Congenital heart defects have traditionally been divided into acyanotic or cyanotic defects. Based on the nurse's knowledge of congenital heart defects, this system in clinical practice is

Correct Answer: D

Rationale: The classification is problematic because children with acyanotic heart defects may develop cyanosis, complicating the differentiation between acyanotic and cyanotic defects. Choice A is incorrect because the system is not solely based on explaining hemodynamics. Choice B is incorrect because the classification is not based on the ease of identifying children with cyanotic defects. Choice C is incorrect because cyanosis can indeed be present in children with congenital heart defects, especially acyanotic defects that may lead to cyanosis under certain circumstances.

Correct Answer: C

Rationale: Visible peristalsis and weight loss are classic clinical manifestations of pyloric stenosis. The obstruction at the pyloric sphincter causes visible peristalsis as the stomach tries to push food through the narrowed opening, leading to the appearance of waves across the abdomen. Weight loss occurs due to poor feeding and frequent vomiting associated with pyloric stenosis. Choices A, B, and D are incorrect. Abdominal rigidity and pain on palpation, rounded abdomen and hypoactive bowel sounds, as well as distention of the lower abdomen and constipation are not typically seen in pyloric stenosis.

Correct Answer: A

Rationale: Petechiae, infection, and fatigue are common signs and symptoms of leukemia related to bone marrow involvement. Petechiae are small red or purple spots on the skin caused by bleeding under the skin due to low platelet counts. Infection susceptibility increases due to decreased white blood cells from compromised bone marrow function. Fatigue is a common symptom of anemia resulting from decreased red blood cell production. Choices B, C, and D are incorrect as they do not align with the typical signs and symptoms of leukemia associated with bone marrow dysfunction.

Correct Answer: C

Rationale: When palpating the abdomen of an infant with hypertrophic pyloric stenosis (HPS), the nurse would expect to feel an olive-sized mass in the right upper quadrant. This finding is characteristic of HPS due to the hypertrophied pylorus muscle. Choices A, B, and D are incorrect. A distended colon is not typically associated with HPS. Marked tenderness around the umbilicus is not a specific finding of HPS. Rhythmic peristaltic waves in the lower abdomen are not expected in HPS, as the condition primarily affects the pylorus region of the stomach.

Correct Answer: A

Rationale: The correct answer is A: 'Mental retardation occurs if PKU is untreated.' Phenylketonuria (PKU) is a metabolic disorder that results in the inability to metabolize phenylalanine properly. Without proper dietary management, high levels of phenylalanine can lead to severe mental retardation and other neurological problems. Therefore, educating parents about the importance of early and consistent treatment to prevent mental retardation is crucial. Choice B is incorrect because testing for PKU is typically done shortly after birth, not immediately. Choice C is incorrect because treatment for PKU primarily involves strict dietary management to control phenylalanine intake, not lifelong medications. Choice D is incorrect because PKU is inherited in an autosomal recessive pattern, not as an autosomal dominant gene.