PLAB 1 Renal Questions: 10 Free Practice MCQs

Ten PLAB 1-style renal questions with the answer and the reasoning behind it. They come from the UK.med bank, which has 110 renal questions and many more across every topic.

1. 1 / 10

   A 79-year-old with vomiting and poor intake takes ramipril, a diuretic and an over-the-counter NSAID and is hypovolaemic.

   Which medication safety action is most appropriate?

   • A. Assess for AKI and review medicines that can worsen kidney injury
   • B. Continue every medicine unchanged without checking renal function
   • C. Add a second NSAID for symptom control
   • D. Diagnose AKI from the medicine list alone
   Show answer

   Answer: A. Assess for AKI and review medicines that can worsen kidney injury

   Why: NICE NG148 identifies hypovolaemia and recent use of NSAIDs, ACE inhibitors and diuretics as reasons to investigate for AKI during acute illness. Check renal function against baseline and review medicines. A drug list alone does not diagnose AKI, and adding an NSAID could worsen kidney injury.

   • B. Continuing all medicines unchanged overlooks the interaction between volume depletion and drugs that can worsen kidney injury.
   • C. Adding another NSAID increases nephrotoxic exposure during hypovolaemia.
   • D. These medicines and risks prompt investigation but do not establish AKI without clinical and renal function assessment.

   Sources: NICE NG148 recommendations 1.1.1 and 1.6.4

2. 2 / 10

   A 68-year-old with sepsis develops acute kidney injury. The source of the creatinine rise is not yet clear, and there is no history of urinary obstruction.

   Which initial investigation should be performed as soon as AKI is suspected or detected?

   • A. Renal biopsy before urine testing
   • B. No urine testing unless visible haematuria develops
   • C. Urine dipstick testing for blood, protein, leucocytes, nitrites and glucose
   • D. Renal tract ultrasound in every patient before reviewing the history
   Show answer

   Answer: C. Urine dipstick testing for blood, protein, leucocytes, nitrites and glucose

   Why: NICE NG148 recommendation 1.4.2 recommends urine dipstick testing for blood, protein, leucocytes, nitrites and glucose in all people as soon as AKI is suspected or detected, with results documented and acted on. Ultrasound is targeted to suspected obstruction or an unclear cause rather than used routinely in every case.

   • A. Biopsy is not the routine first investigation. Urine dipstick testing is recommended promptly.
   • B. NICE recommends dipstick testing even without visible haematuria.
   • D. Ultrasound is not routinely offered when the cause of AKI has been identified; it is urgent when pyonephrosis is suspected.

   Sources: NICE NG148 recommendation 1.4.2; NICE NG148 recommendations 1.4.4 and 1.4.5

3. 3 / 10

   A 72-year-old admitted with pneumonia has a serum creatinine rise of 28 micromol/L over 36 hours from a documented baseline.

   How should this change be interpreted?

   • A. It meets the NICE biochemical criterion for acute kidney injury
   • B. It is too small because the increase is under 50 micromol/L
   • C. It confirms chronic kidney disease only
   • D. AKI is present only if urine output is also low
   Show answer

   Answer: A. It meets the NICE biochemical criterion for acute kidney injury

   Why: NICE NG148 defines an AKI criterion as a creatinine rise of at least 26 micromol/litre within 48 hours. This patient’s rise of 28 within 36 hours qualifies. Oliguria is another criterion, but it is not required when the creatinine criterion is met.

   • B. The absolute rise need not reach 50 micromol/litre; NICE uses a 26 micromol/litre rise within 48 hours.
   • C. The acute change during admission meets an AKI criterion and cannot be labelled chronic kidney disease alone.
   • D. A qualifying creatinine rise is sufficient; low urine output is an alternative criterion, not a requirement.

   Sources: NICE NG148 recommendation 1.3.1

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5. 4 / 10

   A 68-year-old with an acute febrile illness has diabetes and CKD with eGFR 54 mL/min/1.73 m2.

   What renal assessment should be arranged?

   • A. Measure creatinine and compare it with baseline
   • B. Wait for uraemic symptoms before testing
   • C. Measure eGFR once without checking previous results
   • D. Order ultrasound as the first test in every case
   Show answer

   Answer: A. Measure creatinine and compare it with baseline

   Why: NICE NG148 recommends investigating for AKI in acute illness when risk factors such as CKD, diabetes or age 65 and over are present. Measure serum creatinine and compare it with baseline. A single eGFR or routine first-line ultrasound does not answer whether an acute creatinine change has occurred.

   • B. Waiting for uraemic symptoms may miss AKI, which can be identified by laboratory change before symptoms develop.
   • C. A single eGFR does not establish an acute change; compare serum creatinine with the person’s baseline.
   • D. Ultrasound is not the first test for every at-risk patient; start by checking creatinine against baseline.

   Sources: NICE NG148 recommendation 1.1.1

6. 5 / 10

   A 74-year-old with acute diarrhoea, vomiting and reduced oral intake is taking ramipril for hypertension. Their creatinine is rising and they are clinically hypovolaemic.

   Which medicine-related action is recommended while the patient is acutely unwell?

   • A. Consider temporarily stopping ramipril until the clinical condition has improved and stabilised
   • B. Continue ramipril unchanged because the AKI is likely pre-renal and will correct with fluids
   • C. Permanently discontinue ramipril in every patient who develops AKI, whatever the cause
   • D. Delay medication review until outpatient follow-up
   Show answer

   Answer: A. Consider temporarily stopping ramipril until the clinical condition has improved and stabilised

   Why: NICE NG148 recommendation 1.2.14 says to consider temporarily stopping ACE inhibitors and ARBs in people with diarrhoea, vomiting or sepsis until their clinical condition has improved and stabilised. Recommendation 1.1.1 also identifies hypovolaemia and recent exposure to medicines such as ACE inhibitors, NSAIDs and diuretics as AKI risk factors. Treat the acute illness and hypovolaemia, and individualise the medication plan.

   • B. NICE recommends considering temporarily stopping an ACE inhibitor or ARB during diarrhoea or vomiting until the clinical condition has improved and stabilised.
   • C. The NICE recommendation is to consider temporary cessation during the acute illness, not permanent discontinuation for every patient.
   • D. Medication review is part of acute assessment, and NICE gives specific advice for ACE inhibitors and ARBs during diarrhoea or vomiting.

   Sources: NICE NG148 recommendations 1.1.1 and 1.2.14

7. 6 / 10

   A 72-year-old male with a history of small cell lung cancer presents with confusion and mild lethargy. Labs show: Sodium 118 mmol/L, serum osmolality 240 mOsm/kg (low), urinary osmolality 350 mOsm/kg (high), and urinary sodium 45 mmol/L (high). On examination, he is clinically euvolaemic.

   What is the most appropriate first-line treatment for his hyponatraemia?

   • A. Intravenous infusion of 0.9% normal saline
   • B. Intravenous infusion of 3% hypertonic saline
   • C. Fluid restriction to 500-1000 mL/day
   • D. Intravenous Demeclocycline
   Show answer

   Answer: C. Fluid restriction to 500-1000 mL/day

   Why: This patient presents with classic SIADH, likely secondary to small cell lung cancer. In euvolaemic hyponatraemia due to SIADH, first-line therapy is fluid restriction (usually 800-1000 mL/day). Normal saline should be avoided. Hypertonic saline is reserved for acute severe symptoms.

   • A. Normal saline will worsen hyponatraemia in SIADH because the kidney will excrete the sodium while retaining the water due to high ADH levels.
   • B. Hypertonic saline is reserved for severe, life-threatening symptoms (e.g. seizures, coma, severe confusion) to prevent osmotic demyelination from rapid correction.
   • D. Demeclocycline is a tetracycline derivative that induces nephrogenic DI, but is used second-line if fluid restriction is unsuccessful or poorly tolerated.

   Sources: European Society of Endocrinology Guidelines on Hyponatraemia

8. 7 / 10

   A 72-year-old male with chronic kidney disease (CKD stage 3b, eGFR 35 mL/min/1.73m2) is scheduled to undergo an elective coronary angiogram using iodinated contrast. He is not in heart failure.

   What is the most appropriate strategy to prevent contrast-induced acute kidney injury (CI-AKI) according to clinical guidelines?

   • A. Oral N-acetylcysteine (NAC) 600mg twice daily for 48 hours without fluids
   • B. Intravenous Furosemide infusion during the procedure to maintain high urine output
   • C. Intravenous volume expansion with 0.9% sodium chloride or 1.4% sodium bicarbonate
   • D. Discontinuation of his Aspirin and Atorvastatin 24 hours prior to the procedure
   Show answer

   Answer: C. Intravenous volume expansion with 0.9% sodium chloride or 1.4% sodium bicarbonate

   Why: Contrast-induced acute kidney injury (CI-AKI) is a risk in patients with eGFR < 30 mL/min/1.73m2 (or < 45 with other risk factors like diabetes). NICE CG169 and KDIGO guidelines recommend intravenous volume expansion with either 0.9% sodium chloride or 1.4% sodium bicarbonate before and after the procedure. Forced diuresis with diuretics must be avoided.

   • A. Evidence for NAC is weak and inconsistent. It should not be used as a standalone or substitute for intravenous fluid hydration.
   • B. Forced diuresis with loop diuretics is contraindicated as it worsens intravascular dehydration and increases the risk of contrast-induced kidney injury.
   • D. Aspirin and statins do not increase the risk of contrast-induced AKI. Nephrotoxic drugs like NSAIDs or Metformin should be held, but not standard antiplatelets or statins.

   Sources: NICE CG169; KDIGO Guidelines

9. 8 / 10

   A 62-year-old man with type 2 diabetes has his annual diabetic renal review. His eGFR is stable at 54 mL/min/1.73m2. However, his urine albumin-to-creatinine ratio (ACR) is elevated at 35 mg/mmol. His clinic blood pressure is 138/84 mmHg.

   What is the recommended first-line pharmacological treatment to manage his CKD and what is his target blood pressure according to NICE guidelines?

   • A. Start Amlodipine 5mg daily, and target a blood pressure below 140/90 mmHg as in the general population
   • B. Start Furosemide 40mg daily, and target a blood pressure below 130/80 mmHg
   • C. No treatment is required as his eGFR is > 45 mL/min/1.73m2, so repeat the ACR in 12 months
   • D. Initiate an ACE inhibitor (e.g. Ramipril) or ARB, and target a blood pressure below 130/80 mmHg
   Show answer

   Answer: D. Initiate an ACE inhibitor (e.g. Ramipril) or ARB, and target a blood pressure below 130/80 mmHg

   Why: NICE guideline NG203 states that in patients with CKD, an ACE inhibitor or ARB should be offered if they have: (1) diabetes and ACR >= 3 mg/mmol, (2) hypertension and ACR >= 30 mg/mmol, or (3) ACR >= 70 mg/mmol regardless of diabetes/hypertension. For patients with an ACR >= 30 mg/mmol, the target blood pressure is < 130/80 mmHg (compared to < 140/90 mmHg for non-proteinuric CKD).

   • A. Amlodipine is not first-line for proteinuric CKD as it does not reduce intraglomerular pressure. ACE inhibitors/ARBs are specifically indicated for their antiproteinuric and renoprotective effects.
   • B. Loop diuretics are used to manage fluid overload in CKD, not as first-line antiproteinuric agents. An ACEi/ARB is required.
   • C. Even with stable eGFR, a urine ACR of 35 mg/mmol indicates significant proteinuria (microalbuminuria), which carries a high risk of progression to end-stage renal disease and cardiovascular events, necessitating treatment.

   Sources: NICE NG203

10. 9 / 10

    A 61-year-old has AKI, fever, flank pain and hydronephrosis is suspected clinically, raising concern for an infected obstructed kidney.

    What is the appropriate timing for urinary tract ultrasound when pyonephrosis is suspected?

    • A. Within 24 hours in all patients with any degree of AKI
    • B. After 72 hours of antibiotics if kidney function has not improved
    • C. Only after outpatient renal clinic review
    • D. Immediately, with the scan performed within 6 hours of assessment
    Show answer

    Answer: D. Immediately, with the scan performed within 6 hours of assessment

    Why: NICE NG148 recommendation 1.4.5 says to offer immediate urinary tract ultrasound, performed within 6 hours of assessment, when pyonephrosis is suspected in a person with AKI. Recommendation 1.4.4 says not to routinely offer ultrasound when the cause of AKI has already been identified.

    • A. The specific urgent 6-hour recommendation applies when pyonephrosis is suspected; ultrasound is not routine for every AKI with an identified cause.
    • B. Suspected infected obstruction requires immediate imaging, not a wait-and-see delay.
    • C. NICE calls for immediate ultrasound within 6 hours in suspected pyonephrosis with AKI.

    Sources: NICE NG148 recommendations 1.4.4 and 1.4.5

11. 10 / 10

    A 65-year-old man with CKD stage 3 has had vomiting and poor intake for 3 days. He is dizzy on standing, has dry mucous membranes, low jugular venous pressure and no peripheral oedema or lung crackles. Creatinine is 250 micromol/L, above his baseline of 130 micromol/L, and urine output is reduced.

    What is the most appropriate immediate management?

    • A. Continue all usual medicines, including any ACE inhibitor or NSAID, and arrange repeat creatinine testing with the GP in one week despite the postural hypotension and clear volume depletion
    • B. Stop potentially kidney harming medicines, replace the documented volume deficit with isotonic intravenous fluid in reassessed amounts, monitor urine output and renal blood tests, and seek specialist advice if complications develop
    • C. Start haemodialysis because the creatinine is 250 micromol/L
    • D. Arrange renal biopsy before correcting the volume deficit
    Show answer

    Answer: B. Stop potentially kidney harming medicines, replace the documented volume deficit with isotonic intravenous fluid in reassessed amounts, monitor urine output and renal blood tests, and seek specialist advice if complications develop

    Why: The rise in creatinine meets criteria for acute kidney injury, and the examination suggests intravascular volume depletion. Correct the likely cause, review medicines that can worsen kidney injury, and reassess closely; renal replacement therapy is not triggered by creatinine alone.

    • A. The patient has acute kidney injury and hypovolaemia, so delaying treatment and continuing potentially harmful medicines is unsafe.
    • C. NICE says renal replacement decisions depend on complications and the whole clinical picture, not an isolated creatinine value.
    • D. Biopsy is not the first step when the history and examination indicate a likely volume responsive cause.

    Sources: NICE NG148, recommendations 1.3.1 and 1.5.6 to 1.5.9

Exam-style questions written by MedHub for practice. They are not official exam questions.