Renal and urology · Easy
This case is fictional and exists for study. It describes no real patient.
62 years · male
A 62-year-old male presents for a routine annual review at his general practice clinic. He has a 10-year history of type 2 diabetes mellitus and hypertension. He feels well, with no shortness of breath, ankle swelling, gross haematuria, or dysuria. His current medications include metformin and amlodipine. On examination, he appears well. Physical examination is unremarkable, with normal heart sounds, clear lung fields, and no peripheral oedema. Laboratory investigation results from a routine check-up 1 week ago are reviewed.
Vital signs
- HR
- 72 bpm
- BP
- 142/86 mmHg
- RR
- 15/min
- Temp
- 36.6 °C
- SpO₂
- 98%
Examination findings
- Normal heart sounds, no murmur
- Bilateral vesicular breath sounds, no crackles
- No peripheral ankle oedema
Investigations
| Serum Creatinine | 155 µmol/L | reference: 60-110 |
| eGFR | 42 mL/min/1.73m2 | reference: >90 |
| Serum Potassium | 4.6 mmol/L | reference: 3.5-5.0 |
| Urine Albumin-to-Creatinine Ratio (ACR) | 28 mg/mmol | reference: <3.0 |
| HbA1c | 58 mmol/mol | reference: <48 |
Question 1 of 3
To confirm the diagnosis of chronic kidney disease (CKD) in accordance with clinical guidelines, which of the following is the most appropriate next step?
Chronic kidney disease (CKD) is defined as abnormalities of kidney structure or function present for more than 3 months. FIELD questions[0].explanation — replace entire field with: "Chronic kidney disease is defined by abnormalities of kidney structure or function present for more than 3 months, so confirming it requires two separate steps. First, because this patient has no previous eGFR result, NICE (NG203) advises repeating the eGFR and serum creatinine within 2 weeks to exclude acute kidney injury, allowing for the biological and analytical variability of serum creatinine (around ±5%). Second, the diagnosis of CKD is established only by demonstrating that the reduced eGFR and/or the raised ACR persist for at least 3 months; an initial ACR of 3 to less than 70 mg/mmol should also be confirmed on a subsequent early morning sample. No 2-week repeat is offered here, and the question asks what confirms the diagnosis, so repeating the eGFR and creatinine at 3 months is the correct choice: it is the test that establishes chronicity. Urgent CT renal angiography is indicated for suspected renal artery stenosis or a vascular emergency, not for routine CKD confirmation. Renal biopsy is reserved for unexplained or rapidly progressive acute kidney injury, or nephrotic-range proteinuria, not for typical diabetic kidney disease. A 24-hour urine collection is no longer standard; a spot urine ACR is preferred." FIELD questions[0].teaching_point — replace entire field with: "A diagnosis of chronic kidney disease requires a reduced eGFR and/or raised ACR persisting for at least 3 months. This is distinct from the confirmatory repeat within 2 weeks that NICE requires after a first reduced eGFR with no previous result, which is what excludes acute kidney injury." OPTIONAL, same case — append to key_learning_points: "A newly detected eGFR below 60 mL/min/1.73m2 with no previous result must be repeated within 2 weeks to exclude acute kidney injury; the 3-month repeat establishes chronicity, not acuity." Urgent CT renal angiography is indicated for suspected renal artery stenosis or vascular emergency, not routine CKD confirmation. Renal biopsy is reserved for unexplained acute renal failure or heavy nephrotic proteinuria, not standard diabetic nephropathy. A 24-hour urine collection is no longer standard; spot urine ACR is preferred.
Teaching point: A diagnosis of chronic kidney disease requires demonstration of impaired renal function or structural damage persisting for at least 3 months.
Question 2 of 3
Which of the following medications is the most appropriate initial therapy to delay the progression of kidney disease in this patient?
ACE inhibitors (such as ramipril) or ARBs are the first-line antihypertensive agents in patients with chronic kidney disease and diabetes, especially in the presence of micro- or macroalbuminuria (elevated ACR), as they decrease intraglomerular pressure and slow CKD progression. Furosemide is a loop diuretic used primarily for fluid overload, not first-line renoprotection. Spironolactone is a potassium-sparing diuretic that carries a high risk of hyperkalaemia in CKD and is not first-line. Atenolol is a beta-blocker and not first-line for diabetic nephropathy renoprotection.
Teaching point: ACE inhibitors or ARBs are first-line agents to reduce proteinuria and slow progression of diabetic kidney disease.
Question 3 of 3
Two weeks after initiating the recommended renoprotective blood pressure medication, repeat blood tests show serum creatinine has increased to 170 umol/L (a 9.6% increase from baseline) and potassium is 4.8 mmol/L. Which of the following is the single most appropriate action?
An increase in serum creatinine of up to 30% (or decrease in eGFR of up to 25%) following initiation of an ACE inhibitor or ARB is acceptable and expected due to haemodynamically mediated reduction in intraglomerular pressure. If potassium remains <= 5.0 mmol/L and creatinine rise is < 30%, the medication should be continued and bloods rechecked in 2-4 weeks. Discontinuing or halving the dose is unnecessary unless creatinine increases > 30% or significant hyperkalaemia develops. Urgent nephrology referral is not warranted for expected mild haemodynamic shifts.
Teaching point: A creatinine rise of up to 30% after starting an ACE inhibitor is acceptable and does not require stopping therapy if potassium is stable.
Key learning points
- CKD is defined by evidence of kidney damage or eGFR < 60 mL/min/1.73m2 persisting for at least 3 months.
- ACE inhibitors or ARBs are indicated for patients with diabetes and CKD with elevated urine ACR to slow renal disease progression.
- A transient rise in creatinine of up to 30% after starting an ACE inhibitor is expected and does not require discontinuation.
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