Medical management of Stones Flashcards
What is the prevalence of nephrolithiasis?
- 8% overall
- 6% in men
- 1% in women
With health conditions are associated with nephrolithiasis?
Obesity
HTN
Diabetes
What diet has been shown to be potentially beneficial for recurrent stone forming men?
High fluid
Low sodium
Low animal protein
Normal Ca
What dietary factors may enhance stone formation?
Low calcium
Low fluid
Sugary drinks
High animal protein
What medical conditions should be asked about during evaluation of a stone patient?
Obesity Hyperthyroidism Gout RTA type I Diabetes Hyperparathyroidism Bowel or pancreatic dz
What medications are associated with stone formation?
Probenacid Protease inhibitors Lipase inhibitors Triamterene Chemotherapy Vitamins C/D Topiramate Acetazolamide Zonisamide
What laboratory workup should be included in the evaluation of a stone patient?
BMP
Ca
Uric acid
UA
What is the AUA guideline for a stone patient with high serum Ca?
PTH
Vit D
When should one suspect hyperparathyroidism in a Stone patient?
High serum Ca
CaP stones
Elevated urinary Ca
High Ca with normal mid range PTH?
Primary hyperparathyroidism
Potential causes of CaP stones?
RTA type 1
Primary hyperPTH
Medullary sponge
Carbonic anhydrase i
What can nephrocalcinosis indicate?
RTA type 1
Primary HyperPTH
Primary hyperoxaluria
Medullary sponge
When should a 24 urine analysis be obtained?
Recurrent stone formers
Interested first timers
High risk formers
What makes high risk stone formers?
Family history Solitary kidney Intestinal malabsorption rUTIs Obesity/diabetes Type 1 RTA Primary hyperPTH
What are the AUA guidelines for metabolic testing for nephrolithiasis?
one or two 24-hour urine collections obtained on a random diet
What should a 24 hour urine analysis include at minimum?
Total volume, pH, calcium, oxalate, uric acid, citrate, sodium, potassium and creatinine.
What are the roles of fasting calcium and calcium load testing?
They should not be used.
What is the recommended daily fluid volume to prevent stones?
fluid intake that will achieve a urine volume of at least 2.5 liters daily
What is the recommended calcium intake for stone formers?
Normal Ca intake
1000-1200 mg/day
Low Ca intake may lead to increased oxalate absorption.
What is the recommended sodium intake for stone formers?
2300 mg/day
What are the diet recommendations for Ca oxalate stones?
Limit oxalate rich foods and keep normal calcium consumption
Calcium stone and lower urinary citrate diet recommendations?
increase fruits and vegetables. Limit non dairy animal protein.
Uric acid/calcium stones with high uric acid diet recommendations?
Limit non dairy protein.
Cysteine stones, diet recommendations?
Limit sodium and protein intake.
Medical tx options for patient with high urine calcium and recurrent calcium stones?
HCTZ 25mg BID, 50mg qd
Chlorthalidone 25mg qd
Indapamide 2.5mg qd
What additional medication may be needed when on thiazides?
Potassium supplementation.
Tx for patient with recurrent calcium stones and low urinary citrate?
Clinicians should offer potassium citrate therapy to patients with recurrent calcium stones and low or relatively low urinary citrate.
Medical treatment for a patient with recurrent calcium oxalate stones, hyperuricosuira, and normal urinary calcium?
Allopurinol
What is the cutoff for hyperuricosuria?
> 800mg/day
Medical treatment for a patient with recurrent calcium stones in which 24 hour urine analysis failed to identify an abnormality?
Thiazide diuretics
Potassium citrate
What medical therapy is available for uric acid or cysteine stones?
Alkalinization of the urine with potassium citrate to 6 for uric acid and 7 for cysteine
Role of allopurinol in uric acid stones?
Do not use as first line tx. Alkalinization is the first line treatment. Allopurinol can only be considered if patient continues to form uric acid stones on adequate alkaliniztion therapy.
What is the first line medical therapy for Cysteine stones?
irst-line therapy for patients with cystine stones is increased fluid intake, restriction of sodium and protein intake, and urinary alkalinization.
What are the second and third line treatments for Cysteine stones?
2nd line: Tiopronin
3rd line: d-penicillamine, captopril
What is the medical treatment for patients with struvite stones that are recurrent and not treated adequately with surgical therapy?
acetohydroxamic acid (AHA), it is a urease inhibitor.
What are the notable adverse effects of Acetohydroxamic acid?
Patients taking this medication should be closely monitored for phlebitis and hypercoagulable phenomena.
How should patients on medical therapy for stones be followed up?
linicians should obtain a single 24-hour urine specimen for stone risk factors within six months of the initiation of treatment to assess response to dietary and/or medical therapy. Then annually thereafter. Blood testing should be tailored to specific medication.
