Nephrolithiasis

Question 1

What is the 3rd most common urinary tract disorder?

Answer 1

Nephrolithiasis

Question 2

Is nephrolithiasis more common in men or women?

Answer 2

Men

Question 3

What causes neprholithiasis?

Answer 3

Ambient concentrations of stone material exceed solubility in urine - allows crystals to grow

Basically “supersaturation” of urine

Question 4

What could a patient with neprholithiasis be lacking that helps to fight off the production of stones?

Answer 4

Inhibitors that retard crystal formation and growth

Question 5

What could cause supersaturation?

Answer 5

Increased excretion of poorly soluble substances

Question 6

Genetic disorder causing stone formation involving genes SLC2A1 and SLC7A9

Answer 6

Cystinuria

Question 7

What factors can lead to stone formation?

Answer 7

Supersaturation PLUS heredity or environment (diet, obesity)

Question 8

Most common type of urinary stone?

Answer 8

Calcium oxalate

Question 9

What are the different types of urinary stones?

Answer 9

Calcium oxalate
Calcium phosphate
Struvite
Uric acid
Cystine

Question 10

Frequently have smooth-edge ground-glass appearance

Answer 10

Cystine stones

Question 11

Can be radiolucent

Answer 11

Uric acid stones

Question 12

If a uric acid stone is radiopaque, it must be combined with??

Answer 12

Calcium

Question 13

What are some things that can cause calcium stones?

Answer 13

Idioipathic hyeprcalciuria
Primary hyperparathyroidism
Hypocitraturia
Hyperuricosuria
Renal tubular acidosis
Hyperoxaluria (Dietary, enteric, primary)
Colon resection, ileostomy
Habit, environment

Question 14

Produced by UTI with urease-producing bacteria; Usually greater than 2cm (large)

Answer 14

Struvite stone

Question 15

What bacteria could cause a struvite stone?

Answer 15

Proteus, Klebsiella, pseudamonas, enterobacter

Question 16

What is the treatment for Struvite stones?

Answer 16

Prevent UTIs

Question 17

What causes uric acid stones?

Answer 17

Low 24h urine pH (less than 5.6)

Question 18

What are some common comorbidities in patients with uric acid stones?

Answer 18

Obese or diabetic - both decrease urine pH via insulin resistance

Question 19

What is the treatment for uric acid stones?

Answer 19

Increase urine pH to greater than 6 with potassium citrate

Question 20

What are some other things a patient can do to prevent uric acid stones?

Answer 20

Allopurinol

Low purine diet (decrease fish, shellfish, meats)

Question 21

Cystine stones are caused by an ____ ____ inherited abnormality

Answer 21

Autosomal recessive

Question 22

How do you treat cystine stones?

Answer 22

Increase urine volume to 3L daily and increase urine pH to greater than 7 with potassium citrate

Question 23

What agents may be used to prevent cystine stones?

Answer 23

Chelating agents

Question 24

Geographic risk factors for nephrolithiasis include?

Answer 24

High humidity

High temperature

Question 25

What type of diet can increase risk factors for nephrolithiasis?

Answer 25

High animal protein diet | High salt intake

Question 26

A family history risk factor for nephrolithiasis is having a ___ ____ relative with a history of calcium stones

Answer 26

1st degree

Question 27

Will decreasing calcium in the diet help decrease the risk for nephrolithiasis?

Answer 27

No! In fact it could increase the risk because your body will absorb more oxalate from diet

Question 28

What are the most common signs and symptoms of nephrolithiasis?

Answer 28

Unilateral flank pain Sudden onset Renal colic Hematuria

Question 29

If your patient has persistent urinary frequency without evident infection, where could a stone be located?

Answer 29

Ureterovesical junction

Question 30

Gold standard for the diagnosis of kidney stones?

Answer 30

Non-contrast CT

Question 31

What types of radiography could you get to diagnose nephrolithiasis?

Answer 31

Non-contrast CT* KUB x-rays Intravenous pyelography Renal ultrasonography

Question 32

What is the benefit of doing a CT scan on a patient with suspected nephrolithiasis?

Answer 32

Stone type can be suggested by radiographic density

Question 33

Low radiographic density

Answer 33

Uric acid or cystine

Question 34

High radiographic density

Answer 34

Calcium

Question 35

Have a laminar rugged appearance, often full casts of the renal pelvis and calyces. "Stag horn" conformation

Answer 35

Struvite stones

Question 36

What is the procedure of choice for diagnosing nephrolithiasis in a patient who needs to avoid radiation (pregnancy, etc.)

Answer 36

Ultrasound

Question 37

Limitations of X-ray when diagnosing nephrolithiasis

Answer 37

Will show large radiopaque stones like calcium, struvite, and cystine but will MISS radiolucent uric acid stones and could also miss small stones will NOT detect obstruction

Question 38

Why is IVP no longer the diagnostic procedure of choice?

Answer 38

Potential contrast reactions, lower sensitivity, and higher radiation exposure than non-contrast CT

Question 39

What would you want to order to workup nephrolithiasis?

Answer 39

Urinalysis for blood and cystine crystals Stone analysis BMP (check calcium and creatinine); Thyroid 24 hour urine analysis for recurrent stone formers

Question 40

What is the most common abnormality found in patients who produce recurrent calcium stones?

Answer 40

Idopathic hypercalcuria Elevated excretion of calcium with normal blood calcium

Question 41

What is the best way to acutely manage a patient with nephrolithiasis?

Answer 41

Pain management (opiods, NSAID) Hydration Strain urine

Question 42

When should you consider hospitalization of a patient with nephrolithiasis?

Answer 42

Cannot tolerate oral intake | Uncontrolled pain or fever

Question 43

How long before shock wave lithotripsy does a patient need to stop taking their NSAIDs?

Answer 43

3 days

Question 44

Possible advantage of decreasing ureteral smooth muscle tone thereby directly treating mechanism (ureteral spasm)

Answer 44

NSAIDs

Question 45

When does a patient with nephrolithiasis need extracorporeal shock wave lithotripsy or rigid and flexible ureteroscopy?

Answer 45

Stone greater than 10mm | Urosepsis requiring emergent decompression

Question 46

What is emergent decompression?

Answer 46

When a patient needs a stent or nephrostomy tube to pass a kidney stone

Question 47

Most stones less than or equal to __mm will pass spontaneously

Answer 47

5mm

Question 48

Stones that are greater than or equal to ___mm will not pass on their own

Answer 48

10mm

Question 49

What is the most important indicator of stone passage?

Answer 49

Size

Question 50

Stones located in the ____ ____ are less likely to pass spontaneously compared to stones in the ureterovesicular junction

Answer 50

Proximal ureter

Question 51

Stone passage is significantly more likely and occurs faster with ____ vs conservative treatment alone

Answer 51

Flomax

Question 52

Alpha blocker

Answer 52

Tamsulosin (Flomax)

Question 53

Calcium channel blocker that may increase passage rate of ureteral stones

Answer 53

Nifedipine

Question 54

When should you have your patient consult urology?

Answer 54

``` Urosepsis Renal failure Obstruction Solitary kidney Concomitant pyelonephritis Stone greater than 10mm Have not passed stone in 4-6 weeks ```

Question 55

What are the 3 minimally invasive surgical techniques available for removal of a kidney stone?

Answer 55

Shock wave lithotripsy Percutaneous nephrolithotomy Rigid and flexible ureteroscopy with or without stent placement

Question 56

Treatment of choice for most small (Proximal) renal calculi

Answer 56

SWL (Shock wave lithotripsy)

Question 57

Treatment of choice for stone removal of larger (greater than 2cm) renal stones including stag horn calculi

Answer 57

Percutaneous nephrolithotomy (PNL)

Question 58

Treatment of choice for the majority of middle and distal ureteral stones and ureteral calculi that have failed shock wave lithotripsy

Answer 58

Ureteroscopy

Question 59

___ patients will experience stone recurrence within 5 years

Answer 59

1/3

Question 60

___ patients will experience stone recurrence within 10 years

Answer 60

1/2

Question 61

What is key for preventing nephrolithiasis?

Answer 61

Increase fluid intake! Maintain urine volume of greater than 2L

Question 62

What diet changes can be made to decrease Ca+ Oxalate stone formation?

Answer 62

Decrease oxalate intake (rhubarb, spinach, nuts, seeds) Decrease animal protein intake Decrease sodium intake Increase fluid intake