A physician-validated, board-style question from the Active Transport QBank. Try it, then check the reasoning for every option.
A 1-year-old boy is brought to the physician because of irritability and poor feeding that began 2 days ago. His mother reports that he has been crying more than usual during this period. He refused to eat his breakfast that morning and has not taken in any food or water since that time. He has not vomited. When changing the boy's diapers this morning, the mother noticed his urine had a strong smell and pink color. He has not passed urine since then. He was born at term and has been healthy. He appears ill. His temperature is 36.8°C (98.2°F), pulse is 116/min, and blood pressure is 98/54 mm Hg. The boy cries when the lower abdomen is palpated. Which of the following is the most appropriate next step in management?
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A
Perform renal ultrasoundIncorrect. Renal ultrasound is useful for evaluating anatomy after a confirmed UTI but does not address the immediate need to decompress the bladder or obtain a sterile culture specimen.
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B
Obtain clean catch urine sampleIncorrect. Clean-catch urine is unreliable in non-toilet-trained infants (high contamination rate) and won't relieve retention.
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C
Perform transurethral catheterizationCorrect. Transurethral catheterization simultaneously relieves urinary retention, decompresses the bladder, and obtains a sterile urine sample for analysis and culture — the priority next step.
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D
Administer cefiximeIncorrect. Empiric antibiotics (cefixime) should follow urine culture sampling — starting them before obtaining urine compromises microbiologic diagnosis.
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E
Administer oral antibiotics empiricallyIncorrect. Empiric oral antibiotics should follow obtaining a sterile urine sample for culture. Starting them first compromises microbiologic diagnosis and does not relieve the urinary retention causing this child's abdominal pain.
↑ Tap an answer to reveal the reasoning
Answer: C. A 1-year-old with irritability, poor feeding, decreased oral intake for over a day, lower-abdominal tenderness, and an inability to pass urine (with the last void showing strong-smelling pink urine) has urinary retention with suspected UTI, possibly with bladder distention and acute obstruction. The most urgent next step is to relieve the retention and obtain a sterile urine sample for culture: transurethral (in-and-out) catheterization simultaneously decompresses the bladder, allows accurate urine collection for analysis and culture, and rules out post-renal obstruction.
Clean-catch sampling is unreliable in nontoilet-trained infants and would also fail to relieve retention. Renal ultrasound is appropriate later to evaluate for anatomic abnormalities (e.g., vesicoureteral reflux, ureterocele, posterior urethral valves) but won't relieve retention or yield a culture-quality specimen. Empiric cefixime should be started after urine culture is obtained — not before sampling. Diagnostic pearl: UTI in a febrile infant always warrants catheterized (or suprapubic) urine sampling for definitive culture, plus consideration of imaging if UTI is confirmed.
**Why each option:**
**A.** Incorrect. Renal ultrasound is useful for evaluating anatomy after a confirmed UTI but does not address the immediate need to decompress the bladder or obtain a sterile culture specimen.
**B.** Incorrect. Clean-catch urine is unreliable in non-toilet-trained infants (high contamination rate) and won't relieve retention.
**C.** Correct. Transurethral catheterization simultaneously relieves urinary retention, decompresses the bladder, and obtains a sterile urine sample for analysis and culture — the priority next step.
**D.** Incorrect. Empiric antibiotics (cefixime) should follow urine culture sampling — starting them before obtaining urine compromises microbiologic diagnosis.