Renal Calculi Flashcards
Factors that promote crystallization
Concentration of urine Stasis pH Nidus Other crystals A lack of inhibitors (Mg and citrate)
Calcium stones
Most common 75%
Asso with underlying abnormalities: hyper ca, hyper calciuria, hyper oxaluria, hyper uricosuria, low levels of inhibitors (citrate and mg)
Struvite stones
Aka infection stones or stag horn stones
20% of stones
Caused by urease producing organisms proteus, pseudomonas or klebsiella, NEVER E. coli.
Urea is broken down➡️ammonia➡️ alkaline pH➡️ precipitation of crystals
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Uric acid stones
Dehydration Low urine pH High red meat intake Chronic diarrhea Hyper uricosuria
Cysteine stones
Rare autosomal recessive aminoaciduria COLA cysteine ornathine lysine and arginine Only homozygous form stones Gen have fam hx Gen present in childhood.
Indinavir stones
Protease inhibitor
May form stones
Very soft stones that do not even show on uncontrasted CT.
Complications
UTI: pyelonephritis, pyeloneohrosis, perinephric abscess/ fistula
Obstruction: hydronephrosis, renal failure
Chronic irritation: leukoplakia leading to squamous ca of renal pelvis
Haematuria
Impairment of kidney function
Special investigations and who gets stone work up!
Urine MC&S AXR IVP Metabolic evaluation: serum/ 24 hour collection Stone analysis
Stone work up: children, multiple stones, single kidney, fam hx of stones, bilateral stones.
Treatment
General: high fluids, reduced salt, reduced meat, do not reduce calcium.
Medical: pain mess, anti spasmodics (alpha blocker) steroids and fluids.
Uric acid: urine alkalisation, allopurinol
Calcium: medical + thiazides diuretic, potassium citrate
Infective: antibiotics and prevent recurrence
Cystine: urine alkalinisation and pennicillamine
Surgical: ESWL for
Types of stones
Radio opaque: calcium( oxolate and calcium phosphate), struvite, cystine.
Non opaque: Uric acid(but does show on CT), indinavir
