Saturday, March 13, 2010

About Kidney Stones

What are kidney stones?

A kidney stone is a hard gravel-like mass in the kidney, ureter tube from the kidney to the bladder or in the urethra tube that passes urine out of the body. Kidney stones are usually made of mineral salts (most commonly calcium but sometimes uric acid, the gout chemical).

What should I know and do for kidney stones?

Symptoms include:

Pain that usually begins suddenly and commonly comes in waves of intensity
Pain that is in the back or flank and seems to move to the lower abdomen, groin or legs
Dark or bloody urine
Take medication exactly as directed.
Do not drive while taking these pain medicines.
Drink at least 2-3 quarts of fluids a day (water is best) to flush out the particle(s). Reverse osmosis filtered water for drinking water has much less mineral content and might be helpful for long term use.
Strong Narcotic pain medications as well as Ibuprofen if approved by your doctor help manage pain.
Also, at a recent Urologic conference studies were presented that found Medical expulsive therapy with off label use of (non FDA approved use for kidney stones) steroids, nifedipine calcium channel blocker, Flomax (tamsulosin), (as well as considering a low dose Viagra type medication) as a potential powerful tools to reduce acute painful stones working their way down when the stones are smaller than 10mm and certainly if 3-5mm.

What should I do if I think I have kidney stones?

Strain your urine so that you can catch the stone if and when it passes. Cheesecloth works well for this, as does any porous clothing material. If you do catch the stone or little chunks of sand or gravel, take them to your doctor so it can be analyzed. Your doctor may suggest a diet change based on the type of stones you have.

You should have at least an x ray called the KUB as well as routine lab work and a urine analysis and culture with the onset of likely kidney stone. Cat scan without contrast via stone protocol is now the best study to confirm a stone and assess position size and degree of urine tube blockage. The only downside is the cost and the modestly higher radiation dose especially in those with a history of multiple stones so sometimes a simple KUB and ultrasound can be done instead.

If you are female or have more than one stone or an infection related stone a more thorough investigation including a 24 hour urine test are in order. Also, if you don’t pass a stone within 10-14 days, you should seek help from a urologist as early permanent kidney damage starts to occur when the urine tube is blocked by a stone within 14 days and if fully blocked, a kidney will become non functional by 6 weeks from onset.

Stones <4mm have greater than an 80% chance of passing on their own within the 10 day wait period. Stones 4-6mm have about a 60% chance of passing on their own. Stones 6-8mm have a 40% chance of passing and stones >8mm should be referred to an urologist immediately for removal.

To help prevent formation of kidney stones:

If you have more than one kidney stone, especially if you have a family history of stones, you are more likely to have kidney stones again. But you can take steps to help prevent them:

Exercise on a regular basis at least 3 times a week

Follow diet instructions provided by your doctor

Drink more fluids. Try to drink enough water to keep your urine clear, about 8 to 10 glasses of water per day. Slowly increase how much you drink, perhaps adding one more glass of water a day until you are drinking 8 to 10 glasses a day. This slow increase will give your body time to adjust to the extra fluids. You are drinking enough water when your urine is clear or light yellow. If it is dark yellow, you are not drinking enough fluids. If you have kidney, heart, or liver disease and have fluid restrictions, talk with your doctor before increasing how much you drink.

Change your diet. This may be helpful, but it depends on what is causing your kidney stones. Your doctor may do more tests before deciding whether changing your diet will help reduce your risk of developing another stone. The results of these tests may suggest that it could be helpful to do one or more of the following:
Increasing how much fiber you eat. Fiber includes oat bran, beans, whole wheat breads, wheat cereals, cabbage, and carrots.
Eating less beef, pork, and poultry.
Eating a moderate or high amount of calcium-rich foods, such as dairy products. Getting your recommended amounts of calcium, combined with a diet low in sodium and protein, may decrease your risk of kidney stones.7 In older people and younger women, one study indicates that eating more calcium-rich foods reduces the risk of kidney stones.8
Avoiding foods that are high in oxalate such as dark green vegetables, nuts, and chocolate.
Not adding salt when you cook or eat. Try removing the salt shaker from your table.


If you get more kidney stones despite drinking more fluids and making changes to your diet, your doctor may give you medicine to help dissolve your stones or to prevent new ones from forming. You may also receive medicine if you have a disease that increases your risk of forming kidney stones. Which medicine you take depends on the type of stone you may have.

Medicine to prevent calcium stones

About 80% of kidney stones are calcium stones.  Calcium stones that have already formed cannot be dissolved by changing your diet or taking medicines. There are medicines that may keep calcium stones from getting bigger or may prevent new calcium stones from forming:
Thiazides (such as hydrochlorothiazide, chlorthalidone).
Potassium citrate (Urocit-K).
Orthophosphate (Neutra-Phos).
Cholestyramine (Questran).

When and why should I follow up with the doctor?

If you have nausea or vomiting and can not keep fluids down.
If you develop more intense pain in the back or abdomen
If you notice blood in your urine or your urine is dark
If you have difficulty passing you urine
If you develop fever or chills

Make sure that even if your pain has subsided or that you have passed what you think was the stone that you call your doctor’s office and let your doctor know. Also, find out if any further testing for follow- up is needed. Commonly a CAT scan or an Ultrasound is performed to make sure that there is no hidden blockage of the ureter tube which may lead to painless loss of a kidney over 4-6 weeks time. Lastly depending on the type of stone, the number of stones you have or have had and the size of your stones, your doctor may want you to follow-up for a more detailed evaluation, blood work and 24 hour urine analysis for stone forming tendencies that may have a stronger genetic component and put you at increased future risk of recurrent stones and other seemingly unrelated health problems.

Note- high amounts of protein in the diet and high amounts of sodium in the diet force an increase in urinary calcium which then binds to the usually excreted urinary oxalate from dietary sources such as fruits and vegetables and can increase stone risk.

Note on pain medications containing Tylenol/acetaminophen:

Take medications as directed, never more. Realize that there is acetaminophen in most prescription pain medications, and severe or permanent liver damage can result from prolonged use and after taking higher doses than recommended of this medicine.

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