eMedicine Specialties > Infectious Diseases > Sexually Transmitted Diseases

Chlamydial Genitourinary Infections

Author: Larry I Lutwick, MD, Professor of Medicine, State University of New York, Downstate Medical School; Director, Infectious Diseases, Veterans Affairs New York Harbor Health Care System, Brooklyn Campus
Coauthor(s): Renuka Heddurshetti, MD, Fellow in Infectious Diseases, Department of Internal Medicine, State University of New York at Brooklyn; Jeffrey Blitstein, MD, Staff Physician, Department of Internal Medicine, Division of Infectious Disease, VA New York Harbor Health Care System at Brooklyn
Contributor Information and Disclosures

Updated: Apr 20, 2009

Introduction

Background

Chlamydiae are small gram-negative obligate intracellular microorganisms that preferentially infect squamocolumnar epithelial cells.

Chlamydia trachomatis is one of the 4 species (also including Chlamydia puerorum, Chlamydia psittaci, and Chlamydia pneumoniae) in the genus Chlamydia. C trachomatis can be differentiated into 18 serovars (serologically variant strains) based on monoclonal antibody–based typing assays. Serovars A, B, Ba, and C are associated with trachoma (a serious eye disease that can lead to blindness), serovars D-K are associated with genital tract infections, and L1-L3 are associated with lymphogranuloma venereum ([LGV] see Lymphogranuloma Venereum).

Pathophysiology

The pathophysiologic mechanisms of chlamydiae are poorly understood at best. The initial response to infected epithelial cells is a neutrophilic infiltration followed by lymphocytes, macrophages, plasma cells, and eosinophilic invasion. The release of cytokines and interferons by the infected epithelial cell initializes this inflammatory cascade.

Infection with chlamydial organisms invokes a humoral cell response, resulting in secretory immunoglobulin A (IgA) and circulatory immunoglobulin M (IgM) and immunoglobulin G (IgG) antibodies and a cellular immune response. Recent studies have implicated a 40-kd major outer membrane protein (MOMP) and a 60-kd heat-shock protein (Chsp60) in the immunopathologic response, but further studies are needed to better understand these cell-mediated immune responses.

Chlamydiae have a unique biphasic life cycle that is adaptable to both intracellular and extracellular environments. In the extracellular milieu, the so-called elementary body (EB) is found. EBs are metabolically inactive infectious particles; functionally, they are spore-type structures. Once inside a susceptible host cell, the EB prevents phagosome-lysozyme fusion and then undergoes reorganization to form a reticulate body (RB).

The RB synthesizes its own DNA, RNA, and proteins but requires energy in the form of adenosine triphosphate (ATP) from the host cell. After a sufficient amount of RBs have formed, some transform back into EBs, exiting the cell to infect others.

Frequency

United States

Chlamydia is the most commonly reported infectious disease in the United States—estimated at 4 million infections annually with prevalence rates of higher than 10% in sexually active adolescent females.

International

In 1995, the World Health Organization (WHO) estimated 89 million cases of C trachomatis infection worldwide.

Mortality/Morbidity

Although urogenital carriage of chlamydiae often is asymptomatic, the most common manifestation of disease is local mucosal inflammation associated with a discharge, urethritis in the male, and urethritis/vaginitis/cervicitis in the female.

• Chlamydia is one of the leading causes of pelvic inflammatory disease (PID) and infertility in women. The risk of ectopic pregnancy in women who have had PID is 7-10 times greater than that for women without a history of PID. In 15% of women who have contracted PID, chronic abdominal pain is a long-term manifestation that most likely is related to pelvic adhesions in the ovaries and fallopian tubes.
• Chlamydial infections increase the risk for acquiring HIV infection by increasing genital mucosal inflammation.
• Pregnant women infected with chlamydia can pass the infection on to their infants during delivery, which may develop into chlamydial pneumonia or chlamydial conjunctivitis.

Race

The incidence of chlamydial infection is not related to race per se but rather to the sexual histories of the individuals and, particularly, to the frequency and use (or nonuse) of barrier protection.

Sex

Although the presence of asymptomatic infection with genitourinary chlamydiae can differ, acquisition is similar for both sexes.

Age

Age factors in chlamydial genitourinary infection relate to the age of first sexual exposure and the frequency of exposure.

Clinical

History

C trachomatis is a sexually transmitted microorganism responsible for a wide spectrum of diseases that include cervicitis, salpingitis, endometritis, urethritis, epididymitis, conjunctivitis, and neonatal pneumonia. In contrast to gonorrhea infection, most men and women who are infected are asymptomatic, and, therefore, diagnosis is delayed until a positive screening result or upon discovering a symptomatic partner. In July 2007, The US Preventive Services Task Force Screening released a new recommendation statement for chlamydial infections.

Routine chlamydia screening in sexually active young women is recommended to prevent consequences of untreated chlamydial infection (eg, pelvic inflammatory disease, infertility, ectopic pregnancy, chronic pelvic pain). Fewer than half of young, sexually active females in the United States are screened for chlamydia, reports Morbidity and Mortality Weekly Report. Nationally, the annual screening rate increased from 25.3% in 2000 to 43.6% in 2006 and then decreased slightly to 41.6% in 2007.¹

• Risk factors
  • Nonwhite race
  • Multiple sexual partners
  • Age younger than 19 years
  • Poor socioeconomic conditions
  • Single marital status
  • Nonbarrier contraceptive use
• Neonatal risk
  • Conjunctivitis
  • Neonatal pneumonia

Physical

• Women
  • Easily induced endocervical bleeding
  • Mucopurulent endocervical discharge
  • Intermenstrual bleeding
  • Cervical discharge
  • Dysuria
  • Abdominal pain
• Men
  • Urethral discharge
  • Urinary frequency and/or urgency
  • Dysuria
  • Scrotal pain/tenderness
  • Perineal fullness (related to prostatitis)

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