The nurse is caring for a client who reports periods of exacerbations and remissions of bloody diarrhea and abdominal pain. A recent X-ray indicated a continuous pattern of lesions in the large bowel. What underlying condition does the nurse suspect?

Choice A reason: Pyrexia (fever) occurs when pyrogens, like cytokines (IL-1, IL-6), released during infection or inflammation, act on the hypothalamus to raise the body’s temperature set point. This triggers heat production via shivering and vasoconstriction, conserving heat to create a fever, enhancing immune response. This statement accurately describes the primary mechanism of pyrexia.

Choice B reason: Peripheral vasoconstriction occurs during fever to conserve heat but is a response, not the cause, of pyrexia. It results from hypothalamic signaling after pyrogens reset the thermostat. This statement is inaccurate, as vasoconstriction is a secondary effect, not the initiating physiologic mechanism of fever development.

Choice C reason: Fever increases, not decreases, metabolic rate to generate heat via thermogenesis. Pyrogens elevate the hypothalamic set point, prompting energy expenditure through shivering and muscle activity. This statement is inaccurate, as reduced metabolism would lower body temperature, counteracting the fever response triggered by infection or inflammation.

Choice D reason: Prostaglandin synthesis, particularly PGE2, in the hypothalamus is stimulated by pyrogens, raising the temperature set point to cause fever. Inhibiting prostaglandin synthesis (e.g., by NSAIDs) reduces fever, not causes it. This statement is inaccurate, as prostaglandin inhibition opposes the physiologic mechanism of pyrexia.

Choice A reason: Inflammation and hematoma formation occur immediately after a fracture, initiating healing by recruiting immune cells and growth factors. However, this stage does not restore ‘normal’ bone structure, as it involves soft tissue response, not bone remodeling. This statement is inaccurate, as the bone remains structurally abnormal during this early phase.

Choice B reason: Callus formation, occurring 2-6 weeks post-fracture, involves soft and hard callus bridging the fracture. While critical, it represents a temporary, weaker structure, not ‘normal’ bone. Osteoblasts form a cartilaginous matrix, but full strength and normal bone architecture require further remodeling, making this statement less accurate.

Choice C reason: Woven bone formation, where osteoblasts convert callus into disorganized woven bone, marks progression toward normal bone structure. This bone is later remodeled by osteoclasts and osteoblasts into lamellar bone, restoring strength and architecture. This statement is accurate, as woven bone formation approaches ‘normal’ bone structure during healing.

Choice D reason: Osteoclast proliferation resorbs bone during remodeling but does not directly restore ‘normal’ bone. Excessive osteoclast activity could weaken the bone. Osteoblasts, not osteoclasts, drive the formation of woven and lamellar bone, making this statement inaccurate, as osteoclasts support remodeling, not normalization, of bone structure.