Correct Answer: B

Rationale: The correct answer is B: Paroxysmal abdominal pain. Colic in infants is characterized by paroxysmal abdominal pain, leading to excessive crying and fussiness. It is not caused by inadequate peristalsis (Choice A), an allergic response to certain proteins in milk (Choice C), or a protective mechanism designed to eliminate foreign proteins (Choice D). Understanding that colic is primarily associated with abdominal pain helps healthcare providers provide appropriate care and support to parents dealing with colicky infants.

Correct Answer: D

Rationale: In a child with hypothyroidism, weight gain is a typical finding due to the slowed metabolism associated with the condition. This occurs because thyroid hormone levels are insufficient to regulate metabolism effectively. Choices A, B, and C are not typically associated with hypothyroidism. Nervousness is more commonly seen in conditions like hyperthyroidism, where there is an excess of thyroid hormones. Heat intolerance may be seen in hyperthyroidism as well, where the body's metabolism is increased. Smooth velvety skin is a characteristic finding in conditions like Cushing's syndrome, where there is excess cortisol production.

Correct Answer: A

Rationale: The correct first intervention when managing a child with diabetic ketoacidosis is to begin intravenous saline solution to address dehydration and restore electrolyte balance. Rehydration is essential to improve perfusion and correct electrolyte imbalances. Administering insulin without addressing dehydration can potentially lead to further complications. Placing the child on a cardiac monitor or pulse oximetry monitor is important but not the initial priority in managing DKA.

Correct Answer: C

Rationale: The priority nursing action after a corrective surgery for hypertrophic pyloric stenosis (HPS) is to assess the IV site for infiltration. This is crucial to ensure proper fluid administration and prevent complications such as extravasation or infiltration. Applying restraints (Choice A) is not indicated in this scenario and can compromise the infant's comfort and safety. Administering a mild sedative (Choice B) is not necessary and should only be done based on specific clinical indications. Attaching the nasogastric tube to wall suction (Choice D) may be important for certain conditions but is not the priority immediately post-surgery; assessing the IV site is more urgent to prevent potential complications related to IV therapy.

Correct Answer: B

Rationale: The correct answer is B: Tissue oxygen needs. Polycythemia occurs as the body's response to chronic hypoxia by increasing RBC production to enhance oxygen delivery. In tetralogy of Fallot, a congenital heart defect, the heart's structure causes reduced oxygen levels in the blood. This chronic hypoxia stimulates the bone marrow to produce more red blood cells, leading to an elevated RBC count. Choice A is incorrect as low blood pressure is not directly related to polycythemia in this context. Choice C, diminished iron level, is not the cause of polycythemia in tetralogy of Fallot. Choice D, hypertrophic cardiac muscle, is not the primary cause of the elevated RBC count in this case.