Acute renal failure management US Medical PG Practice Questions and MCQs
Practice US Medical PG questions for Acute renal failure management. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Acute renal failure management US Medical PG Question 1: A 62-year-old woman with type 2 diabetes mellitus comes to the physician because of a 3-month history of fatigue and weakness. Her hemoglobin A1c concentration was 13.5% 12 weeks ago. Her blood pressure is 152/92 mm Hg. Examination shows lower extremity edema. Serum studies show:
K+ 5.1 mEq/L
Phosphorus 5.0 mg/dL
Ca2+ 7.8 mg/dL
Urea nitrogen 60 mg/dL
Creatinine 2.2 mg/dL
Which of the following is the best parameter for early detection of this patient’s renal condition?
- A. Serum total protein
- B. Serum creatinine
- C. Urinary red blood cell casts
- D. Serum urea nitrogen
- E. Urinary albumin (Correct Answer)
Acute renal failure management Explanation: ***Urinary albumin***
- **Microalbuminuria** is often the earliest detectable sign of **diabetic nephropathy**, occurring before changes in GFR or serum creatinine become apparent.
- Regular screening for urinary albumin in diabetic patients allows for early intervention to slow the progression of **renal damage**.
*Serum total protein*
- **Hypoalbuminemia** can be seen in advanced renal disease due to significant proteinuria, but it is not an early marker.
- Other conditions like **liver disease** or **malnutrition** can also cause altered serum total protein, making it less specific for early renal damage.
*Serum creatinine*
- **Serum creatinine** levels rise significantly only after a substantial portion of kidney function (around 50%) has been lost.
- Therefore, it is a marker of established renal dysfunction rather than an early indicator.
*Urinary red blood cell casts*
- The presence of **red blood cell casts** in urine indicates **glomerulonephritis** or other inflammatory conditions affecting the glomeruli.
- While concerning, it is not the typical or earliest presentation of **diabetic nephropathy**, which primarily involves proteinuria.
*Serum urea nitrogen*
- **Blood urea nitrogen (BUN)** levels, like creatinine, increase with declining kidney function and are used to assess the severity of **renal impairment**.
- However, BUN levels can also be influenced by factors like **hydration status** and **protein intake**, and they are not an early marker of nascent renal disease.
Acute renal failure management US Medical PG Question 2: A 55-year-old man with a history of IV drug abuse presents to the emergency department with an altered mental status. He was found unconscious in the park by police. His temperature is 100.0°F (37.8°C), blood pressure is 87/48 mmHg, pulse is 150/min, respirations are 17/min, and oxygen saturation is 98% on room air. Physical exam is notable for multiple scars and abscesses in the antecubital fossa. His laboratory studies are ordered as seen below.
Serum:
Na+: 139 mEq/L
Cl-: 105 mEq/L
K+: 4.3 mEq/L
HCO3-: 19 mEq/L
BUN: 20 mg/dL
Glucose: 95 mg/dL
Creatinine: 1.5 mg/dL
Ca2+: 10.2 mg/dL
Which of the following is the most appropriate treatment for this patient’s blood pressure and acid-base status?
- A. Ringer lactate (Correct Answer)
- B. Dextrose 5% normal saline
- C. Sodium bicarbonate
- D. Hypertonic saline
- E. Normal saline
Acute renal failure management Explanation: ***Ringer lactate***
- This patient presents with **hypotension** (BP 87/48 mmHg) and **metabolic acidosis** (HCO3- 19 mEq/L, with an elevated anion gap if calculated). Ringer lactate is a **balanced crystalloid solution** that contains lactate, which is metabolized to bicarbonate in the liver, helping to correct metabolic acidosis while providing fluid resuscitation.
- The patient's history of **IV drug abuse**, fever, and altered mental status suggests a possible underlying infection (e.g., sepsis), which often presents with hypotension and metabolic acidosis requiring aggressive fluid resuscitation with a balanced solution.
*Dextrose 5% normal saline*
- While it provides fluids and some sodium, Dextrose 5% normal saline contains **free water**, which is not ideal for a patient with hypotension and may exacerbate cerebral edema if present.
- It does not contain bicarbonate precursors and therefore would not directly address the patient's **metabolic acidosis**.
*Sodium bicarbonate*
- Administering sodium bicarbonate directly might be considered for severe metabolic acidosis, but **fluid resuscitation with a balanced solution** like Ringer lactate is usually the initial step to address both hypotension and acidosis.
- Excessive or rapid administration of sodium bicarbonate can lead to **alkalosis**, worsening intracellular acidosis, and fluid overload.
*Hypertonic saline*
- **Hypertonic saline** is primarily used to treat severe **hyponatremia** or to reduce intracranial pressure.
- It would not be appropriate for a patient with normal sodium levels and hypotension, as it could lead to further dehydration or worsen hypernatremia.
*Normal saline*
- **Normal saline (0.9% NaCl)** is an isotonic crystalloid often used for fluid resuscitation, but it has a high chloride content.
- Large volumes of normal saline can worsen or induce **hyperchloremic metabolic acidosis**, which would be detrimental to a patient who already has metabolic acidosis.
Acute renal failure management US Medical PG Question 3: A 56-year-old man is brought to the Emergency Department with intense chest pain that radiates to his left arm and jaw. He also complains of feeling lightheaded. Upon arrival, his blood pressure is 104/60 mm Hg, pulse is 102/min, respiratory rate is 25/min, body temperature is 36.5°C (97.7°F), and oxygen saturation is 94% on room air. An electrocardiogram shows an ST-segment elevation in I, aVL, and V5-6. The patient is transferred to the cardiac interventional suite for a percutaneous coronary intervention. The patient is admitted to the hospital after successful revascularization. During his first night on the ICU floor his urinary output is 0.15 mL/kg/h. Urinalysis shows muddy brown casts. Which of the following outcomes specific to the patient’s condition would you expect to find?
- A. Blood urea nitrogen (BUN):Serum creatinine ratio (Cr) < 15:1 (Correct Answer)
- B. Urinary osmolality 900 mOsmol/kg (normal: 500–800 mOsmol/kg)
- C. Urinary osmolality 550 mOsmol/kg (normal: 500–800 mOsmol/kg)
- D. FENa+ < 1%
- E. Blood urea nitrogen (BUN):Serum creatinine ratio (Cr) > 20:1
Acute renal failure management Explanation: ***Blood urea nitrogen (BUN):Serum creatinine ratio (Cr) < 15:1***
- The patient's presentation with **ST-segment elevation myocardial infarction (STEMI)** followed by low urinary output and **muddy brown casts** strongly indicates **acute tubular necrosis (ATN)**, a form of intrinsic renal failure.
- In ATN, **tubular damage** impairs reabsorption of urea more than creatinine, leading to a **BUN:Cr ratio typically less than 15:1**.
*Urinary osmolality 900 mOsmol/kg (normal: 500–800 mOsmol/kg)*
- A urinary osmolality of 900 mOsmol/kg indicates appropriately concentrated urine, which is characteristic of **prerenal azotemia**, not ATN.
- In ATN, the damaged tubules lose their ability to concentrate urine, resulting in **isosthenuric** urine with osmolality typically **< 350 mOsmol/kg** (approaching plasma osmolality).
*Urinary osmolality 550 mOsmol/kg (normal: 500–800 mOsmol/kg)*
- While 550 mOsmol/kg is within the normal range, it is still **too concentrated for ATN**.
- In ATN, damaged tubules cannot effectively concentrate urine, resulting in **urine osmolality < 350 mOsmol/kg** (isosthenuric, similar to plasma osmolality of ~290 mOsmol/kg).
- This value of 550 mOsmol/kg suggests preserved concentrating ability, which would be more consistent with prerenal azotemia or normal renal function.
*FENa+ < 1%*
- A **fractional excretion of sodium (FENa+) less than 1%** indicates good tubular reabsorption of sodium and is characteristic of **prerenal azotemia**, where the kidneys are attempting to conserve volume.
- In ATN, the damaged tubules cannot effectively reabsorb sodium, so the **FENa+ is typically greater than 2%**.
*Blood urea nitrogen (BUN):Serum creatinine ratio (Cr) > 20:1*
- A **BUN:Cr ratio greater than 20:1** is characteristic of **prerenal azotemia**, reflecting decreased renal perfusion causing increased urea reabsorption relative to creatinine.
- In ATN, the **tubular damage** leads to inefficient urea reabsorption, keeping the ratio **below 15:1**.
Acute renal failure management US Medical PG Question 4: A 33-year-old man presents to the emergency department because of an episode of bloody emesis. He has had increasing dyspnea over the past 2 days. He was diagnosed with peptic ulcer disease last year. He has been on regular hemodialysis for the past 2 years because of end-stage renal disease. He skipped his last dialysis session because of an unexpected business trip. He has no history of liver disease. His supine blood pressure is 110/80 mm Hg and upright is 90/70, pulse is 110/min, respirations are 22/min, and temperature is 36.2°C (97.2°F). The distal extremities are cold to touch, and the outstretched hand shows flapping tremor. A bloody nasogastric lavage is also noted, which eventually clears after saline irrigation. Intravenous isotonic saline and high-dose proton pump inhibitors are initiated, and the patient is admitted into the intensive care unit. Which of the following is the most appropriate next step in the management of this patient?
- A. Observation in the intensive care unit
- B. Double-balloon tamponade
- C. Hemodialysis (Correct Answer)
- D. Transfusion of packed red blood cells
- E. Esophagogastroduodenoscopy
Acute renal failure management Explanation: ***Hemodialysis***
- The patient has **end-stage renal disease** and missed his last dialysis session, leading to **uremic crisis** with **dyspnea** (fluid overload) and **asterixis** (uremic encephalopathy).
- **Uremic platelet dysfunction** also contributes to the GI bleeding, making dialysis essential to correct coagulopathy.
- Emergency hemodialysis is the most critical intervention to remove accumulated toxins, correct fluid overload, and improve hemostasis before any invasive procedures.
*Observation in the intensive care unit*
- While ICU admission is appropriate for monitoring, passive observation without addressing the underlying **uremia** will not resolve the critical issues of **fluid overload**, **uremic encephalopathy**, and **uremic coagulopathy**.
- The patient's missed dialysis session and severe symptoms necessitate active intervention, not just observation.
*Double-balloon tamponade*
- This procedure is reserved for **life-threatening variceal bleeding** that is refractory to endoscopic treatment.
- The patient's history of **peptic ulcer disease** (not cirrhosis) and the clearing of bloody lavage with saline irrigation suggest non-variceal bleeding, making tamponade inappropriate.
*Transfusion of packed red blood cells*
- While the patient shows signs of **orthostatic hypotension** and **tachycardia** suggesting hypovolemia, the GI bleeding has **stabilized** (NG lavage cleared with irrigation).
- Transfusion may be needed based on hemoglobin levels, but it does not address the **immediately life-threatening uremic crisis** with encephalopathy and platelet dysfunction.
- The most urgent priority is dialysis to stabilize the patient for subsequent procedures.
*Esophagogastroduodenoscopy*
- EGD is indicated to identify and potentially treat the source of **upper GI bleeding** in a patient with **peptic ulcer disease**.
- However, the patient's severe **uremic symptoms**, **encephalopathy**, and **coagulopathy** must be addressed first to safely perform this invasive procedure and optimize outcomes.
Acute renal failure management US Medical PG Question 5: Ten days after being discharged from the hospital, a 42-year-old man comes to the emergency department because of reduced urine output for 3 days. Physical examination is normal. Serum creatinine concentration is 2.9 mg/dL. Urinalysis shows brownish granular casts and 2+ proteinuria. Renal biopsy shows patchy necrosis of the proximal convoluted tubule with sloughing of tubular cells into the lumen and preservation of tubular basement membranes. Administration of which of the following drugs during this patient's hospitalization is most likely the cause of the observed decrease in renal function?
- A. Aspirin
- B. Acyclovir
- C. Omeprazole
- D. Captopril
- E. Gentamicin (Correct Answer)
Acute renal failure management Explanation: ***Gentamicin***
- The patient's presentation with **acute kidney injury** (reduced urine output, elevated creatinine) and characteristic urinalysis findings (**brownish granular casts**, proteinuria) points to **acute tubular necrosis (ATN)**.
- **Gentamicin** is an **aminoglycoside antibiotic** well-known for causing ATN, particularly with prolonged use or in susceptible patients. The biopsy findings of **patchy necrosis of the proximal convoluted tubule** and **sloughing of tubular cells** with preserved basement membranes are classic for ATN.
*Aspirin*
- **Aspirin**, especially at high doses or in sensitive individuals, can cause **analgesic nephropathy** (chronic interstitial nephritis) or, less commonly, acute interstitial nephritis.
- It does not typically cause ATN with the specific biopsy findings described, and its primary renal toxicity is often related to **prostaglandin inhibition**.
*Acyclovir*
- **Acyclovir** can cause acute kidney injury, but it primarily does so through **crystalluria** and **tubular obstruction**, leading to acute interstitial nephritis or acute kidney injury due to crystal deposition.
- The biopsy findings described (patchy tubular necrosis, sloughing cells) are not typical for acyclovir-induced nephrotoxicity.
*Omeprazole*
- **Omeprazole**, a proton pump inhibitor, is most commonly associated with **acute interstitial nephritis (AIN)**, an allergic reaction affecting the renal interstitium.
- AIN would typically present with eosinophiluria, white blood cell casts, and interstitial inflammation on biopsy, rather than primary tubular necrosis.
*Captopril*
- **Captopril**, an ACE inhibitor, can cause acute kidney injury, particularly in patients with **renal artery stenosis** or volume depletion, by altering glomerular hemodynamics.
- It typically does not cause direct tubular necrosis or the specific histological changes seen in ATN; rather, it primarily reduces **glomerular filtration pressure**.
Acute renal failure management US Medical PG Question 6: An 84-year-old man is brought to the physician by the staff of a group home where he resides because of worsening confusion and decreased urinary output. His nurse reports that the patient has not been drinking much for the last 3 days. Examination shows a decreased skin turgor and dry oral mucosa. His pulse is 105/min and blood pressure is 100/65 mm Hg. His serum creatinine is 3.1 mg/dL and a urea nitrogen is 42 mg/dL. Urine studies show multiple brownish granular casts. Which of the following processes is most likely involved in the pathogenesis of this patient's condition?
- A. Immune complex deposition in mesangium
- B. Leukocytic infiltration of renal interstitium
- C. Necrosis of renal papillae
- D. Necrosis of tubular epithelial cells (Correct Answer)
- E. Disruption of glomerular podocytes
Acute renal failure management Explanation: ***Necrosis of tubular epithelial cells***
- The patient presents with classic signs of **acute kidney injury (AKI)**, including confusion, decreased urinary output, decreased skin turgor, dry oral mucosa, tachycardia, hypotension, elevated creatinine (3.1 mg/dL), and urea nitrogen (42 mg/dL).
- The presence of **brownish granular casts** in the urine is highly suggestive of **acute tubular necrosis (ATN)**, secondary to ischemia caused by severe dehydration and hypoperfusion.
*Immune complex deposition in mesangium*
- This typically points to a **glomerular pathology**, such as IgA nephropathy or post-infectious glomerulonephritis.
- These conditions would usually present with **hematuria** and **proteinuria**, not necessarily brownish granular casts or the acute dehydration found here.
*Leukocytic infiltration of renal interstitium*
- This finding is characteristic of **acute interstitial nephritis**, which is often caused by drug hypersensitivity or infection.
- The clinical presentation with dehydration and granular casts is not typical for acute interstitial nephritis.
*Necrosis of renal papillae*
- **Renal papillary necrosis** is often associated with analgesic abuse, sickle cell disease, diabetes, or obstruction.
- While it can cause AKI, it typically presents with **flank pain** and **hematuria**, and the urine sediment would show ghost cells or fragments of necrotic papillae, not specifically brownish granular casts.
*Disruption of glomerular podocytes*
- **Podocyte disruption** is seen in primary glomerular diseases like minimal change disease or focal segmental glomerulosclerosis.
- These conditions primarily cause **nephrotic syndrome** (heavy proteinuria, edema), which is not the main presentation here.
Acute renal failure management US Medical PG Question 7: An asymptomatic 15-year-old high school wrestler with no family history of renal disease is completing his preseason physical exam. He submits a urine sample for a dipstick examination, which tests positive for protein. What is the next appropriate step in management?
- A. Renal ultrasound
- B. Urine culture
- C. Repeat dipstick on a separate occasion (Correct Answer)
- D. Spot urine-protein-to-creatinine ratio
- E. 24 hour urine collection
Acute renal failure management Explanation: ***Repeat dipstick on a separate occasion***
- An asymptomatic patient with an isolated positive urine dipstick for protein, especially an active adolescent, often experiences **transient proteinuria** due to factors like exercise or stress.
- Repeating the dipstick on a separate occasion can help differentiate between transient and persistent proteinuria, with **orthostatic (postural) proteinuria** being a common benign cause in this age group.
*Renal ultrasound*
- **Renal ultrasound** is typically indicated for evaluating structural abnormalities of the kidneys, hydronephrosis, or in cases of persistent hematuria, recurrent UTIs, or declining renal function.
- It is not the initial step for isolated, asymptomatic proteinuria without other concerning symptoms.
*Urine culture*
- A **urine culture** is performed to diagnose urinary tract infections (UTIs) when symptoms like dysuria, frequency, or fever are present, or if the dipstick shows signs of infection (nitrites, leukocyte esterase).
- This patient is asymptomatic, and the primary concern is proteinuria, not infection.
*Spot urine-protein-to-creatinine ratio*
- The **spot urine protein-to-creatinine ratio** is used to quantify proteinuria, especially after persistent proteinuria has been established, or to monitor known renal disease.
- Before quantifying, it's crucial to confirm the proteinuria is persistent and not transient.
*24 hour urine collection*
- A **24-hour urine collection** is the gold standard for accurately measuring the total amount of protein excreted in a day.
- However, it is an inconvenient test and typically reserved for quantifying known persistent proteinuria, not as a first step after an initial positive dipstick in an asymptomatic individual.
Acute renal failure management US Medical PG Question 8: A 63-year-old man undergoes uncomplicated laparoscopic cholecystectomy for acute cholecystitis and is admitted to the surgical ward for postoperative management. On postoperative day 1, routine laboratory studies reveal an increase in serum creatinine to 1.46 mg/dL from 0.98 mg/dL before the operation; BUN is 37 mg/dL, increased from 18 mg/dL on prior measurement; K is 4.8 mEq/L and CO2 is 19 mEq/L. The patient has an indwelling urinary catheter in place, draining minimal urine over the last few hours. Which of the following is the most appropriate next step in management?
- A. Initiate emergent hemodialysis
- B. Obtain bilateral renal ultrasonography
- C. Obtain urinalysis
- D. Evaluate urinary catheter for obstruction (Correct Answer)
- E. Administer IV fluid bolus
Acute renal failure management Explanation: ***Evaluate urinary catheter for obstruction***
- The patient presents with **acute kidney injury (AKI)** evidenced by elevated BUN and creatinine, along with minimal urine output, raising suspicion for a **post-renal obstruction**.
- Given the presence of an indwelling urinary catheter, a **mechanical obstruction** (e.g., kink, clot) is the most immediate and easily reversible cause to investigate.
*Initiate emergent hemodialysis*
- While the patient has AKI, there are no immediate life-threatening indications for **emergent hemodialysis** such as severe hyperkalemia, refractory acidosis, or pulmonary edema.
- Furthermore, investigating and potentially reversing the cause of AKI should precede considering dialysis.
*Obtain bilateral renal ultrasonography*
- **Renal ultrasonography** is appropriate for evaluating post-renal causes after simpler causes of obstruction, such as a catheter issue, have been ruled out.
- It would be used to assess for hydronephrosis, which indicates **ureteral or bladder outlet obstruction**.
*Obtain urinalysis*
- A **urinalysis** can help characterize intrinsic renal causes of AKI (e.g., ATN, interstitial nephritis) but is less helpful in initial assessment of a suspected acute obstruction related to a catheter.
- The immediate priority is to rule out a mechanical issue with the indwelling catheter.
*Administer IV fluid bolus*
- The patient's BUN/creatinine ratio (approximately 25:1) suggests a potential **pre-renal etiology** (volume depletion), but the minimal urine output with an indwelling catheter warrants ruling out obstruction first.
- Administering fluids without addressing a potential obstruction could worsen patient outcome if the obstruction is present.
Acute renal failure management US Medical PG Question 9: A 49-year-old woman presents to the emergency room with bloody stool and malaise. She developed a fever and acute left lower quadrant abdominal pain earlier in the day. She has had 2 bowel movements with bright red blood. Her past medical history is notable for hyperlipidemia, hypertension, and diabetes mellitus. She takes lovastatin, hydrochlorothiazide, metformin, glyburide, and aspirin. Her temperature is 102.9°F (39.4°C), blood pressure is 101/61 mmHg, pulse is 110/min, and respirations are 22/min. On exam, she is fully alert and oriented. She is tender in the left lower quadrant. A computerized tomography (CT) scan is performed demonstrating acute diverticulitis. She is admitted and started on broad-spectrum antibiotics. 48 hours later, her urine output is significantly decreased. Her abdominal pain has improved but she has started vomiting and appears confused. She has new bilateral lower extremity edema and decreased breath sounds at the lung bases. Laboratory analysis upon admission and 48 hours later is shown below:
Admission:
Hemoglobin: 11.9 g/dl
Hematocrit: 34%
Leukocyte count: 11,500/mm^3
Platelet count: 180,000/ mm^3
Serum:
Na+: 141 mEq/L
Cl-: 103 mEq/L
K+: 4.5 mEq/L
HCO3-: 23 mEq/L
BUN: 21 mg/dL
Glucose: 110 mg/dL
Creatinine: 0.9 mg/dL
48 hours later:
Hemoglobin: 10.1 g/dl
Hematocrit: 28%
Leukocyte count: 11,500 cells/mm^3
Platelet count: 195,000/ mm^3
Serum:
Na+: 138 mEq/L
Cl-: 100 mEq/L
K+: 5.1 mEq/L
HCO3-: 24 mEq/L
BUN: 30 mg/dL
Glucose: 120 mg/dL
Creatinine: 2.1 mg/dL
Which of the following findings would most likely be seen on urine microscopy?
- A. Waxy casts
- B. Muddy brown casts (Correct Answer)
- C. White blood cell casts
- D. Fatty casts
- E. Hyaline casts
Acute renal failure management Explanation: ***Muddy brown casts***
- The patient's presentation with **acute kidney injury** (creatinine rising from 0.9 to 2.1 mg/dL in 48 hours) along with signs of **sepsis** (fever, hypotension, altered mental status, decreased urine output) strongly suggests **acute tubular necrosis (ATN)**, a common cause of intrinsic renal failure.
- **Muddy brown casts** composed of degenerating renal tubular epithelial cells and granular material are pathognomonic for **acute tubular necrosis** and indicate significant tubular damage.
*Waxy casts*
- **Waxy casts** are typically associated with **chronic renal failure** and advanced renal disease, indicating prolonged tubular stasis and severe urine flow reduction.
- While the patient has acute kidney injury, her history does not suggest pre-existing chronic kidney disease to this extent.
*White blood cell casts*
- **White blood cell casts** are characteristic of **interstitial nephritis** or **pyelonephritis**, indicating inflammation or infection within the kidney parenchyma.
- Although the patient has a possible infection (diverticulitis, sepsis), the rapid decline in renal function with a clear rise in creatinine points more directly to ATN rather than primarily interstitial inflammation.
*Fatty casts*
- **Fatty casts** are typically seen in **nephrotic syndrome**, a condition characterized by massive proteinuria, hypoalbuminemia, and significant edema.
- The patient's symptoms are more consistent with acute kidney injury due to sepsis, and there is no information to suggest nephrotic-range proteinuria.
*Hyaline casts*
- **Hyaline casts** can be found in **healthy individuals** from concentrated urine or after exercise and are non-specific, indicating only mild tubular protein aggregation.
- They are not indicative of significant renal pathology like ATN and would not explain the patient's acute and severe renal deterioration.
Acute renal failure management US Medical PG Question 10: A 25-year-old man is brought to the emergency department because of a 6-day history of fever and chills. During this period, he has had generalized weakness, chest pain, and night sweats. He has a bicuspid aortic valve and recurrent migraine attacks. He has smoked one pack of cigarettes daily for 5 years. He does not drink alcohol. He has experimented with intravenous drugs in the past but has not used any illicit drugs in the last two months. Current medications include propranolol and a multivitamin. He appears ill. His temperature is 39°C (102.2°F), pulse is 108/min, respirations are 14/min, and blood pressure is 150/50 mm Hg. Diffuse crackles are heard. A grade 3/6 high-pitched, early diastolic, decrescendo murmur is best heard along the left sternal border. An S3 gallop is heard. The remainder of the physical examination shows no abnormalities. Laboratory studies show:
Hemoglobin 13.1 g/dL
Leukocyte count 13,300/mm3
Platelet count 270,000/mm3
Serum
Glucose 92 mg/dL
Creatinine 0.9 mg/dL
Total bilirubin 0.4 mg/dL
AST 25 U/L
ALT 28 U/L
Three sets of blood cultures are sent to the laboratory. Transthoracic echocardiography confirms the diagnosis. In addition to antibiotic therapy, which of the following is the most appropriate next step in management?
- A. Transcatheter aortic valve implantation (TAVI)
- B. Repeat echocardiography in 4 weeks
- C. Cardiac MRI
- D. Mechanical valve replacement of the aortic valve
- E. Porcine valve replacement of the aortic valve (Correct Answer)
Acute renal failure management Explanation: ***Porcine valve replacement of the aortic valve***
- The patient presents with **infective endocarditis** (fever, history of IV drug use, bicuspid aortic valve) complicated by **severe aortic regurgitation** with **hemodynamic compromise** (wide pulse pressure 150/50 mmHg, diffuse crackles, S3 gallop indicating heart failure). The presence of heart failure, severe regurgitation, and hemodynamic instability are **class I indications for urgent surgical valve replacement** in infective endocarditis.
- For this **25-year-old with a history of IV drug use**, a **bioprosthetic (porcine) valve** is preferred over mechanical valve because it **avoids the need for lifelong anticoagulation**. In patients with **history of substance abuse**, there are significant concerns about **compliance with warfarin therapy** and the associated bleeding risks. Additionally, the risk of **recurrent endocarditis** from future IV drug use makes avoiding anticoagulation particularly important, as warfarin increases bleeding complications.
- The **new diastolic murmur**, **S3 gallop**, and **low diastolic blood pressure (50 mmHg)** indicate critical hemodynamic compromise requiring prompt surgical intervention once antibiotic therapy is initiated.
*Mechanical valve replacement of the aortic valve*
- While mechanical valves offer **greater durability** and are often considered for young patients due to longevity (avoiding repeat surgery), they require **lifelong anticoagulation with warfarin**.
- In this patient with **recent IV drug use history** (stopped only 2 months ago), there are significant concerns about **medication compliance** and the **high risk of bleeding complications** with anticoagulation. The risk of **recurrent IV drug use** and potential for trauma also makes anticoagulation particularly hazardous.
- Though mechanical valve is a viable option, the **patient's social history** makes bioprosthetic valve the safer choice despite his young age.
*Transcatheter aortic valve implantation (TAVI)*
- **TAVI** is primarily indicated for **aortic stenosis** in elderly or high-surgical-risk patients, not for **aortic regurgitation** in young patients.
- The presence of **active infection** is a **relative contraindication** to TAVI due to risk of seeding the new prosthetic valve and technical challenges with valve seating in an inflamed annulus.
*Repeat echocardiography in 4 weeks*
- Delayed follow-up would be appropriate for **stable, medically managed endocarditis** or mild valve dysfunction.
- This patient has **acute, severe heart failure** with hemodynamic instability requiring **urgent surgical intervention**, not watchful waiting.
*Cardiac MRI*
- While cardiac MRI provides detailed anatomical and functional information, it is **not indicated** when the diagnosis has already been **confirmed by echocardiography** and the patient requires **urgent surgical management**.
- Further imaging would only delay necessary treatment in a hemodynamically unstable patient.
More Acute renal failure management US Medical PG questions available in the OnCourse app. Practice MCQs, flashcards, and get detailed explanations.
