Urolithiasis Flashcards
1
Q
What is the two tumb rules when it comes to positioning of laser fibers in the urether?
A
Aim at 1/4 of the diameter of the stone
When you see the fiber your scope is safe
2
Q
When was ESWL approved for urolithiasis?
A
1986
3
Q
Indications for ESWL
A
non obese patient
stones ≤ 2 cm
pelvic stones
stone in upper and middle calyceal groups
less effective on ureteral stones
4
Q
What are “hard stones”?
A
Density >1000 HU
Calcium oxalate
monohydrate
cystine
brushite
5
Q
Prognostic factors for successful ESWL-treatment:
A
Number of stones Lower pole? Composition (<1000 HU?) UT Anatomy BMI >30 Duration of obstruction Available equpment Experience of operator
6
Q
What are the benefit of ESWL for pediatric patients?
A
minimally invasive high stone free rates easier passage of fragments low complication rate no renal damage need for stenting rare
- general anasthesia in children < 10 years
7
Q
Contraindications for ESWL:
A
Preganancy Anticoagulants Uncontrolled urinary infection Severe skeletal anomalies Morbid obesity Arterial anerurysm (in the vicinity) Anatomical obstruction distally to the stone
8
Q
ESWL-complications:
A
Steinstrasse 4-7% Development of the residual stones 21-59% Renal colic 2-4% Infection (sepsis 1-2,7%) Concussion Hematuria
9
Q
What is the use for double J-stents in ESWL?
A
Prevents obstruction and colic
Does not reduce steinstrasse and infections
10
Q
What is the effect of α1-blockers on ureteral lithiasis?
A
Reduction of time for the expulsion of fragments
Reduction of the renal colic episodes
Increase of SFR
11
Q
When should antibiotics be used in prophylaxis for ESWL?
A
Internal stent placement
Increased bacterial burden (nephrostomy tube, indwelling catheter, infectious stones)
Positive culture
12
Q
What are the biggest risk factors for kidney stones?
A
Male
Caucasian
Old age
Overweight/obese
13
Q
Name 3 non-infectious stones:
A
Calcium oxalate
Calcium phosphate
Uric acid
14
Q
Name 3 infectious stones:
A
Magnesium ammonium phosphate
Carbonate apatitie
Ammonium urate
15
Q
Name 3 stones caused by genetic disorders:
A
Cystine
Xantine
2,8-Dihydroxyadenine
16
Q
How are kidney stones mostly composed (in %)?
A
calcium-based 78-85% uric acid 5-10% struvite 1-4% cystine 1% drugs/metabolites <1%
17
Q
Name 3 kidney stones caused by drugs:
A
Indinavir
amoxicillin
ciproloxacin
18
Q
When should stone analysis be performed?
A
First stone
and
recurrent stones despite drug therapy
early recurrence after complete stone clearance
late recurrence after long stone-free period because composition may change
19
Q
What health risk factors is urolithiasis associated with?
A
diabetes obesity metabolic syndrome osteoporos cardiovascular pathologies renal failure
20
Q
What is the stone recurrence rate at 2, 5, 10 and 15 years?
A
11%
20%
31%
39%
21
Q
How common is hightly recurrent stone disease?
A
~10%
22
Q
When taking a medical history of a stone forming patient what should be included?
A
Stone history
Dietary habits
Medication charts
heredity IBD malignancies gout obesity diabetes
23
Q
What diagnostic imaging should be performed on a stone forming patient?
A
Ultrasound
Enhanced helical CT
Determination av Hounsfield units
24
Q
What blood analysis’ should be performed on a stone forming patient?
A
Creatinine
Calcium
Uric acid
25
What urine analysis' should be performed on a stone forming patient?
```
pH
dipstick test
urine culture
microscopy of urinary sediment
cyanide nitroprusside test (cystine)
```
2 x 24 hour collection
any time for noobstructing stones, > 6 weeks after stone removal/passage
26
What should stone forming patientes be adviced when it comes to fluid intake?
Aim for urine volume >2,5L
27
What are the dietary recommendations for stone forming patients?
```
Normal calcium intake
Low sodium (Na(Cl)
Low animal protein intake
Low fat intake
Moderate oxalate intake
Reduce simple sugar intake
Eat vegetables and fruit
```
Fluids for urine volume >2L
28
What causes Uric acid stones?
LOW URINE PH + HYPERURICOSURIA
insuline resistance excess purine intake
metabolic syndrome proliferative syndromes
obesity gout
type 2 diabetes type 2 diabetes
diarrhea uricosuric drugs
29
How do you treat Uric acid stones?
```
Increase fluid intake
Urine alkalinization (Potassium citrate)
Decrease protein intake
Decrease sugar intake
Allopurinol
```
30
Why is hypocitraturia bad?
Acidic pH consumes citrates and favour calcium oxalate stones
Citrate is a potent inhibitor of cristallization
31
What can Thiazides cause?
| and by what mechanism?
Hypoctiraturia
Thiazides --> hypokalemia ---> intracellular acidosis---> inhitibs synthesis and promotes citrate reabsorption into the cell
=treat hypokalemia
(Potassium=Kalium)
32
Name a source of potassium that can lower the risk for stone disease?
Orange juice
| cranberry and grapefruit juice can increase the risk
33
What can cause Hyperoxaluria?
Increased oxalate intake
High urinary concentration because of low urine volume
Reduced calcium intake (calcium decreases oxalate absorbtion)
34
How do you treat Hyperoxaluria?
```
Increase fluid intake
Eat less oxalates and fat
Increase calcium intake
Vitamin B6
Correction of bowel pathology when possible
```
35
What can cause Hypercalciuria?
```
Low diures
High calcium intake
High protein intake
High salt intake
Metabolism
```
36
How do you treat Hypercalciuria?
More fluids
Limit calcium intake
Limit protein intake
Limit salt intake
Thiazide diuretics--->
increase calcium reabsorption
OBS give potassium supplementation to prevent Hypokalemia and hypocitraturia
37
What can cause Cystine stones?
```
Low diures
Low urinary pH
High urinary cystine levels
-high methionin food (parmesan, eggs, horse-meat...)
-high protein intake
-high salt intake
```
38
How do you treat Cystine stones?
```
Increase fluid intake
Alkalinization (potassium citrate)
Medicate with Tipronine (breaks cystine in two)
Lower intake of methionin
Reduce protein intake
Reduce salt intake
```
39
How do you treat infectous stones?
Remove stone
| Treat UTI
40
Does position of the patient matter when performing PNL?
More a preference of the surgeon
41
Why is a posterior calyx preferable for acess when perorming PNL?
There is an avascular fielt known as Brodels bloodless line between the anterior and posterior divisions
42
What is the risk when using balloon dilators for access when performing PNL?
They can dislocate the stone out of the system
43
What are the major complications of PCNL?
```
Rupture of collecting system
Hemorrhage
Pleural injury
Injury to adjacent organs
Fever and sepsis
```
44
PCNL stands for:
Percutaneous Nephrolithonomy also PNL
45
What are the indications for open or laparoscopic surgery for stones?
```
Anatomical abnormalities:
-horseshoe kidneys
-malrotated kidneys
-UPJO with stones
-ectopic kidneys
Stones in symptomatic diverticula
When other treatment options are unavailable or have failed
```
46
How often should a stone that has not been treated be checked?
Every 6 months initially, than yearly
47
What is mandatory before endoscopic stone treatment?
Urine culture/microscopy
Treatment of UTI
Peri-operative antibiotic prophylaxis
48
What is the mean ureteral diameter?
10F
49
What is the mean ureteral length?
30 cm
50
How much better are digital systems for endoscopic stone removal?
saves 20-25% of time
51
What is normal renal pelvic pressure (RPP)?
5-15 mm Hg
52
When will you damage the fornix with elevated renal pelvic pressure?
At 80-100 mm Hg
53
What does elevated renal pelvic pressure (RPP) cause?
epithelial damage
resorption of irrigation fluid (containing bacteria and endotoxins)
pyelo-interstitial or pyelo-lymphatic/pyelo-tubular reflux--> nephrotic damage ---> renal scarring
54
Late complications of URS:
ureteral stricture
| persistent vesicoureteral reflux
55
Early complications of URS:
ureteral stripping
guidewire under the mucosa
perforation
mucosal injury etc
```
hypothermia
bleeding
push up of the stone
hematuria
renal colic
fewer or urosepsis
```
56
Problems with stents:
```
Stent related symptoms
Encrustation
Infection
Migration
Hyperplastic reaction
Extrinsic mechanical pressure
Long-term patency
```
57
What is different with stents in pregnant women?
A higher tendency for ureteral sten ecrustation
| Change stent every 2 months
58
Symptoms from stents:
Frequency
Dysuria
Urgency
Suprapubic pain
59
What is the depth of penetration of a Ho:YAG-laser?
0,4 mm
60
What is true for Retropulsion and stone treatment using Ho:YAG-laser?
More energy = more Retropulsion
61
What are the settings for DUST-vaporisation?
Long Pulse 800 µsec
Low Energy 0,5 J
High Frequency 15-10 Hz
62
What are the settings for Fragments?
Short Pulse 200 µsec
High Energy 1,5-2 J
Low Frequency 5 Hz
63
What is the Moses technology?
The laser emits part of the energy to create an initial bubble,
the remaining energy is discharged once the bubble is formed, so that it can pass through the already formed vapor channel
64
Is bigger laser fibres better?
No size does not affect fragmentation efficiency
small fibres gives less retropulsion
small fibres gives more space in the working channel
65
Should laser fibres be stripped or unstripped?
Better performance if stripped
66
When is the laser fibre most damaged?
Hard stones
High energy
Short pulse duration
67
What lab work should be ordered for a patient presenting with an acute stone episode?
WBC with differential, urinalysis, BUN, Cr, and electrolytes. If patient is febrile do not forget urine C/S
68
What are imaging options for patients with suspected urolithiasis?
1. CT stone protocol (best test)
2. KUB XR (not all stones will show)
3. KUB U/S may detect hydro but more difficult to assess stones in the ureter
69
What is first line imaging for suspected stones in children?
KUB U/S
70
What are indications for prompt intervention with stones?
1. Septic stones
2. Stones in a solitary kidney
3. Stones causing intractable pain
4. Stones causing bilateral obstruction
5. Stones causing an inability to tolerates oral intake secondary to nausea/vomiting/pain
6. Prolonged complete or high grade unilateral urinary obstruction
71
List changes that occur in the kidney and ureter during acute ureteral obstruction?
1. 0-90mins - increased ipsilateral renal blood flow, and increased intra-ureteral pressure
2. 90 - 300mins - decreased ipsilateral renal blood flow and increased contralateral renal blood flow with continued increased intra-ureteral pressure
3. 300mins to 18 hours - decreased intra-ureteral pressure with decreased ipsilateral renal blood flow but increased contralateral renal blood flow.
72
What are chronic changes that can occur in the ureter as a result of obstruction and what is the timeline?
1. Hypertrophy of ureteral musculature - within 3 days
2. Scarring and fibrosis of the ureter - may begin within 2 weeks
3. If a stone is causing complete obstruction - permanent renal damage is thought to occur after approximately one month
73
How does thiazide work for prevention of stones?
Thiazides increase re-absorption of calcium in the proximal and distal tubules of the nephron and inhibit sodium re-absorption in the distal tubules.
74
How do thiazides prevent stone formation?
They decrease the urinary excretion of calcium and correct acidosis. A low sodium diet enhances the hypocalciuric effects of thiazides.
75
What are side effects of thiazides?
Hypokalemia, weakness, fatigue and ED
76
How does citrate/bicarbonate work for prevention of stones?
Citrate (converted to bicarbonate in the liver) and bicarbonate work correcting acidosis and increasing urinary pH and urinary citrate.
77
What is the preferred urinary alkalizer for preventing calcium oxalate urolithiasis?
Potassium citrate (K-citrate)
78
In patients with renal insufficiency or whom are at risk for hyperkalemia what is preferred to alkalinize urine?
Sodium citrate
79
What are side effects of potassium citrate?
Hyperkalemia, peptic ulcers, diarrhea and metabolic acidosis
80
What is the adult dose of potassium citrate?
20meq PO BID or TID (titrate based on urine pH > 5.5)
81
What is the most common metabolic abnormality in stone formers?
Hypercalciuria
82
What is the most common stone composition in industrialized countries?
Calcium oxalate
83
What is the most common cause of urolithiasis?
Dehydration
84
In what conditions are calcium oxalate stones the most commonly formed?
healthy adults, healthy children, intestinal bypass, inflammatory bowel diseases, and renal failure
85
In what patients are calcium phosphate stones the most commonly formed?
hyperparathyroidism, Type I RTA, medullary sponge kidney, and carbonic anhydrase inhibitor use
86
For patients who form uric acid stones what is their relative serum and urine uric acid levels to normal people?
The same, not elevated.
87
What are 3 unique characteristics of uric acid stones?
Form in acidic urine pH<6
Radiolucent
Dissolve with urinary alkalization
88
What are unique characteristics of struvite stones (magnesium, ammonium phosphate)?
1. Most staghorn calculi are composed of struvite
2. They are most commonly caused by UTI (urease splitting organisms)
3. They form in alkaline urine and dissolve with urinary acidification
89
What are unique characteristics of cystine stones?
1. Cause cystinuria (usually homozygotes)
| 2. Form in acidic urine and dissolve with urinary alkalization
90
What are unique characteristics of matrix stones?
1. Most commonly caused by UTI's (proteus)
2. Form in alkaline urine
3. Are radiolucent
91
What are unique characteristics of ammonium acid urate stones?
Common causes include laxative abuse, UTI, urinary phosphate deficiency.
Radiolucent
92
What are unique characteristics of protease inhibitor stones (indinavir (crixivan), nelfinavir.
Cause = precipitated drug
Stones are radiolucent (not visible on CT scan)
Form in urine with pH > 5
93
What are types of hard stones and what considerations should be given to managing these?
Calcium oxalate monohydrate, and cystine stones are very hard.
Hard stones can be resistant to ESWL, and pulsed dye laser. Holmium laser is effective against both these types of stones.
94
List the radiolucent stone types?
1. Uric acid
2. Xanthine
3. Matrix
4. 2,8 - dihydroxyadenine
5. Triamterene
6. Protease inhibitor stones (not visible on XR or CT)
7. Silica
95
List 12 disease states that that increase the risk of urolithiasis?
1. Obesity
2. DM
3. Gout
4. Metabolic acidosis
5. Hypertension
6. Type I RTA
7. Sarcoidosis (leads to hypercalciuria)
8. Cystinuria
9. Inflammatory bowel disease
10. Chronic diarrhea
11. Medullary sponge kidney (calcium stones)
12. Adult polycystic kidney disease
13. Hypokalemia (causes intracellular acidosis)
14. Anatomic factors causing urinary stasis or obstruction
15. Low urine volume (poor hydration)
16. UTI
96
What abnormalities in urine composition lead to increased risk of stone formation?
1. Hypercalciuria
2. Hypocitraturia
3. Hyperoxaluria
4. Hyperuricosuria
5. Hypomagnesiuria
6. Xanthinuria
balance of: urinary pH, crystal inhibitor and crystal promoters.
97
What dietary factors promote formation of urolithiasis?
1. Potential renal acid load (PRAL) - foods that generate circulating acid and lead to decreased citrate ex. eggs, cheese (high PRAL), fruits and veggies (low PRAL)
2. High sodium intake - increased urinary calcium, decreased urinary citrate
3. Low fibre diet
4. High oxalate diet
5. Carbonated drinks that contain phosphoric acid
98
What are the two categories of stone formation inhibitors and what are some agents in each category?
Organic: citrate, urea, nephrocalcin, tamm-horsfall proteins, calgranulin, glycosaminoglycans, bikunin, and uropontin
Inorganic: pyrophosphate, magnesium, trace elements, (zinc)
99
How does citrate work to decrease stone formation?
Decreases calcium stone formation by:
| complexes with calcium to lower urinary calcium concentration and directly inhibits calcium crystallization
100
How does urea work to decrease stone formation?
Decreases uric acid stone formation by increasing solubility of uric acid (no influence on calcium stones)
101
How do UTI's increase stone risk?
1. Cause hypocitraturia
2. Urease producing organisms split urinary urea into ammonia and bicarbonate which alkalinizes the urine
3. UTI may decrease ureteral peristalsis
102
What UTI organisms produce urease?
1. Proteus
2. Klebsiella
3. Serratia
4. Staphylococcus
5. Morganella
6. Providencia
7. Enterobacter
103
What types of stones are associated with UTI?
Struvite, matrix, carbonate apatite
104
What changes does acidosis cause in urinary composition?
1. Increased urine calcium
2. Increased urine phosphate
3. Decreased urine citrate
105
Through what mechanism does a prolonged acidosis cause hypercalciuria?
Leads to bone demineralization, which increases calcium delivery to the kidneys and results in hypercalciuria
106
Which stones form in acidic urine?
1. Amino acid stones (cystine, leucine, tyrosine)
| 2. Uric acid stones (usually form at a pH < 6)
107
Which stones form in alkaline urine?
1. Matrix stones
2. Stones that contain phosphate, carbonate or ammonia)
[struvite, calcium phosphate, calcium carbonate]
108
Which stones can form over a variety of pH's?
Calcium oxalate, hippuric acid
109
What medications increase ones risk for urolithiasis?
1. Vitamin C (gets metabolized to oxalate)
2. Vitamin D (high doses) - leads to increased calcium absorption and hence hypercalciuria
3. Triamterene (precipitates in the urine)
4. Protease inhibitors
5. Furosemide (increases calcium excretion in the urine)
6. Acetazolamide
7. Agents that increase uric acid in urine (salicylates, probinecid)
110
What patients should undergo a metabolic stone workup?
1. Large stone burden
2. Recurrent stone formers
3. Nephrocalcinosis
4. Pediatric stone formers
5. Uncommon stone composition (cystine, uric acid)
6. Stone arising from UTI
7. Family history of stones
8. Medical, genetic, or anatomic condition that increases stone forming risk)
9. Solitary kidney
10. Professionals whom if developed renal colic while working could be deleterious to others (pilots, bus drivers, truck drivers, surgeons)
111
When should you perform a metabolic stone workup?
At least one month after stones have been treated, or if stents present they have been removed or if infection present it has been eradicated.
112
What is the initial metabolic workup that all patients with urolithiasis should have?
1. Hx and Px
Ask about fluid consumption, diet, UTI, medications, prior urolithiasis, and family history of urolithiasis
2. Analyses stone composition
3. Urinanalysis including urine pH
4. Serum chemistries: Na, K, Cl, HCO3-, uric acid, calcium, and creatinine. (If Ca elevated or stone predominantly calcium phosphate order a serum PTH)
113
What should a 24 hour urine study test include?
1. pH measurement
2. Total urinary volume
3. Urinary calcium
4. Urinary oxalate
5. Urinary citrate
6. Urinary uric acid
7. Urinary sodium
8. Urinary potassium
9. Urinary creatinine
114
How do you know if the 24 hour urine study is incomplete?
If the 24 hour urinary creatinine excretion is abnormally low.
Normal urinary creatinine excretions are:
M 14-26mg/kg/day
F 11-20mg/kg/day
115
What are general recommendations to make to patients for stone prevention?
1. Oral fluid intake should be sufficient to generate 2.5L of urine per day.
2. Fluids containing citrate are ideal (lemon, orange, lime etc)
3. Encourage low sodium diet (<100meq/day) - decreases urinary calcium and increases urinary citrate
4. Reduce PRAL (potential renal acid load) foods
- reduce intake of non-dairy animal protein
- reduce intake of cheese and eggs
- increase intake of fruits and vegetables
5. Low oxalate diet
6. Avoid high doses of vitamin C (>500mg/day)
7. Moderate calcium intake (1000-1200mg/day)
8. High fibre diet
9. Weight loss in obese patients
116
When should citrate medications be considered? What are your two options for dietary citrate supplementation?
Urinary alkalinizer used for calcium oxalate stones.
K-citrate is first choice, sodium citrate is another option but increased sodium can promote stone formation
117
How does allopurinol work as a stone formation inhibitor and when should it be prescribed?
Decreases serum uric acid by inhibiting xanthine oxidase (enzyme responsible for converting hypoxanthine to xanthine and xanthine to uric acid.
Allopurinol prevents uric acid stones ONLY when there is hyperuricosuria, this is REGARDLESS of hyperuricosemia.
118
When should magnesium be give as a stone formation inhibitor?
Most useful in patients with hypomagnesuria and calcium stones
119
What is the main side effect of magnesium supplementation?
Diarrhea
120
When can pyridoxine (vitamin B6) be given as a stone formation inhibitor?
Used to treat primary hyperuxaluria - needs to be given with thiols to prevent neurologic side effects.
121
What is acetohydroxamic acid (AHA) used for as a stone formation inhibitor?
AHA - inhibits urease and reduces the growth of struvite stones (its use is restricted to patients whom which have residual or recurrent struvite stones after surgical therapies have been exhausted)
122
What are side effects of AHA?
nausea/vomiting, anorexia, tremor, anxiety, headache (30%), hemolytic anemia (15%) alopecia, DVT, rash after drinking EtoH
123
How do you define hypercalciuria?
Urinary calcium > 200mg/day
124
What are the 4 different types of hypercalciuria?
1. Absorptive
2. Renal
3. Resorptive
4. Unclassified
125
What is the pathophysiology of ABSORPTIVE hypercalciuria?
Primary mechanism is excess intestinal absorption of calcium
126
What is the pathophysiology in RENAL hypercalciuria?
Primary mechanism is impaired renal tubular reaborption of calcium
127
What is the pathophysiology in RESORPTIVE hypercalciuria?
Primary mechanism is hypersecretion of PTH. (hyperparathyroidism)
128
What is the definition of hypomagnesuria?
Urinary magnesium < 50mg/day
129
How do you treat hypomagnesuria?
Dietary magnesium (magnesium oxide 400-500mg PO BID) watch out for diarrhea
130
How do you define hyperuricosuria?
Urinary uric acid > 600mg/24h
131
What are the TWO types of stones that one is at increased risk of forming if they have hyperuricosuria?
Uric acid stones, and calcium oxalate stones.
132
Most common metabolic abnormality, type of stone, and cause of urolithiasis in the US:
1. Metabolic abnormality: hypercalciuria
2. Type of stone in industrialized countries: calcium oxalate
3. Cause: dehydration
133
Calcium oxalate stones
Most common renal and bladder stones in adults, children, intestinal bypass, IBD, and renal failure
Most common cause = dehydration
Forms in urine with wide range of pH
Radio-opaque
Calcium oxalate monohydrate = whewellite (crystals are ovals and dumbbells)
Calcium oxalate dihydrate = weddellite (crystals are envelopes and octahedrons)
134
Calcium phosphate stones
More common in patients with hyperparathyroidism, RTA type 1, medullary sponge kidney, and carbonic anhydrase inhibitor use
Formed in alkaline urine
Radio-opaque
Mineral name = apatite
Crystal shape = powder like and often causes cloudy urine
135
Uric acid (urate) stones
Normally have normal serum and urine uric acid levels
Most common cause = dehydration
Forms in acidic urine (usually pH <6.0)
Radiolucent (can't see)
Dissolves with urinary alkalinization
Stone shape = parallelograms, double headed arrows, some in rosettes
136
Magnesium ammonium phosphate (also called struvite or triple phosphate)
Most staghorn calculi are composed of struvite
Most common cause = UTI
Forms in alkaline urine
Radio-opaque
Dissolves with urinary acidification
Crystal shape = coffin lids
137
Stones that form in alkaline urine
Struvite
Calcium phosphate
Matrix
138
Cystine Stones
Cause - cystinuria (usually homozygotes)
Forms in acidic urine
Radiopaque
Dissolves with urinary alkalinization
Crystals = regular hexagons
139
Matrix Stones
Most common cause = UTI (Proteus)
Forms in alkaline urine
Radiolucent
140
Ammonium acid urate
Common causes = intestinal malabsorption, UTI, phosphate deficiency,
Radiolucent
141
Protease inhibitor stones
Stones from precipitated drug - Indinavir, nelfinavir
Radiolucent and not visible on non-contrast CT scan
Forms in urine with pH of 5 or less
Acidifying urine to dissolve stones not practical because of extremely low pH required
142
List of radiolucent stones
Uric acid (urate)
Xanthine
Matrix
Ammonium urate
Protease inhibitor stones
Silica
143
Urine chemistry abnormalities that would PROMOTE stone formation
Hypercalciuria
Hypocitraturia
Hyperoxaluria
Hyperuricosuria
Hypomagnesiuria
Xanthinuria
144
High sodium intake increases stone risk by:
Increasing urinary calcium and decreasing urinary citrate
145
Organic inhibitors of crystallization
Citrate - decreases calcium stone formation by complexing with calcium and lowering calcium saturation, also directly inhibits calcium crystallization
Urea - decreases uric acid stone formation by increasing the solubility of uric acid (no influence on calcium stone formation)
Others: nephrocalcin, Tamm-Horsfall protein, calgranulin, GAGs, bikunin and uropontin (a form of osteopontin)
146
Inorganic inhibitors of crystallization
Pyrophosphate - no way to increase this in the urine
Magnesium - increases solubility of calcium, phosphate, and oxalate
Trace elements, especially zinc
147
How UTI Increases Stone Risk
1. UTI causes hypocitraturia
2. Urease producing organisms split urinary urea into ammonia and bicarbonate, which alkalized urine and increases the risk of stones formed in alkaline urine, especially struvite
3. UTI may decrease ureteral peristalsis
148
Urease producing bacteria
Proteus
Klebsiella
Serratia
Staphylococcus
Morganella
Providencia
Enterobacter
149
Stones often associated with UTI
Struvite
Matrix
Carbonate apatite
Ammonium urate
150
Acidosis increases stone risk.
Acidosis causes the following changes in urinary composition:
Increased urine calcium
Increased urine phosphate
Decreased urine citrate
Prolonged acidosis causes bone demineralization, which increases calcium delivery to the kidney and results in hypercalciuria
151
Medications that may lead to urolithiasis
Vitamin C - metabolized to oxalate, increases urinary oxalate
Vitamin D (high doses) - increases calcium absorption, which increases calcium to kidney
Triamterene (diuretic) - precipitates in urine and forms radiolucent stones
Protease inhibitors (Indinavir and nelfinavir) - precipitate and forms radiolucent stones
Furosemide - increases calcium excretion in urine
Acetazolamide - carbonic anhydrase inhibitor creases a renal tubular acidosis and increases risk of calcium stones.
-Can be used to prevent uric acid and cystine stones (when citrate does not adequately alkalinize urine, it can be added to increase the urine pH)
Topiramate - stones composed of calcium phosphate
Zonisamide
152
Type I (distal) renal tubular acidosis
Impairment in hydrogen ion secretion in the distal tubule, resulting in a persistently high urine pH (> 5.5) and systemic acidosis
Plasma bicarbonate is frequently < 15 mEq/L (15 mmol/L), and hypokalemia, hypercalciuria, and decreased citrate excretion are often present
Nephrocalcinosis and nephrolithiasis are possible complications of hypercalciuria and hypocitraturia if urine is relatively alkaline
153
Oral medication for urinary alkalinization
Citrate and bicarbonate prevent stones by correcting acidosis, increasing urinary pH and increasing urinary citrate
Oral citrate is changed to bicarb ny the liver (doesn't actually deliver citrate to kidney)
154
Most common stone compositions in patients with gout?
Calcium oxalate monohydrate (45%)
Uric acid (52%)
155
Medical conditions that increase risk of overall stone disease
Obesity
HTN
Diabetes
Hyperthyroidism
Gout
RTA type I
Bone disease
Primary hyperparathyroidism
Malabsorptive GI states
156
Nutritional factors associated with stone formation
Calcium intake below or highly above the recommended dietary allowance
High sodium intake
Low fluid intake
Low fruit and vegetable intake
High intake of animal-derived purines
157
Serum studies to order in screening evaluation of stone formers
Electrolytes: sodium, potassium, chloride, bicarbonate
Calcium
Creatinine
Uric acid
158
When to suspect primary hyperthyroidism
Serum calcium is high or high normal
Predominantly calcium phosphate stones
Elevated urinary calcium
If suspected, get intact PTH
- Mid-range PTH in the face of higher serum calcium (inappropriately normal PTH)
- High or high-normal PTH when vitamin D levels are low
(The diagnosis of primary hyperparathyroidism (PHPT) is usually made by finding a PTH concentration that is frankly elevated or within the normal range but inappropriately normal given the patient's hypercalcemia)
159
Calcium phosphate stone composition more likely to be associated with the following medical conditions:
RTA Type 1
Medullary sponge kidney
Primary hyperparathyroidism
Use of carbonic anhydrase inhibitors
160
Medical Management of Kidney Stones Guidelines:
For pts with calcium stones and relatively high urinary calcium, what should they do with their diet?
Guideline Statement 9:
Clinicians should counsel patients with calcium stones and relatively high urinary calcium to limit sodium intake and consume 1,000-1,200 mg per day of dietary calcium
Target of <2,300 mg sodium daily
161
Med Mgmt Guideline Statement 10:
Clinicians should counsel patients with calcium oxalate stones and relatively high urinary oxalate to...
...limit intake of oxalate rich foods and maintain normal calcium consumption
162
Med Mgmt Guideline Statement 13:
Clinicians should counsel patients with cystine stones to limit...
...sodium and protein intake
High fluid intake is particularly important for cysteine stone formers
Need to decrease urinary cysteine concentration to below 250 mg/L
163
Med Mgmt Guideline Statement 14:
Clinicians should offer -------------- to patients with high or relatively high urine calcium and recurrent calcium stones
Thiazide diuretics
(HCTZ, chlorthalidone, indapamide)
May need to supplement potassium as these cause hypokalemia
Should still restrict sodium in the diet
164
Med Mgmt Guideline Statement 15:
Clinicians should offer ------------ therapy to patients with recurrent calcium stones and low or relatively low urinary citrate
Potassium Citrate
Potassium citrate is preferred over sodium citrate as the sodium load may increase urine calcium excretion
Sodium bicarb or sodium citrate can be considered if patient is hyperkalemic
165
Med Mgmt Guideline Statement 16:
Clinicians should offer allopurinol to pat
166
Primary hyperparathyroidism:
A. Is more common in male patients
B. Is diagnosed with ultrasound of the neck
C. Has its peak incidence at about 50 years of age
D. Is combined with renal stones in more than 50% of patients
C. Has its peak incidence at about 50 years of age
167
What is the next step after percutaneus nephrolithotomy (PNL) when bleeding occurs from the nephrostomy tract?
A. Endoscopic exploration
B. Continous irrigation from the nephrostomy tube
C. Insertion of a larger nephrostomy catheter
D. Closure of the nephrostomy catheter allowing tamponade
D. Closure of the nephrostomy catheter allowing tamponade
168
A young woman is diagnosed with acute uncomplicated bacterial cystitis. Which pathogen is considered to be the most likely?
A. Escherichia coli
B. Proteus vulgaris
C. Enterococcus faecalis
D. Staphylococcus aureus
A. Escherichia coli
169
Which organisms produce urease?
A. Proteus mirabilis, Klebsiella pneumonia, Pseudomonas aeruginosa
B. Escherichia coli, Proteus mirabilis, Klebsiella oxytoca, Candida humicola
C. Enterococcus faecalis, Proteus vulgaris, Providencia stuartii, Escherichia coli
D. Staphylococcus epidermis, Klebsiella oxytoca, Proteus vulgaris
A. Proteus mirabilis, Klebsiella pneumonia, Pseudomonas aeruginosa
170
Which of the following Stones are radiolucent?
A. Uric acid, Amonium urate, Xanthine, 2.8-dihydroxyadenine
B. Uric acid, cystine, ammonium urate, Xanthine
C. Xanthine, Uric acid, Cystine, Apatite
D. Calcium phosphates, Apatite, Cystine, Uric acid
A. Uric acid, Amonium urate, Xanthine, 2.8-dihydroxyadenine
171
Which kidney stone situation is the best indication for laparoscopic surgery?
A. Pelvic kidney
B. Horseshoe kidney
C. Ureteropelvic junction obstruction
D. Congenital megaureter
C. Ureteropelvic junction obstruction
172
Which statement regarding general prevention of kidney stone recurrence is correct?
A. Calcium intake should be restricted
B. High intake of animal protein should be encouraged
C. A vegetarian diet decreases urinary pH because it is usually more acidic
D. Vegetable intake should be encouraged because of the beneficial effects of fibre
D. Vegetable intake should be encouraged because of the beneficial effects of fibre
173
What is the main side effect of the antituberculosis drug Ethambutol!
A. Ototoxicity
B. Optic neuritis
C. Hepatotoxicity
D. Renal insufficiency
B. Optic neuritis
174
Which of the following is NOT a complication of epididymo-orchitis?
A. Abscess formation
B. Testicular infarction
C. Testicular atrophy
D. Testicular torsion
D. Testicular torsion
175
Chemolysis is an effective means of therapy for the following stones EXEPT:
A. Calcium phosphate stones
B. Cystine stones
C. Uric acid stones
D. Infection stones
A. Calcium phosphate stones
176
Wich is the best method of imaging for renal tuberculosis?
A. Choline PET CT
B. CT urography
D. Renogram
C. Retrograde pyelography
B. CT urography
177
A 19-year-old man presents with acute pain and swelling of his left scrotum. Which is the most common cause?
A. Viral epididymitis
B. Bacterial epididymitis
C. Viral orchitis
D. Bacterial orchitis
B. Bacterial epididymitis
178
Thiazide diuretics are indicated in renal lithiasis to correct:
A. Hyperoxaluria
B. Idiopatic hypercalciuria
C. Hyperuricemia due to underexcretion
D. Hyperuricemia due to overproduction
B. Idiopatic hypercalciuria
179
Which type of stone is related to Sarcoidosis?
A. Xanthine
B. Uric acid
C. Calcium oxalate
D. Magnesium ammonium phosphate
C. Calcium oxalate
180
Hypercalciuria in primary hyperparathyroidism shows:
A. High serum calcium, high urine cyclic AMP, high intestinal calcium absorption
B. High serum calcium, high urine cyclic AMP, normal intestinal calcium absorption
C. High serum calcium, normal urine cyclic AMP, normal intestinal calcium absorption
D. High serum calcium, normal or low urine cyclic AMP, high intestinal calcium absorption
A. High serum calcium, high urine cyclic AMP, high intestinal calcium absorption
181
A 45-year-old female patient comes to the emergency departement suffering right flank pain. A stone of 12 mm is identifiera in the renal pelvis of the right kidney. Which is the preferred approach for this patient?
A. PNL
B. ESWL
C. ESWL + PNL
D. Ureteroscopy
B. ESWL
182
Which statement about Pyelonephritic scarring is correct?
A. It always progresses to end-stage renal failiure
B. It is a risk in patients with sterile low-grade vesico-ureteric reflux
C. It is a high-risk for patients with recurrent urinary tract infection (UTI)
D. It is most commonly developed in early childhood in the presence of reflux and UTI
D. It is most commonly developed in early childhood in the presence of reflux and UTI
183
Which di-basic amino acid is the least soluble in urine?
A. Lysine
B. Cystine
C. Arginine
D. Ornithine
B. Cystine
184
Which is the most effective treatment for calcium oxalate 3 cm stone in the renal pelvis?
A. Flexible ureteroscopy
B. Percutaneous nephrolithotripsy
C. Shock wave lithotripsy
D. Chemolysis
B. Percutaneous nephrolithotripsy
185
Which antibiotic is contraindicated for prophylaxis in a newborn with prenatal hydronephrosis?
A. Amoxycillin
B. Trimethorprim sulfamethaxazole
C. Nitrofurantoin
D. Cefaclor
B. Trimethorprim sulfamethaxazole
186
Which sign is indicative for SIRS (severe inflammatory response syndrome)?
A. WBC 11/nL
B. PCO2 30 mmHg
C. Respiration 18/min
D. Temperature 36.6C
B. PCO2 30 mmHg
