Nephro: 50 High-Yield Facts (Nephrology) for MRCP Part 1

TL;DR

Nephro: 50 High-Yield Facts (Nephrology) is a rapid revision guide tailored for MRCP Part 1, focusing on the most tested renal concepts—electrolytes, acid–base balance, AKI/CKD, and glomerular disease. This article highlights key exam patterns, common traps, and a clinical case to consolidate learning. Use it alongside question practice for optimal retention.\

Why this matters

Nephrology is one of the most consistently tested areas in MRCP Part 1, often combining physiology, pharmacology, and clinical reasoning in a single question. Candidates frequently lose marks not due to lack of knowledge, but due to misinterpretation—especially in electrolyte disturbances and acid–base disorders.

For a structured overview of the exam, visit:👉 https://www.crackmedicine.co.uk/mrcp-part-1/

To reinforce learning with exam-style questions:👉 https://www.crackmedicine.co.uk/qbank/

Core Sections

1. Acute Kidney Injury (AKI)

1. Pre-renal AKI: urea rises disproportionately compared to creatinine

2. Fractional excretion of sodium (FeNa) <1% → pre-renal

3. Acute tubular necrosis: muddy brown casts

4. Post-renal causes must always be excluded (ultrasound first-line)

5. Hyperkalaemia is the most dangerous complication

2. Chronic Kidney Disease (CKD)

6. Defined as eGFR <60 mL/min/1.73 m² for >3 months

7. Secondary hyperparathyroidism: ↑PTH, ↓Ca, ↑phosphate

8. Normocytic normochromic anaemia due to ↓EPO

9. ACE inhibitors slow progression but may increase creatinine initially

10. Cardiovascular disease is the leading cause of death

3. Electrolytes (Very High Yield)

Electrolyte	Key Feature	Typical Cause
Hyponatraemia	Low serum osmolality	SIADH
Hypernatraemia	Water loss	Diabetes insipidus
Hyperkalaemia	Peaked T waves	Renal failure
Hypokalaemia	U waves	Diuretics
Hypercalcaemia	“Bones, stones…”	Malignancy
Hypocalcaemia	Tetany	Hypoparathyroidism

11. SIADH: euvolaemic hyponatraemia with concentrated urine

12. Hyperkalaemia ECG progression: peaked T → wide QRS → sine wave

13. Calcium gluconate stabilises myocardium, not potassium

4. Acid–Base Disorders

14. Metabolic acidosis: ↓HCO₃⁻

15. High anion gap: MUDPILES (methanol, uraemia, DKA, etc.)

16. Normal anion gap: diarrhoea, renal tubular acidosis

17. Winter’s formula checks compensation

18. Respiratory alkalosis: pregnancy, sepsis, anxiety

5. Glomerular Disease

Feature	Nephritic	Nephrotic
Proteinuria	Mild	>3.5 g/day
Haematuria	Present	Rare
Oedema	Mild	Severe
BP	High	Variable

19. Post-streptococcal GN: low complement (C3)

20. IgA nephropathy: follows URTI (“synpharyngitic”)

21. Minimal change disease: steroid-responsive

22. Membranous nephropathy: malignancy association

23. FSGS: associated with HIV, obesity

6. Renal Tubular Disorders

24. Type 1 RTA: distal acidification defect

25. Type 2 RTA: proximal bicarbonate loss

26. Type 4 RTA: hyperkalaemia due to hypoaldosteronism

27. Fanconi syndrome: proximal tubular dysfunction

7. Renal Pharmacology

28. ACE inhibitors: hyperkalaemia risk

29. NSAIDs: reduce GFR (afferent arteriole constriction)

30. Loop diuretics: act on thick ascending limb

31. Thiazides: cause hypercalcaemia

32. Spironolactone: potassium-sparing

8. Dialysis & Transplant

33. Indications: AEIOU (Acidosis, Electrolytes, Intoxication, Overload, Uraemia)

34. Peritoneal dialysis → peritonitis risk

35. Rejection types: hyperacute, acute, chronic

36. Tacrolimus: nephrotoxicity + tremor

9. Miscellaneous

37. Polycystic kidney disease: berry aneurysms

38. Renal cell carcinoma: haematuria + flank pain + mass

39. Wilms tumour: paediatric tumour

40. Goodpasture’s: lungs + kidneys

41. Alport syndrome: hearing loss + nephritis

10. Quick Revision Pearls

42. Proteinuria >3.5 g/day = nephrotic

43. Oliguria <400 mL/day

44. Anuria <100 mL/day

45. eGFR trend > single creatinine

46. Urinalysis is often the most useful first test

47. Always assess volume status

48. AKI + rash → think interstitial nephritis

49. Hyperphosphataemia → hypocalcaemia

50. Review medications in all renal cases

Practical Example / Mini-Case

Case: A 65-year-old man presents with weakness. ECG shows peaked T waves. Potassium is 6.8 mmol/L.

Question: What is the first step?

Answer: IV calcium gluconate

Explanation: This stabilises cardiac membranes immediately. Potassium-lowering measures (insulin, salbutamol) follow. This is a classic MRCP Part 1 emergency scenario.

Common Pitfalls

• Confusing SIADH with hypovolaemic hyponatraemia

• Missing early ECG changes in hyperkalaemia

• Misclassifying nephritic vs nephrotic syndromes

• Overlooking drug-induced renal injury (NSAIDs, ACE inhibitors)

• Ignoring compensation in acid–base disorders

FAQs

1. How important is nephrology in MRCP Part 1?

Very high yield—especially electrolytes and acid–base. Questions often integrate multiple concepts.

2. What is the best revision strategy?

Focus on patterns, revise tables, and practise MCQs regularly.

3. Which electrolyte disorder is most tested?

Hyperkalaemia and hyponatraemia are the most common.

4. Are formulas essential?

Yes, but interpretation matters more than memorisation.

5. How can I improve accuracy?

Use timed practice:👉 https://www.crackmedicine.co.uk/mock-tests/

Ready to start?

Strengthen your nephrology preparation with structured learning and targeted practice. Start with the full exam guide here:👉 https://www.crackmedicine.co.uk/mrcp-part-1/

Then test your knowledge using:👉 https://www.crackmedicine.co.uk/qbank/

For deeper conceptual clarity, explore:👉 https://www.crackmedicine.co.uk/lectures/

Sources

• MRCP(UK) official syllabus: https://www.mrcpuk.org/mrcpuk-examinations

• KDIGO Clinical Guidelines: https://kdigo.org/guidelines/

• NICE CKD Guidelines: https://www.nice.org.uk/guidance/ng203

• Oxford Handbook of Clinical Medicine (latest edition)