Urolithiasis Flashcards
At what locations are kidneys stones most likely to obstruct?
Pelvic-ureter jucntion
Crossing the ilium at the pelvic brim
Vesico-ureteric junction
What are the risk factors for urolithiasis?
Male Age 20-50 years Comorbidities <1200ml fluid intake / day High animal protein/salt, low calcium diet Sedentary lifestyle Hot climate
What is the most common type of kidney stone?
Calcium oxalate
What is the likely cause of cysteine stones?
Genetic
What condition is associated with uric acid stones?
Gout
What are struvite stones composed of?
Magnesium
Ammonium
Phosphate
What type of kidney stones are associated with infection?
Struvite stones
What type of stones are stag horn calculi usually?
Struvite stones
What is the cause of xanthine stones?
Genetic enzyme deficiency resulting in a build up on xanthine deposits
What is the saturation product?
The level at which no more solute will dissolve in solution without a change in pH or temperature
What is the formation product?
The level at which spontaneous stone formation occurs
What factors increase the likelihood of kidney stone formation?
Low volume, low pH, low citrate, low magnesium, high uric acid, high calcium, high oxalate
How can kidney stones present?
Incidental finding
Colicky loin to groin pain, patient cannot settle and can lie still
Visible/non-visible haematuria
Sepsis
What initial investigations into urolithiasis should eb conducted?
U&Es, CRP, FBC, urinalysis, CT
What biochemical tests should be conducted for a first kidney stone?
Calcium Urate Urine dip MSS Sodium nitroprusside Stone analysis
What biochemical tests should be conducted for recurrent kidney stones?
Calcium
Urate
Venous Bicarbonate
24 hour urine analysis
What form of imaging is used in urolithiasis?
CT
X-ray for monitoring of recurrent stones
Medical therapy of kidney stones is with analgesia. Why are NSAIDs preferred in this case?
NSAIDs reduce pain by reducting glomerular pressure and ureteric peristalsis
What are the surgical options for treatment of urolithiasis?
Ureteroscopy and basket Ureteroscopy and fragmentation Flexible ureteroscopy Extracorporeal schokwave lithotripsy Percutaneous nephrolithotomy Emergency stent or nephrostomy
Why should patients with kidney stones be admitted?
Uncontollable paain Fever Sepsis Solitary kidney with ureteric stone Bilateral ureteric stones Renal failure caused by obstructing stones
What are the differentials for an emergency presentation of nephrolithiasis?
Ruptured abdominal aortic aneurysm
Testicular/penile pathology
Appendicitis
Gynaecological pathology
Npehrostomy is preferred to ureteric stents in nephrolithiasis with sepsis. T/F?
False - these both have similar outcomes so whichever is safest and most easily available should be used
In a non-emergency settle a patient with a >20mm non lower pole kidney stone can be treated with what surgical options?
Percutaneous nephrolithotripsy
Shock wave lithotripsy
In a non-emergency settle a patient with a 10-20mm non lower pole kidney stone can be treated with what surgical options?
Shock wave lithotripsy
Endourology
In a non-emergency settle a patient with a <10mm non lower pole kidney stone can be treated with what surgical options?
Percutaneous nephrolithotripsy
Shock wave lithotripsy
In a non-emergency settle a patient with a 10-20mm lower pole kidney stone can be treated with what surgical options?
Shock wave lithotripsy
Endourology
What types of shockwaves can be used in extracorporeal shockwave lithotripsy?
Electrohydraulic
Electromagnetic
Piezoelectric
How does extracorporeal shockwave lithotripsy act to dissipate renal stones?
Shearing and spalling of the stone
Shockwave in a fluid causes a micro bubble, and dissolved gas in fluid around the bubble expands into the bubble and the bubble collapses creating microjets which pit the stone surface
What are stag horn calculi?
Kidney stones which fill all or part of the renal pelvis and branch into several or all of the calyces.
