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A previously healthy 6-month-old girl is brought to the emergency department (ED) with 3 days of fever and vomiting. Physical examination is significant for fever (39.3°C) and mild dehydration. A catheterized urinalysis shows specific gravity of 1.030, pH of 6.1, 1+ ketones, 3+ leukocyte esterase, 1+ protein, 1+ blood, and positive nitrites. Her urine microscopy shows 50 to 100 white blood cells (WBCs)/high-power field (HPF), < 5 red blood cells (RBCs)/HPF, and bacteria. The urine culture is pending. Her parents would like to know if she has a urinary tract infection (UTI).

Which of the following positive results in this child has the highest sensitivity for presumptively diagnosing UTI?

A. Leukocyte esterase on urinalysis

B. Nitrites on urinalysis

C. WBCs on urine microscopy

D. RBCs on urine microscopy

E. Bacteria on urine microscopy

Answer: A

In infants and children who are not toilet trained, the urine sample for urinalysis and urine culture should be obtained via catheterization or suprapubic aspiration. A diagnosis of UTI requires pyuria (≥ 3 WBCs/HPF or ≥ trace leukocyte esterase on dipstick) and at least 50,000 colony-forming units of a single bacterial species per milliliter of urine from a clean catch or catheterized specimen. Results from the urinalysis are typically available before the preliminary urine culture. In a febrile infant with symptoms suggestive of UTI, a urinalysis with leukocyte esterase or nitrites or a urine microscopy with bacteria or WBCs increases suspicion for a UTI. Nitrites have the highest specificity (98%) but result from the conversion of dietary nitrates to nitrites by gram-negative enteric bacteria and require 4 hours in the bladder. A false-negative result may occur from insufficient bladder time in young children who frequently empty their bladders. The highest sensitivity for a diagnosis of UTI is positive results for leukocyte esterase or nitrites (93%), followed by leukocyte esterase only (83%), bacteria on microscopy (81%), WBCs on microscopy (73%), and nitrites only (53%).

You are called to the emergent delivery of a G1P0 mother. Her ultrasound in triage was significant for oligohydramnios. On initial exam, the infant is noted to have mild respiratory distress. His exam is also remarkable for abnormal abdominal musculature and testes that are not palpable. Of the following, which statement is most accurate about the patient’s condition?

A. This condition is only seen in males.

B. Most cases are diagnosed prenatally on ultrasound.

C. Vesicoureteral reflux (VUR) is a rare complication.


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