Kidney Stones (Nephrolithiasis) Symptoms, Causes, Treatment
- What are Kidney Stones?
- Kidney stones causes
- Risk factors
- Kidney stones symptoms
- Treatment
- Diagnosis
- Diet
Some Facts About Kidney Stones
- Most kidney stones pass out of the body without any intervention.
- Stones occur more frequently in men.
- While all humans form calcium oxalate crystals, most do not form stones.
- Once a person gets more than one stone, other stones are likely to develop.
- Caucasians are more prone to develop kidney stones than African Americans.
Kidney stones are one of the most common disorders of the urinary tract. Kidney stones (renal lithiasis) are small, hard deposits of mineral and acid salts on the inner surfaces of the kidneys. Normally, the substances that make up kidney stones are diluted in the urine. When urine is concentrated, though, minerals may crystallize, stick together and solidify. The result is a kidney stone.
Kidney stones are usually painless when in the kidney but can cause severe pain as they travel from the kidneys to the bladder. An attack of this pain is called renal or uteric colic.
Painful as they are, kidney stones usually cause no permanent damage.
In most people the underlying cause isn't known. Some people with kidney stones have lower levels of citrate in their urine, which usually stops the stones forming.
The chemical composition of stones depends on the chemical imbalance in the urine. The four most common types of stones are comprised of calcium, uric acid, struvite, and cystine.
- Calcium stones. Calcium stones are the most common type. Approximately 85% of stones are composed predominantly of calcium compounds (calcium oxalate or calcium phosphate). The most common cause of calcium stone production is excess calcium in the urine (hypercalciuria). Calcium stones are more common in people who have excess levels of vitamin D or who have an overactive parathyroid gland.
- Uric acid. Approximately 10% of patients with kidney stone disease develop this type of stone. Digestion produces uric acid. Excess amounts of uric acid can be caused by eating a lot of meat. If the acid level in the urine is high or too much acid is excreted, the uric acid may not dissolve and uric acid stones may form. Genetics may play a role in the development of uric acid stones, which are more common in men.
- Struvite stones. Struvite stones (infection stones) develop when a urinary tract infection affects the chemical balance of the urine. Bacteria in the urinary tract release chemicals that neutralize acid in the urine, which enables bacteria to grow more quickly and promotes struvite stone development. Struvite stones are more common in women because they have urinary tract infections more often. The stones usually develop as jagged structures called "staghorns" and can grow to be quite large.
- Cystine stones. Cystine is an amino acid in protein that does not dissolve well. Some people inherit a rare, congenital (i.e., present at birth) condition that results in large amounts of cystine in the urine. This condition (called cystinuria) causes cystine stones that are difficult to treat and requires life-long therapy. Only one in a hundred kidney stones are caused by this condition. Cystine stones tend to develop earlier in life than other kidney stones, usually between the ages of 10 and 30 years.
Several factors increase the risk for developing kidney stones, including:
- Inadequate fluid intake and dehydration
- Reduced urinary flow and volume
- Certain chemical levels in the urine that are too high (e.g., calcium, oxalate, uric acid) or too low (e.g., citrate)
- Anything that blocks or reduces the flow of urine (e.g., urinary obstruction, genetic abnormality)
- Family history of kidney stones
- Being aged between 20 and 40
- High-protein, high-sodium and low-calcium diet
- High blood pressure doubles the risk of forming kidney stones.
- Taking certain medicines such as diuretics (water tablets), antacids and thyroid medications
- Having only one kidney, or an abnormally shaped kidney
- Disease of the small intestine or a small intestinal bypass
Medications that may cause Kidney Stones as a side effect:
| Drug | Incidence |
|---|---|
| Abilify Tablets | 1% or less |
| Aceon Tablets (2 mg, 4 mg, 8 mg) | 0.3% to 1% |
| Aciphex Tablets | |
| Axid Oral Solution | |
| Bextra Tablets | Rare |
| Caduet Tablets | Less than 2% |
| Celebrex Capsules | 0.1% to 1.9% |
| Celexa | Rare |
| Cipro I.V. Pharmacy Bulk Package | Less than 1% |
| Cipro I.V. | 1% or less |
| Cipro XR Tablets | |
| Cipro | |
| Clinoril Tablets | |
| Copaxone for Injection | Infrequent |
| Crixivan Capsules | 8.7% to 12.4% |
| Daranide Tablets | |
| Dyazide Capsules | |
| Dyrenium Capsules | Rare |
| Effexor Tablets | Infrequent |
| Effexor XR Capsules | Infrequent |
| Evoxac Capsules | Less than 1% |
| Exelon Capsules | Infrequent |
| Exelon Oral Solution | Infrequent |
| Fortovase Capsules | Rare |
| HIVID Tablets | Less than 1% |
| Humira Injection | Less than 5% |
| Imitrex Injection | Rare |
| Imitrex Nasal Spray | |
| Imitrex Tablets | |
| Kaletra | Less than 2% |
| Lexapro Oral Solution | Infrequent |
| Lexapro Tablets | Infrequent |
| Lipitor Tablets | Less than 2% |
| Maxzide | |
| Miacalcin Nasal Spray | Less than 1% |
| Neurontin Capsules, Oral Solution, Tablets | Rare |
| Nipent for Injection | Less than 3% |
| Norvir | Less than 2% |
| Paxil CR Controlled-Release Tablets | Rare |
| Paxil | Rare |
| Permax Tablets | Infrequent |
| Prevacid Delayed-Release Capsules | Less than 1% |
| Prevacid NapraPAC | Less than 1% |
| Prevacid SoluTab Delayed-Release Orally Disintegrating Tablets | Less than 1% |
| Prevacid for Delayed-Release Oral Suspension | Less than 1% |
| Prevpac | Less than 1% |
| Protonix I.V. | Less than 1% |
| Protonix Tablets | Less than 1% |
| Relafen Tablets | Less than 1% |
| Remicade for I.V. Injection | Greater than or equal to 0.2% |
| Reminyl | Infrequent |
| Requip Tablets | Infrequent |
| Rescriptor Tablets | |
| Reyataz Capsules | Less than 3% |
| Rilutek Tablets | Infrequent |
| Rocephin Injectable Vials, ADD-Vantage, Galaxy, Bulk | |
| Sandostatin Injection | Less than 1% |
| Sandostatin LAR Depot | 5% to 15% |
| Sonata Capsules | Infrequent |
| Sustiva Capsules | Up to 1% |
| Symbyax Capsules | Rare |
| Tasmar Tablets | Infrequent |
| Teveten HCT Tablets | Less than 1% |
| Teveten Tablets | Less than 1% |
| Topamax Sprinkle Capsules | Frequent |
| Topamax Tablets | Frequent |
| Tricor Tablets | |
| Trileptal Oral Suspension | |
| Trileptal Tablets | |
| Uniretic Tablets | Less than 1% |
| Viracept | Less than 2% |
| Zonegran Capsules | Rare |
Kidney stones often do not cause any symptoms. However, if a kidney stone causes a blockage, or moves into the ureter, it may cause some of the following symptoms:
- Severe pain or aching in the back on one or both sides
- Sudden spasms of excruciating pain (renal or uteric colic) - this usually starts in the back below the ribs, before radiating around the abdomen, and sometimes to the groin and genitalia
- Bloody, cloudy or smelly urine
- Frequent urge to urinate
- Burning sensation during urination
- Fever and chills
A small stone (usually 4 mm in diameter or less) has a 90% chance of spontaneous passage. Stones that are 8 mm in diameter or larger usually require medical intervention.
Kidney stones can pass through the urinary system with plenty of water - 2 to 3 quarts a day - and staying physically active to help move the stone along. Doctor may prescribe paracetamol or codeine to reduce the pain. Doctor also usually asks the patient to save the passed stone(s) for testing. It can be caught in a cup or tea strainer used only for this purpose.
Stones that can't be treated with more-conservative measures — either because they're too large to pass on their own or because they cause bleeding, kidney damage or ongoing urinary tract infections — may need professional treatment:
- Ureteroscope or endoscope removal – some kidney stones can be removed using an instrument inserted into the urethra (where urine empties from the bladder) and through the bladder to where the stone is located.
- Percutaneous nephrolithotomy – a small cut is made in the back and a special instrument is used to remove the kidney stone.
- Extracorporeal shock-wave lithotripsy (ESWL) – ultrasound waves are used to break the kidney stone into smaller pieces, which can pass out with the urine. It is used for stones less than 2 cm in size.
How are Kidney Stones diagnosed?
Doctors can usually diagnose kidney stones by asking about the symptoms and examining. Tests may be done to confirm the diagnosis and to reveal the size, location and type of stone:
- Blood tests - to identify excess amounts of certain chemicals related to the formation of stones
- Urine analysiss - to look for signs of infection
- Abdominal X-ray - can visualize most kidney stones and can help to judge changes in the size of a stone over time.
- Intravenous urogram (IVU) - this involves an injection of a special dye that shows up the whole urinary system on X-ray images, revealing stones that can't usually be seen
- Ultrasound scan - this diagnostic technique combines high-frequency radio waves and computer processing to view internal organs. It's safe, painless and noninvasive, but it may miss small stones, especially if they're located in a ureter or bladder.
- Computerized tomography (CT) scan - this imaging test has become the standard of care for evaluating acute kidney stones. It's rapidly performed, can identify stones regardless of composition and doesn't require the use of contrast dye. It is thought to be the most accurate diagnostic test.
Diet plays an important role in the development of kidney stones, especially in persons who are predisposed to the condition. A diet high in sodium, fats, meat, and sugar, and low in fiber, vegetable protein, and unrefined carbohydrates increases the risk for renal stone disease. Recurrent kidney stones may form in patients who are sensitive to the chemical byproducts of animal protein and who consume large amounts of meat. High doses of vitamin C (i.e., more than 500 mg per day) can result in high levels of oxalate in the urine (hyperoxaluria) and increase the risk for kidney stones.
A simple and most important lifestyle change to prevent stones is to drink more liquids - water is best. Someone who tends to form stones should try to drink enough liquids throughout the day to produce at least 2 quarts of urine in every 24-hour period.
In the past, people who form calcium stones were told to avoid dairy products and other foods with high calcium content. Recent studies have shown that foods high in calcium, including dairy products, may help prevent calcium stones.
High-oxalate foods - higher to lower:
- rhubarb
- spinach
- beets
- swiss chard
- wheat germ
- soybean crackers
- peanuts
- okra
- chocolate
- black Indian tea
- sweet potatoes
Medium-oxalate foods - higher to lower:
- grits
- grapes
- celery
- green pepper
- red raspberries
- fruit cake
- strawberries
- marmalade
- liver
More information about Kidney Stones:
Sources & References
- 1. National Kidney and Urologic Diseases Information Clearinghouse Kidney Stones in Adults
- 2. Mayo Foundation Kidney stones
- 3. UrologyChannel Kidney
Stones