A 21-year-old woman comes to the office for evaluation of urinary frequency and urgency for the past 2 days. She has also noticed scant vaginal discharge. The patient has never had these symptoms before. She has no chronic medical conditions, and she takes a combination oral contraceptive pill daily. The patient has been sexually active with multiple partners over the last year. She is a college student and does not use tobacco, alcohol, or illicit drugs. A urine sample is obtained for urinalysis and culture. Which of the following additional findings would be most suggestive of a diagnosis of pyelonephritis?

Question

A 21-year-old woman comes to the office for evaluation of urinary frequency and urgency for the past 2 days.  She has also noticed scant vaginal discharge.  The patient has never had these symptoms before.  She has no chronic medical conditions, and she takes a combination oral contraceptive pill daily.  The patient has been sexually active with multiple partners over the last year.  She is a college student and does not use tobacco, alcohol, or illicit drugs.  A urine sample is obtained for urinalysis and culture.  Which of the following additional findings would be most suggestive of a diagnosis of pyelonephritis?

Quizplus · Accepted Answer

11ec160b_3925_26f4_9249_d7e267589361_MD0001_00 This patient has urinary frequency and urgency consistent with a urinary tract infection (UTI). Women are more susceptible to UTIs because the female urethra is closer to the rectum and shorter than the male urethra. Sexual intercourse is often a precipitating factor because it introduces enteric bacteria to the periurethral area, leading to ascending infection of the bladder. UTIs are categorized into either upper (eg, pyelonephritis) or lower (eg, cystitis) infections based on the ascension of bacteria through the urinary tract. Pyelonephritis and cystitis can share concomitant clinical features including dysuria, suprapubic pressure, and hematuria. Urinalysis with microscopy is often performed to confirm the diagnosis of UTI, but both upper and lower UTIs can show hematuria, pyuria (presence of urine white blood cells [WBCs]), and bacteriuria (Choices A and D). However, the presence of WBC casts on urinalysis differentiates between upper and lower UTIs and can confirm the diagnosis of pyelonephritis. This is because WBC casts are formed only in renal tubules, where WBCs precipitate with Tamm-Horsfall protein secreted by tubular epithelial cells. WBC casts can also be seen with other intrarenal disorders (eg, acute interstitial nephritis), but urinary frequency and urgency are not typically present. (Choices B and C) Fever and leukocytosis are nonspecific signs indicating systemic inflammation. Although they are usually present with pyelonephritis and absent with lower UTIs (eg, cystitis), they may occur in numerous other conditions (eg, pelvic inflammatory disease). In contrast, urine WBC casts are specific for intrarenal pathology. (Choice E) In patients with urinary frequency and urgency, sterile pyuria (WBCs but no bacteria) is suggestive of urethritis from an atypical organism such as Chlamydia trachomatis or Ureaplasma species. Educational objective: Both upper (eg, pyelonephritis) and lower (eg, cystitis) urinary tract infections (UTIs) can show microscopic hematuria, pyuria, and bacteriuria on urinalysis with microscopy. However, the presence of white blood cell (WBC) casts can confirm the diagnosis of pyelonephritis in patients with UTI symptoms because WBC casts form only in the renal tubules.

A 21-Year-Old Woman Comes to the Office for Evaluation of Urinary