The nervous parent asks when the big "soft spot" (anterior fontanel) will be closed. The nurse's most informative response would be

A. Metabolic alkalosis is not a common acid-base imbalance associated with ARF. Instead, metabolic acidosis is more commonly observed due to the retention of metabolic waste products.

B. Water and sodium (Na) retention: In ARF, the kidneys are unable to effectively filter and excrete waste products and excess fluids. This leads to the retention of water and sodium, contributing to fluid overload.

C. Anemia: ARF can lead to decreased erythropoietin production by the kidneys, which can result in anemia due to reduced red blood cell production.

D. Hyperkalemia: The impaired kidney function in ARF may result in the inability to regulate potassium levels. Elevated levels of potassium (hyperkalemia) can be a dangerous complication.

E. Increased urinary output is not a typical finding in ARF. Instead, the hallmark of ARF is a reduction in urine output or oliguria.

A.Pyloric stenosis is a condition where there's narrowing of the opening between the stomach and the small intestine. It is not related to inadequate motility of the intestine.

B.Enterocolitis refers to inflammation of the small intestine and colon. While this can cause obstruction in some cases, it's not the primary cause of inadequate motility as seen in the question.

C.Encopresis is the voluntary or involuntary passage of feces outside the toilet in children who should be toilet trained. It is not a cause of mechanical intestinal obstruction.

D. Hirschsprung's disease is a congenital disorder where there is inadequate motility in part of the intestine, leading to mechanical obstruction. It usually affects the colon and is due to the absence of ganglion cells in the affected segment of the bowel.

So, Hirschsprung's disease is the specific condition that leads to inadequate motility and mechanical obstruction of part of the intestine in infants.