Question 1

Which of the following best defines acute kidney injury (AKI)?

 

A. Decrease in GFR over several months

B. Increase in creatinine ≥0.3 mg/dL within 48 hours

C. Creatinine increase ≥1 mg/dL over 6 months

D. Persistent proteinuria >3 months

E. Hematuria with hypertension

 

Question 2

Which of the following urine outputs meets KDIGO criteria for AKI?

 

A. <1 mL/kg/hr for 2 hours

B. <0.5 mL/kg/hr for 6 hours

C. <1 mL/kg/hr for 12 hours

D. <0.5 mL/kg/hr for 2 hours

E. <0.2 mL/kg/hr for 1 hour

 

Question 3

Which category of AKI is caused by reduced renal perfusion without structural kidney damage?

 

A. Postrenal

B. Intrinsic

C. Prerenal

D. Tubulointerstitial

E. Glomerular

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Question 4

Which laboratory finding most strongly suggests prerenal azotemia?

 

A. FENa >2%

B. Urine sodium >40 mEq/L

C. FENa <1%

D. Urine osmolality <300 mOsm/kg

E. BUN/Cr <10

 

Question 5

Which of the following represents an intrinsic renal cause of AKI due to glomerular disease?

 

A. Acute tubular necrosis

B. Acute interstitial nephritis

C. Acute glomerulonephritis

D. Bladder outlet obstruction

E. Renal artery stenosis

 

Question 6

Which of the following is a postrenal cause of AKI?

 

A. Hypovolemia

B. Sepsis

C. Glomerulonephritis

D. Acute tubular necrosis

E. Bladder outlet obstruction

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Question 7

Which urine microscopy finding is most associated with acute tubular necrosis?

 

A. Dysmorphic RBCs

B. Muddy brown granular casts

C. Hyaline casts

D. RBC casts

E. WBC casts

 

Question 8

Which urine microscopy finding is most characteristic of acute glomerulonephritis?

 

A. WBC casts

B. Muddy brown casts

C. Hyaline casts

D. Dysmorphic RBCs and RBC casts

E. Oval fat bodies

 

Question 9

Which electrolyte abnormality is most life‑threatening in AKI?

 

A. Hyperphosphatemia

B. Hypocalcemia

C. Hyperkalemia

D. Hyponatremia

E. Hypomagnesemia

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Question 10

Which of the following is an indication for emergent dialysis in AKI?

 

A. Mild hyperphosphatemia

B. Mild metabolic acidosis

C. BUN 40 mg/dL

D. Creatinine 2 mg/dL

E. Hyperkalemia with ECG changes

 

Question 11

A 14‑year‑old boy presents with cola‑colored urine and periorbital edema one week after a streptococcal throat infection. Creatinine is elevated and urinalysis shows RBC casts. What type of AKI is most likely present?

 

A. Prerenal AKI

B. Postrenal AKI

C. Intrinsic AKI due to glomerulonephritis

D. Intrinsic AKI due to tubular necrosis

E. Acute interstitial nephritis

 

Question 12

A 16‑year‑old girl develops AKI after receiving IV Pantoprazole. Urine microscopy shows muddy brown casts. What is the most likely diagnosis?

 

A. Acute tubular necrosis

B. Acute interstitial nephritis

C. Prerenal AKI

D. Postrenal AKI

E. Minimal change disease

 

Question 13

A 15‑year‑old boy presents with decreased urine output and flank pain. Ultrasound shows bilateral hydronephrosis. What is the most likely category of AKI?

 

A. Prerenal

B. Intrinsic renal

C. Postrenal

D. Glomerular

E. Tubulointerstitial

 

Question 14

A 13‑year‑old girl with systemic lupus erythematosus develops rising creatinine and hematuria. Urine microscopy shows RBC casts. What is the most likely cause of AKI?

 

A. Acute tubular necrosis

B. Postrenal obstruction

C. Acute interstitial nephritis

D. Lupus glomerulonephritis

E. Prerenal azotemia

 

Question 15

A hospitalized patient develops AKI after starting antibiotics. Urinalysis shows WBCs and eosinophils. What is the most likely diagnosis?

 

A. Acute tubular necrosis

B. Acute interstitial nephritis

C. Glomerulonephritis

D. Postrenal obstruction

E. Prerenal azotemia

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Question 16

A 14‑year‑old boy presents with rhabdomyolysis after a football injury. Creatinine rises rapidly. What is the most likely mechanism of AKI?

 

A. Glomerular immune injury

B. Tubular obstruction and toxicity from myoglobin

C. Renal artery stenosis

D. Bladder obstruction

E. Interstitial fibrosis

 

Question 17

A patient with heart failure develops AKI after aggressive diuresis. Urine sodium is 8 mEq/L and FENa is 0.5%. What is the most likely cause?

 

A. Prerenal AKI

B. Acute tubular necrosis

C. Postrenal obstruction

D. Acute interstitial nephritis

E. Glomerulonephritis

 

Question 18

A patient presents with anuria after pelvic surgery. Foley catheter drainage yields 800 mL urine immediately. What is the most likely cause of AKI?

 

A. Acute tubular necrosis

B. Glomerulonephritis

C. Acute interstitial nephritis

D. Renal artery thrombosis

E. Bladder outlet obstruction

 

Question 19

A 12‑year‑old boy presents with hematuria, hypertension, and decreased urine output. Complement levels are low. Which condition is most likely responsible for the AKI?

 

A. IgA nephropathy

B. Post‑streptococcal glomerulonephritis

C. Acute interstitial nephritis

D. Rhabdomyolysis

E. Obstructive uropathy

 

Question 20

A patient with AKI develops confusion, pulmonary edema, and potassium of 6.8 mEq/L despite medical therapy. What is the most appropriate next step?

 

A. Increase IV fluids

B. Restrict dietary potassium

C. Administer sodium bicarbonate

D. Give loop diuretics

E. Start dialysis

 

 

Answer Key

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Question 1: B.  KDIGO defines AKI as an increase in creatinine ≥0.3 mg/dL within 48 hours or ≥1.5× baseline within 7 days, or reduced urine output.

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Question 2: B. Urine output <0.5 mL/kg/hr for ≥6 hours meets KDIGO AKI criteria.

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Question 3: C. Prerenal AKI results from decreased renal perfusion without structural kidney injury.

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Question 4: C. FENa <1% suggests prerenal physiology where the kidney avidly retains sodium.

 

Question 5: C. Acute glomerulonephritis represents intrinsic AKI due to inflammatory injury of the glomerulus.

 

Question 6: E. Postrenal AKI occurs when urine outflow is obstructed.

 

Question 7: B. Muddy brown granular casts are classic for acute tubular necrosis.

 

Question 8: D. Dysmorphic RBCs and RBC casts indicate glomerular bleeding typical of glomerulonephritis.

 

Question 9: C. Hyperkalemia is the most immediately life‑threatening electrolyte disturbance in AKI.

 

Question 10: E. Refractory hyperkalemia with ECG changes is an indication for emergent dialysis.

 

Question 11: C. Post‑infectious glomerulonephritis causes intrinsic AKI with hematuria and RBC casts.

 

Question 12: A/ Certain nephrotoxic medications are known to cause acute tubular necrosis.

 

Question 13: C. Hydronephrosis indicates urinary tract obstruction causing postrenal AKI.

 

Question 14: D. Lupus nephritis causes glomerular inflammation leading to intrinsic AKI.

 

Question 15: B. Drug reactions with eosinophils suggest acute interstitial nephritis.

 

Question 16: B/ Myoglobin from rhabdomyolysis causes tubular toxicity and obstruction.

 

Question 17: A. Low urine sodium and FENa indicate prerenal physiology.

 

Question 18: E. Immediate urine output after Foley suggests bladder outlet obstruction.

 

Question 19: B. Low complement with hematuria and hypertension suggests PSGN.

 

Question 20: E. Refractory hyperkalemia and pulmonary edema are indications for urgent dialysis.