Kidney stones are small, solid pieces of material that form inside your kidneys when salts and other mineral substances in your urine bond together. Stones are common and often vary in shape and size, with some growing to be quite large. A small stone may pass out of the kidney and through the urinary tract without causing any discomfort, while a larger stone may remain in the kidney or travel down the urinary tract and become stuck in the ureter (a tube that carries urine from the kidney to the bladder). When they’re small, stones may pass on their own without causing pain.
Remarkable increase in number of kidney related diseases and other urological conditions affecting population has generated need to create awareness regarding kidney health, and timely screening and diagnosis of disease to receive treatment. Various organizations and companies across the world are working in the way of raising awareness for receiving affordable and equitable access to screening, diagnosis and treatment options.
Kidney Stones: Types and Formation
There are five major types of kidney stones: calcium oxalate, calcium phosphate, uric acid, struvite (magnesium ammonium phosphate), and cystine. Calcium oxalate is by far the most common, comprising approximately 75% of kidney stones.
Calcium stones are the most common type of kidney stones. They are composed of either calcium oxalate or calcium phosphate compounds. They are formed when calcium binds to oxalate (or phosphate) in the urine. On the other hand, dietary calcium can bind oxalate in the intestine and prevents its absorption through the gut, so there is less in the urine to form stones.
Calcium phosphate stones are less common than calcium oxalate stones. Causes include hyperparathyroidism (when the body produces too much parathyroid hormone), renal tubular acidosis (a kidney condition that causes a buildup of acid in the body), and urinary tract infections. It is important to understand if one of these conditions is behind the formation of calcium phosphate stones.
Uric acid stones generally form when urine is too acidic, causing otherwise normal levels of uric acid to dissolve into the urine where it may crystallize forming stones. Therefore, by alkalizing the pH of the urine, we can prevent crystal formation.
Struvite stones are composed of magnesium ammonium phosphate, and unlike other stones, form in alkaline urine. Most commonly, these types of stones form due to a bacterial infection that raises the urine pH to alkaline levels. To dissolve these stones, acetohydroxamic acid (AHA) is used to reduce urine pH and ammonia.
Cystine stone formation (also called cystinuria) is a relatively uncommon type of stone and the result of a genetic condition. As a result, urinary elevations of the amino acid cystine results in stone formation. Cystine stones can often be managed by improving hydration and maintaining alkaline urinary pH through diet and medication.