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MRCP Part 1 Nephrology — Common Traps & Fixes

TL;DR

Many candidates lose marks in mrcp part 1 nephrology — common traps & how to avoid them because of subtle wording, overlapping pathologies and mis-reading lab data. This guide summarises the most frequent pitfalls in renal physiology, electrolytes and glomerular disease questions — with clinician-led advice on how to fix them. Learn how to spot distractors, read labs correctly and approach every renal stem with confidence.


Why this matters

The examination MRCP Part 1 plays a central role in your transition to higher specialist training, and nephrology questions form a non-trivial share of the paper: one review lists renal medicine among the major topics. studymrcp.com+2Doctors Relocate+2Despite this, candidates often stumble not for lack of knowledge, but because of exam-style traps — ambiguous wording, overlapping syndromes, subtle biochemical cues. The key to scoring high in the nephrology section is therefore not only knowing renal physiology and pathology, but also anticipating how the question tries to mislead. At Crack Medicine, we equip you to think like the examiner and avoid these common errors. In this post we’ll unpack the five most-tested sub-topics in nephrology, and the five most common traps you’ll encounter — with practical tips, a mini-case and a study-checklist to embed into your revision for the Parent Hub: MRCP Part 1 overview.


Scope: five most-tested sub-topics in nephrology

Here are the high-yield sub-topics you must prioritise:

  1. Electrolyte & acid–base disorders

    • For example hyponatraemia, hyperkalaemia, renal tubular acidosis.

    • Key tip: always integrate clinical volume-status with urine/serum values rather than memorising numbers.

  2. Glomerular diseases (nephritic vs nephrotic syndromes)

    • Recognise patterns of haematuria, proteinuria and oedema.

    • Key tip: if the stem says “proteinuria > 3.5 g/day” + hypoalbuminaemia, that is nephrotic-range.

  3. Acute kidney injury (AKI) vs chronic kidney disease (CKD)

    • Many questions ask you to differentiate based on history, ultrasound findings, rate of change.

    • Key tip: always ask “is this acute?” — look for small kidneys for CKD.

  4. Fluid & sodium disorders (including SIADH vs hypovolaemia vs salt‐wasting)

    • e.g., hyponatraemia in different states of volume.

    • Key tip: urine sodium and clinical volume status matter. See the detailed trap below.

  5. Renal vascular & cystic diseases (e.g., autosomal dominant polycystic kidney disease, renovascular disease)

    • Frequently appear through family history, hypertension and incidental cysts.

    • Key tip: pay attention to age, family history and extrarenal features (e.g., liver cysts).


Five most common traps & how to avoid them

Trap

Description

How to avoid it

1

“Most common cause” type questions that ignore context.

Always check the stem: e.g., diabetic nephropathy is common overall, but if the patient is non-diabetic and adult with heavy proteinuria, membranous nephropathy is likelier.

2

Mis-classifying sodium disorders (especially SIADH vs hypovolaemia).

Don’t rely on one lab value — integrate volume status, urine sodium >30 mmol/L suggests SIADH. Merck Manuals+1

3

Confusing AKI with CKD based on creatinine alone.

Always look for supporting features: anaemia, small kidneys (CKD) vs rapid rise (AKI).

4

Mixing renal tubular acidosis types.

Memorise the key differences (urine pH, K⁺ levels).

5

Drug-induced renal problems overlooked.

Create a mental drug-list (NSAIDs, ACE-inhibitors, aminoglycosides) and ask: is this a drug effect?


Practical Example / Mini-Case

Question: A 67-year-old woman with bronchiectasis is admitted with confusion and hyponatraemia (Na⁺ 118 mmol/L; plasma osmolality low). Urine sodium is 40 mmol/L. She is clinically euvolaemic. Which is the most likely cause?Answer: SIADH secondary to chronic lung disease. Explanation: Euvolaemia + low serum osmolality + inappropriately high urine sodium = SIADH. RACGP+1 Exam tip: Always exclude adrenal/thyroid causes, note urinary sodium >30 mmol/L and euvolaemia => SIADH.


Diagram explaining common nephrology exam traps for MRCP Part 1 including GFR, RPF, and electrolyte balance.

Study-Tip Checklist for Nephrology in MRCP Part 1

  • Use timed question banks with a renal filter: practise stems that include labs + subtle descriptors.

  • On each question, pause to ask: “what is the volume status?”, “what is the urine sodium/osmolality?”, “is this acute or chronic?”

  • Make one-page summary sheets for each of the five high-yield subtopics above.

  • Use nightly review for three nights of ‘renal’ questions and mark out the trap you fell into.

  • In the week before exam, practise one full renal mock-block and review error-patterns.

  • Link your revision to the wider clinical picture via our Free MRCP MCQs and timed sets using Start a mock test.


FAQs

1. How many nephrology questions are in MRCP Part 1?

There is no fixed number, but renal medicine is listed within the subject-weighting as about 14 questions in some analyses. studymrcp.com+1

2. What’s the hardest nephrology topic for MRCP candidates?

Acid–base disorders and renal tubular acidosis tend to be the most frequently missed areas, as they require integration of clinical, biochemical and urinary data.

3. Should I focus more on physiology or pathology in renal revision?

Both are important. However, physiology often underpins the trap-questions (e.g., filtration fraction, GFR/RPF) and deserves extra attention.

4. Can I guess if I don’t know the answer?

Yes. The exam uses a ‘best of five’ format with no negative marking, so a considered guess (after eliminating options) is better than leaving blank. MedCourse+1

5. Will reviewing drug-lists really help?

Absolutely. Drug-induced renal injury is a common hidden trap in nephrology stems — knowing the usual drug classes can turn a wrong answer into the correct one.


Ready to start

Nephrology can be a source of marks — and traps — in your MRCP Part 1 revision. Use this guide to pinpoint the key areas and avoid the common pitfalls discussed. Then practise using our Free MRCP MCQs and test your readiness with a full-length set of mock questions via Start a mock test. For deeper, structured teaching—including lectures, video summaries and the full renal system module—explore our expert-led content series. You’ll get monthly new mock tests, performance analytics and focused feedback to refine your preparation.


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