What is the physiologic mechanism behind the development of pyrexia?
Release of pyrogens resetting the hypothalamic thermostat
Increased peripheral vasoconstriction reducing heat loss
Decreased metabolic rate increasing heat production
Inhibition of prostaglandin synthesis in the hypothalamus
The Correct Answer is A
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.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is D
Explanation
Choice A reason: Chronic kidney disease (CKD) does not primarily cause anemia by leaking red blood cells (RBCs) into urine. While hematuria may occur in some renal conditions, anemia in CKD results mainly from reduced erythropoietin production, not RBC loss. This statement is inaccurate, as it misrepresents the primary mechanism of anemia in CKD.
Choice B reason: Inflammation in CKD may contribute to anemia by suppressing erythropoiesis through cytokine release, but it does not directly attack RBCs. The primary cause is erythropoietin deficiency due to impaired renal function. This statement is inaccurate, as it overstates inflammation’s role and ignores the key hormonal mechanism in CKD-related anemia.
Choice C reason: High vascular pressure in CKD can damage kidneys but does not directly cause RBCs to burst (hemolysis). Anemia in CKD stems from reduced erythropoietin, not mechanical RBC destruction. This statement is inaccurate, as it incorrectly links hypertension’s renal effects to direct RBC damage, misrepresenting the anemia’s cause.
Choice D reason: CKD causes anemia due to reduced erythropoietin synthesis by damaged kidneys. Erythropoietin stimulates RBC production in bone marrow. In CKD, impaired renal function decreases erythropoietin, leading to anemia. This statement is accurate, as it correctly identifies the hormonal deficiency as the primary cause of low RBC counts in CKD.
Correct Answer is B
Explanation
Choice A reason: Crohn’s disease does not always spread to the liver. While it can cause liver complications like primary sclerosing cholangitis or fatty liver in some cases, this is not universal. This statement is inaccurate, as liver involvement is a complication, not a defining feature of Crohn’s disease.
Choice B reason: Crohn’s disease is characterized by a patchy, or “skip lesion,” pattern of bowel involvement, affecting any part of the gastrointestinal tract discontinuously. Inflammation is transmural, causing fistulas or strictures. This statement is accurate, as the patchy distribution is a hallmark distinguishing it from ulcerative colitis.
Choice C reason: Continuous bowel involvement is characteristic of ulcerative colitis, not Crohn’s disease. Crohn’s affects the bowel in a segmental, patchy manner, with healthy areas between lesions. This statement is inaccurate, as it incorrectly describes Crohn’s tissue involvement pattern, which is distinctly non-continuous.
Choice D reason: Crohn’s disease increases cardiovascular risk due to chronic inflammation, but stroke is not a well-established direct complication. Inflammatory markers may contribute to atherosclerosis, but stroke risk is less specific than patchy bowel involvement. This statement is inaccurate, as it overstates a specific stroke association.
Whether you are a student looking to ace your exams or a practicing nurse seeking to enhance your expertise , our nursing education contents will empower you with the confidence and competence to make a difference in the lives of patients and become a respected leader in the healthcare field.
Visit Naxlex, invest in your future and unlock endless possibilities with our unparalleled nursing education contents today
Report Wrong Answer on the Current Question
Do you disagree with the answer? If yes, what is your expected answer? Explain.
Kindly be descriptive with the issue you are facing.