Background
Urethritis is defined as infection-induced inflammation of the urethra. Although various clinical conditions may result in irritation of the urethra, the term urethritis is typically reserved to describe urethral inflammation caused by a sexually transmitted disease (STD). Urethritis is normally categorized into one of two forms, based on etiology: gonococcal urethritis (GU) and nongonococcal urethritis (NGU).
Pathophysiology
Urethritis is an inflammatory condition that can be infectious or posttraumatic in nature. Infectious causes of urethritis are typically sexually transmitted and categorized as either gonococcal urethritis (ie, due to infections with Neisseria gonorrhoeae) or NGU (ie, due to infections with Chlamydia trachomatis, Ureaplasma urealyticum, Mycoplasma hominis, Mycoplasma genitalium, or Trichomonas vaginalis).
Rare infectious causes of urethritis include lymphogranuloma venereum, herpes genitalis, syphilis, mycobacterial infection, and bacterial infections that are typically associated with cystitis (usually gram-negative rods) in the presence of urethral stricture. Other rare but reported causes of urethritis include viral, streptococcal, anaerobic, and meningococcal infections.
Posttraumatic urethritis can occur in 2%-20% of patients practicing intermittent catheterization and following instrumentation or foreign body insertion. Urethritis is 10 times more likely to occur with latex catheters than with silicone catheters.
Urethritis may be associated with other infectious syndromes, such as epididymitis, orchitis, prostatitis, proctitis, reactive arthritis, iritis, pneumonia, otitis media, and urinary tract infection.
Epidemiology
Frequency
United States
Urethritis occurs in 4 million Americans each year. The incidence of gonococcal urethritis is estimated at over 700,000 new cases annually, and the incidence of NGU is approximately 3 million new cases annually. Both infections are significantly underreported. The incidence of gonococcal urethritis has declined steadily since 2000, and the incidence of NGU is increasing. NGU incidence is highest in the summer months.
International
Worldwide, approximately 62 million new cases of gonococcal urethritis and 89 million new cases of NGU are reported each year.
Mortality/Morbidity
- Approximately 10%-40% of women with urethritis eventually develop pelvic inflammatory disease (PID), which may subsequently cause infertility and ectopic pregnancy secondary to postinflammatory scar formation in the fallopian tubes. PID can occur even in women with asymptomatic infections.
- Children born to mothers with Chlamydia infection may develop conjunctivitis, iritis, otitis media, or pneumonia if exposed to the organism while passing through the birth canal. Performing cesarean delivery in patients with known chlamydial infections and routine treatment of all newborns with antichlamydial eyedrops has decreased the incidence of this problem in developed countries.
- Disseminated gonococcal infection (DGI) and reactive arthritis develop in less than 1% of female patients with urethritis.
- Morbidity due to urethritis in males is less common (1%-2%), typically taking the form of urethral stricture or stenosis due to postinflammatory scar formation. Other potential complications of urethritis in males include prostatitis, acute epididymitis, abscess formation, proctitis, infertility, abnormal semen, DGI, and reactive arthritis.
- Reactive arthritis is characterized by NGU, anterior uveitis, and arthritis and is strongly associated with the gene for HLA-B27. Rare but serious complications of DGI include arthritis, meningitis, and endocarditis.
- Mortality rates are minimal in patients with gonococcal urethritis or NGU.
Race
- Urethritis has no racial predilection; however, persons of low socioeconomic class are affected more often than persons of higher socioeconomic class.
Sex
- Urethritis has no sexual predilection; however, data may be skewed because urethritis is underrecognized in women. Up to 75% of females with the condition can be asymptomatic or may instead present with cystitis, vaginitis, or cervicitis. Homosexual males are at a greater risk for urethritis than are (1) heterosexual males or (2) females in general.
Age
- Urethritis may occur in any sexually active person, but incidence is highest among people aged 20-24 years.
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