Nephro-urolithiasis Flashcards
• Discuss the clinical presentation and principles of management of patients with renal pain and ureteric colic. • Describe the aetiology, clinical presentation, investigation and treatment of urinary tract calculi
Types of renal calculi (5)
Calcium oxalate - COMMONEST
Calcium phosphate
Uric acid
Struvite ('infection/triple stone')
CystineCause of cystine calculi
Inborn error of metabolism, cystinuria, an autosomal-recessive disorder that results in abnormal renal tubular re-absorption of some amino acids including cystine
Symptoms(4) /signs (1) of renal calculi
Acute severe flank pain/back pain -may radiate anteriorly to groin and testicles (in males) Dysuria Nausea/vomiting Urinary frequency/urgency
Microscopic haematuria
Struvite (infection/triple stones) are associated with what organisms
urea-splitting organisms (bacteria) which convert urea to ammonia making urine more alkaline, favouring precipitation
Pathophysiology of renal calculi
Elevated levels of urinary solutes such as calcium, uric acid, oxalate as well as decreased levels of stone inhibitors such as citrate and magnesium.
Low urinary volume and abnormally low/high urinary pH also contribute
All of these can lead to urine supersaturation –> solutes more likely to precipitate out of solution and form crystals
Investigations of renal calculi
- biochemical (5)
- imaging (3; 1 is first line)
Urinalysis - dipstick, microscopy Bloods -FBC - may have increased WBCs if infection -U+Es -serum creatinine
Imaging
- non contrast CT KUB (FIRST LINE)
- plain KUB XR
- CT urogram
First line imaging investigation of kidney/ureteric stones (nephro-urolithiasis)
Non contrast CT abdo
Kidney stones are usually removed endoscopically but what are the indications for open surgical stone treatment (Very RARE) (2)
large stones >10mm
If percutaenous nephro-lithotomy (PCNL) or endoscopic shockwave lithotripsy (EWSL) not adequate
Extracorporeal shock wave lithotripsy (ESWL) and ureteroscopy are considered first-line treatment for surgical removal of stones but when is a Percutaneous Nephrolithotomy (PCNL) indicated (3)
proximal ureteric stones (i.e. in the lower pole of the kidney)
large (>20 mm)
those that have failed therapy with ESWL and ureteroscopy, e.g. cystine stones
How does a percutaneous nephro-lithotomy (not considered open surgery) work
A small incision is made in your back and the nephroscope is passed through it and into your kidney. The stone is either pulled out or broken into smaller pieces using a laser or pneumatic energy
Usually scope is guided by XR
How does Extracorporeal shock wave lithotripsy (ESWL) work
Using ultrasound (high-frequency sound waves) to pinpoint where a kidney stone is. Ultrasound shock waves are then sent to the stone from a machine to break it into smaller pieces, so it can be passed in your urine
ESWL often ineffective for treating which type of stones (2)
cystine
> 2cm stones
Treatment of nephrolithiasis
- if acute confirmed stone but no obstruction and <10mm (conservative (3), medication (1))
- if > 10mm or causes obstruction of ureter (surgical (3))
Hydration
NSAIDs analgesia
Anti emetics
Alpha blockers - to relax ureter
ESWL - shockwave lithotripsy
Ureteroscopy
PCNL - percutaenous nephro-lithotomy
Treatment of ureteric stones (slightly different to kidney stones) (2)
Ureteric stent
Ureteroscopy - better for lower ureteric stones
Symptoms/signs of a kidney stone that has gone and obstructed the ureter and caused an infection (4)
Groin pain - as stone as passed down ureter anteriorly
Fever
Tachycardia
Hypotension
