STI Fundamentals

1
STI Fundamentals

• Gina Dallabetta
• Family Health International
• May 2003

2
Overview

• Lightening review of
• common pathogens
• complications
• diagnostics/management

3
STI Pathogens

• Classifications
• Curable vs not-curable
• Sexual transmission in adults predominantly by
  sexual intercourse vs. sexual transmission
  described but not predominant mode
• About 30 pathogens described

4
Rationale for Effective STI Prevention and Control

• High priority for preserving reproductive health,
  especially among women.
• Role in preventing some cancers and neurologic
  disease.
• Cost-effective approach to prevent neonatal
  morbidity and mortality.
• HIV prevention.

5
Diseases Characterized by Genital Ulcers

• Herpes simplex
• Chancroid
• Syhilis
• Granuloma Inguinale
• Lymphogranuloma venereum

6
Herpes Simplex

• Key features
• Life-long, recurrent viral infection
• HSV-2 HSV-1
• Most dont know they are infected, shed
  intermittently without symptoms, transmission
  inadvertent
• 1o infection severe, recurrent resolve except in
  HIV
• Diagnosis
• Culture, PCR, antigen detection (DFA), Tzanck
  prep
• Management
• Antiviral management symptoms, chronic
  suppressive Rx in frequent recurrences and in HIV
• Partner counseling
• Complications
• neonatal herpes infections, HIV

7
Chancroid

• Key Features
• Bacterial infection - H. ducreyi
• Strongly associated with sex work
• Diagnosis
• Culture (fastidious organism)
• PCR
• Management
• Antibiotics (single dose usually) or longer in
  HIV infected
• Partner treatment for exposure 10 days prior
• Complications
• HIV infection
• Slow healing (months)

8
Syphilis

• Key features
• Systemic bacterial infection - T. pallidum
• Multiple phases of disease, 1o (ulcer), 2o (rash
  ), latent, neurological, 3o (cardiovascular,
  eye, gummas)
• Diagnosis
• Ulcers - PCR, dark-field
• Other - serology - non-treponemal (RPR, VDRL,
  TRUST) and treponemal (FTA-ABS, MHATP, TPHA,
  TPPA),
• Congenital - includes x-rays of long bones
• Management
• Antibiotics
• Partner treatment (look back depends on stage of
  disease)

9
Syphilis

• Complications
• HIV
• Long term sequelae of untreated infection
  (cardiovascular and neurologic)
• Transmission to fetus during pregnancy
• fetal loss
• stillbirth
• neonatal death
• infant death
• congenital syphilis
• (Zambia - 42 of stillbirths and 30 of
  perinatal deaths attributed to syphilis)

10
Diseases Characterized by Urethritis and
Cervicitis

• Gonorrhea
• Chlamydial infection
• Non-gonococcal urethritis
• Mucopuruluent cervicitis

11
Gonorrhea

• Key Features
• Bacterial infection - N. gonorrhoeae
• Men usually symptomatic, women usually not
• Genital, anal and pharyngeal infections
• Antibiotic resistance common and constantly
  changing
• Co-infection with Chlamydia trachomatis common
• Diagnosis
• Gram stain (male urethra only), culture, PCR,
  antigen detection
• Management
• Single dose antibiotics ( co-therapy for CT)
• Partner management - 60 days or most recent
  partner

12
Gonorrhea

• Complications
• Upper tract infections
• epididymitis in men
• PID in women - infertility, ectopic pregnancy,
  death
• DGI, meningitis, endocarditis
• Congenital infections
• ophthalmia neonatorum (30 - 47 transmission)
• disseminated infections
• HIV infection - marked increased viral shedding
  with infection

13
Chlamydial infection

• Key Features
• Bacterial infection - C. trachomatis
• More prevalent in adolescents and young adults
• Diagnosis
• PCR, culture, antigen detection
• Management
• Antibiotics (usually 7 days) or with long acting
  macrolides
• Partner management - 60 days or most recent if
  longer

14
Chlamydial infection

• Complications
• Upper tract infections
• epididymitis in men
• PID in women (often subclinical) - infertility,
  ectopic pregnancy, death
• Congenital infections
• ophthalmia neonatorum
• pneumonia
• HIV infection (micro-ulcerations on cervix)

15
NGU and MPC

• NGU (non-gonococcal urethritis)
• dysuria/urethal prutiis
• 5 WBCs gram stain
• C. trachomatis majority of cases, T. vaginalis
  and U. urealyticum and indeterminate
• Partner management 60 day look back
• MPC (mucopurulent cervicitis)
• mucopurulent discharge, friability, increased WBC
  on gram stain
• C. trachomatis, N. gonorrhea can cause
• Partner management - based on diagnosis

16
Diseases Characterized by Vaginal Discharge

• Bacterial Vaginosis
• Trichomoniasis
• Vulvovaginal Candidasis

17
Bacterial Vaginosis

• Key features
• dis-equilibrium syndrome - high concentrations of
  anaerobic bacteria and low H2O2-producing
  lactobacilli
• non-sexually active women rarely affected but
  treatment of male partner not-beneficial
• Diagnosis
• bedside tests, gram stain, commercially available
  tests
• Treatment
• topical or oral antibiotics
• Complications
• Adverse pregnancy outcomes - PROM, preterm birth,
  postpartum endometritis
• Post surgical endometritis, PID, ?? HIV

18
Trichomonaisis

• Key features
• Caused by a protozoan, T. vaginalis
• Can be transmitted by fomites
• Diagnosis
• Wet mount microscopy, culture
• Treatment
• Metronidazole single dose of 7 days
• Partner management - treatment of all partners
• Complications
• Associated with adverse pregnancy outcome - PROM
  and premature delivery and LBW

19
Vulvovaginal Candidiasis

• Key features
• Overgrowth syndrome usually caused by C.
  albicans, a yeast
• Not-usually acquired through sexual intercourse
• Diagnosis
• Wet mount, gram stain of vaginal discharge
• positive culture NOT an indication for treatment
  - found in 10 - 20 normal women
• Management
• Short-course topical formulations
• oral antifungal available
• Complications
• none
• Immunocompromised women require longer term
  therapy

20
Human Papilloma Virus

• Key features
• Associated with Genital Warts and Genital Cancers
• Infection with multiple HPV types possible
• Diagnosis
• Genital warts - visual
• Subclinical - acetic acid, PAP tests, HPV DNA --
  colposcopy
• Management
• Genital warts - possibility of spontaneous
  resolution
• topical podophyllin, TCA cryotherapy surgical
  removal intralesional interferon lasar surgery
• Abnormal PAP - surgical

21
Hepatitis A, B, C

• Hepatitis A
• transmission by fecal-oral route
• childhood illness in most of developing world
• vaccine preventable
• Hepatitis B
• Sexual transmission accounts for most HBV in the
  US
• vaccine preventable
• Hepatitis C
• Most common chronic bloodborne infection in US
• Sexual transmission plays limited role

22
(No Transcript)