Urinary Tract Calculi

Question 1

What are urinary tract calculi?

Answer 1

crystal deposition within the urinary tract

AKA. nephrolithiasis.

Question 2

What are the 4 types of stone in urinary tract calculi? List them from most common to least common

Answer 2

Calcium oxalate
Struvite
Urate
Cysteine

Question 3

What is the most common cause of urinary tract calculi?

Answer 3

Idiopathic

Question 4

Give 4 metabolic causes of urinary tract calculi

Answer 4

Hypercalciuria
Hyperuricaemia
Hypercystinuria
Hyperoxaluria

Question 5

Give 2 non metabolic causes of urinary tract calculi

Answer 5

UTI

Drugs: Indinavir

Question 6

Give 2 risk factors for urinary tract calculi

Answer 6

Low fluid intake

Structural urinary tract abnormalities (e.g. horseshoe kidney)

Question 7

List 4 symptoms of urinary tract calculi

Answer 7

Often ASYMPTOMATIC 
SEVERE loin to groin pain 
Nausea + vomiting  
Urinary urgency, frequency or retention  
Haematuria

Question 8

Describe the epidemiology of urinary tract calculi

Answer 8

COMMON
2-3% of general population
M > F
Age group affected: 20-50 yrs
Bladder stones more common in developing countries
Upper urinary tract stones more common in industrialised countries

Question 9

List 3 signs of urinary tract calculi

Answer 9

Loin to lower abdominal tenderness
NO signs of peritonism
Signs of systemic sepsis if there is an obstruction + infection above the stone

Question 10

What bloods should be taken in urinary tract calculi?

Answer 10

FBC: high WCC if infection  
U+Es: check renal function 
Calcium (Hyperparathyroidism)
Urate (Uric acid high in Gout)
Phosphate (hyperparathyroidism)

Question 11

What urinalysis is performed in urinary tract calculi?

Answer 11

Dipstick: haematuria is common

MC+S: Infection

Question 12

Why perform an X-ray KUB for urinary tract calculi?

Answer 12

X-Ray KUB

80% of kidney stones are radio-opaque

Question 13

What imaging modalities are usually used in suspected renal tract calculi?

Answer 13

Non contrast CT: Calcification, Hydronephrosis

US (Pregnant/ Kids)

Question 14

What is the acute management of urinary tract calculi?

Answer 14

Analgesia
Bed rest
Fluid replacement
Urine collection: try to retrieve any stone that has passed

Question 15

Give 3 surgical interventions for urinary tract calculi?

Answer 15

Urethroscopy
Extracorporeal shock wave lithotripsy (ESWL)
Percutaneous Nephrolithotomy (PCNL)

Question 16

What is Urethroscopy?

Answer 16

A scope is passed into the bladder + up the ureter to visualise the stone
Remove by basket or break up with a laser
If stone cant be removed, insert a JJ stent to allow urine drainage

Question 17

What is extracorporeal shock wave lithotripsy?

Answer 17

Electromagnetic shockwave focused onto the calculus to break it up into smaller fragments that can pass spontaneously
Non-invasive

Question 18

When is Percutaneous Nephrolithotomy performed?

Answer 18

For large, complex stones (e.g. staghorn calculi)

After making a nephrostomy tract, a nephroscope is inserted, which allows disintegration + removal of stones

Question 19

What general management should you do for urinary tract calculi?

Answer 19

TREAT CAUSE
Depends on the cause e.g.
Parathyroidectomy if hypercalcaemia due to hyperparathyroidism
Allopurinol if hyperuricaemia

Question 20

What advice can you give to patients prophylactically for urinary tract calculi?

Answer 20

Increase oral fluid intake

Question 21

List 3 complications of urinary tract calculi

Answer 21

Infection (PYELONEPHRITIS)
Septicaemia
Urinary retention

Question 22

Give 2 complications of ureteroscopy for urinary tract calculi

Answer 22

Perforation

False passage

Question 23

What is the prognosis in urinary tract calculi?

Answer 23

GOOD
However, infection of the calculus could lead to irreversible renal scarring
Recurrence of about 50% over 5 yrs

Question 24

What is the main ddx in older men?

Answer 24

Leaking AAA

Question 25

What happens to most stones that are <5mm?

Answer 25

Pass spontaneously

Question 26

How should an obstructed, infected kidney be treated?

Answer 26

As an EMERGENCY

Treat ASAP to relieve obstruction (e.g. by placing a percutaneous nephrostomy)

Question 27

Give 2 complications of extracorporeal shock wave lithotripsy for urinary tract calculi?

Answer 27

Pain

Haematuria