoid or mucopurulent discharge.

Chlamydia

  • Pathogen Characteristics: Obligate intracellular bacteria, with a developmental cycle including infectious forms (elementary bodies) and non-infectious forms (reticulate bodies).

  • Clinical Manifestations:

    • Commonly asymptomatic (80%), but symptomatic cases may present with mucopurulent discharge.

    • Reiter syndrome: Associated with urethritis, conjunctivitis, polyarthritis, and mucosal lesions.

Specimen Collection for Chlamydia

  • Endocervical Sample: Details on proper technique for collecting urethral and endocervical swabs.

Chlamydia Diagnostics

  • Non-Culture Tests: Nucleic Acid Amplification Tests (NAATs) are the test of choice due to high sensitivity.

Treatment for Chlamydia

  • Recommended Regimens:

    • Azithromycin 1 g orally in a single dose or Doxycycline 100 mg orally twice daily for 7 days.

  • Alternative Regimens: Erythromycin, Levofloxacin, Ofloxacin with specific dosages outlined.

Case Study: Vaginal Discharge

  • Patient Details: 32-year-old woman with ten days history of vaginal discharge, foul-smelling and itchy, differential diagnosis discussed.

Vaginitis Overview

  • Common Conditions: Bacterial vaginosis (25%-50%), Vulvovaginal candidiasis (15%-35%), Trichomoniasis (5%-35%).

Types of Vaginal Discharge

  • Significance:

    • Purulent: Gonorrhea.

    • Mucoid: Chlamydia; Mycoplasma.

    • Frothy: Trichomoniasis.

    • Malodorous fishy: Bacterial vaginosis.

    • Thick and cheesy: Candidiasis.

Diagnosis of Vaginitis

  • Diagnostic criteria for common conditions based on symptoms, type of discharge, and microscopy results:

    • Bacterial vaginosis: Clue cells and a fishy smell noted.

Treatment of Vaginitis

  • Bacterial Vaginosis: Insight into the potential role of probiotics in treatment.

Further Readings

  • Suggested literature for deeper understanding:

    • Medical Microbiology – 8e by Murray et al.

    • Diagnostic Microbiology – 12e by Bailey and Scott’s.

    • Online resources: WHO, CDC, NHS for updated information on STIs.