Renal and Genitourinary Tract Infections in Adolescents and Young Adults

Lawrence J. D’Angelo

Shamir Tuchman

Genitourinary tract infections are common in adolescents and young adults (AYAs). Those most often diagnosed include cystitis, pyelonephritis, urethritis, and asymptomatic bacteriuria.

CYSTITIS

Epidemiology

Over the course of a lifetime, urinary tract infections (UTIs) occur three to five times more commonly in women than in men. For adolescents, this difference may be as great as 50-fold.
One in three females will have at least one episode of acute cystitis during adolescence or young adulthood.¹ Hooton et al.² defined the annual incidence of a lower UTI in a cohort of sexually active female university students to be 0.7 infections/person-year. One infection appears to predispose an individual to more, with Foxman³ finding that 27% of young women had at least one recurrence within 6 months of the first infection and 2.7% had a second recurrence in this same period.
Risk factors for infection
- Females: Females are at greater risk than males because of a short urethra, which has close proximity to vaginal and rectal microorganisms. Other risk factors for UTIs include the following (although many of these risk factors are not well substantiated in the literature):
  - Coitus and coital behaviors (diaphragm use, coital frequency, use of spermicide-coated condoms, and having a new sexual partner)
  - Pregnancy
  - Previous UTIs
  - Nonsecretor of ABO blood group antigens (bind bacteria to vaginal epithelial cells)⁴
  - Catheterization or instrumentation of the urethra⁵
  - Anatomical abnormalities (e.g., urethral stenosis, neurogenic bladder, and nephrolithiasis)
  - Obesity⁶
  - Having a first-degree relative with a history of UTIs⁷
- Males: Because UTIs in general and cystitis in particular are so much less frequent in males, risk factors and pathophysiology are less well understood. In nonsexually active male adolescents, bladder and renal infections are more likely to result from structural or functional abnormalities of the perineum and/or urinary tract. Additional factors may include the following:
  - Blood group B or AB nonsecretor; P1 blood group phenotype
  - Insertive anal intercourse⁸
  - Sexual partner with vaginal colonization by uropathogens
  - Uncircumcised⁹

Microbiology

Females

The most common organism causing acute cystitis is Escherichia coli (75% to 90%). Older literature suggested the importance of Staphylococcus saprophyticus in AYAs, but it now appears that other gram-negative organisms cause most of the remainder of the infections.¹⁰ Organisms such as Klebsiella species, Pseudomonas aeruginosa, Enterobacter and Proteus species, Staphylococcus aureus, Streptococcus faecalis, and Serratia marcescens may play a greater role in recurrent or chronic, rather than in acute, infections. Gram-positive organisms such as Staphylococcus saprophyticus, enterococci, and group B streptococcus are less frequent pathogens; recent studies have shown that in women with symptoms suggestive of UTI, positive midstream cultures for the latter two organisms have a very low positive predictive value when compared to catheterized specimens,¹¹ implying that these are likely colonizers of the external periurethral area. In addition, emerging evidence suggests that Mycoplasma genitalium is associated with urethritis in women (see Chapter 56).¹²

Males

Approximately three-fourths of UTIs in male AYAs are due to gram-negative bacilli, but E. coli infections are not nearly as common as in women. Gram-positive organisms, particularly enterococci and coagulase-negative staphylococci, account for approximately one-fifth of infections. Sexually transmitted pathogens such as Trichomonas vaginalis, Neisseria gonorrhoeae, Chlamydia trachomatis, Mycoplasma hominis, and Gardnerella vaginalis can cause urethral, epididymal, and prostate infections that can be confused with UTIs in AYAs.¹³ Furthermore, M. genitalium has been shown to cause non-gonococcal urethritis (NGU) in men, with the highest prevalence in men who are C. trachomatis negative (see Chapter 56).¹²

Symptoms and Signs

Females

In women, the most common symptoms of UTIs are dysuria, frequency, hesitancy, suprapubic pain or pressure, overt pyuria and hematuria. These symptoms are often difficult to localize. For example, in female patients, dysuria can be related to infections in the bladder, urethra, vulva, or vaginal tract. In this case, the location and timing of the dysuria are occasionally helpful. Dysuria
associated with cystitis or urethritis is often described as internal pain and is usually worse when a patient initiates micturition. External pain or “terminal pain” (at the end of micturition) is more often associated with other conditions such as a vulvar inflammation, upper genital tract infection, or a herpes simplex infection.

TABLE 26.1 Differential Diagnosis of Acute Dysuria in Women

Condition	Pathogen	Pyuria	Hematuria	Bacteriuria	Urine Culture^a	Signs and Symptoms
Cystitis	E. coli, S. saprophyticus, Proteus, Klebsiella sp	Usually	Sometimes	Usually	10²->10⁵	Acute onset, severe symptoms, dysuria, frequency, urgency, suprapubic or low back pain, suprapubic tenderness, internal dysuria
Urethritis	C. trachomatis, N. gonorrhoeae, herpes simplex virus	Usually	Rarely	Rarely	<10²	Gradual onset, mild symptoms, vaginal discharge or bleeding, lower abdominal pain, new sexual partner, cervical or vaginal lesions on examination
Vaginitis	Candida sp, T. vaginalis	Rarely	Rarely	Rarely	<10²	Vaginal discharge or odor, pruritis, dyspareunia, external dysuria, no frequency or urgency, vulvovaginitis on examination
^aColony forming units (CFU)/mL

Table 26.1 lists the pathogens, incidence of pyuria and hematuria, urine culture findings, and signs and symptoms of acute dysuria in women.

Males

Apart from the preceding symptoms, male patients may also have symptoms associated with infections in the prostate (perineal or rectal pain), epididymis (scrotal discomfort or tender epididymis), or testicles (testicular pain and swelling).

Differential Diagnosis of Acute Dysuria

The most common complaint arousing suspicion of a UTI is dysuria. However, dysuria may be a symptom of infection elsewhere in the urinary tract or genital tract, particularly in AYAs.¹⁴,¹⁵ The differential diagnosis of dysuria includes the following:

Females