Symptoms and Causes
Common symptoms of kidney stones include a sharp, cramping pain in the back and side. This feeling often moves to the lower abdomen or groin. The pain often starts suddenly and comes in waves. It can come and go as the body tries to get rid of the stone.
Other signs of a kidney stones, include:
- A feeling of intense need to urinate.
- Urinating more often or a burning feeling during urination.
- Urine that is dark or red due to blood. (Sometimes urine has only small amounts of red blood cells that can't be seen with the naked eye.)
- Nausea and vomiting.
- A feeling of pain at the tip of the penis in men.
Causes
Low Urine Volume
Constantly having a low urine volume is a major risk factor for kidney stones. Low urine volume may come from dehydration (loss of body fluids) from hard exercise, working or living in a hot place, or not drinking enough fluids.
When your urine volume is low, urine is concentrated and dark in color. Concentrated urine means there is less fluid to keep salts dissolved. Increasing fluid intake will water down the salts in your urine. By doing this, you may cut your risk of forming stones.
Adults who form stones should drink enough fluid to make at least 2.5 liters (⅔ gallon) of urine every day. On average, this means you should drink about 3 liters (100 ounces) of fluid per day. Water is generally the best fluid to drink for stone prevention.
Diet
What you eat matters when it comes to your risk of forming kidney stones. One of the more common causes of calcium kidney stones is high levels of calcium in the urine.
High urine calcium levels may be due to the way your body handles calcium, but, remember, it is not always due to how much calcium you eat.
Lowering the amount of calcium in your diet rarely stops stones from forming. Studies have shown that limiting dietary calcium can be bad for bone health and may increase kidney stone risk.
Doctors usually do not tell people to limit dietary calcium in order to lower urine calcium. However, the amount of calcium you consume should not be too high.
Instead of lowering dietary calcium intake, your doctor may try to reduce your urine calcium level by reducing your salt intake.
Having too much salt in your diet is a risk factor for calcium stones. This is because too much salt is passing into the urine, keeping calcium from being reabsorbed from the urine and into the blood.
Reducing salt in the diet lowers urine calcium. This will make it less likely for you to form stones.
Because oxalate is a component of the most common type of kidney stone (calcium oxalate), eating foods rich in oxalate can raise your risk of forming these stones.
A diet high in animal protein, such as beef, fish, chicken and pork, can raise the acid levels in the body and in the urine. High acid levels make it easier for calcium oxalate and uric acid stones to form. The breakdown of meat into uric acid also raises the chance of forming a kidney stone.
Bowel Conditions
Certain bowel conditions that cause diarrhea (such as Crohn's Disease or ulcerative colitis) or surgeries on the intestines (such as gastric bypass surgery) can raise the risk of forming calcium oxalate kidney stones.
Diarrhea may result in loss of large amounts of fluid from the body, lowering urine volume. Your body may also absorb excessive oxalate from the intestine, resulting in more oxalate in your urine. Both low urine volume and high levels of urine oxalate can help to cause calcium oxalate kidney stone formation.
Obesity
Obesity is a risk factor for stones. Obesity may change the acid levels in the urine, leading to stone formation.
Medical conditions
Some medical conditions can also cause an increased risk of kidney stones. Abnormal growth of one or more of the parathyroid glands, which control calcium metabolism, can cause high calcium levels in the blood and urine. This can lead to kidney stones. Another condition called distal renal tubular acidosis, in which there is acid build-up in the body, can raise the risk of calcium phosphate kidney stones.
Medication
Some medications, and calcium and vitamin C supplements, may increase your risk of forming stones. Tell your doctor all the medications and supplements you take, as these could affect your risk of kidney stones. Do not stop taking any of these unless your doctor tells you to.
Family History
The chance of having kidney stones is much higher if you have a family history of stones, such as a parent or sibling.
Source: Urology Care Foundation: The Official Foundation of the American Urological Association