Waiting anxiously from ten thirty this morning till four in the afternoon, bored at the hospital by Jerry's side without stones during the whole freezing and lonesome night, I clipped this out in order not to be stoned on my turn:
The Whys and How-to-Treats of Kidney Stones
Adapted and rearranged from New York Times
Kidney stones can form when urine contains too much of certain substances. These substances can create small crystals that become stones. The biggest risk factor for kidney stones is dehydration.
Kidney stones may not produce symptoms until they begin to move down the tubes (ureters) through which urine empties into the bladder. When this happens, the stones can block the flow of urine out of the kidneys. This causes swelling of the kidney or kidneys, causing pain. The pain is usually severe.
Kidney stones are common. A person who has had kidney stones often gets them again in the future. Kidney stones often occur in premature infants. Some types of stones tend to run in families. Certain kinds of stones can occur with bowel disease, ileal bypass for obesity, or renal tubule defects.
There are different types of kidney stones. The exact cause depends on the type of stone.
1. Calcium stones are most common. They occur more often in men than in women, and usually appear between ages 20 - 30. They are likely to come back. Calcium can combine with other substances, such as oxalate (the most common substance), phosphate, or carbonate to form the stone. Oxalate is present in certain foods. Diseases of the small intestine increase the risk of forming calcium oxalate stones.
2. Cystine (胱胺酸) stones can form in people who have cystinuria. This disorder runs in families and affects both men and women.
3. Struvite (磷酸銨鎂) stones are mostly found in women who have a urinary tract infection. These stones can grow very large and can block the kidney, ureter, or bladder.
4. Uric acid stones are more common in men than in women. They can occur with gout or chemotherapy. Other substances also can form stones.
Dr. Gary Curhan is a nephrologist at Brigham and Women’s Hospital and an associate professor of medicine and epidemiology at Harvard Medical School of Public Health in Boston. He has conducted some of the most extensive research into the causes of and risk factors for kidney stones, with the goal of improving prevention strategies. Lifestyle changes can dramatically reduce the risk of stones. The followings are what he believes everyone should know about kidney stones:
Q: Research shows that kidney stones are increasing. How common are they?
A: About 12 percent of men and 7 percent of women will experience a stone over a lifetime. That makes it a pretty common disease, as common as diabetes. Of course it doesn’t kill people, but it hurts like hell. There have been a few reports in the last several years suggesting that stone incidence seems to be increasing in women. It is becoming, if you will, an equal-opportunity disease.
Q: Why is the incidence increasing, and why in women?
A: Nobody knows for sure. One hypothesis, which probably is a valid one, is that the risk of kidney stones is increased by obesity, and Americans are getting fatter and fatter. Some of this data comes from renowned studies. They’ve found that weight gain and body mass index correlate directly with the increased risk of stones. As for women, a 35-pound weight gain would be associated with a 40 percent increase of stone risk in men and an 80 percent risk in women. The risk is particularly increased for a type of stone called a uric acid stone.
Q: So we’re seeing more uric acid stones?
A: There are several types of stones, the most common being calcium oxalate (草酸鈣). About 75 percent of people form calcium oxalate stones. But we see more uric acid stones in obese individuals, and we’re seeing more calcium phosphate (磷酸鈣) stones as well. The reason is unclear.
Q: Aside from obesity, what else is contributing to the increase in stones?
A: It is pretty well established that for the typical stone former, a low urinary volume is one of the most common causes of stone formation, or a risk factor for stone formation. Drink lots of fluids; anything that makes you pee is good.
Q: Do dairy products rich in calcium contribute to calcium stones?
A: Interestingly enough, epidemiologic data suggests that a healthy intake of dairy products reduces risk of kidney stones. The calcium in dairy products will bind up with oxalate, which is a byproduct of certain foods, preventing it from being absorbed into the bloodstream and then the urine. So it reduces levels of oxalate in the urine and reduces the risk of kidney stones. People with low dairy product intake have higher urinary oxalate levels. But there’s some speculation that increased consumption of calcium supplements may increase the risk of stones, and many women take these supplements to try to prevent osteoporosis.
Q: Why are high-salt diets bad for kidney stones?
A: Sodium and calcium are similar ions. Your kidneys’ job is to get rid of salt to maintain balance, but along with the sodium comes calcium too, increasing calcium in urine. They operate in parallel. You can lower your urinary calcium by lowering salt intake.
Q: Has research shown that high-protein diets raise the risk of stones?
A: Americans tend to grossly over-consume animal protein. The body doesn’t need it, so it breaks it down into uric acid and excretes it through the urine, which can increase risk of uric acid stones. Secondly, protein, especially red meat, contains sulfuric and phosphoric acids that need to be excreted. These lower your urinary pH, which also increases the risk of stones. I recommend to folks no more than 10 ounces of animal protein a day. Americans consume a lot of sucrose in soda pop, and it’s used as a sweetener in a lot of foods.
Q: Is there anything new in the management of kidney stones?
A: There are three mainstays of our treatment of kidney stones if you can’t pass them. The first is shock-wave lithotripsy (超音波碎石術), which is a noninvasive technique in which the stones are pulverized. The second treatment is ureteroscopy (輸尿管內視鏡), where we send a tiny scope (endoscope) through the urinary opening to destroy the stone. If the stone is very large, then it’s removed through surgery from the back. With those three treatment techniques, it’s rare for a person to undergo a traditional surgical procedure with large incisions.
Q: Does lithotripsy increase the risk of diabetes and hypertension?
A: A study noted an association of diabetes and hypertension in long-term follow-up of patients treated at the clinics. There was some criticism of that study. We know that shock waves produce some bruising as they pass through the body. The concern or speculation is that there could be some long-term consequence.
Q: Do you always need surgery if you have a stone?
A: If you have symptoms, like pain or blood in the urine, you want to get it removed. The question is what if you don’t have symptoms? That becomes negotiable. If you had a stone that was too large to be passable, logic dictates that sooner or later that is going to have to be treated. But if they’re small and have a high likelihood of coming through on their own, we’d usually recommend just watching and waiting. They grow little stalactites in the kidney; as long as they’re attached and don’t move around, they often don’t cause trouble.
In short, there'ree five things you need to know about kidney stones:
1. If you pass a stone, try to retrieve it. That way it can be analyzed to find out what type of stone it is. The most common type is a calcium oxalate stone, followed by calcium phosphate stones and uric acid stones. Not knowing the composition of a stone handicaps us, Dr. Curhan said.
2. Drink more fluids. Stones can be prevented if you’re willing to make changes to your diet and lifestyle. Randomized trials have found that making changes in diet can reduce your risk of a recurrence by 40 percent, and observational studies have shown an 80 percent reduction in risk. The most important thing you can do is to drink more fluids.
3. Consider dietary changes and medications. Your treatment depends on what type of stone you have and may consist of dietary changes as well as medications to change the profile of your urine. Evidence suggests that the most important changes are drinking more fluids, increasing all fruits and vegetables, and reducing salt, sugar and animal protein in your diet. If urine calcium levels are high, diuretics (利尿劑) can be used. If you have low urine citrate, potassium citrate (檸檬酸鉀) may be prescribed to help correct the pH in the urine.
4. Make sure you get a blood test and full evaluation when you have a kidney stone. Stones can be symptoms of other systemic disorders like diabetes, high blood pressure, hyper-parathyroid disease and osteoporosis.
5. Get follow-up care. Your doctor should regularly retest your urine with a 24-hour urine test to see if the dietary changes are working.
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