Nephrourolithiasis Flashcards
what is the prevalence of kidney stones in the general population
2-3%
what is the commonest cause of urological emergency admission
“colic” - severe abdominal pain
what is the most common type of stone
calcium oxalate - 45%
what are the other types of stones and how common are they
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
what are the signs of symptoms of kidney stones
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
what investigations should be used for stones
Blood tests - FBC, U&E, Creatinine
Calcium, Albumin, Urate
Parathormone
Urine analysis and culture
24hr urine collections
what can be added to the diet to reduce risk of further stones
citrate - good at reducing crystallisation
what radiological investigations can be used for stones
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
what are indications for surgical removal of stones
Obstruction.
Recurrent gross haematuria.
Recurrent pain and infection.
Progressive loss of kidney function.
Patient occupation
what are the three main techniques for surgical treatment
endoscopic surgery
PCNL - percutaneous nephrolithotomy
ESWL - extracorporeal shock wave lithotripsy
open surgery (now rare)
what are the advantages and disadvantages of open surgery
+
single procedure with least recurrence rate
- Large scar, long hospital stay, general wound complications, longer recovery
what are the indications for open surgery
Non functioning infected kidney with large stones necessitating nephrectomy.
Cases which for technical reasons cannot be managed by PCNL (or ESWL
what are indications for simple partial and total nephrectomy
Non functioning kidney with large staghorn stones or elderly frail patients with complex stones and normal contralateral kidney
what are indications for PCNL
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
what are contraindications for PCNL
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
describe briefly how PCNL works
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
what are complications of PCNL
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
in very simple terms how does ESWL work
“simple” stones too large to pass through - shock waves crush stones - smaller pieces pass out of body in urine
what is ESWL the first line treatment for
renal and ureteric calculi
usually done on a day-case basis with simple analgesia
can be repeated as often as required
what are contraindications for ESWL
hypertensive patients
patients on anticoagulants
pregnant women
not for stones >2cm
cystine stones
if after 2 treatments still not effective
what are indications for open ureterlithotomy
patient not suitable for laparoscopic approach
failed ESWL or ureteroscopy
what are indications for endoscopic ureteroscopy
Severe obstruction, uncontrollable pain, persistent haematuria, lack of progression, failed ESWL and patient occupation
what are the success rates using a rigid ureterscope
lower stones 90-100%
promximal stones 60-70%
what are the complications of ureteroscopy
minor:
Haematuria, fever, small ureteric perforation, minor vesico-ureteric reflux
major:
Major ureteric perforation, ureteric avulsion, ureteral necrosis and stricture formation
what are symptoms of bladder stones
Suprapubic / groin / penile pain
Dysuria, frequency, haematuria
Urinary infection (persistent)
Sudden interruption of urinary stream -usually secondary to outflow obstruction
how are bladder stones usually treated
most treated endoscopically
larger stones can be treated by open excision
what % of renal tract stones are seen on a plain X-ray
~90%
gall stones <10%
