A nurse is assessing a 1-year-old toddler and notices a large abdominal mass and pink-tinged urine on the diaper. Which of the following disorders should the nurse suspect?

Choice A rationale Pyloric stenosis is a condition in infants where the muscle at the outlet of the stomach (pylorus) thickens, blocking the flow of food. Symptoms include projectile vomiting, visible peristaltic waves, and an olive-shaped mass in the epigastrium. It does not typically cause a large abdominal mass or pink-tinged (hematuria) urine. Choice B rationale Nephrotic syndrome is a kidney disorder characterized by excessive protein loss in the urine (proteinuria), leading to severe edema and hypoalbuminemia. While it affects the kidneys and causes significant abdominal swelling due to fluid accumulation (ascites), it usually causes foamy or dark urine, but typically not hematuria and rarely presents as a firm, large mass. Choice C rationale Wilms' tumor, or nephroblastoma, is the most common kidney cancer in children, typically presenting between ages 1 and 5. Classic signs include a firm, non-tender, large abdominal mass that rarely crosses the midline, along with microscopic or gross hematuria (pink-tinged urine). Palpation of the mass should be avoided to prevent rupture and potential spread of the tumor cells. Choice D rationale Intussusception is a condition where a segment of the intestine telescopes into an adjacent section, causing an obstruction. Key symptoms include sudden, intermittent abdominal pain, drawing up of the knees, and currant jelly-like stools (blood and mucus). It can cause a sausage-shaped mass in the right upper quadrant, but not typically a large, firm mass or pink-tinged urine indicative of isolated hematuria.