Nephrourolithiasis

Question 1

what is the prevalence of kidney stones in the general population

Answer 1

2-3%

Question 2

what is the commonest cause of urological emergency admission

Answer 2

“colic” - severe abdominal pain

Question 3

what is the most common type of stone

Answer 3

calcium oxalate - 45%

Question 4

what are the other types of stones and how common are they

Answer 4

calcium oxalate + phosphate - 25%

triple phospahte (infective) = 20%
usually the result of chronic infection in the kidneys 

calcium phosphate - 3%

uric acid - 5%
associated with gout - don’t show up well on x-rays

cystine - 3%
inherited metabolic causes - orange, soapy

**high calcium content stones show up well on X-rays

Question 5

what are the signs of symptoms of kidney stones

Answer 5

Renal pain (fixed in loin)

Ureteric colic* (radiating to groin)

Dysuria / haematuria /
testicular or vulval pain

Urinary infection

Loin tenderness

Pyrexia

*Ureteric colic – more constant than GI colic – doesn’t wax and wane as much as GI colic does with peristalsis etc

Question 6

what investigations should be used for stones

Answer 6

Blood tests - FBC, U&E, Creatinine

Calcium, Albumin, Urate

Parathormone

Urine analysis and culture

24hr urine collections

Question 7

what can be added to the diet to reduce risk of further stones

Answer 7

citrate - good at reducing crystallisation

Question 8

what radiological investigations can be used for stones

Answer 8

US of kidney/bladder/ureter*
- regularly used BUT can miss stones or over diagnose

Intravenous urogram (IVU)

CT KUB*
- more sensitive - can see hydronephritis, can look for other causes of pain

Question 9

what are indications for surgical removal of stones

Answer 9

Obstruction.

Recurrent gross haematuria.

Recurrent pain and infection.

Progressive loss of kidney function.

Patient occupation

Question 10

what are the three main techniques for surgical treatment

Answer 10

endoscopic surgery

PCNL - percutaneous nephrolithotomy

ESWL - extracorporeal shock wave lithotripsy

open surgery (now rare)

Question 11

what are the advantages and disadvantages of open surgery

Answer 11

+
single procedure with least recurrence rate

• Large scar, long hospital stay, general wound complications, longer recovery

Question 12

what are the indications for open surgery

Answer 12

Non functioning infected kidney with large stones necessitating nephrectomy.

Cases which for technical reasons cannot be managed by PCNL (or ESWL

Question 13

what are indications for simple partial and total nephrectomy

Answer 13

Non functioning kidney with large staghorn stones or elderly frail patients with complex stones and normal contralateral kidney

Question 14

what are indications for PCNL

Answer 14

Large stone burden (risk of Steinstrasse)

Associated PUJ stenosis.
Infundibular stricture.

Calyceal diverticulum.

Morbid obesity or skeletal deformity.

ESWL resistant stones e.g. Cystine.

Lack of availability of ESWL

Question 15

what are contraindications for PCNL

Answer 15

Uncorrected coagulopathy.

Active Urinary Tract Infection.

Obesity or unusual body habitus unsuitable for X-ray tables.

Relative contraindications include small kidneys and severe perirenal fibrosis

Question 16

describe briefly how PCNL works

Answer 16

guide wire inserted up ureters - retrograde catheter or balloon catheter opened in renal pelvis - contrast injected

guided by ultrasound or x-ray renal punctures made through back - accesses the collecting system to remove stones

Question 17

what are complications of PCNL

Answer 17

pseudo-aneurysm or AV fistula

UT injury

• pelvic tear
• ureteral tear
• stricture of PUJ

injury to adjacent organs

• bowel injury
• pneumothorax
• liver, spleen

systemic

• fever, sepsis
• MI

Question 18

in very simple terms how does ESWL work

Answer 18

“simple” stones too large to pass through - shock waves crush stones - smaller pieces pass out of body in urine

Question 19

what is ESWL the first line treatment for

Answer 19

renal and ureteric calculi

usually done on a day-case basis with simple analgesia

can be repeated as often as required

Question 20

what are contraindications for ESWL

Answer 20

hypertensive patients

patients on anticoagulants

pregnant women

not for stones >2cm

cystine stones

if after 2 treatments still not effective

Question 21

what are indications for open ureterlithotomy

Answer 21

patient not suitable for laparoscopic approach

failed ESWL or ureteroscopy

Question 22

what are indications for endoscopic ureteroscopy

Answer 22

Severe obstruction, uncontrollable pain, persistent haematuria, lack of progression, failed ESWL and patient occupation

Question 23

what are the success rates using a rigid ureterscope

Answer 23

lower stones 90-100%

promximal stones 60-70%

Question 24

what are the complications of ureteroscopy

Answer 24

minor:
Haematuria, fever, small ureteric perforation, minor vesico-ureteric reflux

major:
Major ureteric perforation, ureteric avulsion, ureteral necrosis and stricture formation

Question 25

what are symptoms of bladder stones

Answer 25

Suprapubic / groin / penile pain

Dysuria, frequency, haematuria

Urinary infection (persistent)

Sudden interruption of urinary stream -usually secondary to outflow obstruction

Question 26

how are bladder stones usually treated

Answer 26

most treated endoscopically

larger stones can be treated by open excision

Question 27

what % of renal tract stones are seen on a plain X-ray

Answer 27

~90%

gall stones <10%