General knowledge stones Flashcards
stone cyrstal appearance
Envelope / tetrahedral = calcium oxalate
Coffin lid = struvite
Hexangonal = cystinuria
Uric = amorphous fibres or irregular plates
Phosphate or brushite – spike
Calcium apatite = amorphous
Ca ox mono COM- thin and plate like, dumbbell shape
urinary PH and stone association
Ph greater than 7 suggestive of infection or RTA
RTA PH constantly above 5.8 / 6
if urinary PH <5.4 RTA excluded
PH less than 5.5 suggests uric acid lithaisis
infection stones
magnesium ammonium phosphate
ammonium urate
highly carbonated apatite
non infection stones
Ca oxalate
Ca phosphate
uric acid
genetic
cystinuria
xanthine
2,8 dihydroxyadenine
hypocitrauria and PH
can be result of any acidotic state
Because acidosis will both decrease endogenous renal citrate production and increased renal tubular absorption of citrate
enteric hyperoxaluria
intestinal malabsorption fat from any cause
increases luminal fatty acids and bile salts
bind calcium
reduces ca to complex to oxalate to form soluble complex lost in stool
increases luminal oxalate available for absorption
bile salts also increase colonic permeability to oxalate
urinary calcium low, urine PH low
animal protein and stone formation -4
hypocitraturia
low urine PH
hypoxaluria
hyperuricosuria
stones in laxative abuse
ammonium urate stone
intracellular acidosis due to chronic dehydration
diabetes and urinary PH
reduced PH
reduced urinary ammonium
defect ammoniogenesis due to insulin resistance at level of kidney
high BMI and stones
excrete increased levels oxalate, uric acid, Na and Phos and more likely to have urinary supersaturation uric acid
action of thiazide diuretics in idiopathic hypercalcuria
prevent Na being exchanged for Ca in DCT
more sodium excreted in urine and less calcium
mechanism in RTA and met acidosis
Met acidosis causes loss of Ca in urine alkaline urine reduces tubular reab of citrate hypocitraturia ca phosphate stones
uric acid stone formation urinary Ph
low urinary PH less than 5.5
low urinary PH due to impaired ammoniogenesis with insulin resistance
cystinuria defect
defect of COAL kidney and intestinal transepithelial transport defect for amino acids cystine, ornigthine, arginine and lysine
inability to reasb these amino acids
others highly soluble, cystine is not, esp not soluble at lower urinary PH levels
