Hematuria and Nephrolithiasis

Question 1

Is a positive dipstick test for hematuria confirmatory for blood?

Answer 1

No. A further microscopic confirmation is required.

Question 2

What are the imposters of hematuria?

Answer 2

• Free hemoglobinuria
• Myoglobinuria
• Menstrual contamination

Question 3

Can hematuria be caused by anticoagulant therapy?

Answer 3

Not usually - only when there is massive overdose

Question 4

What is the definition of microscopic hematuria?

Answer 4

≥ 2 RBC’s/hpf

Question 5

What are some sequelae of gross hematuria?

Answer 5

• Acute urinary retention due to clot formation

- Anemia from pronounced loss

Question 6

What is gross hematuria often associated with?

Answer 6

Urologic Cancer

Question 7

What are the main glomerular causes of microscopic hematuria in those below 50 years old?

Answer 7

IgA Nephropathy
Alport’s Syndrome
Thin Basement Membrane Disease
Mild Focal GN

Question 8

What are the main glomerular causes of microscopic hematuria in those above 50 years old?

Answer 8

IgA Nephropathy
Alport’s Syndrome
Mild Focal GN

Question 9

What are some of the risk factors of urologic cancer?

Answer 9

• Cigarette smoking
• Occupational exposures: Leather, dye, rubber/tire manufacturing industries
• Phenacetin use (analgesic)
• Aristolochic acid use (herbal diet agent)

Question 10

What features suggest glomerular hematuria?

Answer 10

• RBC casts
• Dysmorphic RBC’s, acanthocytes
• Proteinuria (ratio > 0.3 or >300mg/day)
• Elevated renal indices (BUN, Creatinine)

Question 11

What features suggest non-glomerular hematuria?

Answer 11

• Isomorphic RBC’s
• No proteinuria
• Normal renal indices

Question 12

What is a major technique used for the management of gross hematuria?

Answer 12

Large bore Foley catheterization

Question 13

What is the typical patient with kidney stones in NA?

Answer 13

White males

Question 14

What time of the year is the rate of kidney stones the highest?

Answer 14

In the summer

Question 15

What is the presentation with a stone in the upper ureter?

Answer 15

• Flank pain, upper anterior abdominal pain

Question 16

What is the presentation with a stone in the lower ureter?

Answer 16

• Groin pain, ipsilateral testicular/labial pain

Question 17

What is the composition of most kidney stones?

Answer 17

Calcium

Question 18

What are the other possibilities for the composition of kidney stones?

Answer 18

• 10-15% Uric acid
• 10-15% Magnesium ammonium phosphate a.k.a. Struvite
•

Question 19

How does kidney stone formation occur?

Answer 19

Stone formation starts with supersaturation with nucleation as the key phase

Question 20

What factors can promote stone formation?

Answer 20

• Increased urinary ion excretion

* Decreased urine volume

Question 21

What compounds are promoters of stone formation?

Answer 21

Hydrogen ions (low pH), sodium, magnesium, uric acid

Question 22

What substances prevent stone formation?

Answer 22

Citrate

Question 23

What is the major cause of nephrolithiasis?

Answer 23

Hypercalciuria

Question 24

What is the most common cause of hypercalciuria?

Answer 24

Idiopathic - familial

Question 25

What are some other causes of hypercalciuria?

Answer 25

* Hyperparathyroidism * Vitamin D excess * Sarcoidosis (D3 production in granulomas) * Glucocorticoid excess

Question 26

What is the interaction of Ca2+ and oxalate in the GI tract?

Answer 26

* Dietary calcium binds with oxalate and impedes absorption | * Any unbound oxalate absorbed in colon

Question 27

What happens to absorbed oxalate?

Answer 27

* Absorbed oxalate excreted * Excreted oxalate binds to urinary calcium * Can lead to stone formation

Question 28

How does low dietary Ca lead to kidney stones?

Answer 28

Low dietary Ca means that oxalate is more easily absorbed unimpeded to be excreted in the kidney which leads to increased stone formation

Question 29

What are the causes of uric acid stones?

Answer 29

* Chronic metabolic acidosis | * Low urinary pH (

Question 30

What causes the formation of struvite stones?

Answer 30

Bacterial infection. Main cause is Proteus mirabilis

Question 31

How do struvite stones affect the urine?

Answer 31

Results in ammonia and persistently alkaline urine, promotes struvite formation

Question 32

What is the cause of cystine stones?

Answer 32

Cystinuria - autosomal recessive disorder that is rare

Question 33

What is the preferred imaging method for kidney stones?

Answer 33

CT scan without contrast preferred

Question 34

In what situations is medical management of kidney stones reasonable?

Answer 34

* Small stones (less than 5 mm) * Distal ureteral location * Adequate pain control with analgesics * No associated UTI or localized obstruction

Question 35

In what situations is interventional management of kidney stones reasonable?

Answer 35

* Larger stones (>6mm), especially proximal * Not passing after 4 weeks of medical therapy * Intractable pain * Associated UTI or localized obstruction

Question 36

What is done to prevent future Ca2+ stones?

Answer 36

* Low sodium, low animal protein diet * NORMAL dietary calcium * Medication: thiazide diuretic

Question 37

What is done to prevent future uric acid stones?

Answer 37

* Low purine, low animal protein diet | * Medication: sodium bicarbonate, potassium citrate and allopurinol