Causes of Calcium Oxalate Kidney Stones

Calcium Oxalate Kidney Stones – Causes

Kidney stone is a common problem faced by the male population worldwide.  This is probably due to increased incidences of urinary obstruction occurring in them that tend to promote the development and growth of kidney stones.  While kidney stones can be made up of various mineral elements that occur naturally in urine, calcium stones are the most encountered ones.

Whatever may be the type, almost all forms of kidney stones are easily created when undiluted urine is secreted.  Normal urine produced will contain more of water molecules and minimal amounts of mineral waste materials.  High concentrated urine, however, will consist more of mineral matters than water molecules, leaving many behind in an undissolved state.  These undissolved mineral salts will slowly begin to crystallize and develop further into a renal calculus.

Of the two types, calcium oxalate and calcium phosphate stones, calcium oxalate stones are the most frequently formed ones.  Our body requires only a certain amount of calcium which is mostly got from dietary sources.  Those calcium compounds not absorbed by the body can combine with other mineral elements and get eliminated out via stools, or may spill into the urinary system.  Once in the urinary system, with excess calcium and oxalate levels and less water content to dissolve them, they can combine together and form tiny stones in the kidneys.  When the urine is acidic, meaning in an undiluted form, calcium salts separate easily from the solution and take the form of crystals.

Certain disease conditions also contribute to this state of hypercalciuria that promote the formation of calcium oxalate kidney stones.  a)  Parathyroid is an endocrine gland that release hormones required for metabolizing calcium in our body.  A defective parathyroid gland (read over active gland) will increase the release of these hormones, in turn causing an increase in urinary calcium levels.  b)  Any intestinal disorders that increase the absorption of calcium and urinary calcium levels will also contribute to kidney stone formations.  c)  A high-calcium diet will cause the intestines to absorb calcium in large amounts, again increasing calcium levels in urine.  d)  Also, increased sodium intake will increase urinary calcium levels.  As the kidneys filter out sodium from the blood, calcium compounds are also removed which is excreted in urine.


Oxalates are produced by the liver as well as got from dietary sources.  High intake of oxalate containing foods and less of dietary calcium will increase the presence of oxalates in urine.  As stated earlier, oxalates present in the intestine usually combine with calcium and are expelled out along with a bowel movement.  When there is insufficient calcium salts for oxalates to bind to, they are excreted into the urinary system, where they find calcium compounds and adhere to form kidney stones.

Genetic disorders that increase the formation of oxalates in the liver will also result in hyperoxaluria.  The enzyme that brings about a chemical reaction within resulting in oxalate formation, functions imperfectly, and this is what causes the increase in oxalate release.  Since only minimal amount of oxalates are required for certain body functions, the rest gets deposited in urine increasing the risk of calcium oxalate stone formation.