A 29-year-old woman at 32 weeks gestation presents to the obstetric assessment unit with headache and right upper quadrant pain. She has no significant past medical history. Blood pressure is 168/112 mmHg. Blood tests show: haemoglobin 102 g/L, platelets 88 × 10^9/L, ALT 245 U/L, AST 312 U/L, bilirubin 34 μmol/L, creatinine 145 μmol/L (booking creatinine was 68 μmol/L), LDH 680 U/L. Urinalysis shows protein 3+. Peripheral blood film shows schistocytes. What is the most appropriate immediate management?

Commence IV labetalol, IV magnesium sulphate, and arrange immediate delivery

Commence IV magnesium sulphate and plan delivery within 24-48 hours

Commence plasma exchange for thrombotic thrombocytopenic purpura

Commence high-dose corticosteroids for HELLP syndrome

Transfuse platelets and arrange delivery once platelets >100 × 10^9/L

A 38-year-old man with chronic kidney disease stage 5 (eGFR 10 mL/min/1.73m²) secondary to focal segmental glomerulosclerosis is being prepared for renal replacement therapy. He has preserved urine output of approximately 1500 mL per day. He works full-time as a teacher and wishes to minimize time spent on dialysis. Blood tests show: haemoglobin 108 g/L, potassium 5.1 mmol/L, phosphate 1.72 mmol/L, albumin 36 g/L. He has good manual dexterity and lives with his partner. Which renal replacement modality would be most appropriate to offer first?

Automated peritoneal dialysis (APD)

Continuous ambulatory peritoneal dialysis (CAPD)

In-centre haemodialysis three times weekly

Pre-emptive renal transplantation

A 48-year-old woman with no significant past medical history presents to the emergency department with a 6-hour history of severe right loin pain. CT KUB confirms a 5 mm stone at the right pelviureteric junction with mild hydronephrosis. She is afebrile. Blood tests show: white cells 9.2 × 10^9/L, CRP 8 mg/L, creatinine 78 μmol/L. Urinalysis shows blood 3+, leucocytes 1+, nitrites negative. She has been given adequate analgesia with diclofenac and morphine. What is the most appropriate next step in her management?

Discharge with analgesia, alpha-blocker, and follow-up in stone clinic

Admit for IV antibiotics due to obstructive pyelonephritis

Arrange urgent ureteroscopy and stone extraction within 48 hours

Insert percutaneous nephrostomy for decompression

Arrange extracorporeal shock wave lithotripsy (ESWL) within one week

A 52-year-old woman presents to the emergency department with confusion and agitation. Her husband reports she has had watery diarrhoea for 5 days. She has a history of bipolar disorder treated with lithium for 15 years. Blood tests show: sodium 128 mmol/L, potassium 3.2 mmol/L, creatinine 245 μmol/L (baseline 85 μmol/L), lithium level 2.8 mmol/L (therapeutic range 0.6-1.0). ECG shows sinus tachycardia at 105 bpm. What is the most appropriate immediate management?

Stop lithium, give IV 0.9% saline, and arrange urgent haemodialysis

Stop lithium, give IV 0.9% saline, and recheck lithium level in 12 hours

Continue lithium, correct dehydration, and arrange gastroenterology review

Stop lithium, give hypertonic saline for hyponatraemia, then arrange dialysis

Stop lithium, give IV fluids, and start haemofiltration

A 67-year-old man with chronic kidney disease stage 3a (eGFR 52 mL/min/1.73m²) secondary to diabetic nephropathy attends for annual review. He takes metformin, gliclazide, ramipril, atorvastatin, and aspirin. Blood tests show: HbA1c 64 mmol/mol, creatinine 128 μmol/L (stable from previous), potassium 5.4 mmol/L, bicarbonate 19 mmol/L. Urine albumin:creatinine ratio is 45 mg/mmol. Blood pressure is 138/82 mmHg. What is the most appropriate modification to his management?

Add SGLT2 inhibitor for renoprotection

Increase ramipril dose to maximize renoprotection

Stop ramipril due to hyperkalaemia and worsening renal function

Add sodium bicarbonate supplementation for metabolic acidosis

Add spironolactone for additional proteinuria reduction

A 34-year-old previously healthy woman presents with oliguria and peripheral oedema. Blood tests show: creatinine 320 μmol/L (baseline 72 μmol/L two weeks ago), urea 22.4 mmol/L, albumin 28 g/L. Urinalysis shows protein 4+, blood 2+, and no leucocytes or nitrites. Urine protein:creatinine ratio is 520 mg/mmol. Renal biopsy shows crescentic glomerulonephritis. Serology shows: ANCA negative, anti-GBM negative, ANA 1:640 (speckled pattern), anti-dsDNA positive, C3 0.42 g/L (normal 0.75-1.65), C4 0.08 g/L (normal 0.14-0.54). What is the most likely diagnosis?

Anti-GBM disease (Goodpasture syndrome)

Post-streptococcal glomerulonephritis

A 56-year-old woman with chronic kidney disease stage 4 (eGFR 20 mL/min/1.73m²) secondary to IgA nephropathy presents for routine review. She reports increasing fatigue. Blood tests show: haemoglobin 95 g/L, ferritin 280 μg/L, transferrin saturation 28%, PTH 18.5 pmol/L (normal 1.6-6.9), corrected calcium 2.12 mmol/L, phosphate 1.85 mmol/L, 25-hydroxyvitamin D 32 nmol/L. What is the most appropriate initial management of her secondary hyperparathyroidism?

Start colecalciferol 20,000 units weekly

Start alfacalcidol 250 nanograms daily

Start calcium carbonate 1.25 g three times daily with meals

A 28-year-old man presents to the emergency department with sudden onset severe left-sided loin pain radiating to the groin. He has vomited twice and appears distressed. He has a history of inflammatory bowel disease (Crohn's disease) and has undergone two small bowel resections. CT KUB shows a 7 mm calculus at the left vesicoureteric junction with moderate hydronephrosis. Blood tests show: creatinine 88 μmol/L, calcium 2.35 mmol/L, uric acid 380 μmol/L. What is the most likely stone composition in this patient?

Struvite (magnesium ammonium phosphate)

Renal colic for UKMLA AKT: High-Yield Medicine (Core Systems) Lessons

Quick Overview

Renal colic is acute flank pain caused by urinary tract stones (nephrolithiasis/urolithiasis). Affects ~10-15% of adults; recurrence rate 50% within 5-10 years. Critical to distinguish simple colic from complicated presentations requiring urgent intervention (obstruction with infection, AKI, bilateral obstruction). NICE CG118 provides evidence-based pathways for diagnosis and management.

Core Facts & Concepts

Stone Types & Composition

Calcium oxalate (75-80%) - most common, radio-opaque
Uric acid (5-10%) - radiolucent on plain X-ray
Struvite (10-15%) - infection stones (Proteus), staghorn calculi
Cystine (<1%) - genetic, hexagonal crystals

Clinical Presentation

🚩 Classic triad: Colicky flank pain radiating to groin + haematuria + nausea/vomiting
Pain severity: 10/10, restless patient (vs peritonitis = still)
Location predicts stone position: loin (renal pelvis), iliac fossa (mid-ureter), suprapubic (vesicoureteric junction)

Figure 1: CT KUB showing radio-opaque calculus in proximal right ureter with proximal hydronephrosis

Imaging Gold Standard

Non-contrast CT KUB - sensitivity 95-98%, specificity 96-100% (NICE CG118)
Shows stone size, location, degree of obstruction (hydronephrosis)
Ultrasound - alternative in pregnancy, children; detects hydronephrosis but misses small stones

Stone Size Predicts Passage

Stone Size	Spontaneous Passage Rate	Timeframe
<5mm	90%	4 weeks
5-7mm	50%	Variable
>7mm	10%	Unlikely - needs intervention

Problem-Solving Approach

1. Immediate Analgesia (NICE CG118)

First-line: NSAIDs (diclofenac 50mg PO/100mg PR) - superior to opiates, reduces ureteric spasm
Second-line: Opiates (morphine IV/SC) if NSAIDs contraindicated (AKI, bleeding risk)
Anti-emetics: Metoclopramide 10mg IV/IM

2. Urgent Urology Referral Indications 🚩

Obstructed infected kidney (sepsis + hydronephrosis) - emergency nephrostomy/stent
AKI (Cr >150 or rising) with bilateral obstruction or solitary kidney
Uncontrolled pain despite adequate analgesia
Persistent vomiting preventing oral intake

Figure 2: Ultrasound showing moderate hydronephrosis with dilated renal pelvis and calyces

3. Conservative vs Interventional Management

Conservative (Medical Expulsive Therapy):
- Stones <10mm, no infection, controlled pain
- Alpha-blocker (tamsulosin 400mcg OD) - increases passage rate for 5-10mm stones
- Adequate hydration (2-3L/day), analgesia, 4-6 week trial
Interventional:
- Extracorporeal Shock Wave Lithotripsy (ESWL) - stones <20mm, renal/upper ureter
- Ureteroscopy + laser lithotripsy - stones >15mm or failed ESWL
- Percutaneous nephrolithotomy (PCNL) - large/staghorn calculi >20mm

4. Exclude Infection

Urinalysis + culture (leucocytes, nitrites)
Blood cultures if septic
Obstructive pyelonephritis = urological emergency (mortality 20-40% if delayed)

Analysis Framework

Differential Diagnosis of Acute Flank Pain

Diagnosis	Key Discriminator	Investigation
Renal colic	Colicky, radiates to groin, haematuria	CT KUB: stone visible
Pyelonephritis	Fever, dysuria, CVA tenderness	Urine culture positive
AAA	Pulsatile mass, >50yrs, smoker	Urgent CT angiogram
Musculoskeletal	Positional, tender paraspinal muscles	Clinical diagnosis
Ovarian pathology	Female, lower abdomen, menstrual history	Pelvic USS

Red Flags Requiring Immediate Action 🚩

Fever + obstructed kidney = sepsis risk
Bilateral obstruction = AKI risk
Solitary kidney = renal failure risk
Anuria >12 hours = complete obstruction

Visual Aid

NICE CG118 Management Pathway

Clinical Scenario	Action	Timeframe
Uncomplicated <10mm	Conservative + tamsulosin	Review 4-6 weeks
10-20mm renal/upper ureter	ESWL	Elective
>20mm or staghorn	PCNL	Elective
Infected obstructed kidney	Nephrostomy/stent + antibiotics	<6 hours

Key Points Summary

✓ Analgesia first: NSAIDs (diclofenac) superior to opiates for renal colic pain relief

✓ CT KUB non-contrast = gold standard imaging (95-98% sensitivity); USS alternative in pregnancy

✓ 90% of stones <5mm pass spontaneously within 4 weeks; >7mm unlikely without intervention

✓ Urgent urology referral: Obstructed infected kidney (sepsis), AKI with obstruction, uncontrolled pain

✓ Medical Expulsive Therapy: Tamsulosin 400mcg OD for 5-10mm stones increases passage rate

✓ Emergency nephrostomy/stent required for obstructive pyelonephritis within 6 hours (mortality risk)

✓ Stone composition matters: Calcium oxalate (radio-opaque, 75%), uric acid (radiolucent, needs CT)

⚠️ Warning: Never discharge febrile patient with hydronephrosis without urology review - obstructive pyelonephritis has 20-40% mortality if untreated

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Renal colic