Alternative Names: Urolithiasis, Nephrolithiasis
Kidney stones are painful urinary disorders that start as salt/chemical crystals which precipitate out from urine. Under normal circumstances, the urine contains substances that prevent crystallization but for patients with this condition, these inhibitory substances are ineffective. Tiny crystals will pass out along with the urinary flow without causing problems. At least 1% of people will pass a kidney stone during their lifetime, producing some of the most severe pain possible.
Kidney stones may contain various forms of salts – the most common is calcium in combination with either phosphate or oxalate. These salts are an essential part of our daily dietary intake and requirement. Other types of stones are the struvite stone (caused by infection), uric acid stone and cystine stone.
The reasons why some people develop kidney stones are not fully understood. Aside from more obvious risk factors, metabolic conditions e.g. hyperparathyroidism, cystinuria (inherited disease), and hyperoxaluria (inherited disease) are also common causes of stone formation.
Most kidney stones contain crystals of multiple types. However, usually one type predominates, and determining the type helps to identify the underlying cause:
The bleeding may be caused by abrasion along the urinary tract as the stone travels.
Painful and/or difficult urination is a common sign of a kidney stone.
A kidney stone that is obstructing will cause damage to the kidneys in the long run if left untreated and may even lead to end stage kidney failure. Anyone with a past history of kidney stones should have regular screening performed as the recurrence rate is high.
When the immune system triggers inflammation in other parts of the body because of ulcerative colitis, kidney stones may result. This influence is usually mild and stones may not be a problem once the colitis is treated.
Increased calcium and phosphorous excretion in the urine may cause kidney stones.
When potassium levels fall too low, urine citrate also drops, decreasing your protection against stones.
Excessive intake of diuretics may give rise to excess calcium in the urine.
Restricted water consumption is an important causative factor.
The American Academy of Family Physicians notes that high animal protein intake is largely responsible for the high prevalence of kidney stones in the United States, which can cause severe pain or even urinary obstruction and kidney damage. Plant protein did not seem to have a harmful effect. [American Family Physician 60 (1999): p.2269]
A Dr. Scudder, writing in 1874, wrote: "[Hydrangea] is a valuable remedy in diseases of urinary apparatus. It gives tone to the kidneys, improving their functional activity, and thus tends to arrest the formation of urinary deposits and calculi. It relieves irritation of the bladder and urethra and hence proves serviceable in cases of gravel."
A Dr. Ellingwood wrote, in 1905: "About the year 1830 experiments were conducted to prove [Hydrangea's] influence in relieving pain caused by the presence and passage of urinary calculi, and favorable reports were made of its direct usefulness. Its influence controlled the pain in a satisfactory manner, relieved general distress, and soothed irritation."
Prevention is very important especially in those with a high likelihood of developing this condition since the recurrence rate of stone formation is very high. Drinking a lot of water is the best preventative measure: drink enough to produce approximately 2 liters (one-half gallon) of urine per day. Adequate fluid intake helps prevent kidney stone problems by allowing most small stones to pass through.
Those with a tendency to form calcium stones may want to avoid foods rich in calcium, such as dairy products.
A study published September, 2004 in the journal Urology suggests people prone to kidney stones should limit their intake of caffeine and cut down on the amount of coffee they drink. People who consumed caffeine in amounts equal to two cups of coffee showed elevated levels of calcium in their urine, which can increase the risk of developing stones, especially for people prone to stones. "Caffeine consumption may modestly increase risk of calcium oxalate stone formation," concluded the researchers.
Those prone to getting calcium oxalate stones are advised to avoid the consumption of foods high in oxalates.
For prevention of stone formation, medical therapy is available for those with known predisposing conditions. For those with stones, pain-killers (as prescribed by a doctor) can provide great relief. In addition, some medications may help break down larger stones.
Thiazides lower urinary calcium excretion, which helps prevent calcium-based kidney stone formation.
By increasing calcium solubility (especially in the urine) and reducing calcium absorption, magnesium can help prevent kidney stones, especially those composed of calcium oxalate. Research has shown this effect in a high percentage of people who form kidney stones regularly. It is thought that calcium oxalate stones are most likely to form in people who are magnesium deficient, so it may just be correcting that deficiency.
High levels of urinary calcium, due to an excess of non-absorbable calcium being consumed, can cause crystallization and subsequent stone formation. Those with a tendency to form calcium stones are advised to abstain from taking non-prescribed calcium pill supplements.
Surgical intervention – cystoscope or open surgery – may be required if other physical intervention, such as shockwave therapy (F-SWL) to break up stone(s) is unsuccessful.
Vitamin B6 deficiency leads to an increase in kidney stones as a result of elevated urinary oxalate levels. Vitamin B6 supplementation inhibits the production of oxalate in the body and can reduce elevated urinary oxalate in some stone formers who are not necessarily B6 deficient.
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