Medical Animation: Kidney Stone Disease

0:01 a kidney stone can be as small as the head of a pin almost invisible to the naked eye but as every stone former knows the pain resulting from this tiny crystal structure can be enormous inside kidney stone disease kidney stones or renal calculi are Aggregates of crystals enclosed in a matrix that develop within the kidneys they're classified according to the specific types of crystals they contain and fall into five major categories calcium oxalate calcium phosphate struvite uric acid and cyane the most common is calcium

0:50 oxalate how is a stone formed the first step is nucleation ions such as calcium and oxalate that have been filtered into the urine by the kidney spontaneously joined together to form a solid Crystal ntis this is called nucleation there are two kinds of nucleation in homogeneous nucleation crystals form around a nucleus with the same composition crystals of a different composition can also form around the nucleus organic material such as cell debris may be deposited between the crystals as a matrix this is heterog genous nucleation the tiny Crystal formations travel down the nefron and are usually

1:37 deposited at the renal papilla where they undergo the next major phase growth crystals that have already formed then begin to stick together forming large Aggregates as we can see crystals can aggregate very quickly new stones are retained in the kidney where they can continue to grow for an unspecified length of time until for reasons that are not well understood they are displaced and travel through the kidney into the urer if a stone continues to grow until it reaches a critical size which can be as small as 4 to 5 mm in diameter it may be too large to pass easily through the urer the edges of the stone may become wedged inside the urer at the Ural

2:23 pelvic Junction where the urer crosses over the iliac artery or at the Ural vesicle Junction the result pain and obstruction until the stone slowly passes into the bladder and eventually passes out of the body in the urine stream in the US it is estimated that 133% of men and 7% of women will develop a kidney stone during their lifetime fortunately in about 78% of these patients stones will be expelled spontaneously but stones that become lodged in the urer May require lithotripsy or percutaneous or endoscopic removal it's important to note that nearly half of all firsttime Stone formers will have another Stone

3:09 episode within the next four years recurrent Stone formers are at even greater risk and may form a new stone every 2 or 3 years but what actually causes crystals to form why do some crystals develop into kidney stones and others do not one critical factor is super atation of the urine with stone forming salts super saturation is the driving force for crystallization in undersaturated urine crystals cannot form the other important factor is a deficiency in substances called Inhibitors Inhibitors the nucleation growth and aggregation process by binding ions needed for Crystal formation and growth one of the

3:57 most important Inhibitors is citrate urine saturation and inhibitor levels explain why in normal patients large crystals are not formed their urine is not as saturated and they have sufficient quantities of Inhibitors present but the urine of patients with kidney stones is more saturated it may also lack Inhibitors that increase the propensity for crystallization of stone forming salts there are two reasons for this first stone for formers are known to suffer from a variety of metabolic disturbances that increase the amount of stone forming substances excreted in the urine and also decrease the excretion of Inhibitors second a number of common

4:44 nutritional and environmental factors can cause abnormalities in the urine these factors may also exaggerate underlying abnormalities due to metabolic disturbances environmental stresses for example play a significant role in stone disease especially factors that trigger excess water conservation in the kidney such as inadequate fluid intake dehydration is a major cause of kidney stones which is why people living in areas with high temperatures and humidity have a higher incidence of stone formation a diet high in sodium is a double risk because it increases calcium excretion and reduces urinary levels of stone inhibiting citrate too much animal protein creates similar problems encouraging Stone

5:29 growth by increasing urinary uric acid and reducing urinary citrate certain medications are also known to encourage Stone formation or growth in susceptible patients including common supplements such as Vitamin C there is no cure for kidney stones but once an acute episode has been resolved the key to therapy is simple preventing recurrence and fortunately the most common Stones calcium oxalate and calcium phosphate can be effectively managed with a combination of diet and lifestyle changes and medication compliance with proven management guidelines such as increasing fluid intake and avoiding Stone promoting foods can significantly reduce

6:15 Stone recurrence medical therapies such as thide diuretics and potassium citrate are also highly effective in appropriate patients and can reduce the need for expensive assisted stone removal procedures such as sh wave lithotripsy swl the economic burden of kidney stones is significant with medical costs reaching billions of dollars annually effective management of this painful disease remains a key priority at Mission pharmacal the leader in Innovative Stone disease Therapies