Lecture 15 - Kidney Stones Flashcards

1
Q

The vast majority of nephrolithiases (about 80%) are composed of ______.

About 3-13% are composed of ____ ____.

Only about 1-2% are composed of _____ –> keep in mind this is an autosomal ______ disease, so symptoms are evident in ______ (children or adults?).

______ stones (triple phosphate) are associated with chronic infections with bacteria that split _____ into _____ and phosphate.

A

Calcium

Uric acid

Cystine

Autosomal Recessive

Children (median age of onset = 12)

Struvite

Urea into NH3

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2
Q

Nephrolithiases are more common in ______ (which gender?) and in ______ (which ethnicity?). The mean age for appearance of kidney stones is in the ______ decade of life. Keep in mind there’s a 40% chance of recurrence by 5 years and 75% by 20 years after the first.

A

Males

Whites

4th decade of life

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3
Q

Though multifactorial, there is a genetic component to acquiring kidney stones, so look to patients’ ______ ______!

A

Family Histories

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4
Q

Kidney stones can have Homogeneous or Heterogeneous _______, so basically what initially seeds the crystal may or may not be what forms the bulk of the crystal.

In some cases, ______ plaques can form and act as points of ______ for crystal formation –> these plaques are Calcium phosphate depositions in the interstitium of the kidney that break into the renal pelvis.

A

Nucleation

Randall’s plaques

Nucleation

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5
Q

The major inhibitor of Ca++ stone formation is ______, which complexes with Ca++ to keep it in solution.

A

Citrate

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6
Q

Some GI disease that cause malabsorption of nutrients can lead to INCREASED absorption of ______ –> this of course increases the likelihood of forming ______ ______ stones.

A

Oxalate

Ca++ Oxalate

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7
Q

Patients with ______ bladder (or _____ ____ injury leading to _____ bladder) are at higher risk of UTI. Which stones are they most at risk for?

A

Neurogenic bladder

Spinal Cord injury leading to Neurogenic bladder

Struvite stones

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8
Q

Patients with Gout, ______, and _____ are at higher risk of forming Uric acid stones.

A

Diabetes

Obesity

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9
Q

For urine pH < 5.5 –> suspect ______ ____ stones.

For urine pH between 6.5 and 7 –> suspect ____ ____ stones.

For urine pH > 7.0 –> suspect _____ stones.

A

Uric Acid

Ca++ Phosphate

Struvite

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10
Q

Specific gravity (SG) of water is 1.0, and the most concentrated urine SG is about 1.03. What can patients do to lower the SG of their urine?

A

Hydrate!

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11
Q

With men putting out about 20mg/kg and women putting out about 15mg/kg, measuring ______ with urine samples will help determine if you’ve collected an adequate sample.

A

Creatinine

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12
Q

Cystine crystals are ______ (what shape?) and are NEVER normally in urine.

A

Hexagonal

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13
Q

Struvite crystals have a characteristic “_____ ____” appearance.

A

Coffin Lid (sort of like emerald cut diamonds.)

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14
Q

Envelope or barbell shapes are characteristic shapes of ____ _____ crystals.

A

Ca++ Oxalate

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15
Q

Uric acid crystals have a characteristic ______ or football shape.

A

Rhomboid

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16
Q

Uric acid is radioluscent, so it is not very visible on _____; instead, you would need a CT scan.

17
Q

Stones up to about ____ or ____ mm are likely to pass on their own. Stones > ____ mm will not likely pass on their own. Stones between ___ and ____ mm MIGHT pass on their own.

A

5 or 6mm –> likely to pass

> 10mm –> probs not

Between 6 and 10mm –> Maybe

18
Q

Hypercalciuria in men is classified as > _____ mg /day. In women: > ____mg/day.

A

Men: > 250mg/day

Women: > 200mg/day

19
Q

______ hypercalciuria is the most common cause of stone formation.

A

Idiopathic

20
Q

Oxalate normally binds _____ in the intestinal lumen which prevents its absorption, but with malabsorption diseases, there’s more FFA in the intestinal lumen that binds ____ –> This leaves Oxalate unbound and capable of being absorbed.

21
Q

There are bacteria in the large intestine that use ______ as a substrate for metabolism –> the absence of these bacteria may contribute to formation of stones.

22
Q

Oral _______ can be given to help reduce oxalate absorption. Keep in mind Ca++ can be given as well.

A

Cholestyramine

23
Q

Primary Hyperoxaluria (PHO) is an uncommon, autosomal _____ disease in which patients are deficient in one of the liver enzymes that metabolize ______ to either _____ or _____ –> this pushes the metabolism to form more Oxalate instead.

A

Recessive

Glyoxalate

Glycolate or Glycine

24
Q

As children with PHO develop worsening CKD and ESRD, their GFR decreases. How does this affect systemic Oxalate?

A

Oxalate will increase in the blood as less is filtered, and this can lead to Oxalate deposits systemically.

25
Citrate is reabsorbed in the ______ of the nephron. The most important regulating factor is _____.
PCT pH
26
For patients with pure Uric acid stones, what is the best treatment?
Alkalinize the urine
27
Treatment for Cystine stones is medication that prevents the precipitation of Cystine's dissociation product: _______. These medications are _______, ______, and _______.
Cysteine Penicillamine, Tiopronin, Captopril
28
Which condition can be treated with high dose Thiazide diuretics?
Hypercalciuria --> thiazide diuretics decrease urine Ca++