bitemedicine - lecture (renal stones) slid

• Pathophysiology, clinical features, investigations, management, prognosis

• Provide important differential diagnoses

• Multi-step SBAs: for a full understanding of the patient journey

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Aims and objectives

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Which is a stone?

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Which is a stone?

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Which is a stone?

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Which is a stone?

History and examinationA 35-year-old male presents to the emergencydepartment with a two-hour history of severe,sudden-onset, right-sided flank pain radiating tohis groin. He has vomited once. He has no lowerurinary tract symptoms.

He has had a previous renal stone.

On examination, there is right flank tendernessbut no other findings.

ObservationsHR 120, BP 140/95, RR 24, SpO2 95%, Temp 37.3

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Case-based discussion: 1

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A 35-year-old male presents to the emergency department with a two-hourhistory of severe, sudden-onset, right-sided flank pain radiating to his groin.He has vomited once. He has no lower urinary tract symptoms.

He has had a previous renal stone.

Q1

What is your next step?

Case history

Oral dihydrocodeine

Urine dip

IV fluid bolus

Oral morphine

PR diclofenac

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Q2 Q3 Q4 Q5

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Explanations

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What is your next step?

Oral dihydrocodeineIn this context, opioids have a poorer analgesic effect and more side effects than NSAIDs

Urine dipShould be performed once symptomatic relief has been offered

IV fluid bolusTachycardia is likely due to pain and there are no features of dehydration on examination

Oral morphineIn this context, opioids have a poorer analgesic effect and more side effects than NSAIDs

PR diclofenacAs per BAUS guidelines, NSAIDs (diclofenac/ibuprofen) should be administered immediately after initial assessment

Q1 Q2 Q3 Q4 Q5

History and examinationA 35-year-old male presents to the emergencydepartment with a two-hour history of severe,sudden-onset, right-sided flank pain radiating tohis groin. He has vomited once. He has no lowerurinary tract symptoms.

He has had a previous renal stone.

On examination, there is right flank tendernessbut no other findings.

ObservationsHR 120, BP 140/95, RR 24, SpO2 95%, Temp 37.3

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Case-based discussion: 1

Definition• Nephrolithiasis is the presence of stones, or calculi, within the urinary tract

Epidemiology and general risk factors• Typically occurs in 30-60-year olds• Twice as common in males• Dehydration• Previous kidney stone(s)

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Introduction

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Basic anatomy

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Basic anatomy

Renal stone

Ureteric stone

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Renal stone

Calyceal stone

PUJ stone

Pelvic stone

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Ureteric stone

Ureteric stone

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VUJ stone

VUJ stone

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A 35-year-old male presents to the emergency department with a two-hourhistory of severe, sudden-onset, right-sided flank pain radiating to his groin.He has vomited once. He has no lower urinary tract symptoms.

He has had a previous renal stone.

Which of the following is the most likely site of obstruction in this patient?

Case history

As the ureter crosses over the coeliac trunk

As the ureter crosses over the uterine artery

Pelviureteric junction

As the ureter crosses anteriorly to the vas deferens

Spinoureteric junction

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Explanations

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Which of the following is the most likely site of obstruction in this patient?

As the ureter crosses over the coeliac trunkThe coeliac trunk arises at T12. The ureter begins at the level of the renal artery/vein (L1-2)

As the ureter crosses over the uterine arteryThe patient is male. Also, the ureter crosses under the uterine artery (water under the bridge)

Pelviureteric junctionOne of the most common sites of renal calculus obstruction

As the ureter crosses anteriorly to the vas deferensThe ureter crosses posteriorly to the vas deferens

Spinoureteric junctionThis does not exist

Q3Q2Q1 Q4 Q5

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Sites of obstruction

Pelviureteric junction (PUJ) of the renal pelvis and ureter

As the ureter enters the pelvis and crosses over the common iliac artery

At the vesicoureteric junction (VUJ) as the ureter enters the bladder

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Stone types

Composition

Calcium oxalate (75%)

Struvite (15%)Calcium phosphate (5%)

Uric acid (5%)

Cysteine (1%)

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Stone types: calcium oxalate

Composition

Calcium oxalate (75%)

Struvite (15%)Calcium phosphate (5%)

Uric acid (5%)

Cysteine (1%)

Risk factors and comments

Hypercalcaemia: e.g. hyperparathyroidism

Envelope-shapedRadio-opaque (less than calcium phosphate stones)

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Which is a stone?

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Stone types: struvite

Composition

Calcium oxalate (75%)

Struvite (15%)Calcium phosphate (5%)

Uric acid (5%)

Cysteine (1%)

Risk factors and comments

UTI with urease-producing organisms

Coffin-lid shaped and may cause staghorn calculiMildly radio-opaque

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Which is a stone?

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Stone types: calcium phosphate

Risk factors and comments

Hypercalcaemia: e.g. hyperparathyroidism

Type 1 and 3 renal tubular acidosisVery radio-opaque

Composition

Calcium oxalate (75%)

Struvite (15%)Calcium phosphate (5%)

Uric acid (5%)

Cysteine (1%)

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Stone types: uric acid

Risk factors and comments

Purine metabolism: gout and malignancy

Rhomboid-shapedRadiolucent

Composition

Calcium oxalate (75%)

Struvite (15%)Calcium phosphate (5%)

Uric acid (5%)

Cysteine (1%)

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Stone types: cysteine

Composition

Calcium oxalate (75%)

Struvite (15%)Calcium phosphate (5%)

Uric acid (5%)

Cysteine (1%)

Risk factors and comments

Cystinuria

Hexagonal-shaped and semi-opaqueMay cause multiple stones

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Other risk factors

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A 35-year-old male presents to the emergency department with a two-hourhistory of severe, sudden-onset, right-sided flank pain radiating to his groin.He has vomited once. He has no lower urinary tract symptoms.

He has had a previous renal stone.

Q2

Which of the following would be a red flag feature in this patient?

Case history

Vomiting

Haematuria

Renal-angle tenderness

Fever

Tachycardia

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Explanations

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Which of the following would be a red flag feature in this patient?

VomitingThis is common secondary to severe pain

HaematuriaAlthough haematuria is usually microscopic, macroscopic haematuria may be present

Renal-angle tendernessFlank or ‘renal-angle’ tenderness may be present with a renal stone and alone is not worrying

FeverThis is very concerning and may suggest urosepsis or pyelonephritis

TachycardiaOften present due to severe pain

Q2 Q3Q1 Q4 Q5

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Clinical features

Symptoms SignsAcute, severe ‘loin-to-groin’ pain Flank or renal-angle tenderness

Nausea and vomiting Hypotension and tachycardia: suggests urosepsis

Urinary urgency/frequency

Haematuria: usually microscopic

Fever: suggests superimposed infection

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Important differential diagnoses

Differential diagnosis CommentsAAA rupture • Sudden onset abdominal pain radiating to back

• Haemodynamic instability• Cardiovascular risk factors present

Acute appendicitis • Peri-umbilical à RIF pain and low-grade fever• Less acute onset

Ectopic pregnancy • Women of child-bearing age• Missed menstrual period• Vaginal spotting and cervical motion tenderness

Pyelonephritis • LUTS: dysuria, frequency, hesitancy• Fever• Less acute onset

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A 35-year-old male presents to the emergency department with a two-hourhistory of severe, sudden-onset, right-sided flank pain radiating to his groin.He has vomited once. He has no lower urinary tract symptoms.

He has had a previous renal stone. Pain has settled with diclofenac andurine dip is +++ blood. Observations are now normal.

What is your imaging of choice in this patient?

Case history

Non-contrast CT KUB

Renal tract ultrasound

MRI abdomen and pelvis

Contrast CT KUB

CT abdomen and pelvis

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Q2 Q4Q3Q1 Q5

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Explanations

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What is your imaging of choice in this patient?

Non-contrast CT KUBConsidered gold-standard by BAUS (97% sensitivity and 95% specificity)

Renal tract ultrasoundPerformed if radiation must be avoided or in a subset of known stone formers

MRI abdomen and pelvisNot performed

Contrast CT KUBA CT KUB is a non-contrast procedure

CT abdomen and pelvisA CT is required but should be performed using a KUB protocol

Q2Q1 Q4Q3 Q5

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InvestigationsBedside• Urinalysis: microscopic haematuria

Bloods• FBC: WBC may be elevated, but if significantly may suggest superimposed infection• CRP: elevated• U&Es: deranged renal function suggests hydronephrosis• Bone profile: elevated calcium may suggest hyperparathyroidism• Blood cultures: if >38°C or features of sepsis• Coagulation profile: if percutaneous intervention is planned

Primary imaging• Non-contrast CT KUB: gold-standard and within 14 hours of admission at the latest

Imaging to consider• Renal tract ultrasound and/or X-ray KUB: may suffice if a known stone former, particularly if CT

KUB performed in the last 3 months (BAUS guidelines)

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A 35-year-old male presents to the emergency department with a two-hourhistory of severe, sudden-onset, right-sided flank pain radiating to his groin.He has vomited once.

Pain has settled with diclofenac and urine dip is +++ blood. Observations arenow normal. CT KUB: 15 mm right-sided mid-ureteric stone.

What is your first-line definitive management option?

Case history

Tamsulosin expulsive therapy

Ureteroscopy

Shockwave lithotripsy

Watchful waiting

Antibiotics and ureteric stenting

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Explanations

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What is your first-line definitive management option?

Tamsulosin expulsive therapyConsidered in <10 mm distal ureteric stones (NICE). BAUS do not recommend routine use

UreteroscopyGenerally first-line surgical management for 10-20 mm ureteric stones (NICE)

Shockwave lithotripsyConsidered in the management of 5-10 mm ureteric and renal stones (EUA/NICE)

Watchful waitingAppropriate for < 5 mm ureteric and renal stones (EUA/NICE)

Antibiotics and ureteric stenting Performed for sepsis/anuria in an obstructed kidney (urological emergency)

Q2Q1 Q3 Q4 Q5

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The golden points when referring a stone patient to urology

1. Basic details (name/DOB etc.)2. A brief background

3. Known stone-former?4. Severity of pain/vomiting and response to medication

5. Presence of fever or features of sepsis6. Renal function

7. CT KUB: stone size, location and evidence of hydronephrosis

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Management

First line• IV fluids and anti-emetics (as required)• Analgesia: an NSAID by any route is first-line (NICE)

Conservative or medical management• Watchful waiting: ureteric and renal stones <5 mm usually pass spontaneously• Medical expulsive therapy: (distal) ureteric stones 5-10 mm (controversial)

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Extracorporeal shock wave lithotripsy (ESWL)

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Ureteroscopy (URS)

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Percutaneous nephrolithotomy (PCNL)

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Surgical management: EUA and NICEKey:

ESWL: extracorporeal shock wave lithotripsy

URS: ureteroscopy

PCNL: percutaneous nephrolithotomy

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Percutaneous nephrostomy

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Ureteric stenting

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Surgical management: EUA and BAUS

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Complications and prognosis

System Complication

Urological • Hydronephrosis• Urosepsis

Procedure-related • Ureteric injury• Bleeding• Sepsis• ESWL haematoma

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Top-decile question

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Explanations

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Which of the following stones would NOT be visible on a non-contrast CT KUB?

Prednisolone-induced stonesNot a recognized condition

Maraviroc-induced stonesThis is an entry inhibitor (HIV medication) and that is not usually associated with stones

Type 3 renal tubular acidosis-induced stonesThis causes calcium phosphate stones which are visible on CT KUB

Indinavir-induced stonesA protease inhibitor (HIV medication) characteristically linked with radiolucent stones

Raltegravir-induced stonesThis is an integrase inhibitor (HIV medication) that is not usually associated with stones

Q1

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Recap

• Renal vs ureteric stones

• There are numerous types of stones with specific risk factors

• Renal colic has a characteristic presentation, but important differentials must always be excluded

• All patients need a urine dip, basic bloods and most will have a non-contrast CT KUB

• Most patients can be managed conservatively

• Surgical options include ESWL, URS, PCNL, nephrostomy and stent insertion

• Patients with features of infection require immediate investigation and management

• Lifetime recurrence is remarkably high

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References

Slide 3 and 22: • Mikael Häggström, M.D. - Author info - Reusing images / CC0. https://commons.wikimedia.org/wiki/File:Spiculated_kidney_stone.jpg• Uploader1977 / CC BY-SA (https://creativecommons.org/licenses/by-sa/3.0). https://commons.wikimedia.org/wiki/File:The_Puffer_Fish.jpg

Slide 4:• Mikael Häggström, M.D. - Author info - Reusing images / CC0. https://commons.wikimedia.org/wiki/File:Spiculated_kidney_stone.jpg• Jolanta Dyr / CC BY-SA (https://creativecommons.org/licenses/by-sa/3.0).

https://commons.wikimedia.org/wiki/File:020613_Interior_of_Manor_in_Pilaszk%C3%B3w_-_14.jpg

Slide 5:• Father.Jack from Coventry, UK / CC BY (https://creativecommons.org/licenses/by/2.0).

https://commons.wikimedia.org/wiki/File:Dough_balls_(1028134868).jpg• Jacek Proszyk / CC0. https://commons.wikimedia.org/wiki/File:Kidney_stone_4mm_05.jpg

Slide 6 and 40:• Willis Lam / CC BY-SA (https://creativecommons.org/licenses/by-sa/2.0).

https://commons.wikimedia.org/wiki/File:Burger_King_Chicken_Nuggets_(15423233415).jpg• RJHall / Public domain. https://commons.wikimedia.org/wiki/File:Kidney_stone_fragments.png

Slides 12, 13, 15, 19, 40, 43: Jordi March i Nogué [1] / CC BY-SA (https://creativecommons.org/licenses/by-sa/3.0). https://commons.wikimedia.org/wiki/File:Urinary_system.svg

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References

Slide 14: Piotr Michał Jaworski; PioM EN DE PL / CC BY-SA (http://creativecommons.org/licenses/by-sa/3.0/). https://commons.wikimedia.org/wiki/File:KidneyStructures.svg

Slide 16: DBCLS 統合TV / CC BY (https://creativecommons.org/licenses/by/4.0). https://commons.wikimedia.org/wiki/File:201405_bladder.png

Slide 21: Nevit Dilmen / CC BY-SA (https://creativecommons.org/licenses/by-sa/3.0). https://commons.wikimedia.org/wiki/File:Radiology_1300236_cr.jpg

Slide 23: © Nevit Dilmen / CC BY-SA (https://creativecommons.org/licenses/by-sa/3.0). https://commons.wikimedia.org/wiki/File:Staghorn_Kidney_Stone_08779.jpg

Slide 24: • Prefeitura de Olinda / CC BY (https://creativecommons.org/licenses/by/2.0).

https://commons.wikimedia.org/wiki/File:3%C2%BA_Festival_da_Tapioca_(1%C2%BA_Dia)_5.jpg• Joel Mills / CC BY-SA (http://creativecommons.org/licenses/by-sa/3.0/). https://commons.wikimedia.org/wiki/File:Struvite_stones.JPG

Slide 26: © Nevit Dilmen / CC BY-SA (https://creativecommons.org/licenses/by-sa/3.0). https://commons.wikimedia.org/wiki/File:Medical_X-Ray_imaging_ALP02_nevit.jpg

Slide 31: Shutterstock basic license

Slide 44: Unknown author / Public domain. https://commons.wikimedia.org/wiki/File:N01224_H_nephrostomy.jpg

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References

Slide 45:• Hildpeyi at the English Wikipedia / CC BY-SA (http://creativecommons.org/licenses/by-sa/3.0/).

https://commons.wikimedia.org/wiki/File:Ureteral_stent.jpg• Lucien Monfils / CC BY-SA (https://creativecommons.org/licenses/by-sa/3.0). https://commons.wikimedia.org/wiki/File:DoubleJ.jpg

•

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