Acute Renal Failure (ARF) questions with complete solutions
What is acute renal failure? Correct Answer--an abrupt decrease in renal function resulting in retention of nitrogenous waste
-result of decreased renal blood flow, intrinsic renal parenchymal diseases, or obstruction of urine flow
-acute tubular necrosis is the most common intrinsic cause of ARF
What is the most common intrinsic cause of ARF? Correct Answer-
acute tubular necrosis
What is the epidemiology of ARF? Correct Answer-1% on admission to hospital
2-5% during hospitalization
What is the etiology of ARF in the hospitalized patient? Correct Answer-In hospitalized adults, the most common cause of ARF is prerenal azotemia--30-60% of all cases
In hospitalized adults, 1-10% of ARF is associated with postrenal azotemia
Acute tubular necrosis (ATN) is most common intrinsic renal disease leading to ARF
**common predisposing factor is prerenal azotemia
**40-60% in post trauma or postoperative patient What is the most common intrinsic renal disease that leads to ARF? Correct Answer-acute tubular necrosis
In hospitalized adults, the most common cause of ARF is what? Correct Answer-prerenal azotemia 30-60%
What is the pathophysiology of prerenal azotemia? Correct Answer-
reduction in glomerular perfusion secondary to decreased volume or situations with decreased circulation (CHF, advanced cirrhosis, and septic states)--high (>20) ratio of BUN to serum creatinine ratio with low urine output
** they look warm, flushed, and sepsis is common (similar to tylenol OD)
What is the pathophysiology of acute tubular necrosis (ATN)? Correct Answer-decreased blood flow with ischemia
What is the clinical presentation of ARF? Correct Answer-Decrease in urine output, dark urine, cola-colored urine, and sx suggestive of uremia,
such as fatigue, weakness, N/V loss of appetite, metallic taste in the mouth, itching, confusion, fluid retention, and HTN
What is the chart review, hx, and px of ARF? Correct Answer--correct diagnosis depend on careful review of patient data and hx
-start with hx and review of chart (look for reduced weight, postural BP and pulse changes, and also a reduced JVP) -examine abdomen for distention of the bladder
What labs would you look at for ARF? Correct Answer-ratio of BUN to creatinine
urinary volume
UA and urine sediment
distinguish btwn prerenal azotemia and acute tubular necrosis
What would the ratio of BUN to creatinine show in ARF? Correct Answer--in prerenal azotemia, BUN/creatinine ratio is > 20:1
-a high level of creatinine that exceeds the elevation of BUN suggests rhabdomyolysis
-within 48 hours if the serum creatinine rises at least 0.3 mg/dl (suspect)
What are other causes of an increased BUN/creatinine ratio? Correct Answer-GI bleeding, use of systemic steroids; catabolism caused by medical problems, or a high protein diet
What would the urinary volume show in ARF? Correct Answer-less than
400 ml/day with oliguria
< 100 ml/day with anuria
What would the UA and urine sediment show in ARF? Correct Answer--
in prerenal failure: moderate number of hyaline and finely granular casts
may be seen
What is acute renal failure? Correct Answer--an abrupt decrease in renal function resulting in retention of nitrogenous waste
-result of decreased renal blood flow, intrinsic renal parenchymal diseases, or obstruction of urine flow
-acute tubular necrosis is the most common intrinsic cause of ARF
What is the most common intrinsic cause of ARF? Correct Answer-
acute tubular necrosis
What is the epidemiology of ARF? Correct Answer-1% on admission to hospital
2-5% during hospitalization
What is the etiology of ARF in the hospitalized patient? Correct Answer-In hospitalized adults, the most common cause of ARF is prerenal azotemia--30-60% of all cases
In hospitalized adults, 1-10% of ARF is associated with postrenal azotemia
Acute tubular necrosis (ATN) is most common intrinsic renal disease leading to ARF
**common predisposing factor is prerenal azotemia
**40-60% in post trauma or postoperative patient What is the most common intrinsic renal disease that leads to ARF? Correct Answer-acute tubular necrosis
In hospitalized adults, the most common cause of ARF is what? Correct Answer-prerenal azotemia 30-60%
What is the pathophysiology of prerenal azotemia? Correct Answer-
reduction in glomerular perfusion secondary to decreased volume or situations with decreased circulation (CHF, advanced cirrhosis, and septic states)--high (>20) ratio of BUN to serum creatinine ratio with low urine output
** they look warm, flushed, and sepsis is common (similar to tylenol OD)
What is the pathophysiology of acute tubular necrosis (ATN)? Correct Answer-decreased blood flow with ischemia
What is the clinical presentation of ARF? Correct Answer-Decrease in urine output, dark urine, cola-colored urine, and sx suggestive of uremia,
such as fatigue, weakness, N/V loss of appetite, metallic taste in the mouth, itching, confusion, fluid retention, and HTN
What is the chart review, hx, and px of ARF? Correct Answer--correct diagnosis depend on careful review of patient data and hx
-start with hx and review of chart (look for reduced weight, postural BP and pulse changes, and also a reduced JVP) -examine abdomen for distention of the bladder
What labs would you look at for ARF? Correct Answer-ratio of BUN to creatinine
urinary volume
UA and urine sediment
distinguish btwn prerenal azotemia and acute tubular necrosis
What would the ratio of BUN to creatinine show in ARF? Correct Answer--in prerenal azotemia, BUN/creatinine ratio is > 20:1
-a high level of creatinine that exceeds the elevation of BUN suggests rhabdomyolysis
-within 48 hours if the serum creatinine rises at least 0.3 mg/dl (suspect)
What are other causes of an increased BUN/creatinine ratio? Correct Answer-GI bleeding, use of systemic steroids; catabolism caused by medical problems, or a high protein diet
What would the urinary volume show in ARF? Correct Answer-less than
400 ml/day with oliguria
< 100 ml/day with anuria
What would the UA and urine sediment show in ARF? Correct Answer--
in prerenal failure: moderate number of hyaline and finely granular casts
may be seen
