A 16-year-old girl comes to the office due to 2 days of a burning sensation with urination. She had sexual intercourse with her partner last week and used a condom for contraception. The patient says, "I always urinate right after sex." She has no vaginal discharge, and vital signs are normal. Examination shows suprapubic tenderness. Urinalysis reveals positive nitrites, positive leukocyte esterase, 50 white blood cells/hpf, and many bacteria. Urine β-hCG is negative. Which of the following is the most likely cause of this patient's infection?

Question

A 16-year-old girl comes to the office due to 2 days of a burning sensation with urination.  She had sexual intercourse with her partner last week and used a condom for contraception.  The patient says, "I always urinate right after sex."  She has no vaginal discharge, and vital signs are normal.  Examination shows suprapubic tenderness.  Urinalysis reveals positive nitrites, positive leukocyte esterase, 50 white blood cells/hpf, and many bacteria.  Urine β-hCG is negative.  Which of the following is the most likely cause of this patient's infection?

Quizplus · Accepted Answer

This patient's dysuria, suprapubic tenderness, and urinalysis abnormalities suggest acute simple cystitis. Women are at much greater risk than men for urinary tract infections (UTIs) because they have a shorter urethra lying in close proximity to the anus and vaginal introitus, which allows enteric flora (eg, Escherichia coli) to spread to the vaginal opening and subsequently ascend through the urethra to the bladder. The major risk factor in otherwise healthy young women is recent sexual intercourse. Although urinating after intercourse flushes bacteria from the lower urinary tract (thereby reducing UTI risk), patients may still develop a UTI. (Choice B) Hematologic infections generally enter the urinary tract through the glomeruli and cause pyelonephritis. Although pyuria and bacteriuria are usually present, most patients are systemically ill with fever, chills, and/or fatigue. Hematologic dissemination directly to the bladder is uncommon. (Choice C) Lymphatic spread of infection is common in skin and soft tissue infections (eg, cellulitis) and is often marked by erythematous streaks on the skin. Lymphatic spread to the urinary tract system is uncommon. (Choice D) Although poor genital hygiene can increase the risk that bacteria spread from the anus to the vaginal introitus, the primary mechanism of acute simple cystitis is the ascending spread of bacteria through the urethra to the bladder. (Choice E) Sexually transmitted infections, particularly Chlamydia trachomatis, Trichomonas vaginalis, and Neisseria gonorrhea, often cause dysuria in women. However, these infections are frequently associated with vaginal discharge. In addition, suprapubic tenderness less common. Educational objective: Women are at high risk for urinary tract infections due to a shorter urethra that is close to the anus and vaginal introitus, which allows enteric pathogens to colonize the vagina and ascend to the bladder. Acute simple cystitis is generally marked by dysuria, urinary frequency/urgency, suprapubic tenderness, and pyuria/bacteriuria on urinalysis.

A 16-Year-Old Girl Comes to the Office Due to 2