Read more about this disease, some with Classification – Types – Signs and symptoms – Genetics – Pathophysiology – Diagnosis – Screening – Prevention – Treatment and management – Cures and much more, some including pictures and video when available.
Kidney stones, also called renal calculi, are solid concretions (crystal aggregations) of dissolved minerals in urine; calculi typically form inside the kidneys or bladder. The terms nephrolithiasis and urolithiasis refer to the presence of calculi in the kidneys and urinary tract, respectively.
The kidneys are a pair of organs that are primarily responsible for filtering metabolites and minerals from the circulatory system. These secretions are then passed to the bladder and out of the body as urine. Some of the substances found in urine are able to crystalize, and in a concentrated form these chemicals can precipitate into a solid deposit attached to the kidney walls. These crystals can grow through a process of accretion to form a kidney stone.[1] In medical terminology these deposits are known as renal calculi (Latin renal, “kidney” and calculi, “pebbles”).[2]
Renal calculi can vary in size from as small as grains of sand to as large as a golf ball.[3] Kidney stones typically leave the body by passage in the urine stream, and many stones are formed and passed without causing symptoms. If stones grow to sufficient size before passage—on the order of at least 2-3 millimeters—they can cause obstruction of the ureter. The resulting obstruction with dilation or stretching of the upper ureter and renal pelvis as well as spasm of muscle, trying to move the stone, can cause severe episodic pain, most commonly felt in the flank, lower abdomen and groin (a condition called renal colic). Renal colic can be associated with nausea and vomiting due to the embryological association of the kidneys with the intestinal tract. Hematuria (bloody urine) is commonly present due to damage to the lining of the urinary tract.
Within the United States, about 10–15% of adults will be diagnosed with a kidney stone,[4] and the total cost for treating this condition was US$2 billion in 2003.[5] The incidence rate increases to 20–25% in the Middle East, because of increased risk of dehydration in hot climates. (The typical Arabian diet is also 50% lower in calcium and 250% higher in oxalates compared to Western diets, increasing the net risk.)[6] Recurrence rates are estimated at about 10% per year, totalling 50% over a 5–10 year period and 75% over 20 years.[7] Men are affected approximately 4 times more often than women. Recent evidence has shown an increase in pediatric cases.[8]
The existence of kidney stones has been recorded since the beginning of civilization, and lithotomy for the removal of stones is one of the earliest known surgical procedures.[9] In 1901, a stone was discovered in the pelvis of an ancient Egyptian mummy, and was dated to 4,800 BC. Medical text from ancient Mesopotamia, India, China, Persia, Greece and Rome all mentioned calculous disease. Part of the Hippocratic oath contains an admonition about the dangers of operating on the bladder for stones. The Roman medical treatise De Medicina by Cornelius Celsus contained a description of lithotomy, and this work served as the basis for this procedure up until the 18th century.[10]
New techniques in lithotomy began to emerge starting in 1520, but the operation remained risky. It was only after Henry J. Bigelow popularized the technique of litholopaxy in 1878 that the mortality rate dropped from about 24% down to 2.4%. However, other treatment techniques were developed that continued to produce a high level of mortality, especially among inexperienced urologists.[10][11] In 1980, Dornier MedTech introduced extracorporeal shock wave lithotripsy for breaking up stones via acoustical pulses, and this technique has come into widespread use.[12]
Kidney stones can be due to underlying metabolic conditions, such as renal tubular acidosis,[7] Dent’s disease[13], Hyperparathyroidism[14] and medullary sponge kidney.[15] Many health facilities will screen for such disorders in patients with recurrent kidney stones.[citation needed] This is typically done with a 24 hour urine collection that is chemically analyzed for deficiencies and excesses that promote stone formation. Kidney stones are also more common in patients with Crohn’s disease.[16]
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