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Flashcards in UROLITHIASIS Deck (45)
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1

1. What is nephrolithiasis?
2. Stones can be found where? 3
3. What is probably the most excruciating painful event a person can endure?

1. Nephrolithiasis refers to stones in the kidney
2. Stone can be found in the kidney, ureter or bladder of the urinary tract


3. Acute renal colic

2

Nephrolithiasis
Pathophysiology
Stones are thought to be caused by 2 basic phenomena

1st phenomena? 2

1. Supersaturation of urine by stone-forming constituents, including calcium, oxalate, and uric acid

2. Crystals or foreign bodies can act as a nidus which ions from supersaturated urine form microscopic crystalline structures

3

Nephrolithiasis
Pathophysiology
Stones are thought to be caused by 2 basic phenomena

2nd phenomena? 4

More likely responsible for what kind of stones?

2nd phenomena

1. Deposition of stone material on a renal papillary calcium phosphate nidus (Randall plaque)

2. Calcium phosphate precipitates the basement membrane of the thin loops of Henle, and erodes into the interstitium and then accumulates in subepithelial space of the renal papilla

3. Subendothial deposits (Randall plaque) eventually erode through the papillary urothilium

4. Stone matrix, calcium phosphate, and calcium oxalate gradually deposit on the nidus to create a urinary stone


More likely responsible for calcium oxalate stones

4

Nephrolithiasis
Etiology?
2

1. Low fluid intake with low volume of urine production produces high concentrations of stone forming solutes

2. Hypercalcuria is a common metabolic abnormality

5

Nephrolithiasis:
Hypercalcuria is a common metabolic abnormality.

How does this happen? 3

1. Some cases are related to increase in intestinal absorption of calcium

2. Some are related to excess reabsorption of calcium from bone

3. An inability of renal tubules to properly reclaim calcium in glomerular filtrate

6

Nephrolithiasis
Types of Stones seen? 5

1. Calcium
2. Uric acid
3. Cystine
4. Struvite
5. Xanthine

7

Nephrolithiasis
African Americans have ________ incident of stones than Caucasian

lower

8

Nephrolithiasis: Risk factors?
3

1. Family history
2. Gout
3. Primary hyperparathyroidism

9

1. Most stones develop in _____ years old
2. Peak incident is at age ______
3. Stone in children are ____?
4. What practices can cut stone recurrence by 60%? 3

Known as the “stone clinic” effect

1. 20-49

2. 35-45

3. rare

4.
-Increase fluid intake,
-regular visits to a provider who advises increase fluids, and
-dietary modifications

10

Nephrolithiasis: Clinical practice
1. Patients report what kind of symptoms? 3

2. Stones where usually cause the most pain?

3. Symptoms? 4

1. Patients report
-pain,
-infection, or
-hematuria

2. Stone in the kidney usually do not cause pain, stones in the ureter usually cause pain from obstruction (hydronephrosis)

3. Symptoms
-Acute onset sever flank pain radiating into the groin
-Gross/microscopic hematuria
-Nausea/Vomiting
-Fever/Chills (only with infection)

11

Nephrolithiasis
Work up?
7

1. UA
2. CBC
3. CMP/BMP
4. 24 hour urine
5. KUB
6. Renal US
7. CT scan

12

Work up for Nephrolithiasis. What are we looking for in the following:
1. UA? 3
2. CBC? 1
3. CMP/BMP? 3

1. UA
-Can have hematuria (gross/microscopic) No hematuria does not reduce chance of stone
-Always look for bacteria (nitrites)
-or leukocytes (Infection more serious)

2. CBC
Looking for elevated WBC
-Usually >15,000/μL

3.
-Electrolytes
-BUN/Cr levels
-Parathyroid hormone level with ionized calcium level

13

What is happening with the following Calcium and PTH levels:
1. Normal and Normal?
2. Low and High?
3. Low and Normal or Low?
4. High and High?
5. High and Low?
6. Normal and High?

Interpretation
1. Calcium regulation system functioning OK

2. PTH is responding correctly; may run other tests to check for other causes of hypocalcemia

3. PTH not responding correctly; probably have hypoparathyroidism

4. Parathyroid gland producing too much PTH; may do imaging studies to check for hyperparathyroidism

5. PTH is responding correctly; may run other tests to check for non-parathyroid-related causes of elevated calcium

6. Mild hyperparathyroidism

14

Nephrolithiasis

Work-Up
1. 24 hour urine is used to identify what?

2. Most common findings? 4

1. Used to identify urinary risk factors

2. Most common findings
-Hypercalcuria
-Hyperoxaluria
-Hyperuricosuria
-hypocitraturia

15

Nephrolithiasis
24 hour urine
Evaluates for:

10

1. Volume
2. pH
3. Calcium
4. Sodium
5. Phosphate
6. Citrate
7. Uric acid
8. Cystine
9. Oxalate
10. Magnesium

16

Nephrolithiasis Imaging
1. KUB: Good for? 3

2. Advantages? 2


1. Good for:
-Monitoring stones
-Large stones, may miss small stones
-Radiopaque stones

2.
-Less radiation
-inexpensive

17

Nephrolithiasis
1. Renal US good for what?
2. Difficult to see what?
3. Advantage?
4. Test of choice for what?

5. What is the Gold Standard for stones?

1. Renal Ultrasound-Good for diagnosing hydronephrosis
2. Difficult to see ureteral stones
3. -No radiation

4. Test of choice for pregnancy


5. CT scan (without contrast)
Gold standard for stones
95-99% specificity compared to IVP

18

Treatment of Nephrolithiasis
Depends on several factors such as?
6

1. Stone size
2. Infection with obstructing stone
3. Solitary kidney
4. Pregnancy
5. Patient preference
6. Surgical

19

Nephrolithiasis: Stone size
1. less than 4mm __% passage on own
2. 5-7mm___%
3. >8mm ____%

1. 80

2. 50

3. 0-10

20

Nephrolithiasis: Infection with obstructing stone
1. First thing to do?
2. What do they need?
3. Worry for what?

1. Consult Urologist
2. Needs ureteral stent placement same day
3. Worry for sepsis

21

Nephrolithiasis: Factors cont.
1. Solitary kidney management? 2

2. Pregnancy options? 2

3. Patient preference Try to pass on own, given that you educate on chances of passage. What are the options if they want to pass it?
2

1.
-Consult Urologist
-Stent placement same day or stone removal

2. Stent placement vs. pain medication

3.
-Alpha-blocker (Flomax, Doxazozin)
-NSAIDS and pain medication

22

Nephrolithiasis: Treatment
Surgical Options?
5

1. Stent placement vs. Percutaneous nephrostomy

2. ESWL (Extracorporeal ShockWave Lithotripsy)
3. Ureteroscopy

4. Percutaneous Nephrostolithotomy (PNL)

5. Open nephrostomy

23

Nephrolithiasis: Treatment
Medicines
5

1. Flomax 0.4mg one PO qday
2. Ketorolac 30mg IM/IV single dose
3. Hydrocodone or Oxycodone
4. Metoclopramide 10mg IM/IV q4-6 hours prn
5. Morphine 1-2mg IV q2-4 hours prn

24

Nephrolithiasis
Treatment
Diet Considerations?
5

1. Increase fluids above 2 liters in 24 hours
2. Avoid excess salt and protein intake
3. Moderation in foods high in oxilate
4. Do not limit calcium d/t hyperoxaluria
5. Restricted to 600-800 mg/d

25

Nephrolithiasis
Treatment
Diet Considerations: Moderation in foods high in oxilate such as? 3

1. Green leafy vegetables
2. Chocolates
3. Tea

26

Nephrolithiasis
Types of stones
5

1. Calcium oxalate
2. Uric acid
3. Cystine
4. Struvite
5. xanthine

27

Nephrolithiasis
1. Whats the most common stone?

2. What is the most common radiolucent stone?

1. Calcium oxalate stones
2. Uric acid stones

28

Nephrolithiasis

1. Calcium oxalate stones: formation is caused by what?
2. Uric acid stones: What causes the formation of this?

1. Calcium oxalate stones
-Formation is caused by high calcium and high oxalate excretion

2. Uric acid stones
-Low urine volume and acidic urine pH promote precipitation of uric acid

29

Nephrolithiasis: Cystine stones
1. Caused by what?

2. Describe the process?

1. A genetic cause of kidney stones (1-7000 births)

2. Patients with cystinuria have impairment of renal cystine transport with decreased proximal tubular reabsorbtion of filtered cystine resulting in increased urinary cystine excretion and stone formation

30

Nephrolithiasis
Struvite stones
1. Grow how quickly?
2. Can grow into what?
3. Caused by what?

Xanthine stones
1. How common?
2. Caused by what?
3. Cannot be oxidized into what?

Struvite stones
1. Can grow rapidly over weeks or months
2. Can grow into staghorn calculus
3. Caused by UTI
-Urease-producing organism (Proteus & Klebsiella)

Xanthine stones
1. Are rare
2. Caused by inborn defect of xanthine oxidase
3. Xanthine cannot be oxidized to uric acid