The 4 Stages of Passing a Kidney Stone
Here’s what passing kidney stones feels like and what you can do to help things along
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Medically reviewed by Matthew Wosnitzer, MD
There are four stages of passing a kidney stone: The stone forms, leaves the kidney, reaches the bladder and causes pressure, and finally, exits the body.
Sometimes, a kidney stone will pass on its own, but this can be very painful. There are also times when you may need to seek medical care for help passing a kidney stone.
This article will cover the stages of passing a kidney stone, as well as what to know about the symptoms at each stage and when to seek medical attention.
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What Are Kidney Stones?
Your kidneys remove fluid and waste from your body. If you have too much salt, minerals, or chemicals in your body and not enough urine, the extra material can form crystals in your kidneys.
Other particles may attach to the crystals and form a hard object (a “stone”) that your body may try to pass.
Kidney stones are categorized by the main material they’re made from. The most common are calcium (oxalate), uric acid, and cystine stones. Struvite stones are made of magnesium ammonium phosphate and are often associated with a urinary tract infection (UTI). These stones can get large quickly.
How Common Are Kidney Stones?
About 1 out of every 10 people in the United States will have a kidney stone at some point in their life. They are more common in men than women. They also seem to be more common in white people than people of other races.
Stages of Passing a Kidney Stone
The development and natural passing of kidney stones can be broken down into four stages.
1) Kidney Stone Formation
Kidney stones can form if urine becomes concentrated because there is not enough water in the body. This allows crystals to form and attract other materials.
The creation of a kidney stone is not painful.
2) The Stone Leaves Kidney
The second stage of passing a kidney stone is when the stone has entered the tube that connects your kidneys to your bladder (ureter).
Pain can come in waves as the ureter spasms to try to pass the stone. The stone can get stuck at the junction of ureter and renal pelvis (ureteropelvic junction) or in the ureter itself, or near the junction of the ureter and the bladder (ureterovesical junction)
3) Bladder Pressure Builds
When the stone reaches the bladder, the pressure builds up in the organ. At this stage of passing a kidney stone, you will feel an urgent need to urinate frequently. Typically, the majority of intense pain is improved or resolved once the stone exits the ureter
4) The Kidney Stone Exits the Body
When you urinate, the kidney stone can be pushed out of the bladder and passed out of your body via the urethra. There is usually little or no pain during the last stage.
How Long Does It Take to Pass a Kidney Stone?
How long it takes to pass a kidney stone depends on how big it is. A stone less than 4 millimeters (mm) can pass in a week or two. Larger stones can take up to four to six weeks to pass.
What Does Passing a Kidney Stone Feel Like?
Most people associate the pain of passing a kidney stone with stage 4, or when it actually exits the body. But pain is most associated with stage 2 (when it leaves the kidney).
If the stone is small enough, it can go through all of the stages without you even realizing it. In other cases, the pain of passing a kidney stone can be severe. Some rank it as being worse than giving birth.
You may experience the following symptoms of larger kidney stones:
Severe back, side, or abdominal pain (often on one side) that may come on suddenly
Pain that comes in waves several times an hour
Urgent need to urinate
Pain when you urinate
Blood in your urine
Nausea or vomiting
Fever and chills (This may be caused by a urinary tract infection, which is dangerous if it occurs at the same time as passing a kidney stone and warrants immediate medical attention.)
When kidney stones move in your body, they can cause intense pain that almost feels like someone is jabbing you with a knife.
What Do Kidney Stones Look Like When They Pass?
Kidney stones are pebble-like objects that vary in size. They can be as small as a grain of sand to as large as a ping-pong ball. Kidney stones can be smooth or have jagged sharp edges, and are usually yellow or brown.
When to Call a Healthcare Provider
If you have extreme pain, a fever, or are vomiting while passing a kidney stone, seek medical care right away.
Kidney stones can lead to infections that need to be treated. If you’re not sure what to do, call your provider. They may have you go to urgent care or the emergency room.
What Helps Kidney Stones Pass Quickly?
If you have a kidney stone, you might be able to pass it on your own. There are a few things you can do to help the process along:
Stay hydrated. Drinking plenty of water or another hydrating fluid to help flush out a kidney stone is one of the most important things you can do.
Avoid irritating drinks. Try to reduce how much coffee, tea, alcohol, and soda you drink while you’re trying to pass a kidney stone. Focus on drinking water. If you don’t like drinking plain water, try adding a little lemon. It contains citrate, a natural chemical that might help dissolve a stone.
Think about your diet. Try not to snack on salty foods or add salt to your meals, as a high-sodium diet can be a risk factor for kidney stones. You also don’t want to eat too much protein, since it can also raise your risk. While kidney stones can form from calcium and oxalates, you don’t want to cut these nutrients out of your diet. You just want to be mindful of how much you consume.
Get moving. If you’re in a lot of pain you might not want to move, but walking around can actually help the stone pass faster.
To help ease discomfort as you wait for a stone to fully pass:
Use heat. A heating pad can help ease the pain of passing a kidney stone. Soaking in a warm bathtub might also be helpful.
Take OTC painkillers. An over-the-counter pain reliever like Motrin (ibuprofen) may help with pain and inflammation. However, if you have severe kidney stone pain OTC pain medications may not be enough.
You may have some discomfort after you’ve passed the stone. If these at-home remedies do not help, call your provider.
How Can I Force a Kidney Stone to Pass at Home?
You can't reliably force a kidney stone to pass, but drinking plenty of water is the best way to encourage one to move through your system.
If You Cannot Pass a Kidney Stone at Home
If you end up calling your provider or going to the ER because you have a kidney stone that’s not passing, there are a few things they may try.
Sometimes, your provider might prescribe you a medication called Flomax (tamsulosin) to help pass a large kidney stone. However, research is not clear on whether the medication is always helpful for this purpose.
You might need to have a surgical procedure called shock wave lithotripsy that uses sound waves to break the stone up into smaller pieces, making it easier to pass. Surgeons can also use a special camera called ureteroscope (a narrow tube with a camera at the end) to get to the stone in the ureter or kidney and break it up using laser. You will be sedated during the procedure, so you won’t feel any pain or discomfort.
Surgeons can also use an endoscope (a narrow tube with a camera at the end) to get to the stone and break it up. You will be sedated during the procedure, so you won’t feel any pain or discomfort.
After the stone is taken out, it will go to a lab to see what it was made of. This can help you figure out if there are any steps you can take to reduce your chances of getting more kidney stones.
Related: Kidney Stone Surgery: Everything You Need to Know
Can You Prevent Kidney Stones?
You can’t always prevent kidney stones. For example, if you already have kidney disease, you may not be able to avoid them.
You might also need to be on certain medications that can lead to the formation of kidney stones, including diuretics (which increase calcium excretion in the urine) and antacids (which can have stone-forming minerals in them).
But whether these apply to you or not, it's always worth taking steps to try to prevent kidney stones from occurring, including:
Stay hydrated. Making sure you don’t get dehydrated is important if you’re prone to getting kidney stones.
Watch your diet. Be aware of the foods you eat often and try to limit those high in protein, salt, and processed sugar. Eating citrus fruits is beneficial for preventing kidney stones.
Can Cranberry Juice Help Prevent Kidney Stones?
Research suggests that whether cranberry juice and cranberry extract supplements could help prevent kidney stones depends on the type of kidney stones you get. For example, if you get oxalate stones, drinking cranberry juice could actually make kidney stones more likely to form since it’s high in oxalates. However, other studies have shown the opposite.
Related: How to Prevent Kidney Stones
Summary
There are four stages of passing a kidney stone: formation, moving into the ureter, reaching the bladder, and exiting the body in urine.
Kidney stones can be very painful, but once the stone passes you should feel much better. While you might be able to pass a kidney stone on your own at home, if you’re in extreme pain and have a fever, you should seek medical care.
If you can’t pass a kidney stone on your own, you might need to have it broken up or taken out surgically.
Related: Kidney Pain
