Urolithiasis

Question 1

Definition of urolithiasis

Answer 1

Formation of stones anywhere in the genitourinary system (from the kidney to the bladder).

Question 2

Who is at risk for developing stones

Answer 2

• 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

Question 3

Renal Colic

Answer 3

Excruciating unilateral flank or lower abdominal pain

Question 4

Differential dx

Answer 4

• Renal or ureteral stone
• bacterial cystitis or pyelonephritis
• hydronephrosis
• acute abdomen (bowel, biliary, pancreas or aortic abdominal aneurysm sources)
• Gynecologic
• Radicular pain
• referred pain

Question 5

Other signs and symptoms

Answer 5

• hematuria
• dysuria
• urinary frequency or urgency
• Small volume urination
• urinary retention

Question 6

Calcium stone

Answer 6

• 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

Question 7

Uric Acid Stones

Answer 7

• Account for 10% of stones
• M > F
• Urine that contains too much uric acid
• Common w/ gout
• Brown to red colored

Question 8

Struvite stones

Answer 8

• 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

Question 9

Cystine Stones (Cystinuria)

Answer 9

• Accounts for 1% of stones
• rate genetic condition that promotes urinary excretion of cystine
• honey colored

Question 10

UA

Answer 10

-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

Question 11

Renal stone protocol CT

Answer 11

• 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

Question 12

Abdominal xray

Answer 12

• Size and location
• More sensitive with calcium stones
• 45% sensitive, 71% specific
• Useful in known stone disease

Question 13

Abdominal US

Answer 13

• Preferred in pregnant patient

- Sensitive to hydronephrosis

Question 14

Definition of hydronephrosis

Answer 14

abnormal enlargement of the kidney

Question 15

Priorities for renal stone

Answer 15

+- hospitalize

• tx for pain, nausea/vomiting,
• possible fluid intake
• urology/nephrology consult
• possible removal

Question 16

Urologist consult

Answer 16

• Evidence of obstruction
• Associated with urinary tract infection
• Single kidney
• Significant urinary bleeding
• Pregnant
• Get OB/GYN involved

Question 17

Infection in urolithiasis

Answer 17

-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

Question 18

Obstructive Renal Failure

Answer 18

• 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

Question 19

Stone size and passing

Answer 19

• < 5 mm should pass on own
• 1-2 weeks should pass
• 80% of patients require no intervention beyond pain control

Question 20

Extracorporeal shock wave lithotripsy

Answer 20

• 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

Question 21

Ureteroscopy

Answer 21

• Ureteral stones
• definitive procedures
• outpatient
• can be invasive
• can commonly require postoperative ureteral stent
• Complications with ureteral stricture or injury

Question 22

Ureteroenoscopy

Answer 22

• Renal stones <2cm
• definitive procedures
• outpatient
• may be difficult to clear fragments
• commonly requires postoperative ureteral stent
• complications can be ureteral stricture or injury

Question 23

Percutaneous nephrolithotomy

Answer 23

• 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

Question 24

Stone passage

Answer 24

• 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)

Question 25

Ca Channel blockers for stone passage

Answer 25

• nifedipine 30 mg daily (off label use)

- –vasodilator = decreased spasms

Question 26

Medical workup & eval

Answer 26

• parathyroid evaluation (PTH)
• Metabolic testing on random diet- (24 hr urine collections)
• Stone evaluations

Question 27

Treatment options for preventions: Metabolic stone disease

Answer 27

• 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