312 Nephrolithiasis Flashcards
Which drug is most appropriate to manage colicky pain in nephrolithiasis? A. Ketorolac B. Tramadol C. Morphine D. Hysocine
A. Ketorolac NSAID
Most common type of renal stones
Calcium oxalate 75% Calcium phosphate 15% Uric acid 8% Struvite 1% Cystine less than 1%
True or false. Radiographic evidence of a second stone should be considered a recurrence even if the stone as not yet caused symptoms
True.
Conditions that predispose to stone formation
GI Malabsorption eg in IBD, gastric bypass surgery Primary Hyperparathyroidism Obesity DM type 2 Distal renal tubular acidosis
Point at which concentration product exceed the solubility product
Supersaturation
Most clinically important inhibitor of calcium containing stones
Urine citrate
Calcium phosphate at the tip of the renal papilla
Randall’s plaque
Initiating event in calcium phosphate stone development
Tubular plugs of calcium phosphate
Dietary factors that are associated with increased risk of Nephrolithiasis
Animal protein Oxalate Sodium Sucrose Fructose
Dietary factors associated with lower risk of Nephrolithiasis
Calcium
Potassium
Phytate
How does calcium intake lead to decreased risk of Nephrolithiasis
Intake of calcium leads to reduction in intestinal absorption of dietary oxalate that results in lower urine oxalate
Strong risk factor for calcium oxalate stone formation
Urinary oxalate
Supplement associated with increased risk of calcium stone formation especially among men
Vitamin C supplements
Urine output of less than what doubles the risk of stone formation
Urine output less than 1L/day
Drinks associated with reduced risk of stone formation
Coffee Tea Beer Wine Orange juice
Types of stone based on urine pH
Less than 5.5
More then 6.5
No influenced by urine pH
Less than 5.5: Uric acid
More then 6.5: calcium phosphate
No influenced by urine pH: calcium oxalate
Autosomal recessive disorder that causes excessive endogenius oxalate generation by the liver with consequent calcium oxalate stone formation and crystal deposition in organs
Primary hyperoxaluria
Autosomal recessive disorder that causes abnormal reabsorption of filtered basic amino acids
Cystinuria
Two common presentation for individuals with an acute stone event
Renal colic
Painless gross hematuria
Mimicker of renal colic. Where is the stone if pain is like acute cholecystitis
Right ureteral pelvic junction
Mimicker of renal colic. Where is the stone if us is like acute appendicitis
Right pelvic brim
Mimicker of renal colic. Where is the stone if it is like acute diverticulitis
Left pelvic brim
Whre is the stone if patient presents with urine urgency and frequency
Ureterovesical junction
Pain reliever to be given to renal colic that is associated with fewer side effect and effective
IV NSAID
Drug that when given can increase rate if spontaneous stone passage
Alpha blocker
True or false. First time stone formers will have recurrence within 10 years
True.
Cornerstone of which therapeutic recommendation in the management of Nephrolithiasis is based
24 hour urine collection
Gold standard in the diagnosis of Nephrolithiasis
Helical CT without contrast
Urine collection sample before committing patient to long term lifestyle changes
2 urine collection
Target urine volume to reduce stone formation
2L/ day
Drug that can lower urine calcium excretion
Thiazide
Foods with high oxalate contents
Spinach, rhubarb, almonds and potatoes
Natural inhibitor of calcium oxalate and calcium phosphate stones
Citrate
Type stone more common in patients with distal renal tubular acidosis and primary Hyperparathyroidism
Calcium phosphate
Two main risk factor of Uric acid stone formation
Low urine pH
hight Uric acid excretion
Predominant influence on urine acid solubility
Urine pH
If you have Uric acid stone, what is the target urine pH and how is this achieved?
Target urine pH: 6.5
Alkalinize urine with NaHCO3 or Potassium citrate
What is the target urine pH for Cystine stones and how is this achieved
Target pH: above 7.5
Alkalinize with Potassium citrate or sodium Bicarbonate
Treatment for Cystine stone which covalently bind to cystine
Tiopronin: preferred
Penicillamine
Organism that is associated with Struvite stone
Proteus mirabilis
K pneumoniae
Providencia spp
Also known as infection or triple phosphate stone
Struvite stone
What is the usual pH in Struvite stone
pH more than 8.0
Urease inhibitor drug given to patient with Struvite stone
Acetohydroxamic acid
True or false. Increased dietary calcium is predisposed to kidney stone
False. Low calcium
Single most strong predictor of nephrolithiasis
Hematuria
Pain control on nephrolithiasis
Ketorolac + meperidine/ morphine
Size of stone warranting urologic evaluation
Stone more than 10 mm (ESWL or endoscopic)
Urosepsis for emergent decompression (ureteral sent or nephrostomy tube)
What to with stone less than 10 mm
Medical management
Rate of spontaneous passage is determined by size and location of stone
87% = 1 mm 76%= 2-3 mm
78%= UVJ stone
How to facilitate stone passage
Alpha blockers
Less effective for 5 mm size
Examples of medical expulsive therapy
Alpha blocker: tamsulosin in 5-10 mm diameter
Ca channel: Nifedipine
How to prevent calcium stones
Hydrochlorothiazide
K citrate/ NaHCO3
What causes hyperoxaluria
High dose Supplemental vitamin C
Post bariatric surgery
High oxalate diet
How to deal with hyperoxaluria
Ca Carbonate or citrate 1-4 g/dl
Potassium alkali to correct acidosis
True or false. Cautious alkali supplementation in calcium phosphate stone
True.
