What is a kidney stone? | Kidney stone diagnosis | Kidney stones treatment options | Kidney stones medications | Best kidney stones medications | Side effects of kidney stones | Kidney stones home remedies | FAQ | Resources
Kidneys are among the body’s hardest-working organs. They tirelessly filter waste, minerals, and excess water from the body and keep the body’s fluids and minerals in a delicate balance. For a variety of reasons, however, sometimes the kidney can get out of balance and supersaturated minerals, salts, or other substances start to clump together into crystals commonly known as kidney stones. Fortunately, a variety of successful treatments and lifestyle changes can help expel or remove those stones and prevent them from forming again.
What is a kidney stone?
A kidney stone is a hard deposit, like a small pebble or crystal, composed of minerals or substances normally found in the urine. Most kidney stones are small and will pass out of the body through the urine. When they pass, they can cause anywhere from mild discomfort to extreme pain. Small kidney stones usually required nothing more than drinking a lot of water and taking pain relievers to expel the stone. Larger kidney stones will need to be dissolved with medications, broken up into smaller pieces using sound waves or lasers, or removed with surgery.
Kidney stones are relatively common, but their prevalence depends on location and ethnicity. In the United States, about 1 in 11 people will have a kidney stone at some point in their life.
Most people with kidney stones will pass only one stone in their lifetime with no lasting damage to the urinary tract. However, recurrent kidney stones are a serious condition that puts people at risk for chronic kidney disease and metabolic bone disease.
Symptoms of kidney stones typically are not noticeable until the stone starts to move or grows too large. In fact, oftentimes small stones pass without causing any symptoms at all. When a stone moves out of the kidney into the ureter, a tube that connects the kidneys to the bladder, it can cause pain in the side and back ribs that ranges from discomfort to severe shooting pain. If the stone is large enough, it also can block urine flow, resulting in swelling of the kidney and decreased urination. As the stone passes through the ureter, it may cut the tissues, so blood may appear in the urine.
How are kidney stones diagnosed?
Usually, it is the sharp and severe pain of a stone moving through the ureter that motivates a patient to see a healthcare professional. The healthcare provider, however, is interested in more than just getting the stone out. Kidney stones are typically a symptom, not a disease, so the healthcare provider will want to know what caused it.
A healthcare professional will ask about medical history and perform a physical examination. Imaging the stone is required for diagnosis, as it determines both the location and size of the stone. Imaging is usually done with an ultrasound or a CT scan (computed tomography). X-rays are seldom used for kidney stone diagnosis these days.
In addition, the provider will usually perform blood tests and urine tests to determine what mineral or substance is causing the stone and possibly determine an underlying cause.
Finally, when the stone passes or is removed, the physician or healthcare provider may want to have it tested to determine the cause of stone formation. Recurrent stone formation is a hazardous condition, so preventing the formation of future stones is an essential part of kidney stone treatment.
There are four types of kidney stones, each with different causes and risk factors:
- Calcium stones (calcium oxalate or calcium phosphate) represent the majority of kidney stones diagnosis. Risk factors include excess weight, a diet high in oxalate-rich foods or animal protein, dehydration, digestive diseases, and intestinal or bariatric/weight loss
- Uric acid stones occur in about 1 in 10 patients and are formed when the acid levels in the urine get too high. Risk factors include diabetes, excess weight, a diet high in meat, and chronic diarrhea.
- Struvite stones, made of magnesium, occur in about 1 in 12 patients and are due to urinary tract infection bacteria increasing ammonia in the urine that makes the urine too alkaline. Struvite stones grow very quickly and can do a lot of damage. Struvite stones have a high risk of recurrence, so preventive treatment is very common after the first stone.
- Cystine stones are due to an inherited condition in which the body filters too much cystine, an amino acid, into the urine. Cystine stones occur in about 1 in a 100 patients. The underlying condition is a medically serious one, so preventive treatment is always required after the first stone. The primary risk factor is a family history of cystine stones or the underlying medical condition.
Kidney stone treatment options
Kidney stones are nearly always a symptom of an underlying medical condition. Healthcare providers are concerned both with removing or expelling the stone and determining the condition that caused it. Treatment typically involves removing the stone and preventing its recurrence.
Passing the stone naturally
For a small stone, the treatment is to let it pass naturally through the urinary tract. The patient will be asked to drink plenty of water and take pain relievers. The healthcare professional may also prescribe medications that relax the ureter muscles, making it wider so that the stone passes more quickly.
A popular myth is that medications can “dissolve” kidney stones. That is only true for stones that are composed of uric acid. Alkalizers can neutralize the acid in the urine so the uric acid crystals become soluble and start to dissolve. Struvite stones will require antibiotics as well as drugs that reduce ammonia in the urine.
Stones that are too large to pass are usually broken up inside the kidneys or ureter using extracorporeal shock wave lithotripsy (ESWL). Using a device outside the body, high energy sound waves are directed at the stone to break it up into stone fragments small enough to pass through the urinary tract.
Not every patient is a candidate for ESWL. In those cases, the stone will be removed surgically by inserting a ureteroscope into the urethra up into the urinary tract, breaking the stone with a laser, a procedure called a ureteroscopy. For large stones, the scope will be inserted through a small incision in the back, a procedure called percutaneous nephrolithotomy (PCNL).
Patients who have passed a stone are at a high risk of forming another stone within five years. Each time a person forms a new stone, the probability of a future recurrence almost doubles. Recurrent stone formation can lead to serious consequences such as chronic kidney disease, metabolic bone disease, and end-stage renal disease. A major component of treatment is to prevent recurrence through lifestyle changes, dietary changes, and, in some cases, medication.
Kidney stone medications
Pain medications are used to manage the pain as a kidney stone passes through the urinary tract. Over-the-counter NSAIDs (ibuprofen or naproxen), or acetaminophen are usually sufficient to manage the pain. On rare occasions, a low dose of opioids including morphine or ketorolac may be used in an emergency room setting.
Alpha-blockers and calcium channel blockers
Alpha-blockers and calcium channel blockers relax smooth muscles. They are usually prescribed to relax blood vessels to lower blood pressure or prevent heart pain. For kidney stones, they are used to relax the ureter, making the ureter wider. The stone may pass more quickly with fewer symptoms. Tamsulosin, an alpha-blocker prescribed to treat prostate enlargement, is the go-to drug for stone expulsion. None of these drugs, however, are FDA-approved for treating kidney stones.
Stones formed from uric acid can be “dissolved” using medications. Uric acid is insoluble when acid levels are too high, so alkalizers along with high volumes of water can successfully dissolve 70% to 80% of uric acid stones. Urinary alkalization using citrates or sodium bicarbonate (baking soda) is the primary treatment for both managing and preventing uric acid stones.
Both uric acid and calcium oxalate stones form in urine with a high concentration of uric acid. Allopurinol reduces the body’s production of uric acid to prevent stone formation.
Diuretics increase the amount of water and salts expelled by the kidneys. Along with drinking high volumes of water, thiazide diuretics are the principal treatment for preventing calcium stones.
Chelating agents are molecules that bind to other substances in the body so that the body can expel those substances. A chelator, for instance, might attach only to calcium. The chelated calcium is then expelled with the urine. Citrates are calcium chelators and effectively prevent calcium stones. Penicillamine is a cystine chelator and is used to prevent cystine stones.
Struvite stones are caused by bacterial infections, which are highly likely to recur. Antibiotics to kill the bacteria are the first line of treatment along with acetohydroxamic acid to reduce the ammonia in the urine. Small doses of antibiotics may be prescribed long-term to prevent future infections.
What is the best medication for kidney stones?
Medication will depend on the type of kidney stone and the underlying condition that has caused stone formation. Few drugs actually treat kidney stones, but instead either aid the passing of stones or prevent their recurrence.
|Best medication for kidney stones
||2 to 3 50 mg tablets divided into 2 doses daily
||Abdominal pain, constipation, diarrhea
||One 0.4 mg capsule taken 1/2 hour after the same meal daily
||Headache, dizziness, nasal swelling
|Calcium channel blocker
||One 10 mg capsule 3 times per day
||Dizziness, flushing, headache
|Urinary acid reducer
||Two 15 mEq tablets per day
||Abdominal discomfort, nausea, vomiting
|Xanthine oxidase inhibitor
||One 300 mg tablet per day
||Skin rash, allergic reactions, diarrhea
||One 25 mg tablet per day
||Headache, dizziness, low blood pressure
||8 250 mg capsules per day
||Abdominal pain, loss of taste, diarrhea
The standard dosages above are from the U.S. Food and Drug Administration (FDA) and the National Institute of Health (NIH). Dosage is determined by your healthcare provider based on your medical condition, response to treatment, age, and weight. Other possible side effects exist.
What are the common side effects of kidney stone medications?
Different classes of medications have different side effects. However, this is not a complete list, and you should consult with a healthcare professional for possible side effects and drug interactions based on your specific situation.
Both over-the-counter and prescription NSAIDs typically cause gastrointestinal problems such as abdominal pain, nausea, and even gastrointestinal bleeding.
Alpha-blockers and calcium channel blockers
Alpha-blockers and calcium-channel blockers are most often used to lower blood pressure, so low blood pressure is a common side effect when they’re used for kidney stones. Patients with low blood pressure (hypotension) might not be suitable for a prescription. There is an increased risk for falls particularly elderly and usually increased hydration is recommended.
Urinary alkalizers are relatively safe and have only minimal side effects, such as minor stomach or intestinal complaints.
Allopurinol has few side effects, mainly rash and allergic reactions, which might be severe enough to require hospitalization.
Diuretics increase the amount of water and salts the body expels, so dehydration symptoms are a frequent side effect.
Penicillamine has a high incidence of side effects, some of which can be severe. The most common side effects are abdominal complaints and loss of taste.
Antibiotics are generally safe. Side effects tend to be minimal and are primarily gastrointestinal problems such as nausea, stomach cramping, and bloating.
What are the best home remedies for kidney stones?
Home remedies not only are a good idea, they are essential to passing or preventing kidney stones.
The most essential treatment for both passing and preventing kidney stones is drinking a lot of water. Passing a lot of water through the urinary tract is the only way to pass a kidney stone, and it is a highly effective way to prevent kidney stones.
Eat diuretic foods
If you’re not prescribed a diuretic to pass a kidney stone, consider eating a diet heavy in diuretic foods such as celery, asparagus, parsley, cranberries, or watermelon.
Avoid certain foods
An oxalate-rich diet contributes to the formation of calcium oxalate kidney stones. To prevent kidney stones, avoid foods rich in oxalates such as spinach, potatoes, nuts, beets, rhubarb, and bran. You should also reduce your intake of salt and animal proteins.
Don’t overdo calcium supplements
Even though calcium stones are the most common type of kidney stone, it is not true that reducing calcium intake will help pass or prevent kidney stones. On the contrary, a diet low in calcium may cause kidney stones. But don’t overdo the calcium. High calcium in the body can cause problems much more serious than kidney stones, so only take calcium supplements if your healthcare provider advises you to. Usually 1000-1200 mg elemental calcium intake a day is recommended.
Frequently asked questions about kidney stones
What are the first signs of kidney stones?
Pain in the back or sides is usually the first sign. The pain may be moderate and build over time, or it might be a severe, sharp pain that comes on without any warning.
Can an ultrasound miss kidney stones?
And ultrasound can miss kidney stones, particularly if they have moved into the ureter. The more accurate and preferred imaging test is a non-contrast computed tomography scan, or NCCT.
Which is the best medicine for kidney stones?
There is no best medicine for kidney stones. Small kidney stones will pass out of the body without medical intervention. Medicines can help relieve the pain or speed up the process of passing kidney stones. Some stones will be treated with drugs specific to that type of kidney stone. Large stones, however, will need to be broken up into small pieces through shock waves or laser lithotripsy or be surgically removed.
How can I get immediate relief from kidney stones?
Pain medication can help manage the pain of passing a kidney stone. Passing a small kidney stone usually can take anywhere from two days to several weeks. Immediate relief will occur once the stone has passed out of the urinary tract. The process can be helped along by drinking a lot of water.
How long does it take to recover from kidney stones?
Recovery depends on the type of stone and how it was removed. For a small stone, patients will feel relief as soon as it has passed out of the urinary tract. For larger stones, recovery from surgery might take a few days or weeks. However, kidney stones are usually a symptom of a larger medical problem, so treatment of that underlying condition may take months or years to resolve.
How do you dissolve kidney stones?
It is a myth that kidney stones can be “dissolved.” Of the four types of kidney stones, only uric acid stones can be successfully “dissolved” with medications. Uric acid stones represent about 1 in 10 kidney stone cases.
What size kidney stones require surgery?
Stones that are less than 5 mm in diameter can usually be passed without invasive surgery. Larger stones will require shock wave lithotripsy or ureteroscopy. Stones larger than 2 centimeters or complex stones in the kidney will require percutaneous nephrolithotomy. However, the urologist will consider factors other than just stone size when deciding on surgery, such as kidney health, obstruction of the flow of urine, the rate of stone growth, infection, symptoms, other illness, and patient needs.
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