Lecture 15 - Kidney Stones Flashcards
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.
Calcium
Uric acid
Cystine
Autosomal Recessive
Children (median age of onset = 12)
Struvite
Urea into NH3
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.
Males
Whites
4th decade of life
Though multifactorial, there is a genetic component to acquiring kidney stones, so look to patients’ ______ ______!
Family Histories
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.
Nucleation
Randall’s plaques
Nucleation
The major inhibitor of Ca++ stone formation is ______, which complexes with Ca++ to keep it in solution.
Citrate
Some GI disease that cause malabsorption of nutrients can lead to INCREASED absorption of ______ –> this of course increases the likelihood of forming ______ ______ stones.
Oxalate
Ca++ Oxalate
Patients with ______ bladder (or _____ ____ injury leading to _____ bladder) are at higher risk of UTI. Which stones are they most at risk for?
Neurogenic bladder
Spinal Cord injury leading to Neurogenic bladder
Struvite stones
Patients with Gout, ______, and _____ are at higher risk of forming Uric acid stones.
Diabetes
Obesity
For urine pH < 5.5 –> suspect ______ ____ stones.
For urine pH between 6.5 and 7 –> suspect ____ ____ stones.
For urine pH > 7.0 –> suspect _____ stones.
Uric Acid
Ca++ Phosphate
Struvite
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?
Hydrate!
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.
Creatinine
Cystine crystals are ______ (what shape?) and are NEVER normally in urine.
Hexagonal
Struvite crystals have a characteristic “_____ ____” appearance.
Coffin Lid (sort of like emerald cut diamonds.)
Envelope or barbell shapes are characteristic shapes of ____ _____ crystals.
Ca++ Oxalate
Uric acid crystals have a characteristic ______ or football shape.
Rhomboid
Uric acid is radioluscent, so it is not very visible on _____; instead, you would need a CT scan.
x-ray
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.
5 or 6mm –> likely to pass
> 10mm –> probs not
Between 6 and 10mm –> Maybe
Hypercalciuria in men is classified as > _____ mg /day. In women: > ____mg/day.
Men: > 250mg/day
Women: > 200mg/day
______ hypercalciuria is the most common cause of stone formation.
Idiopathic
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.
Ca++
Ca++
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.
Oxalate
Oral _______ can be given to help reduce oxalate absorption. Keep in mind Ca++ can be given as well.
Cholestyramine
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.
Recessive
Glyoxalate
Glycolate or Glycine
As children with PHO develop worsening CKD and ESRD, their GFR decreases. How does this affect systemic Oxalate?
Oxalate will increase in the blood as less is filtered, and this can lead to Oxalate deposits systemically.
Citrate is reabsorbed in the ______ of the nephron. The most important regulating factor is _____.
PCT
pH
For patients with pure Uric acid stones, what is the best treatment?
Alkalinize the urine
Treatment for Cystine stones is medication that prevents the precipitation of Cystine’s dissociation product: _______. These medications are _______, ______, and _______.
Cysteine
Penicillamine, Tiopronin, Captopril
Which condition can be treated with high dose Thiazide diuretics?
Hypercalciuria –> thiazide diuretics decrease urine Ca++
