Nephrolithiasis

Question 1

What are the three components of nephrolithiasis etiology?

Answer 1

–Too much solute
–Too little solvent (water)
–“Other” physical conditions (stasis, ph)

Question 2

What are five risk factors for stone formation?

Answer 2

1. Hypercalciuria
2. hyperoxaluria
3. hypocitraturia
4. High urine pH (RTA type I in particular)
5. Low urine volume

Question 3

What are five ways to end up with hypercalciuria?

Answer 3

• Higher salt in the diet
• Higher non-dairy animal protein diet
• High Sucrose content in the diet
• Hyperparathyroidism
• Hypercalciuric Hypocalcemia

Question 4

What are two causes of hyperoxaluria?

Answer 4

• Increased intake in high oxalate-containing food
• Decreased in oral calcium intake

Question 5

What are two risk factors for uric acid stones?

Answer 5

Hyperuricemia/hyperuricuria

low urine pH

Question 6

What patients get uric acid stones d/t hyperuricemia/hyperuricaria?

Answer 6

Those with…

1. Gout
2. polycythemia vera
3. tumor lysis syndrome

Question 7

What patients get uric acid stones from low urine pH?

Answer 7

Those who are…

1. Obese
2. DM II
3. High non-dairy animal protein intake

Question 8

What causes cystine stone formation? What is the genetic pattern of inheritance?

Answer 8

Cystinuria (autosomal recessive disorder)

Question 9

During formation of stones, what is the clinical manifestation?

Answer 9

Asymptomatic

Question 10

What are the clinical manifestations of stones as it starts to move?

Answer 10

•Renal colic when stone moves through and/or obstructs one of the ureters
•Micro- or macro-hematuria
•Sometimes associated with UTI
–Fever/leukocytosis/pyuria/sepsis

Question 11

Describe renal colic! (looking for six things here)

Answer 11

• Sudden
• Acute
• Severe
• Non-remitting with positional changes
• Abdominal or back pain
• Unilateral

Question 12

Give a differential diagnosis list for renal colic type pain other than a stone.

Ballpark 10 things

Answer 12

1. •Acute cholecystitis
2. •Acute appendicitis
3. •Acute cystitis/pyelonephritis
4. •Acute diverticulitis
5. •Muscular or skeletal pain
6. •Herpes zoster
7. •Duodenal ulcer
8. •Abdominal aortic aneurysm
9. •Ureteral obstruction by materials other than a stone
10. •Pelvic Inflammatory Disease

Question 13

How does one develop the diagnosis of a renal stone?

(4 steps)

Answer 13

1. •Usually based on clinical presentation
2. •Urine: RBC, WBC, crystals
3. •Leukocytosis, ARF
4. •Imaging

Question 14

What four methods would you use to image stones?

Answer 14

1. –Plain film: May show Calcium stones
2. –IVP—used less frequently now
3. –CT-renal protocol—gold standard
4. –US—may show intrarenal stones and/or hydronephrosis. Not sensitive for ureteral stones

Question 15

What type of crystals are these?

Answer 15

Calcium Phosphate

Question 16

Crystal type?

Answer 16

Calcium oxalate

Question 17

Type of crystals?

Answer 17

Urate

Question 18

What type of crystals?

Answer 18

Struvate

Question 19

Stone type and most likely causative agent?

Answer 19

Struvite stone (magnesium ammonium phosphate)

Proteus Mirabilus

Question 20

Question 21

Question 22

Question 23

Question 24

Question 25

Question 26

What are the medical and surgical therapies for acute attacks?

Answer 26

**_•Medical Therapy_** –Pain control –Nausea control –Propulsive therapy •Calcium channel blockers •Alfa-blockers **_•Surgical Therapy_** –Ureteroscopy with stone removal and stent placement –Percutaneous nephrostomy

Question 27

What is the treatment after acute attack?

Answer 27

•ECWL (lithotripsy) if large stones

Question 28

How does lithotripsy work?

Answer 28

Question 29

What steps do you need to take in order to prevent recurrance of stones?

Answer 29

•Analyze the stone •Collect the information about dietary preferences and fluid intake •Serum Ca, Phosphorus, uric acid •If Ca is elevated, do hypercalcemia work-up –PTH, Vit D level, Protein electrophoresis •24 urine collection for Ca, urate, oxalate, citrate