How Long Does It Take To Pass A Kidney Stone?

Many people either know someone that has had a kidney stone or has had one themselves. It's estimated that one in ten people¹ will have a kidney stone in their lifetime, and the prevalence of kidney stones has grown substantially in recent decades. 

If you or a loved one are suffering from a kidney stone, it can be helpful to understand what they are, their symptoms, and how long it takes for them to pass. Get the answers to all of your kidney stone questions below. 

What are kidney stones?

Kidney stones are crystals of certain substances, like cystine, urate, and calcium, that collect in the kidney when there isn't enough liquid to adequately flush them out in the urine. 

If you have small crystals developing in your kidneys but have enough water in your body to flush them out without causing a blockage, you likely won't experience too much pain when they pass. If they continue to grow, on the other hand, they may create a backlog of urine in your urinary system, which can lead to excruciating pain and other symptoms.

Symptoms of kidney stones

If a kidney stone grows large enough to move around in the kidney or block urine in the ureters — the tubes that transfer urine from the kidneys to the bladder — you may experience the following symptoms:

• A burning sensation when urinating

• Sharp pain on your sides and lower back

• Fluctuating pain that radiates to the groin and lower abdomen

• Dark or cloudy urine

• Foul-smelling urine

• Nausea and vomiting

• Frequent urination

Not everyone with a kidney stone will experience every one of the above symptoms, but if you suspect you may have a kidney stone, keep a close watch on changes in your symptoms and see a doctor if they become severe.

Causes of kidney stones

Kidney stones are caused by an accumulation of salts and minerals in your kidneys. They can be caused by poor diet, being overweight, having some medical conditions, or being on certain medications.

To prevent kidney stones with lifestyle changes, you can follow a kidney-friendly diet with plenty of fruits and vegetables and get adequate physical activity. This can improve your overall health and facilitate weight loss if needed, preventing kidney stones from developing. 

You can also talk with your doctor if you believe medication changes cause your kidney stones, and they may be able to recommend a different medication to prevent more kidney stones in the future. 

You can often prevent kidney stones by drinking enough water (at least 2L a day) and staying adequately hydrated. It's also helpful to stick to water and avoid sugar-sweetened beverages that can make your symptoms worse. 

How long does it take to pass a kidney stone?

How long it takes to pass a kidney stone depends on numerous factors. Smaller stones can pass faster than larger ones, usually within one or two weeks. Larger stones may take two to three weeks to pass completely. Once a kidney stone reaches the bladder, it usually gets passed within a couple of days.

Everybody is different, and it may take some people a longer or shorter amount of time to excrete kidney stones. Men with larger prostates typically take longer to pass kidney stones than average, for example.

The size of a kidney stone

As mentioned above, the size of a kidney stone plays a role in how quickly it might get passed. Kidney stones under 4mm in diameter are typically considered small, while those larger than 4mm are categorized as large. 

You may have passed several small kidney stones the size of sand grains, but you probably wouldn't feel them pass through. Most kidney stones are the size of a small pebble or chickpea, but they can also get as large as a golf ball. 

If your kidney stones are small enough to pass on their own, you probably won't need medical treatment. If they are too large to pass, your doctor may have to use one of the treatments listed below to break up the stone for easier excretion or complete removal.

The location of the kidney stone

Kidney stones are formed in the kidneys and can get stuck in several locations to cause pain. 

Calyceal stones lodge themselves in the calyceal of the kidneys, which connect the main filtration areas of the kidney to the ureter, allowing urine to be transferred to the bladder. Renal pelvic stones sit in the middle of the kidney, above the ureteropelvic junction that connects the calyceal to the ureter. Finally, kidney stones that get stuck in the opening of the ureter are called upper ureteral stones.

The pain from kidney stones usually comes about when the stone is lodged in the urinary tract from the kidney. Stones causing blockage of a kidney may be completely painless. It's also common to feel pain when the stone moves through the urinary tract to the bladder and when it is finally excreted from the body. 

How can the process be sped up?

There are a few different ways to speed the process up for smaller stones that can resolve on their own. One of which is drinking plenty of water. 

Drinking enough water per day can prevent kidney stones from forming in the first place and help flush out small stones that have already developed. Aim to drink enough water to create clear urine unless you have another condition (heart or kidney failure) where drinking this much fluid is not recommended. 

Some people swear by drinking lemon juice or apple cider vinegar to alleviate kidney stones, but this isn't recommended for everyone. It can be helpful for certain types of stones, however. Talk with your doctor about possible remedies that can help speed the process of kidney stone excretion. 

Treatment

For larger kidney stones that cannot be excreted on their own, there are a few treatment options available, such as:

Lithotripsy

Lithotripsy, or extracorporeal shock wave lithotripsy² (ESWL), is a procedure that concentrates sound waves into your kidney. It can break up the kidney stones into smaller pieces that your body can then excrete. People who undergo ESWL often receive anesthesia, as it can produce pain locally and when the stones are excreted from the body. It can also cause bruising in the back and bloody urine, although this should be temporary. 

Alpha-blockers

You can also be given medication to help speed up excreting kidney stones. These medications are called alpha-blockers, which help the muscles in your urinary system relax. This allows kidney stones to pass through your urinary system, especially your ureter, more easily. 

Calcium channel blockers

Calcium channel blockers³ are a medication that helps the heart relax to lower blood pressure. Some institutions also recommend calcium channel blockers for helping to pass kidney stones, especially in those with kidney stones larger than 5mm and otherwise healthy. 

There is mixed evidence on the effectiveness of calcium channel blockers for this use. Still, others believe they can help prevent the need for surgery and other more invasive medical practices. 

Surgery

Surgery is an option for the very large stones that can't be excreted or if ESWL doesn't work as expected. To remove large stones, your surgeon will create a small incision in your lower back and use various instruments to extract the stone. This typically requires general anesthesia, and you will likely have to stay in the hospital for a few days to recover.

If an overactive parathyroid gland causes kidney stones, there is also a surgery that can stop your parathyroid from overproducing hormones causing kidney stones. Finally, your doctor can also remove smaller stones by using a scope inserted through your urethra. The scope is equipped with attachments that can collect and remove the stone. 

When to visit a doctor

Although medical intervention isn't necessarily needed for small kidney stones that can pass on their own, some signs may warrant medical attention, such as:

• Sharp pains on your side or lower back

• Fever and chills

• Nausea and vomiting

• Unbearable pain

• Blood in urine

• Pain when urinating

• Decrease in urine output

The above signs may indicate that a kidney stone is becoming infected, which can lead to more complications down the line. They can also be signs of other conditions resulting in kidney failure. When in doubt, it doesn't hurt to contact your doctor if you are worried about your symptoms. 

The lowdown

Kidney stones can be a painful condition, and they can take a few weeks to pass on their own until your body can excrete them. Keeping yourself adequately hydrated throughout the day can prevent kidney stones from developing and help you pass them more quickly.

However, when other medical interventions are needed, it's best to speak with your doctor sooner rather than later.