How Long Do Kidney Stones Last? Must Know

How long do kidney stones last is probably one of the questions you are asking after knowing you have them. Kidney stones are common and affect millions of Americans, with small stones passing on their own in 1-2 weeks while larger stones need medical intervention. Most people can prevent kidney stones (also known as renal calculi or nephrolithiasis) through adequate hydration, dietary modifications, and regular medical follow-up when necessary. About 1 of 11 Americans will experience kidney stones in their lifetime. The knowledge of which is beneficial for maintaining optimal health.

In this post, you will understand different passage times, recognize the associated symptoms, and follow prevention strategies that will help you effectively manage this common but painful condition.

Key Takeaways

• Small kidney stones less than 4mm may pass naturally in 1-2 weeks in 80% of the time

• Medium stones 4-6mm could take up to 6 weeks, with 60% passing without treatment

• Large stones over 6mm often require medical intervention and rarely pass naturally

• Dehydration is the leading cause, making summer months peak season for kidney stones

• Calcium oxalate stones make up 80% of all kidney stones treated in the United States

• About 1 in 11 Americans will experience kidney stones during their lifetime

• Pain comes in waves and is often described as one of the most severe types humans experience

• Staying hydrated with 2-3 liters of water daily significantly speeds stone passage

What Are Kidney Stones?

Kidney stones are hard mineral deposits that form inside the kidney. These are crystalline structures that develop when your urine contains more crystal-forming substances than the fluid you are taking to dilute it.

About 1 in 11 Americans experience kidney stones in their lifetime. Over the past 30 years, the number of people with kidney stones have been reported to be increasing. It was estimated to be at 3.2% only between the time period of 1976 to 1980 but it rose to 8.8% in 2014 alone. Men are 11% higher risk of developing kidney stones than women with 9% risk.

Kidney stones vary considerably when it comes to size. Some are smaller than sand, tiny grains, and the size of golf balls. These form when minerals get concentrated in your urine, such as:

• Calcium

• Oxalate

• Uric acid

Your kidneys normally filter waste and excess water to create urine. But when your urine becomes too concentrated with substances, crystals can form and stick together.

Most kidney stones are composed of calcium, about 80%, which combines with oxalate or phosphate. Uric acid stones make up about 5-10% of all kidney stones, which tend to develop in people who are undergoing chemotherapy or those suffering from gouty arthritis.

What Causes Kidney Stones?

Kidney stones develop if your urine becomes concentrated with stone-forming crystals. There are several factors that contribute to this formation.

• Dehydration is the most common cause among Americans, especially during summer when the temperature rises

• Usual American diet, which plays a significant role in kidney stone formation.

High sodium (salt) intake can increase calcium excretion in the urine. Excessive protein consumption through meat can increase uric acid levels. This type of dietary pattern in addition to inadequate fluid intake creates an ideal condition for stone formation.

• Genetics also play a role in kidney stone formation.

If your family history is positive for kidney stones, you are more likely to develop it than if you don’t have it.

• Underlying medical conditions like hyperparathyroidism, recurrent urinary tract infections, and digestive diseases can all affect calcium absorption.

Dehydration and Kidney Stones

Dehydration concentrates stone-forming substances in your urine. When you don’t drink enough fluid, your kidneys produce less urine. So it becomes more concentrated with crystals that can crystallize.

It is recommended to drink at least 2.7 liters and 3.7 liters of water a day for women and men, respectively. This includes water from all food sources and beverages consumed. People living in hot climates, who engage in vigorous exercise, or working outdoors need additional fluids.

Your urine color offers the most basic information of your hydration status. Pale yellow roughly indicates a good hydration status, while dark yellow suggests you need to drink more fluids. Transparent or clear urine means you’re drinking too much water.

Hot weather increases the risk for dehydration. The “kidney stone belt” in the United States includes the southeastern states with hot, humid climates, which reports the highest stone incidence.

Dietary Factors in Kidney Stone Formation

Certain foods increase the risk of kidney stone formation by increasing the mineral concentration in the urine.

• Foods that are rich in oxalate, which can contribute to the formation of calcium oxalates, include:

• Spinach

• Nuts

• Chocolate

• Tea

• Sodium can increase calcium excretion in the urine. The recommended daily intake for sodium is only 2.3 grams per day. Processed foods, restaurant foods, and packaged snacks tend to have more salt. So you might want to put this into consideration.

• Food that increases uric acid levels, include:

• Animal meat

• Poultry

• Fish

• Protective foods that help prevent stone formation, include:

• Citrate-rich foods  naturally prevents stone formation as it binds calcium

• Lemons

• Limes

• Oranges

• Adequate calcium intake from food sources reduces stone risk by binding oxalate in the intestines. Foods like low-fat dairy food offer calcium without excess calories.

What Are the Symptoms of Kidney Stones?

The most common symptom of kidney stones is pain. It begins when the stone moves from the kidney to the ureter.

The movement triggers an intense pain that comes and goes as the ureter contracts trying to push the stone through.

The pain could be described as:

• Serious sharp pain in the flank area

• Pain that radiates to the lower abdomen and even to the groin

• Comes in waves and varies in intensity

• Burning sensation when urinating

The other symptoms are discussed in the subsequent sections.

Common Symptoms

Apart from pain, other symptoms of kidney stones may include:

• Blood in urine (hematuria), which occurs in 85% of cases

The urine can appear pink, red, or brown. But sometimes, the blood is only visible under the microscope during testing.

• Persistent nausea and vomiting

Your body naturally responds to intense pain, which often triggers nausea and vomiting. The volume lost during vomiting often worsens the dehydration, potentially slowing the passage of stone.

• Urgency and frequency in urination becomes a dominant symptom when the stone reaches the bladder.

You may feel like you need to urinate more frequently but only pass small amounts of urine. This differs significantly from the frequency brought by urinary tract infection (UTI).

Less Common Symptoms

• Cloudy or foul-smelling urine

This could indicate that there is a concomitant infection along with kidney stones. The combination of infection and foul-smelling urine requires immediate medical intervention to prevent serious complications.

• Persistent low-grade fever with or without chills

This symptom could indicate that there’s a developing infection or inflammation around the stone.

• Difficulty sitting still during stone episodes

A lot of people pace back and forth, or constantly change positions in an attempt to relieve the pain. The restlessness often distinguishes this pain with other abdominal pain.

Some kidney stones produce minimal symptoms or none at all, while the stone passes. There may be mild discomfort on the back or slight changes in urine without realizing that there’s a stone present.

How Are Kidney Stones Diagnosed?

Healthcare providers often diagnose kidney stones through a combination of:

• Medical history

• Physical examination

• Imaging tests

Primary care physicians often initiate the diagnosis. But when symptoms require immediate care, urgent care centers often handle this.

Imaging modalities used include:

• CT (computed tomography) scan without contrast offers the most accurate diagnosis for kidney stones. It can detect as small as 1mm stone and demonstrates its location and density. Most urgent care centers and emergency departments (EDs) have CT-scanning capabilities

• Ultrasound offers a non-radiation imaging option. It is especially useful for pregnant women and children. While it cannot diagnose small stones accurately, they effectively detect larger stones and demonstrate complications like kidney swelling.

• X-rays may detect calcium-containing crystals but may miss uric acid stones. The latter doesn’t show up on standard radiography.

Other tests include:

• Blood tests may be requested to check for kidney function and identify substances that may promote stone formation.

• Urinalysis can detect blood, infection, and type of crystals. A 24-hour urine collection may be recommended for people with recurring stones to analyze the level of minerals and identify strategies for prevention.

The modern-day approach to diagnosing kidney stones typically involves CT scans for a more comprehensive assessment.

How Long Does It Take to Pass a Kidney Stone?

“How long do kidney stones last” depends on a number of factors, which will be discussed in the subsequent section.

Factors Affecting Passage Time

Stone size

Size is the primary factor affecting passage time. As mentioned, small stones less than 4mm usually pass within 1-2 weeks in 80% of people. Stones between 4-6mm may take up to 6 weeks in 60% of people.

For larger stones more than 6mm, they rarely pass naturally and often require medical intervention. These stones may stay in your kidneys for months or even years without intervention. But medical intervention is required instead of waiting for it to pass.

Location

The stone’s location within the urinary tract affects the passage difficulty. Stones located within the kidneys may stay there for months without showing some symptoms. But once the stones enter the ureter, the movement becomes more predictable but will also be painful.

Individual anatomical differences

There are people with wide ureters who may pass the stones easier. Previous history of stone passage does not automatically predict future passage times.

Hydration level

Your hydration status can impact the speed of passing the stone. Well-hydrated individuals often pass stones more easily than those with concentrated urine. Staying well-hydrated may reduce the speed of stone passage. Drinking 2-3 L of water may also help flush the stones through the urinary system quicker.

Age and overall health

Younger individuals tend to pass stones more easily and quickly than older adults or those with underlying medical conditions.

Average Time for Different Stone Sizes

Small kidney stones about 1-4mm have an average passing time of about 8-12 days. Smaller stones are most likely the fastest to pass through the urine.

Large kidney stones about >5mm have an average passing time of 22 days. These stones have a lesser chance of passing out naturally and will take much longer than smaller ones. So often, medical interventions are required for these stones.

What to Expect While Passing a Kidney Stone

You can expect pain while you’re passing a kidney stone. It comes in waves that may last 20-60 minutes per wave as the ureter contracts around the stone. Between episodes, you may feel a little comfortable or may experience mild discomfort.

You should also expect pain to move and change intensity as the stone moves. The pain may start on your back or side (flank), then move toward the lower abdomen and groin as the stone makes its way through the ureter.

The pain does not necessarily correlate with passage time. Some people may experience intense pain for a few hours as the stone moves with some relief as it reaches the bladder. There are also others who may have intermittent pain or discomfort over several weeks.

You may also notice some changes in urination, such as:

• Urgency

• Frequency

• Burning sensation

What Are the Treatment Options for Kidney Stones?

The treatment approach depends on size, location, symptoms, and your overall health. Like mentioned earlier, small <4mm stones may not require any treatment, while those larger than 4mm require medical intervention.

The treatment option starts with conservative management (non-surgical approaches). These methods are less invasive, fewer complications, and work well for appropriate stone sizes.

However, surgery is likely necessary for stones that are too large, create severe symptoms, or create complications like kidney damage or infection.

Your doctor will offer multiple treatment options, such as:

• Stone composition

• Kidney function

• Previous stone history

• Personal history

The treatment goal is removal of stone, preventing complications, and reducing recurrence risk.

Non-Surgical Treatments

Increased fluid intake forms the basic foundation of non-surgical treatment. Drinking 2-3 liters of water on a daily basis can help flush the stone through your urinary system.

Some would recommend you take lemon water, which helps dissolve certain types of stone.

Alpha-blockers like tamsulosin can help relax the muscles in your ureter. This will help in making the stone passage easier and less painful. The prescription medications are commonly available in US pharmacies. It will help in reducing the passage time by several days or weeks.

There are also pain medications that can help you tolerate the process of passing the stone. These are over-the-counter medications including ibuprofen, which lessens the swelling, and acetaminophen for pain. There are also prescription pain medications, which may be necessary for severe cases.

The above non-surgical approach is best for stones that are between 4 to 10 mm in size located in the lower ureter.

Surgical Treatments

Shock wave lithotripsy (SWL)

This procedure uses sound waves to break the stones into smaller pieces, allowing it to pass naturally. It takes about 45-60 minutes to complete. The success rate for this procedure for stones smaller than 2cm is about 70-90%.

Ureteroscopy

It involves inserting a thin, flexible scope through your urethra and bladder to reach the location of the stone. The urologist will break the stone with a laser and remove it directly. Most patients can return to their usual daily activities within 5-7 days with success rates between 50-90%.

Percutaneous nephrolithotomy (PCNL)

This procedure is reserved for larger-sized kidney stones more than 2cm. The success rate of this procedure is between 75% and 98%. Most patients recover within 2-4 weeks.

Pain Management

Pain relief medications include over-the-counter meds, which can offer relief to other people.

• Ibuprofen works well because it can reduce the inflammation around the stone and ureter. You can take 400 mg every four to six hours, as needed for the pain.

• Prescription pain medications are recommended for episodes of severe pain. It includes stronger anti-inflammatory drugs or short-term narcotic pain relievers.

• Heat therapy is an additional pain relief strategy, which is done by applying a heating pad on the painful side for about 15-20 minutes at a time. Warm baths can help relax muscles and reduce the pain.

• Lifestyle remedies for pain management include light walking when possible. However, it is equally important to rest when the pain is severe and don’t force activity.

How Can I Prevent Kidney Stones?

Prevention strategies are aimed at maintaining a dilute urine and reducing substances that are stone-forming. This includes:

• Adequate hydration through increased fluid intake

• Dietary modifications

• Add citrus fruits to your diet

• Regular follow-up with your attending physician (especially for people who have multiple episodes of kidney stones)

When Should You See Your Doctor for Kidney Stones?

See your doctor when you have any of the following:

• Fever with chills

• Inability to urinate or significantly decreased urine output

• Moderately severe symptoms that may affect your daily activities

For any unusual symptoms that you may experience, you should seek your doctor for medical evaluation. Early detection is still best for immediate intervention and prevents progression or complications.

Quick Summary

• Small stones (<4mm): 1-2 weeks passage time, 80% pass naturally

• Medium stones (4-6mm): Up to 6 weeks, 60% pass naturally

• Large stones (>6mm): Up to a year, often need medical treatment

• Pain typically comes in waves and may last several hours

• Staying hydrated speeds up the process significantly

For more information, you can check out these posts:

What Is a Kidney Cleanse and Is It Necessary?

Does Alcohol Cause Kidney Stones?

Frequently Asked Questions

Can kidney stones cause permanent damage?

If left untreated, kidney stones may cause permanent kidney damage or cause infections. Seek medical attention for persistent symptoms.

Is it possible to pass a kidney stone without pain?

Small stones (<4mm) may pass painlessly, but produce discomfort before passing. Consult a doctor if unsure.

How can I tell if I have a kidney stone vs. other conditions?

Kidney stones cause sharp, radiating pain and blood in urine. A doctor can diagnose via imaging or urine tests.

Written by Jaclyn P. Leyson-Azuela, RMT, MD, MPH
Jaclyn P. Leyson-Azuela, RMT, MD, MPH, is a licensed General Practitioner and Public Health Expert. She currently serves as a physician in private practice, combining clinical care with her passion for preventive health and community wellness.

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