A nurse is caring for a 6-week-old infant who has hypertrophic pyloric stenosis (HPS). Which of the following clinical manifestations should the nurse expect?

A. Fever: Osteomyelitis is often associated with fever as it is an infectious process that can cause an elevated body temperature.

B. Unwillingness to move the affected extremity: Children with osteomyelitis may experience pain and discomfort, leading to a reluctance to move the affected limb.

C. A previous closed fracture of an extremity is not typically a direct assessment finding for osteomyelitis. Osteomyelitis is more commonly associated with infections that can spread to the bone, and a previous fracture may not always be present.

D. Redness and swelling at the site: Osteomyelitis can cause local inflammation, leading to redness and swelling at the affected area.

E. Severe pain: Pain is a common symptom of osteomyelitis, and it can be severe, leading to the child's unwillingness to move the affected extremity.

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.