To return a patient with hyponatremia to normal sodium levels, it is safer to restrict fluid intake than to administer sodium:

Correct Answer: C

Rationale: It is safer to restrict fluid intake rather than administer sodium to return a patient with hyponatremia to normal sodium levels to prevent fluid overload symptoms. Restoring normal sodium levels in patients with hyponatremia requires caution to prevent rapid correction which can lead to osmotic demyelination syndrome. By restricting fluid intake, the dilutional effect on sodium levels can be reduced, aiding in a safer and more controlled correction of hyponatremia without causing fluid overload. Administering sodium can lead to rapid changes in sodium levels, increasing the risk of complications.

Correct Answer: B

Rationale: Coarctation of the aorta is a congenital heart defect in which there is a narrowing of the aorta leading to differential pulses in the upper and lower extremities. In neonates, this can manifest as weaker femoral pulses compared to radial pulses due to decreased blood flow to the lower body. This difference in pulse amplitude between the femoral and radial pulses bilaterally is a classic finding in coarctation of the aorta, making it the most likely cause in this scenario. Other conditions like patent ductus arteriosus, diminished cardiac output, or left to right shunting in the heart may not specifically present with this particular pulse amplitude difference.

Correct Answer: A

Rationale: Younger age is a significant risk factor for extraneural metastasis in pediatric brain tumors.

Correct Answer: A

Rationale: Polycythemia, which is an abnormally elevated level of red blood cells in the blood, is commonly associated with congenital heart disease. In cases where there is a congenital heart defect that causes reduced oxygen levels in the blood, the body compensates by producing more red blood cells to try to improve oxygen delivery. This increased red blood cell production can lead to polycythemia. In turn, polycythemia can increase the risk of thrombosis, which is a known risk factor for cerebrovascular accidents (CVAs) or strokes. Therefore, polycythemia is most likely associated with a CVA resulting from congenital heart disease.

Correct Answer: C

Rationale: Leukemia is a type of cancer that affects the blood and bone marrow, leading to an overproduction of abnormal white blood cells. The symptoms of leukemia can include fatigue, weakness, weight loss, frequent infections, fever, bruising or bleeding easily, and bone pain. Given the vague presenting symptoms and the potential involvement of multiple bodily systems, leukemia is a condition that should be suspected and investigated further. Anemia, rheumatic arthritis, and systematic lupus erythematosus can also present with some similar symptoms, but for the given scenario, leukemia is the most probable condition to suspect.