Urolithiasis Flashcards
Definition of urolithiasis
Formation of stones anywhere in the genitourinary system (from the kidney to the bladder).
Who is at risk for developing stones
- Men > Women
- Incidence > after 20 years of age
- Most common between 40-60 years of age
- Caucasian more commonly affected
- More commonly found in hot climates
Renal Colic
Excruciating unilateral flank or lower abdominal pain
Differential dx
- Renal or ureteral stone
- bacterial cystitis or pyelonephritis
- hydronephrosis
- acute abdomen (bowel, biliary, pancreas or aortic abdominal aneurysm sources)
- Gynecologic
- Radicular pain
- referred pain
Other signs and symptoms
- hematuria
- dysuria
- urinary frequency or urgency
- Small volume urination
- urinary retention
Calcium stone
- Ca oxalate
- Ca Phos
- Mixed Ca oxalate and Ca Phos
- most common type of stone
- off white to dark brown or black
- M>F
- R/T poor fluid intake-dehydration
- vitamin, mineral and antacids contribute
- Defect in how kidney handles acid
Uric Acid Stones
- Account for 10% of stones
- M > F
- Urine that contains too much uric acid
- Common w/ gout
- Brown to red colored
Struvite stones
- Accounts for 10% of stones
- Bacteria produce chemical changes in urine that promote struvite crystal growth
- Bacteria live inside stones and cannot be reached by antibiotics
- Stone removal required for definitive treatment
- Chalky to brown colored
Cystine Stones (Cystinuria)
- Accounts for 1% of stones
- rate genetic condition that promotes urinary excretion of cystine
- honey colored
UA
-Rule out infection – obtain culture
-Microhematuria
-Pyuria
-Evaluation for crystals to determine type of stone
pH
-Acidic urine – uric acid stones
-Alkaline urine – presence of infection
-Tx for infected stone is removal
Renal stone protocol CT
- Confirms stone location, size and degree of obstruction
- 100% sensitive and specific for confirming or excluding stone
- May also differentiate other GI related abnormalities or complications
- Degree of renal obstruction
Abdominal xray
- Size and location
- More sensitive with calcium stones
- 45% sensitive, 71% specific
- Useful in known stone disease
Abdominal US
- Preferred in pregnant patient
- Sensitive to hydronephrosis
Definition of hydronephrosis
abnormal enlargement of the kidney
Priorities for renal stone
+- hospitalize
- tx for pain, nausea/vomiting,
- possible fluid intake
- urology/nephrology consult
- possible removal
Urologist consult
- Evidence of obstruction
- Associated with urinary tract infection
- Single kidney
- Significant urinary bleeding
- Pregnant
- Get OB/GYN involved
Infection in urolithiasis
-STAT Urology consultation
s/s of sepsis?
-Stones can be source of infection or a result of infection
-Struvite, staghorn, calcium carbonate
-Need removal regardless of size
-Blood cultures
-Antibiotic therapy – complicated UTI pathway
Obstructive Renal Failure
- Stone
- Enlarged prostate
- Neurogenic bladder
- Mass causing compression
- Decreased urine output
- Elevated creatinine
- Hydronephrosis on CT or US
- STAT Urology consultation to remove obstructing stone w/ or w/o infection
Stone size and passing
- < 5 mm should pass on own
- 1-2 weeks should pass
- 80% of patients require no intervention beyond pain control
Extracorporeal shock wave lithotripsy
- Renal stones <2cm
- Ureteral stones <1cm
- Radiolucent calculi
- Minimally invasive
- Outpatient
- Less effective in pts w/ morbid obesity or hard stones
- could get perinephric hematoma
- could get ureteral obstruction by stone fragments
Ureteroscopy
- Ureteral stones
- definitive procedures
- outpatient
- can be invasive
- can commonly require postoperative ureteral stent
- Complications with ureteral stricture or injury
Ureteroenoscopy
- Renal stones <2cm
- definitive procedures
- outpatient
- may be difficult to clear fragments
- commonly requires postoperative ureteral stent
- complications can be ureteral stricture or injury
Percutaneous nephrolithotomy
- renal stones >2cm
- proximal ureteral stones >1cm
- Definitive procedure
- Can be invasive
- complications can be bleeding, injury to collecting system, or injury to adjacent structures
Stone passage
- strain all urine (send stone to lab)
- consider use of alpha blockers
- –Tamsulosin (Flomax)
- -relaxes bladder neck and/or prostate to facilitate stone passage (s/e floppy iris syndrome, hypotension)
Ca Channel blockers for stone passage
- nifedipine 30 mg daily (off label use)
- –vasodilator = decreased spasms
Medical workup & eval
- parathyroid evaluation (PTH)
- Metabolic testing on random diet- (24 hr urine collections)
- Stone evaluations
Treatment options for preventions: Metabolic stone disease
- High urine Ca- thiazide diuretic, limit sucrose, fructose and Na intake, increase fruit and vegie intake, avoid vitamin C supplmentation
- Low urine citrate-potassium citrate
- high urine uric acid-allopurinol
- high urine oxalate- Ca supplement
