When you go to the hospital for a kidney stone, the team will confirm the stone’s location and size with imaging, manage your pain with IV medications, and then decide whether the stone can pass on its own or needs a procedure to remove it. Most small stones (under 5 to 6 mm) pass without surgery, but larger or complicated stones often require one of several minimally invasive procedures.
Diagnosis in the Emergency Room
The first step is confirming that a kidney stone is actually causing your symptoms. A non-contrast CT scan is the go-to imaging test because it’s fast, highly accurate, and reveals the stone’s size, location, and number. It can also show signs of blockage in your urinary tract. In some cases, a specialized dual-energy CT scan can detect tiny uric acid stones that might otherwise be missed. Standard abdominal X-rays are used less often because they miss small stones.
Ultrasound is an alternative, especially for pregnant women and children, since it avoids radiation exposure. It’s less precise than CT and depends heavily on the skill of the person performing it, but it can reliably detect stones and signs of obstruction.
Along with imaging, you’ll have blood drawn to check your kidney function and look for elevated calcium or uric acid levels. A urine sample screens for blood (present in 60% to 90% of kidney stone cases) and for white blood cells, which signal a possible infection. Infection behind a blocked stone is a serious complication that can escalate quickly, so catching it early changes the entire treatment plan.
Pain Management
Kidney stone pain, called renal colic, can be excruciating. In the emergency room, you’ll typically receive IV anti-inflammatory medication first, since these drugs reduce the swelling in your ureter that contributes to the pain. If that’s not enough, stronger pain relief through an IV is added. Anti-nausea medication is common too, since vomiting frequently accompanies severe stone pain. The goal is to get your pain under control quickly so the medical team can evaluate your situation and make a treatment plan.
You’ll also receive IV fluids. Traditionally, hospitals gave large volumes of saline to help “flush” the stone, but research comparing aggressive hydration (2 liters over 2 hours) to minimal hydration found no clear benefit to flooding the system. Current practice focuses more on keeping you hydrated and comfortable rather than trying to push the stone through with fluid volume alone.
When the Stone Can Pass on Its Own
If imaging shows a small stone with no signs of infection or complete blockage, the hospital will often send you home to let it pass naturally. To help the process along, you may be prescribed a medication that relaxes the muscles in your ureter, making the tube wider so the stone slides through more easily. Studies pooling data from 20 trials found this approach increased stone passage rates by about 50% compared to no medication, with success rates reaching over 95% for stones in the lower ureter.
You’ll go home with pain medication and instructions to drink plenty of water. One important task: you’ll be asked to strain your urine through a filter or mesh so you can catch the stone when it passes. Collecting the stone lets your doctor analyze its composition, which helps prevent future stones. The waiting period typically ranges from one to six weeks.
Shock Wave Lithotripsy
For stones that are too large to pass but not massive, shock wave lithotripsy is a common option. You lie on a table while a machine outside your body sends focused pressure waves through your skin to the stone, pulverizing it into small fragments that you then pass in your urine over the following days and weeks. The machine uses imaging to target the stone precisely.
This procedure usually requires only IV sedation, meaning you’re drowsy but not fully under general anesthesia (though general anesthesia is sometimes used). The surgical time is relatively short and predictable. Recovery is quick since there are no incisions. It works best for stones in the kidney or upper ureter that are moderate in size. Very hard stones or very large ones may not respond well to shock waves.
Ureteroscopy With Laser Lithotripsy
Ureteroscopy is the most versatile procedure for kidney stones and has become increasingly common. A urologist inserts a thin, flexible scope through your urethra and bladder, then up into the ureter to reach the stone directly. A laser fiber threaded through the scope breaks the stone into fragments, which are then plucked out with a tiny basket. No incisions are needed.
You’ll be under general anesthesia for this, so you’re fully asleep and won’t feel anything. Afterward, the urologist often places a temporary stent (a small tube) in your ureter to keep it open while swelling goes down. The stent is removed in a follow-up visit, usually within a week or two. Most people go home the same day.
Surgery for Large or Complex Stones
Stones larger than 2 centimeters (about the size of a nickel) typically need a procedure called percutaneous nephrolithotomy. This is the most involved option but also the most effective for big stones, with success rates that hold up regardless of stone size.
A surgeon makes a small incision in your back and creates a channel directly into the kidney. Instruments passed through this channel break up and remove the stone. Because the access point goes straight to the kidney, even very large or oddly shaped stones can be cleared in a single procedure. This one requires general anesthesia and a hospital stay of one to two days. Recovery takes longer than the other options, typically one to two weeks before returning to normal activity.
Emergency Situations
Most kidney stones are painful but not dangerous. The exceptions are stones that completely block urine flow while an infection is present. This combination can cause infected urine to back up into the kidney, leading to a rapidly worsening condition. Warning signs include fever, chills, and flank pain together. If the hospital identifies this scenario through lab work and imaging, it becomes an emergency requiring immediate drainage of the kidney, usually by placing a stent or a tube through the back into the kidney. The stone itself is dealt with later, once the infection is under control.
What Happens After You Leave
Whether your stone passed naturally or was removed with a procedure, the hospital or your urologist will typically want a follow-up visit to confirm everything cleared. If you caught the stone, it gets sent to a lab to determine its composition (calcium oxalate, uric acid, or other types), which guides long-term prevention strategies like dietary changes.
You may also be asked to do a 24-hour urine collection at home, where you save all your urine for a full day. This test measures how much of certain stone-forming minerals your body is excreting and whether you have low levels of protective substances. The results help identify the underlying metabolic reason you formed a stone in the first place.
Contact your doctor after discharge if you experience severe pain that won’t let up, fever and chills, blood in your urine, cloudy or foul-smelling urine, or a burning sensation when you urinate. These can signal a retained stone fragment, infection, or other complication that needs prompt attention.