abnormally high amounts of cystine into the urine.
Cystine has poor solubility in urine and easily
precipitates to form stones. This genetically
caused disease leads to recurrent stones which can
occur at a young age.
is an amino acid which is used for making proteins.
It contains sulfur which is the basis for preventive
treatment. Drugs containing sulfur,
penicillamine and captopril, are used. These
sulfur containing drugs will bind to the sulfur
component of the cystine. As in other types of
stones, raising urine volume is key to prevention of
new stones or slowing growth of already existing
surgeon with experience in the care of cystinuria
patients is necessary for successful surgical
removal. These stones are very hard and
usually cannot be removed with lithotripsy.
People with cystinuria can go on to develop chronic
kidney infections and permanent kidney scarring.
Like struvite or infectious stones, cystine stones
can develop into large staghorn shaped stones which
fill the cavities of the kidney. Although they are
not made of calcium, they can be seen on xray,
unlike pure uric acid stones which cannot be seen on
xray. Stones can develop in children.
Diagnosis is made by collecting urine for 24 hours
and measuring elevated urine cystine levels.
Distinctive hexagonal crystals are classically seen
on microscopic urine analysis.