Sexually Transmitted Diseases



Sexually Transmitted Diseases


Donald P. Orr

Margaret J. Blythe



Over the past decade, adolescents in the United States have become increasingly responsible with respect to sexual risk behaviors. The average age of first coitus has risen to about 16 years, the proportions of young people reporting use of effective contraceptive methods and condoms have increased, and pregnancy and birth rates to teens have consistently fallen. However, the number of adolescents with sexually transmitted infections (STIs) remains unacceptably high. Two-thirds of STIs are reported among those less than 25 years of age. The rates of gonorrhea, chlamydia, and human papillomavirus (HPV) are highest in women 15 to 19 years old. Nearly half of the new cases of human immunodeficiency virus (HIV) infections in the United States are estimated to occur in individuals under the age of 25 years. Approximately one out of four sexually active teens is estimated to contract an STI each year.


EPIDEMIOLOGY: RISK FACTORS FOR SEXUALLY TRANSMITTED INFECTIONS AND HUMAN IMMUNODEFICIENCY VIRUS

Limited understanding of STIs and of the consequences of specific sexual behaviors contributes to the risk for infection. Ten to 17% of adolescents who deny vaginal coitus report having tried oral-genital contact, and many adolescents misperceive it as “safe” sex. Fortunately, anal “sex” among younger adolescents (associated with increased risk of transmission for HIV) appears less common than once believed.

Condom practices contributing to the risk for STI include inconsistent use, especially as the length of a relationship increases, and limited intervals between acquiring new sexual partners. Overlapping sexual partnerships (more than one partner during a given time period) are the exception. Exchanging sex for money and gifts (e.g., prostitutes, runaways, the homeless, and “street youth”), incarceration, males having sex with males (MSM), injecting drug use, belonging to a racial/ethnic minority group, living in a neighborhood in which STIs are highly prevalent, and being poor are associated with greater risk for STIs. Lack of immunity, cervical ectopy with increased surface area of columnar epithelium exposure to pathogens, lack of sufficient progesterone (anulovatory cycles), and use of injectable progestins are also thought to confer increased risk for adolescents. Supportive data are limited and conflicting.

Delay in seeking care for symptoms increases the spread of infections. Adolescents are at risk because of stigma associated with STIs, lack of access to health care, and concerns about confidentiality. Many fail to understand that adolescents may consent to their own care for confidential evaluation and treatment of STIs in all states and the District of Columbia. Health care providers should be familiar with local laws because codes governing the age of minor consent and the degree of confidentiality are state specific.



APPROACH TO DIAGNOSIS AND MANAGEMENT OF COMMON SEXUALLY TRANSMITTED INFECTIONS

A sexual history should be obtained on all adolescent patients. (See Chapter 89 on interviewing adolescents.) All sexually active individuals are at risk for acquiring an STI. Screening asymptomatic adolescents should occur according to current recommendations described in the next section.


Evaluation of Symptomatic Individuals

Symptomatic individuals should be evaluated based on both on symptoms and on the prevalence of the most common infections. Serologic screening for HIV and syphilis should be obtained as indicated by history and date of last screen. There are no recommendations to obtain test of cure following treatment for STIs except syphilis.



  • Vaginal discharge: Inspect external genitals; obtain vaginal secretions for pH, direct microscopy, and potassium hydroxide (KOH) preparation; send appropriate specimen (cervical swab or urine) to detect chlamydia, gonorrhea, or Trichomonas (polymerase chain reaction [PCR] or culture if available).


  • Urethral discharge/dysuria: Inspect external genitals; send urethral swab or urine to detect chlamydia, gonorrhea, or, if recurrent symptom, Trichomonas (if PCR or culture is available); Gram stain urethral swab/discharge (if available).


  • Genital ulcer/genital pain: Examine for inguinal adenopathy; inspect genitals for lesion(s); swab painful lesions for herpes simplex virus (HSV); swab lesion for darkfield microscopy if available; send blood for syphilis screen; consider chancroid.


  • Treatment of sexual partners: All individuals who have had sexual contact within 60 days with a patient treated for an STI (except HPV or HSV) should be evaluated and empirically treated. Syphilis, gonorrhea, chlamydia, and AIDS are reportable diseases in every state; HIV infection and chancroid are reportable in many states. Because requirements for reporting other STIs differ by state, clinicians must be aware of local requirements.

Patients and partners should be instructed to not have sexual intercourse until therapy is completed and no longer having symptoms or 7 days for those treated with single-dose therapies.


Screening Asymptomatic Adolescents

Most persons infected with STIs are asymptomatic, thus making screening important in management. Nonintrusive testing of urine or vaginal swabs using nucleic acid amplification testing (NAAT) makes screening of asymptomatic adolescents feasible. NAATs are very sensitive and specific, but it is important to remember for this group of tests that the rate of false-positive results increases as the prevalence of infection in the population decreases (Table 95.1). The rates of infection with Chlamydia trachomatis have decreased in regions with intensive screening and treatment programs. Screening and treatment for chlamydia of infected women and partners have been shown to reduce pelvic inflammatory disease (PID) significantly and to be cost effective. Current recommendations are to screen annually all sexually active girls and women less than 25 years of age and pregnant women early in the third trimester.

Recommendations to screen male patients for chlamydia are less clear because no studies on efficacy have been performed. Some clinicians use the presence of leukocyte esterase (LE) in a first-void urine specimen of sexually active male patients as a prescreen to select patients for NAAT testing. Among asymptomatic boys and men, LE has a sensitivity of 59% and specificity of 95% for asymptomatic chlamydia urethritis, thus resulting in a poor positive predictive value (38%) but very good negative predictive value (98%). In one study, screening asymptomatic boys and men for chlamydia was estimated to reduce the risk of PID by 55%. At a prevalence of 5%, the strategy of screening first with LE and then sending only those with positive results for urine-based NAATs was suggested to be the most cost effective.

Although gonorrhea is less prevalent than chlamydia, some recommend screening high-risk sexually active adolescent women annually for Neisseria gonorrhoeae. Screening adolescent boys is not recommended because asymptomatic infection is less common.

Although there are no recommendations for screening, the prevalence of Trichomonas vaginalis among high-risk sexually active women suggests that annual screening may be useful in this population. Prevalence data are insufficient among male adolescents to recommend screening. It seems prudent to screen sexually active adolescents for infection with Treponema pallidum and HIV.

Clinicians should be guided by the prevalence of STIs in their community and knowledge of the adolescent’s sexual behaviors, such as multiple sexual partners, failure to use condoms, or previous STIs. More frequent screening (3- to 6-month intervals) of high-risk populations such as adolescents and MSM has been suggested.


SYNDROMES

The causes of common STI syndromes are listed in Box 95.1.


Nongonococcal Urethritis

Urethritis is characterized by mucoid or mucopurulent urethral discharge and is sometimes accompanied by dysuria or urethral pruritis. Asymptomatic infections are common. Nongonococcal urethritis (NGU) is diagnosed if there are more than five polymorphonuclear leukocytes (PMNs)/oil immersion field and gram-negative intracellular diplococci cannot be identified on urethral smears.

Historically, 15% to 50% of NGU cases have been caused by C. trachomatis, although other organisms are increasingly identified. Using PCR techniques, Mycoplasma genitalium has been found in 18% to 46% of men with NGU; coinfection with chlamydia is common. Culture of M. genitalium is difficult and not widely available; PCR techniques are available in some research laboratories. Trichomonas may cause NGU and has been identified in 6% to 17% of older men with NGU who are attending STI clinics. The role of Ureaplasma urealyticum remains unclear.

Treatment for NGU is the same as chlamydial urethritis. One should suspect M. genitalium or Trichomonas with treatment failures when reinfection is unlikely. Erythromycin and metronidazole, respectively, are recommended; however, a more recent report has suggested that a 5-day course of azithromycin may be more effective for M. genitalium and better tolerated.








TABLE 95.1. SENSITIVITY AND SPECIFICITY OF DIAGNOSTIC TESTS








































































































Diagnostic Method Sensitivity Specificity
Tests for Detection of Chlamydia trachomatis
Tissue culture 70–85% 100%
Direct fluorescent antibody (DFA)*,a 80–85% 99%
Enzyme immunoassay (EIA)† 53–76% 95%
Hybridization (DNA-probe)‡ 65–83% 99%
NAATs
Cervical§, , #, ** 90–94% 98–99%
Urine
   Female§, , # 81–95% 98–99%
   Male§, , # 93–95% 94–98%
Urethra
   Male# 97% 99%
Tests for Detection of Neisseria gonorrhoeae
Culture 80–95% 100%
Gram stain
   Male: symptomatic 90–95% 95–100%
   Male: asymptomatic 50–70% 95–100%
   Females 50–70% 95–100%
Hybridization‡ 92–96% 99%
NAATs
Cervical§, , #, ** 92–100% 99–100%
Urine
   Female, # (§, not FDA approved) 85–91% 99–100%
   Male§, , #
Symptomatic 94–99% 93–100%
Asymptomatic§ 79% 100%
Urethra
   Male, # 99% 98–100%
Vaginal(§(not FDA approved)) 95% 98%
NAATs, nucleic acid amplification tests.
*MicroTrak (Syva).
†Chlamydiazyme EIA (Abbott).
‡Pace2 (Gen-Probe).
§COBAS Amplicor (Roche).
ProbeTec (Becton-Dickinson).
#APTIMA Combo 2 (Gen-Probe).
**Digene Hybrid Capture2 (Digene).




BOX 95.1 Etiology of Common Sexually Transmitted Infection Syndromes

Discharge Syndromes (Urethritis, Cervicitis, Vaginitis)



  • Chlamydia trachomatis


  • Neisseria gonorrhoeae


  • Trichomonas vaginalis


  • Mycoplasma genitalium


  • Ureaplasma urealyticum


  • Herpes simplex virus


  • Candida species

Ulcer Syndromes



  • Treponema pallidum


  • Herpes simplex virus


  • Haemophilus ducreyi


  • Calymmatobacterium granulomatis (granuloma inguinale, rare in the United States)


  • Chlamydia trachomatis serovars L1, L2, or L3 (lymphogranuloma venereum, rare in the United States)

Pelvic Inflammatory Disease



  • Neisseria gonorrhoeae


  • Chlamydia trachomatis


  • “Normal vaginal flora, e.g., anaerobes, Gardnerella vaginalis, Haemophilus influenzae, enteric gram-negative rods, and Streptococcus agalactiae


  • Uncommon: Mycoplasma genitalium, cytomegalovirus, Mycoplasma hominis, Ureaplasma urealyticum

Epididymitis



  • Chlamydia trachomatis


  • Neisseria gonnorrhoeae


  • Enteric organisms, e.g., Escherichia coli

Dermatologic

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Jul 24, 2016 | Posted by in PEDIATRICS | Comments Off on Sexually Transmitted Diseases

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