clinical skills exam questions

Correct Answer: C

Rationale: Rationale: Acute tubular necrosis (ATN) is the most common intrarenal condition causing acute kidney injury. ATN is characterized by damage to the renal tubules due to ischemia or nephrotoxic substances. Prolonged ischemia (choice A) and exposure to nephrotoxic substances (choice B) can lead to ATN. Hypotension for several hours (choice D) can result in ischemic injury, which may lead to ATN but is not the direct cause. Therefore, choice C is correct as it directly relates to the primary intrarenal condition of ATN.

Correct Answer: A

Rationale: The correct answer is A because renin activates the renin-angiotensin-aldosterone cascade. Renin is released by the kidneys in response to low blood pressure or low sodium levels. It acts on angiotensinogen to form angiotensin I, which is then converted to angiotensin II by angiotensin-converting enzyme. Angiotensin II causes vasoconstriction, leading to increased blood pressure, and stimulates aldosterone release, promoting sodium and water retention. Choice B is incorrect because renin does not suppress angiotensin production; it actually initiates the process. Choice C is incorrect because renin's action leads to increased sodium reabsorption by stimulating aldosterone release. Choice D is incorrect because renin does not inhibit aldosterone release; it promotes it as part of the renin-angiotensin-aldosterone cascade.

Correct Answer: D

Rationale: The correct answer is D because continuous venovenous hemodiafiltration (CVVHDF) combines ultrafiltration, convection, and dialysis to maximize fluid and solute removal. Ultrafiltration removes plasma water, convection removes fluids and solutes, and dialysis facilitates solute removal through diffusion. Choice A is incorrect because convection alone does not remove solutes, but CVVHDF combines convection with other methods. Choice B is incorrect because CVVHDF is not specifically used for volume overload, although it does remove fluids. Choice C is incorrect because CVVHDF does not involve adding dialysate to remove solutes; instead, it relies on diffusion for solute removal. In summary, the correct answer D is the best choice as it encompasses all the components needed for comprehensive fluid and solute removal in CVVHDF.

Correct Answer: C

Rationale: Step 1: Syndrome of inappropriate antidiuretic hormone (SIADH) leads to excess water retention, diluting sodium levels in the blood. Step 2: Fluid restriction is the mainstay of treatment to prevent further dilution of sodium. Step 3: Administering 3% normal saline (choice A) can worsen the condition by further increasing sodium levels. Step 4: Exogenous vasopressin (choice B) would exacerbate the problem by increasing water retention. Step 5: Low sodium diet (choice D) may be beneficial in the long term but is not the immediate priority.

Correct Answer: A

Rationale: The correct answer is A: sepsis. Sepsis is a leading cause of acute kidney injury in critically ill patients due to the systemic inflammatory response leading to kidney damage. Fluid overload (B) can contribute but is not the primary cause. Medications (C) and hemodynamic instability (D) can also lead to acute kidney injury but are not as common as sepsis in critically ill patients.