209: Kidney Stones Flashcards
List the kidney stones in order of prevalence
Ca2+ containing stones >>>>>>>
Struvite stones > Uric acid stones > cysteine stones
Does this condition promote or inhibit kidney stone formation?
High citrate
Inhibits stone formation
What are the main risk factor for calcium stones?
What contributes to these risk factor?
- Hypercalciuria
- Secondary to hyeprcalcemia
- Idiopathic
- Hyperoxaluria
- Dietary intake of high-oxalate foods
- Vitamin C intake (metabolized to oxalate)
- General malabsorption in the GI tract
- > increased oxalate reabsorption
- Low Ca2+ intake -> increased oxalate absorption
- Primary hyperoxalosis
A 45-year-old Caucasian male with a history of chronic myeloid leukemia for which he is receiving chemotherapy presents to the emergency room with oliguria and colicky left flank pain. His serum creatinine is 3.0 mg/dL and is urine pH is 5.0. You diagnose nephrolithiasis. His kidney stones, however, are not visible on abdominal x-ray. His stone is most likely composed of which of the following?
- Calcium oxalate
- Struvite
- Uric acid
- Cysteine
c. Uric acid
What are the general risk factors for kidney stone formation?
- Low urine volume
- High sodium diet
- Leads to increased urinary Ca2+
- Reabsorption of Na+ and Ca2+ are coupled
- High sodium diet
- Leads to increased urinary Ca2+
- *->** **decreased Na+ reabsorption
- > decreased Ca2+ reabsorption**
- High protein diet
- Protein metabolism
- -> Increased acid load
- -> Bone resorption to buffer acid = Ca2+ release
- -> Increased urinary Ca2+
What kind of kidney stones are hexagonal?
Cysteine stones
Uric acid stones are more likely to form in [acidic/basic] urine
Uric acid stones are more likely to form in acidic urine
A 30-year-old male with history of two prior episodes of nephrolithiasis presents to establish care in your clinic. He would like to discuss strategies to prevent future kidney stones. He has not had analysis done of his prior kidney stones. You order a 24-hour urine collection for Ca, Na, phosphorus, uric acid, and citrate. Before even obtaining results, which of the following would be an appropriate recommendation?
- Increase dietary sodium intake
- Increase dietary protein intake
- Lower dietary calcium intake
- Increase fluid intake
d. Increase fluid intake
What kind of kidney stones are likely to be the largest?
Struvite stones
Can form staghorn calculi (kidney stones so large that they block more than one renal calyx)
What are the risk factors for cysteine kidney stones?
Inherited disorder of metabolism that impairs cysteine reabsorption in the proximal tubule
What are staghorn calculi?
What kind of kidney stones can form them?
Staghorn calculi = very large kidney stone that blocks more than one renal calyx
Struvite stones are most likely to form staghorn calculi
What are the major risk factors for uric acid stone formation?
- Hyperuricosuria
- Increased dietary intake of purines and animal protein
- High-cell turnover states: uric acid is released from cells when they die
- Hematologic malignancies
- Tumor-lysis syndrome
- Low urinary pH
- Uric acid is less soluble in acidic conditions
What kind of kidney stone is this?
Struvite
Rectagular, “coffin lid”
About ____% of people will have an episode of nephrolithiasis in their lifetime (United States)
About 10% of people will have an episode of nephrolithiasis in their lifetime (United States)
What kind of kidney stone is this?
Calcium stone
Square shaped, looks like an envelope
What kind of kidney stone is this?
Cysteine
Hexagonal shape
Which substances become less soluble as urinary pH increases?
Ammonium urate
Phosphate
What kind of kidney stone is this?
Uric acid
Diamond/rhomboid shape
