Hematuria and Nephrolithiasis Flashcards Preview

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Flashcards in Hematuria and Nephrolithiasis Deck (37):
1

Is a positive dipstick test for hematuria confirmatory for blood?

No. A further microscopic confirmation is required.

2

What are the imposters of hematuria?

• Free hemoglobinuria
• Myoglobinuria
• Menstrual contamination

3

Can hematuria be caused by anticoagulant therapy?

Not usually - only when there is massive overdose

4

What is the definition of microscopic hematuria?

≥ 2 RBC’s/hpf

5

What are some sequelae of gross hematuria?

- Acute urinary retention due to clot formation
- Anemia from pronounced loss

6

What is gross hematuria often associated with?

Urologic Cancer

7

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

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

8

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

IgA Nephropathy
Alport's Syndrome
Mild Focal GN

9

What are some of the risk factors of urologic cancer?

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

10

What features suggest glomerular hematuria?

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

11

What features suggest non-glomerular hematuria?

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

12

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

Large bore Foley catheterization

13

What is the typical patient with kidney stones in NA?

White males

14

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

In the summer

15

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

• Flank pain, upper anterior abdominal pain

16

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

• Groin pain, ipsilateral testicular/labial pain

17

What is the composition of most kidney stones?

Calcium

18

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

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

19

How does kidney stone formation occur?

Stone formation starts with supersaturation with nucleation as the key phase

20

What factors can promote stone formation?

• Increased urinary ion excretion
• Decreased urine volume

21

What compounds are promoters of stone formation?

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

22

What substances prevent stone formation?

Citrate

23

What is the major cause of nephrolithiasis?

Hypercalciuria

24

What is the most common cause of hypercalciuria?

Idiopathic - familial

25

What are some other causes of hypercalciuria?

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

26

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

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

27

What happens to absorbed oxalate?

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

28

How does low dietary Ca lead to kidney stones?

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

29

What are the causes of uric acid stones?

• Chronic metabolic acidosis
• Low urinary pH (

30

What causes the formation of struvite stones?

Bacterial infection. Main cause is Proteus mirabilis

31

How do struvite stones affect the urine?

Results in ammonia and persistently alkaline urine, promotes struvite formation

32

What is the cause of cystine stones?

Cystinuria - autosomal recessive disorder that is rare

33

What is the preferred imaging method for kidney stones?

CT scan without contrast preferred

34

In what situations is medical management of kidney stones reasonable?

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

35

In what situations is interventional management of kidney stones reasonable?

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

36

What is done to prevent future Ca2+ stones?

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

37

What is done to prevent future uric acid stones?

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

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