Nephrolithiasis lecture Flashcards
Supersaturation may result from:
↑ excretion of poorly soluble substances in addition to other confounding factors (i.e., low urine volume, abnormal urine pH)
Nephrolithiasis
calcium oxalate stones
MOST COMMON**
calcium oxalate*
struvite “stag horn”
uric acid
cystine
types of urinary stones
these stones are radiopaque
Calcium oxalate
______ stones frequently have smooth-edged ground-glass appearance.
Cystine
Idiopathic hypercalciuria Primary hyperparathyroidism Hypocitraturia Hyperuricosuria Renal tubular acidosis Dietary hyperoxaluria Enteric hyperoxaluria Primary hyperoxaluria Colon resection, ileostomy Habit, environment
causes of calcium stones
produced by UTI with urease-producing bacteria
usually large stones (> 2 cm)
Proteus, Klebsiella, Pseudomonas and Enterobacter spp.
treatment: prevent UTIs
Struvite stones
caused by low (6 with potassium citrate 20 mEq BID
Allopurinol and low-purine diet (↓ fish, shellfish & meats)
Uric acid stones
autosomally recessive inherited abnormalities
treatment: ↑ urine volumes to 3 L daily and ↑ urine pH to >7 with potassium citrate 20 mEq BID
occasionally chelating agents may be used (i.e., tiopronin)
Cystine stones
Geographic factors:
high humidity
high temps
Kidney stones
Sedentary occupations
High animal protein and high salt intake
Genetic factors
Risk factors for Kidney stones
FH 1st degree relative (calcium stones) Concurrent medical conditions bowel resection gout hyperthyroidism hyperparathyroidism sarcoidosis
Risk factors for kidney stones
Most common: Unilateral flank pain Sudden onset Renal colic (waxes and wanes) Hematuria
signs and symptoms of kidney stones
Less common: Asymptomatic Vague abdominal pain Acute abdominal or flank pain (constant) Nausea Persistent urinary frequency w/o evident infection (stone at ureterovesical junction) Difficulty urinating Penile pain or testicular pain Acute renal insufficiency due to obstruction
Kidney stones
Nephrolithiasis gold standard diagnostic…
non contrast CT scan
X ray will only detect which type of stone?
Calcium
*will miss uric acid and cysteine stones
Which diagnostic should you use in a pregnant woman with kidney stones?
Ultrasound
have a laminar rugged appearance, and are often full casts of the renal pelvis and calyces, the so-called “stag horn” conformation.
Struvite stones
Most patients with nephrolithiasis are treated with….
NSAIDs and opioids*
hydration
strain urine
Likelihood of spontaneous stone passage depends on…
size
location
medical expulsive therapy (MET)
- alpha blockers
- CCBs
can facilitate stone passage
Acute renal failure Urosepsis Urinary obstruction (anuria) Unyielding pain +/- nausea/vomiting Anatomic abnormalities or solitary kidney Concomitant pyelonephritis Stone >10 mm** Have not passed stone after 4-6 weeks**
Consult with urology
Shock wave lithotripsy (SWL)
Percutaneous nephrolithotomy (PNL)
Rigid and flexible ureteroscopy (URS) ± stent placement
Surgical techniques to remove stones
*10-20% require
Lower urine supersaturation by increasing fluid intake is key!
avoid dehydration & maintain urine volume of more than 2L
stone prevention
↓ oxalate intake (i.e., rhubarb, spinach, many nuts & seeds)
↓ animal protein intake
↓ sodium intake
↑ fluid intake
diet changes to help prevent calcium stone formation
