Urothiliasis

Question 1

What is renal colic?

Answer 1

Abdominal pain caused by urolithiasis (stones in the kidney + urinary stones

Question 2

Describe renal colic pain?

Answer 2

In the flank

Radiates to the hypochondrium or the groin

On and off

Question 3

Where is the hypochondrium?

Answer 3

Just below ribcage

On either side

Question 4

What is urolithiasis?

Answer 4

Formation of a stone anywhere in the urinary system

Question 5

What 3 sub-categories of urolithiasis are there?

Answer 5

Nephrolithiasis: stones in kidney
Ureterolithiasis: stones in ureters
Cystolithiasis: stones in bladder

Question 6

What age-group is most commonly affected by urolithiasis?

Answer 6

25-45

Question 7

Where in the urinary system can you get stones?

Answer 7

Anywhere!

Collecting duct to urethral meatus

Question 8

What are the risk factors for getting urolithiasis?

Answer 8

Anatomical abnormalities:

• horseshoe kidney
• PUJO
• spina bifida

Trauma, obstruction

Excess quantities of stone-forming substances in the body

Dehydration

Infection

Poor diet, excess salt + protein

High BMI, inactive lifestyle

Question 9

What is PUJO?

Answer 9

Pelvic-ureteric junction obstruction

Question 10

Describe the mechanism of stone formation?

Answer 10

Nucleation theory:

Crystals form in supersaturated urine

These crystals form stones

Question 11

What can stones be made from?

Answer 11

Calcium phosphate, calcium oxalate
Uric acid
Struvite
Cystine

Question 12

What are stones most commonly made from?

Answer 12

Calcium

Question 13

What is the link between smoking and urolithiasis? Why?

Answer 13

None!

Question 14

What is the link between dairy foods and urolithiasis? Why?

Answer 14

More dairy is better

Calcium in dairy binds to oxalate which means it can’t form stones

Question 15

In what conditions do uric acid stones form?

Answer 15

Acidic urine

Question 16

How can you reduce the risk of getting calcium stones?

Answer 16

Reduce dietary salt
Reduce dietary proteins
Over-hydration
Reduce BMI
Be active

Question 17

How can you reduce the risk of getting uric acid stones?

Answer 17

De-acidify urine

Question 18

How can you reduce the risk of getting cystine stones?

Answer 18

Over-hydration
Urine alkalisation
Cystine binders
Genetic counselling

Question 19

What causes cystine stones?

Answer 19

Genetic condition causing excessive excretion of cystine

There’s a lot of cystine in the urine so it forms stones

Question 20

How does infection cause stones?

Answer 20

Occurs in UTIs caused by urease producing organisms

Excess urease, urease hydrolyses to ammonia which raises the pH of the urine

Results in stones made of ammonium, magnesium, calcium

Question 21

What causes uric acid stones?

Answer 21

Low urine pH, any cause

Question 22

What is the link between ileostomeis and stones?

Answer 22

Ileostomies increase the risk of uric acid stones

Because, ileostomies cause a loss of bicarbonate, so lower urine pH

Question 23

What are the clinical features of urolithiasis?

Answer 23

Can be asymptomatic

Loin pain: side between ribs and hips

Renal colic

UTI symptoms: dysuria, urgency

Urinary tract obstruction

Recurrent UTIs

Haematuria

Question 24

Why is renal colic pain on and off?

Answer 24

Due to peristalsis of the ureters

Question 25

Investigations of suspected urolithiasis?

Answer 25

Urine dip to check for infection Mid stream urine sample for culture Bloods: serum urea, electrolytes, creatinine, calcium CT History: could indicate what type of stone is likely

Question 26

Which stones are visible on CT?

Answer 26

Fully radiopaque - Calcium phosphate and oxalate - Magnesium stones Cystine mildly radiopaque Uric acid not at all

Question 27

Management of urolithiasis?

Answer 27

Analgesic: NSAIDs such as diclofenac are best, morphine if necessary Anti-emetic Increase fluid intake Can give alpha blockers (tamsulosin) or Ca Ch blockers (amlodipine) Give patient 3 weeks to pass themselves before offering surgical (unless signs of infection or obstruction) Interventions: Electrical shock wave lithotripsy (shockwaves to break up stone so can pass fragments) Percutaneous nephrolithotomy (remove stone by sticking big needle into kidney) Ureteroscopy (using lasers to break stone) Open surgery

Question 28

What are the indications for urgent intervention? What would you do?

Answer 28

Signs of: Obstruction and Infection Because infection + obstruction = pyonephrosis Can go into renal failure within 24 hours Or get sepsis, leading to septic shock IV antibiotics (cefuroxime or gentamicin) Percutaneous nephrostomy to drain urine Stent to relieve obstruction

Question 29

What is pyonephrosis?

Answer 29

Infected hydronephrosis (urine backed up into kidney) Infection of the collecting ducts of the kidney Pus accumulation in the renal pelvis And kidney distention Can result in AKI, renal failure, sepsis

Question 30

Management of a patient with infection + a kidney stone?

Answer 30

IV antibiotics cefuroxime, gentamicin Urgent intervention: - stenting - percutaneous nephrostomy

Question 31

What is a percutaneous nephrostomy?

Answer 31

An artificial opening created between the kidney and the skin which allows for the drainage of urine

Question 32

In most cases, what are spiky stones made of?

Answer 32

Calcium oxalate

Question 33

In most cases, what are large, staghorn stones made of?

Answer 33

Infection related stones | Magnesium ammonium phosphate

Question 34

In most cases, what are yellow, crystalline stones made of?

Answer 34

Cystine

Question 35

Indications for stone analysis?

Answer 35

First time stone formers Early recurrance after stone removal Frequent stones despite pharmacological therapy

Question 36

Prevention of further stones?

Answer 36

Drink plenty of water Keep eating Ca foods (dairy) Lifestyle Calcium stones: thiazide diuretics to decrease Ca2+ excretion Uric acid stones: allopurinol Calcium citrate: for Ca oxalate stones