Mock Nephrology Module 2

A 72-year-old man with a history of type 2 diabetes mellitus, hypertension, and chronic kidney disease (baseline creatinine 180 µmol/L, eGFR 32 mL/min/1.73m²) is scheduled for coronary angiography following an episode of unstable angina.

His cardiologist asks for advice on preventing contrast-associated acute kidney injury. He is currently taking metformin, perindopril, and atorvastatin.

Which of the following strategies has the strongest evidence for preventing contrast-associated acute kidney injury in this patient?

A 58-year-old woman is admitted to the intensive care unit with septic shock secondary to a perforated sigmoid diverticulum.

Her baseline creatinine is 65 µmol/L (reference range 45-90 µmol/L). She is commenced on intravenous fluid resuscitation and noradrenaline.

On day 2, her serum creatinine is 140 µmol/L and urine output has been 0.3 mL/kg/h for the past 14 hours. She requires ongoing fluid resuscitation.

Which of the following intravenous fluids should be used for resuscitation in this patient?

A 64-year-old man is in the intensive care unit following an emergency laparotomy for mesenteric ischaemia.

He has oliguric acute kidney injury with the following results:

• potassium 6.8 mmol/L (reference range 3.5-5.0)
• bicarbonate 12 mmol/L (reference range 22-32)
• urea 38 mmol/L (reference range 3.0-8.0)
• creatinine 520 µmol/L (reference range 60-110)

He is haemodynamically unstable on vasopressors. Continuous kidney replacement therapy (CKRT) is commenced.

Which anticoagulation strategy for the CKRT circuit is most likely to prolong filter life span in this patient?

A 55-year-old man with decompensated alcoholic cirrhosis (Child-Pugh C, MELD score 32) is admitted with progressive oliguric renal failure.

His serum creatinine has risen from 110 µmol/L to 310 µmol/L over 5 days.

Urine sodium is 5 mmol/L, urine microscopy is bland, and renal ultrasound shows normal-sized kidneys without obstruction.

He has tense ascites and peripheral oedema. There is no response to a 48-hour albumin challenge (1 g/kg/day).

Which of the following therapies has been shown to improve renal function reversal in this condition?

A 68-year-old man with KDIGO Stage 3 acute kidney injury secondary to septic shock is in the intensive care unit. He is haemodynamically stable on low-dose noradrenaline. His potassium is 5.4 mmol/L (reference range 3.5-5.0), bicarbonate is 18 mmol/L (reference range 22-32), and urea is 32 mmol/L (reference range 3.0-8.0). His urine output has been 0.2 mL/kg/h for the past 24 hours. He has no features of fluid overload.

What is the most appropriate approach regarding the timing of kidney replacement therapy initiation?

A 70-year-old woman is undergoing elective aortic valve replacement with cardiopulmonary bypass.

Her preoperative creatinine is 85 µmol/L (reference range 45-90) and eGFR is 62 mL/min/1.73m².

She has well-controlled hypertension and type 2 diabetes mellitus. The anaesthetic team asks about evidence-based strategies to reduce cardiac surgery-associated acute kidney injury.

Which of the following intraoperative interventions is likely to reduce the incidence of AKI after cardiac surgery?

A 45-year-old man is admitted to the emergency department after being found unconscious following a building collapse.

He has crush injuries to both lower limbs. On arrival, his biochemistry showed the following results:

• Serum creatinine is 220 µmol/L (reference range 60-110)
• Potassium is 7.2 mmol/L (reference range 3.5-5.0)
• Calcium is 1.68 mmol/L (reference range 2.10-2.60)
• Phosphate is 2.8 mmol/L (reference range 0.8-1.5)
• Urate is 0.72 mmol/L (reference range 0.20-0.45)
• CK is 85,000 U/L (reference range 30-200).

An ECG shows tall peaked T waves with widened QRS complexes.

In addition to emergency treatment of hyperkalaemia, which of the following biochemical derangements is most important to correct early in the management of this patient’s acute kidney injury?

A 62-year-old woman in the intensive care unit has been oliguric for 18 hours following emergency surgery for a ruptured abdominal aortic aneurysm.

Her serum creatinine has risen from 75 µmol/L preoperatively to 130 µmol/L.

Intravenous fluids have been administered and she is on noradrenaline.

The ICU team is considering the use of novel biomarkers to assess her risk of progressive AKI.

Which of the following biomarker combinations is classified as a marker of cell stress and has been studied for early AKI risk stratification?

A 78-year-old man is admitted to hospital with community-acquired pneumonia. His baseline creatinine is 95 µmol/L (reference range 60-110).

On admission, his creatinine is 100 µmol/L.

Over the next 48 hours, his creatinine rises to 130 µmol/L. His urine output has been 0.4 mL/kg/h for the past 8 hours.

According to the KDIGO classification, what is the most accurate staging of this patient’s acute kidney injury?

A 66-year-old man is admitted to the intensive care unit following cardiac surgery complicated by prolonged cardiopulmonary bypass time.

Postoperatively, his creatinine rises from a baseline of 90 µmol/L to 200 µmol/L by day 3, meeting criteria for KDIGO Stage 2 AKI.

By day 10, his creatinine has improved to 140 µmol/L and his urine output has normalised.

At 4 months post-surgery, his creatinine is 150 µmol/L with an eGFR of 42 mL/min/1.73m² and urine albumin-to-creatinine ratio of 8 mg/mmol (reference range <3.5).

Which of the following best describes this patient’s current kidney disease classification?

A 62-year-old woman with type 2 diabetes mellitus and hypertension is reviewed in the nephrology clinic.

Her serum creatinine is 180 µmol/L (reference range 45-90), eGFR is 28 mL/min/1.73m², and urine albumin-to-creatinine ratio (ACR) is 45 mg/mmol (reference range: male <2.5, female <3.5).

She is currently taking amlodipine 10 mg daily and metformin 500 mg daily.

Her blood pressure is 148/92 mmHg.

Which of the following is the most appropriate blood pressure target and initial antihypertensive modification for this patient?

A 58-year-old man with IgA nephropathy has a stable eGFR of 38 mL/min/1.73m² (reference range >60) and a urine ACR of 30 mg/mmol (reference range male <2.5).

He is already on ramipril 10 mg daily and his blood pressure is 126/78 mmHg. His HbA1c is 5.4% (reference range <6.0%).

A 58-year-old man with IgA nephropathy has a stable eGFR of 38 mL/min/1.73m² (reference range >60) and a urine ACR of 30 mg/mmol (reference range male <2.5). He is already on ramipril 10 mg daily and his blood pressure is 126/78 mmHg. His HbA1c is 5.4% (reference range <6.0%).

Which of the following additional therapies has been shown in a landmark randomised controlled trial to reduce the composite outcome of declining renal function, end-stage kidney disease, or renal or cardiovascular death in this patient population?

A 70-year-old man with CKD stage 4 (eGFR 22 mL/min/1.73m²) secondary to diabetic nephropathy presents with fatigue.

Lab investigations:

• Haemoglobin is 88 g/L (reference range 130-170)
• MCV is 86 fL (reference range 80-100)
• Ferritin is 80 µg/L (reference range 30-300)
• Transferrin saturation is 15% (reference range 16-45%)
• Reticulocyte count is 35 × 10⁹/L (reference range 20-100 × 10⁹/L) 
• Vitamin B12, folate, and haemolysis screen are normal.

What is the most appropriate initial management step for this patient’s anaemia?

A 65-year-old woman with CKD stage 5 on haemodialysis presents for routine biochemistry review.

Her results are:

• corrected calcium 2.65 mmol/L (reference range 2.10-2.60)
• phosphate 2.1 mmol/L (reference range 0.8-1.5)
• parathyroid hormone (PTH) 85 pmol/L (reference range 1.6-6.9)
• alkaline phosphatase 250 U/L (reference range 30-110)
• 25-hydroxyvitamin D 42 nmol/L (reference range 50-200) my 

She is currently taking calcium carbonate 500 mg three times daily with meals and calcitriol 0.25 µg daily.

Which of the following is the most appropriate next step in managing this patient’s mineral and bone disorder?

A 55-year-old man with CKD stage 3b (eGFR 34 mL/min/1.73m²) secondary to autosomal dominant polycystic kidney disease is reviewed in clinic.

His serum bicarbonate is 18 mmol/L (reference range 22-32), potassium is 4.8 mmol/L (reference range 3.5-5.0), sodium is 139 mmol/L (reference range 135-145), and chloride is 110 mmol/L (reference range 95-110).

He reports progressive fatigue and reduced exercise tolerance.

Which of the following best explains the pathophysiology of his acid-base disturbance?

A 72-year-old woman with CKD stage 4 (eGFR 18 mL/min/1.73m²) secondary to hypertensive nephrosclerosis is found to have the following routine blood results:

• Corrected calcium 2.08 mmol/L (reference range 2.10-2.60)
• Phosphate 1.9 mmol/L (reference range 0.8-1.5)
• PTH 52 pmol/L (reference range 1.6-6.9)
• 25-hydroxyvitamin D 30 nmol/L (reference range 50-200)
• Alkaline phosphatase 180 U/L (reference range 30-110).

Which of the following is the earliest biochemical abnormality to develop in the pathogenesis of her CKD-mineral and bone disorder?

A 60-year-old man with CKD stage 4 (eGFR 20 mL/min/1.73m²) due to type 2 diabetic nephropathy has persistent hyperkalaemia with a serum potassium of 6.2 mmol/L (reference range 3.5-5.0) on two consecutive readings despite dietary counselling.

He is on ramipril 10 mg daily, dapagliflozin 10 mg daily, and frusemide 40 mg daily. His blood pressure is 128/76 mmHg and urine ACR is 55 mg/mmol (reference range male <2.5).

Which of the following is the most appropriate management strategy?

A 68-year-old man with CKD stage 4 (eGFR 24 mL/min/1.73m²) and type 2 diabetes mellitus is on perindopril, dapagliflozin, and metformin.

His haemoglobin has been stable at 105 g/L (reference range 130-170) for 6 months on darbepoetin alfa 40 µg fortnightly.

His iron studies show ferritin 320 µg/L (reference range 30-300), transferrin saturation 28% (reference range 16-45%).

His haemoglobin unexpectedly drops to 92 g/L and a repeat 4 weeks later confirms 90 g/L despite continued ESA therapy.

His haemoglobin target on ESA therapy should not intentionally exceed which of the following?

A 52-year-old woman with no prior medical history is found to have an eGFR of 52 mL/min/1.73m² on routine blood testing.

A repeat eGFR four months later is 54 mL/min/1.73m². Her urine ACR is 1.5 mg/mmol (reference range female <3.5). Urine microscopy shows no haematuria. Renal ultrasound is normal.

Which of the following best describes her kidney disease classification?

A 63-year-old man with CKD stage 4 (eGFR 22 mL/min/1.73m²) secondary to chronic glomerulonephritis presents to his nephrologist with progressive lower back pain and a fragility fracture of the L2 vertebral body after a minor fall.

His blood results show:

• corrected calcium 2.15 mmol/L (reference range 2.10-2.60)
• phosphate 1.7 mmol/L (reference range 0.8-1.5)
• PTH 48 pmol/L (reference range 1.6-6.9)
• alkaline phosphatase 320 U/L (reference range 30-110)
• 25-hydroxyvitamin D 35 nmol/L (reference range 50-200)

A lateral abdominal X-ray shows aortic calcification. DXA scan shows a T-score of -3.2 at the lumbar spine.

Which of the following investigations would provide the most definitive information to guide management of this patient’s bone disease?

A 58-year-old man with end-stage kidney disease (ESKD) secondary to IgA nephropathy has been on haemodialysis for 4 years.

He has a potential 60-year-old living kidney donor (his brother) who is otherwise well with an eGFR of 82 mL/min/1.73m², BMI 27 kg/m², blood pressure 128/78 mmHg on no medications, urine albumin-to-creatinine ratio 1.5 mg/mmol (reference <2.5 mg/mmol), no diabetes, and is a former smoker.

HLA crossmatch is negative and there are no donor-specific antibodies.

Which of the following is the most important consideration when counselling this donor candidate regarding his long-term risk?

A 45-year-old woman receives a deceased donor kidney transplant. Her immunosuppression consists of basiliximab induction, tacrolimus, mycophenolate mofetil, and prednisolone.

She is CMV D+/R-.

At 8 months post-transplant, she presents with fever, malaise, and diarrhoea. Bloods show a white cell count of 3.2 × 10⁹/L (reference 4.0–11.0), platelets 118 × 10⁹/L (reference 150–400), creatinine 142 µmol/L (baseline 110 µmol/L, reference 45–90), and ALT 68 U/L (reference <35).

CMV PCR returns at 45,000 IU/mL.

Which of the following is the most appropriate initial management?

A 52-year-old man is 3 years post deceased donor kidney transplant on tacrolimus, mycophenolate mofetil, and prednisolone.

He presents with a gradually rising creatinine from 120 to 185 µmol/L (reference 60–110) over 6 months. Tacrolimus trough level is 4.8 µg/L.

A transplant biopsy shows peritubular capillaritis, glomerulitis, C4d positivity in peritubular capillaries, and transplant glomerulopathy. Donor-specific antibodies are detected.

What is the most likely diagnosis?

A 38-year-old woman is 6 weeks post living donor kidney transplant. She is on tacrolimus, mycophenolate mofetil, and prednisolone following basiliximab induction.

Her creatinine has risen from 90 to 155 µmol/L (reference 45–90) over 5 days.

Tacrolimus level is 8.2 µg/L.

Renal transplant ultrasound shows normal perfusion and no hydronephrosis. BK virus PCR is negative.

A transplant biopsy shows dense interstitial inflammation with tubulitis. There is no evidence of C4d staining, and donor-specific antibodies are negative.

What is the most appropriate initial treatment?

A 34-year-old woman with a functioning kidney transplant (from 2 years ago) wishes to become pregnant.

Her current immunosuppression is tacrolimus, mycophenolate mofetil, and prednisone.

Creatinine is 95 µmol/L (reference 45–90) and she has no proteinuria. Blood pressure is 122/74 mmHg.

Which of the following adjustments to her immunosuppression regimen is most appropriate before conception?

A 63-year-old man receives a deceased donor kidney transplant. The donor was a 55-year-old who died after circulatory death (DCD) with a cold ischaemia time of 18 hours.

On day 3 post-transplant, the patient remains anuric and creatinine is 780 µmol/L (reference 60–110). He is commenced on haemodialysis.

A renal transplant ultrasound shows normal arterial and venous flow.

Which of the following is the most appropriate next step?

A 48-year-old man is 18 months post kidney transplant.

He has had three squamous cell carcinomas (SCCs) excised from sun-exposed areas in the past 6 months. His current immunosuppression is tacrolimus, mycophenolate mofetil, and prednisolone.

What is the most appropriate modification to his immunosuppressive regimen to reduce further skin cancer risk?

A 42-year-old woman is 4 months post kidney transplant. She is on tacrolimus, mycophenolate mofetil, and prednisolone.

Routine screening shows a BK virus serum PCR of 25,000 copies/mL.

Her creatinine is stable at 105 µmol/L (reference 45–90). Urine BK PCR is positive.

What is the most appropriate initial management?

A 55-year-old man with ESKD secondary to type 2 diabetes mellitus has been on peritoneal dialysis for 18 months. He is being assessed for deceased donor kidney transplant waitlisting.

He has a history of a basal cell carcinoma excised 2 years ago with clear margins, controlled hypertension on two agents, BMI 30 kg/m², HbA1c 7.2% (55 mmol/mol), and no ischaemic heart disease on functional cardiac testing.

His calculated panel reactive antibody (CPRA) is 98%.

What is the factor most likely to limit his access to a compatible deceased donor kidney?

A 50-year-old woman received a kidney transplant from a deceased donor 5 years ago. She is on tacrolimus (trough level 5.1 µg/L), mycophenolate mofetil, and prednisolone.

She presents with progressive proteinuria (urine protein-to-creatinine ratio 180 mg/mmol, reference <15) and a creatinine rise from 130 to 195 µmol/L (reference 45–90) over 12 months.

A transplant biopsy shows mesangial hypercellularity with mesangial IgA deposits on immunofluorescence.

There is no evidence of C4d staining, and donor-specific antibodies are negative.

Which of the following is the most likely cause of her graft dysfunction?