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A 24-year-old man has been diagnosed with acute kidney injury as a result of severe hemorrhaging afier a motor vehicle collision. Which of the following would be expected laboratory values for this patient? A Low urinary osmolality, high urinary sodium concentration B. High urinary osmolality, high urinary sodium concentration Cc. Low urinary osmolality, low urinary sodium concentration D. High urinary osmolality, low urinary sodium concentration ANSWERV ¥ D A high urinary osmolality (usually greater than 900 mOsm/kg) and a low urinary sodium concentration (usually less than 20 mEq/L) are normal physiologic responses to hypoperfusion in patients with normal kidneys. Test Taking Tip Consider that the kidney would want to conserve sodium and water with blood loss. If the kidney is holding onto sodium, little is excreted into the urine, so urinary sodium is low. If the kidney is holding onto water, little is excreted into the urine, so it is concentrated and osmolality is increased. Choose the "Iligh urinary osmolality, low urinary sodium concentration" option. 29-year-old woman has been a patient in the critical care unit for 2 weeks with acute tubular necrosis (ATN) as a result of crush injuries experienced in a motor vehicle collision. She was normotensive on admission. What would be the most common explanation for her ATN? A. Rhabdomyolysis B. Hemorrhage C. Creatinine release D. Cardiac dysrhythmias ANSWERV V A. The most common cause for ATN in a normotensive patient who has experienced crush injuries is rhabdomyolysis with resultant myoglobinuria. Rhabdomyolysis is acute muscle destruction and is associated with myoglobinuria. Myoglobin released from muscle cells may cause acute kidney injury by having a direct toxic effect on tubule epithelial cells or inducing intratubular cast formation. Test Taking Tip The key points in this question are that she had a crush injury and that she was not hypotensive. Hemorthage or dysrhythmias significant cnough to cause ATN certainly would Test Taking Tip Associate phosphorus and calcium with a seesaw. When one side of the seesaw is up, the other is down. This process is consistent with normal and abnormal kidney function. Choose "Hypocalcemia." You do not really need to know what Goodpasture syndrome is to answer the question correctly. Provision of adequate nutrition in a malnourished patient may cause severe deficiency of which of the following electrolytes? A. Potassium B. Magnesium Cc. Calcium D. Phosphate ANSWERVV D. This ofien is called refeeding syndrome. Nutritional support allows the cells to begin making more adenosine triphosphate (ATP), and phosphate supplies are depleted. The same thing happens in diabetic ketoacidosis with treatment when insulin allows glucose to move into the cell increasing production of ATP and depletion of phosphate. A patient is admitted to the critical care unit | year after renal transplant. The patient's serum sodium is 160 mliq/L. Which of the following would be the most likely cause of this patient's elevated sodium level? A. Excessive oral ingestion of sodium B. Heart failure e. Rejection of the kidney D. Corticosteroid therapy ANSWERV Vv D. Rejection would cause the blood urea nitrogen and creatinine to go up, but the sodium would be normal or decreased because of water retention. Heart failure would stimulate aldosterone and retention of sodium and water, so the sodium would be normal but the patient would be fluid overloaded. Nothing is in the case presentation to make you believe that she has been consuming abnormal amounts of sodium. Knowing that post-transplant patients are taking immunosuppressive agents, including corticosteroids, leads you to "Corticosteroid therapy" option. Magnesium sulfate is being given for refractory ventricular tachycardia in a patient with an acute myocardial infarction. The patient becomes hypotensive with respiratory depression and hyporeflexia. What should be done? B. ‘Two units of packed red blood cells ¢c. Nitroglycerin sublingual as needed D. Azathioprine ANSWERV V A. This patient is having symptoms of decreased tissue oxygenation. In acute situations, this would be an indication for blood. In this patient, recombinant human erythropoietin is a more appropriate treatment. Recombinant human erythropoietin is used to treat anemia resulting from reduced renal production of erythropoietin (the hormone that promotes the production of red blood cells). Test Taking Tip Connect the treatment with the cause. The cause of the symptoms is the decreased amount of hemoglobin to carry oxygen. The treatment is to increase the amount of hemoglobin by treating the cause. The cause of anemia in a patient with chronic renal failure is decreased renal production of erythropoietin. Choose the "Recombinant human erythropoietin" option. A patient develops carpopedal spasm and neuromuscular irritability manifested by Chvostek and Trousseau signs. Which electrolyte imbalance should you suspect? A. Hyperkalemia B. Typercalcemia fon Hypermagnesemia D. Hyperphosphatemia ANSWERV V D. The patient's signs/symptoms are associated with hypocalcemia and its reciprocal condition, hyperphosphatemia. The same signs/symptoms also are seen in hypomagnesemia. Test Taking Tip You probably immediately looked for hypocalcemia but could not find it among the options. To answer this question correctly, you need to remember the reciprocal relationship between calcium and phosphorus. A 24-year-old man has been diagnosed with acute kidney injury as a result of severe hemorrhaging after a motor vehicle collision. How would his acute kidney injury be categorized’? A. Prerenal B. Intrarenal D. Bowel perforation ANSWERV ¥ C. Normal dialysate outflow is clear or pale yellow. If the outflow has an amber color, the bladder could have been perforated accidentally during catheter insertion. Test Taking Tip Infection causes the dialysate return to be cloudy, so eliminate that option. Bleeding causes the dialysate return to be pink or red depending on the severity of the bleeding, so eliminate that option. "Bowel perforation" would cause the dialysate return to be brownish, so eliminate that option. "Bladder perforation" would cause any urine that is in the bladder to leak into the peritoncal cavity, discoloring the dialysate return. Choose the "Bladder perforation" option. This question is as easy as color matching. Continuous venovenous hemofiltration (CVVH) is started on a 44-year-old patient for acute oliguric kidney injury. The patient has a history of cardiomyopathy and chronic heart failure. The patient experiences a cardiopulmonary arrest. During the code, lab work reveals a scrum potassium of 8.8 mEq/L. What would be the most appropriate intervention at this time? A. Sodium polystyrene sulfonate (Kayexalate) enema B. Glucose and insulin intravenously Le Sorbitol via a nasogastric tube D. Hemodialysis ANSWERV ¥ B. The most immediate action would be to give glucose and insulin intravenously to drive the potassium temporarily into the cells. This immediate treatment must be followed by some other measure to lower serum potassium, such as Kayexalate and sorbitol and/or hemodialysis. Test Taking Tip This patient is in cardiac arrest, and the chosen action must have immediate effect. All options other than "Glucose and insulin intravenously" will take too long. Which of the following would not be restricted during the oligurie phase of acute kidney injury? A. Protein B. Sodium Cc. Potassium D. Carbohydrates ANSWERV V D. Remember that spironolactone traditionally has been called a potassium-sparing diuretic. ‘Thus it would cause the retention of potassium. Continuous venovenous hemofiltration (CVVH) is started on a 44-year-old patient for acute oliguric kidney injury. The patient has a history of cardiomyopathy and chronic heart failure. Although CAVII is continuing, the patient's blood pressure drops from 120/70 mm IIg to 90/60 mm Hg. You observe a drop in the plasma in the drainage bag. One immediate action would be to: A. increase the infusion rate. B. decrease the infusion rate. Cc. raise the filter above the level of the patient's heart. Dz. lower the filter below the level of the patient's heart ANSWERV V D. Placing the filter below the level of the patient's heart allows the force of gravity to help move the ultrafiltrate. When the patient is hypotensive, the force that pushes the blood through the circuit is decreased, which decreases the amount of ultrafiltrate. Test Taking Tip Increasing the infusion rate might increase the plasma in the drainage bag, which might perpetuate the hypotension. A more "gentle" way of increasing the return would be to lower the drainage bag. Pigment-related acute tubular necrosis (ATN) occurs primarily in patients with which of the following? A. Abdominal trauma B. Knife wounds C. Crush injuries D. Thoracic trauma ANSWERV V C. Crush injuries cause muscle destruction and rhabdomyolysis, which liberates myoglobin into the blood. This heavy pigment potentially causes tubular occlusion and ATN. Myoglobinuria also may occur in electrical burns, status epilepticus, muscle ischemia, and statins A patient with acute kidney injury has the following arterial blood gas results: pH 7.32 Paco2 35 mm Hg A 23-year-old woman is beginning her second hemodialysis treatment for acute kidney injury. Suddenly she complains of headache and nausea. She is agitated and confused, and you notice twitching in her right hand. Which of the following is causing these findings? A. Uremia B. Dialysis disequilibrium syndrome ‘C.. Intracercbral hemorrhage D. Fluid overload ANSWERV ¥ B. Dialysis disequilibrium syndrome occurs when urea is removed from the blood at a rate faster than it is removed from the brain tissue. The greater amount of urea in the brain causes a fluid shift resulting in cerebral edema. A patient with diabetic ketoacidosis was admitted to the critical care unit from the emergency department. His initial laboratory results included serum glucose 660 mg/dl, pH 7.0, and serum potassium of 5 mEq/L. As the pI] is corrected with insulin and fluids, what would be the anticipated change in his potassium? A. The potassium would decrease to approximately 3 mEq/L. B. The potassium would decrease to approximately 4 mEq/L. c. The potassium would remain at approximately 5 mEq/L. D. The potassium would inercase to approximately 6 mEq/L. ANSWERV V A. Changes in pH causes potassium to move either into or out of the cell. Acidosis causes potassium to leave the cell and increases serum potassium levels, whereas alkalosis causes potassium to enter the cell and decreases serum potassium. For every change in pH of 0.1, the potassium moves 0.5 mEq/L in the opposite direction. In this patient the pH has changed 4 * 0.1 from the midline normal pH of 7.4 so the serum potassium is expected to decrease by 2 mEq/L (0.5 x 4) when the pH is corrected. So 5 minus 2 mEq/L is 3 mEq/L and this is what the potassium would be expected to fall to with correction of the pH. Potassium replacement is indicated now even though his potassium is currently at a high normal level. The potassium level will plummet as insulin and fluids correct the blood glucose and pI. Test Taking Tip If you remember there is a change in serum potassium level with pH changes, you eliminate 5 mEq/L. Also, remember the change in pH and the change in scrum potassium is inverse, do you eliminate 6 mEq/L. To choose between 3 mEq/L and 4 mEq/L, you need to know how significant a change is expected. A. Saline, mannitol, and bicarbonate B. Colloids, furosemide, and dopamine iG, Blood, furosemide, and dobutamine D. Lactated Ringer solution, hydrochlorothiazide, and dopamine ANSWERV V A. The destruction of muscle by the electricity has caused myoglobin to appear in the urine. Myoglobin is a heavy pigment that can cause acute tubular necrosis and kidney injury. The treatment for myoglobinuria is to flush the pigments through with fluids, usually saline, and diuretics, usually mannitol. Alkalinization of the urine using sodium bicarbonate intravenously also may be prescribed to increase the excretion of the myoglobin. Which of the following is indicated in acute tubular necrosis (ATN) when the blood urea nitrogen (BUN) is greater than 100 mg/dl? A. Aggressive rehydration B. Diuretics Cc. Dialysis Dd. Nephrectomy ANSWERV V¥ C. Dialysis usually is indicated when the BUN is greater than 100 mg/dl. Aggressive rehydration is indicated long before the BUN is greater than 100 mg/dl. Diuretics may be used early but are not used if the patient is dehydrated or anuric. Nephrectomy is not indicated for ATN A patient has gained | kg since yesterday. How much fluid does this weight gain represent? A 250 ml 500 ml c. 1000 ml D. 2000 ml ANSWERV ¥ C.