Staghorn Calculus

A staghorn calculus, a type of kidney stone with branches, happens in some cases because of repeated infections. The branches can block urine from leaving the kidney, causing kidney failure.


What is a staghorn calculus?

A staghorn calculus is a type of kidney stone. (Calculus in this case means a stone. The plural is calculi or stones.) A staghorn calculus is the name given to a branching kidney stone, and may form if you have repeated urinary tract infections (UTIs). If they form because of infections, they may be made of struvite which is a mix of magnesium, phosphate and ammonium. If they’re the result of a smaller stone growing larger over time, then staghorn calculi are often composed of calcium phosphate, calcium oxalate or a mix of calcium carbonate apatite along with struvite.

The name staghorn refers to the shape of this type of stone, which has branches like a piece of coral or the antlers on a deer. The way that these stone branches grow can block the pelvis and the calyces of your kidney. This can lead to kidney failure. The renal pelvis and calyces are the names of the drainage system for urine (pee) within your kidney. Usually, a staghorn stone is only in one kidney, but it can happen in both kidneys.


Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy

Who is likely to have a staghorn calculus?

Some people are more likely than others to develop staghorn calculi, including:

  • People assigned female at birth.
  • People who’ve had many UTIs.
  • People with a urinary tract that isn’t typical or has a different shape or drainage.
  • People with spinal cord injuries.
  • People with neurogenic bladder.

How does staghorn calculus affect my body?

Staghorn stones can cause complete or partial blockages in your kidneys. The branches of a staghorn stone grow into the renal pelvis, the funnel-shaped structure that collects pee and passes it down the two thin tubes of muscles called ureters. Pee travels from the ureters to the bladder, where it’s stored. If your renal pelvis or ureter is blocked, this can lead to swelling in your kidney.

The staghorn stone can block your calyces, the places in your kidney where urine collection first begins. If the calyces swell because of excess fluid, you can develop caliectasis, which could lead to kidney failure if it’s not treated.


Symptoms and Causes

What are the symptoms of a staghorn calculus?

If you have a staghorn calculus in your kidney, you may:

  • Have a fever.
  • Have a pain on your side between your ribs and your hip.
  • Have blood in your urine (hematuria).
  • Have pus in your urine (pyuria).
  • Be very tired.

What causes a staghorn calculus?

Repeated urinary tract infections can cause staghorn stones, especially when the bacteria that cause the infections produce an enzyme called urease. One of these germs is Proteus mirabilis. This causes the pH of your urine to become less acidic. In turn, crystals can form and lead to a kidney stone. Other causes include:

  • Atypical anatomy that lends itself to stone formation.
  • Blockages in the urinary tract.
  • Long-term use of a urinary catheter.
  • Having had an earlier urinary diversion procedure.
  • Having neurogenic bladder.
  • Long-term untreated kidney stones.

Diagnosis and Tests

How is a staghorn calculus diagnosed?

Your provider may order an X-ray of your kidneys. They can see a staghorn calculus on an X-ray because it’s radiopaque. Radiopaque is a term that means that an object shows up on an X-ray.

Your provider may also order a computed tomography (CT) scan when dealing with a staghorn stone.

Management and Treatment

How is a staghorn calculus treated?

Treating a staghorn calculus usually means surgery. The entire stone, even small pieces, must be removed so they can’t lead to infection or the formation of new stones.

One way to remove staghorn stones is with a percutaneous nephrolithotomy (PCNL). Other treatments include types of lithotripsy, such as holmium or thulium fiber laser lithotripsy.

Percutaneous nephrolithotomy for treating a staghorn calculus

PCNL is a treatment to remove kidney stones that are too large to pass on their own. The surgeon makes a small cut into your back to reach the kidney. A small temporary tube is placed through the cut so that instruments can be brought into the kidney to break up and remove the stone. They use an instrument called a nephroscope, which is special type of camera, to find the stone and take it out.

You’ll get general anesthesia for the operation and may remain one or two days in the hospital. In some cases, your surgeon will leave a small tube in your back for a few days while your kidney heals. But most of the time, they’ll place a ureteral stent — a small internal tube.

Ureteral stent

You may hear about a tubeless surgery. This is a PCNL where you won’t have a drainage tube in your back. You may still have an internal tube called a stent. A ureteral stent is a temporary, small plastic tube that is placed in your ureter and that helps drain urine from your kidney into your bladder. A stent may be placed to help unblock your kidney if a stone or obstruction is present but it also helps the ureter stay open after surgery.

Ureteroscopy for treating a staghorn calculus

A ureteroscopy is a procedure that your provider can do through the ureters, or the tubes that connect the kidney to the bladder. These procedures also use tiny instruments. Another name for ureteroscopy is an ureterorenoscopy. You may hear them called URS or U-scope.

A specific type is flexible ureteroscopy, also called retrograde intrarenal surgery. Your provider can do the procedure without any incisions by passing the instruments through your urethra and to the kidney.

Combination therapy for treating a staghorn calculus

A common complication to all therapies is that treatments aren’t always 100% effective and that there may be small fragments of stone left over. Most of the treatments may involve some blood loss. Your provider may prescribe antibiotics and provide pain relievers after the procedure. There is also a risk of infection because urine is not sterile or clean.


How can I reduce my risk of a staghorn calculus developing after treatment?

You may be able to stop a stone from reforming if you:

  • Follow specific diet recommendations.
  • Take acetohydroxamic acid, a urease inhibitor (this is rare).
  • Take antibiotics to prevent infections.

Outlook / Prognosis

What can I expect if I have a staghorn calculus?

If you have a staghorn stone that is treated, you may develop another stone, or you may not. You should be able to pee normally. Your pain will be relieved.

If you have a staghorn stone that isn’t treated, you may develop other conditions, such as:

  • Xanthogranulomatous pyelonephritis: A kidney infection that can cause sepsis.
  • Caliectasis: Swelling in the calyces of the kidney due to fluid retention.
  • Renal failure: The kidneys become unable to filter out toxins. This can be fatal.
  • Urosepsis: A severe urinary tract infection. This can be fatal.

However, some people who aren’t able to have a surgical procedure are able to do well enough with nonsurgical treatment, called conservative management. You can live with a staghorn calculus with regular doctor’s visits.

How long does it take to recover from treatment for staghorn calculi?

The recovery varies depending on the type of treatment. Any type of open surgery will require a longer period of recovery. Some of the minimally invasive techniques will let you go home the same day. Your provider will let you know when you can go back to work or school and when you can lift heavy objects.

Living With

When should I contact my healthcare provider?

Call your provider or seek medical help after your treatment for staghorn calculus if:

  • You have a fever of 100 degrees Fahrenheit or higher.
  • You have chills and/or are shaking.
  • Your bleeding doesn’t stop or gets worse.
  • Your pain doesn’t improve or gets worse.
  • You aren’t able to pee.

A note from Cleveland Clinic

Staghorn calculi, like other kidney stones, can be frustrating and painful. Your healthcare provider can evaluate you and help you find a solution. Many times, the solution will be a type of surgery. It’s important to treat staghorn stones if possible to avoid kidney failure. Follow any recommendations from your healthcare provider regarding what your diet and activity level.

Medically Reviewed

Last reviewed by a Cleveland Clinic medical professional on 05/06/2022.

Learn more about our editorial process.

Urology 216.444.5600
Kidney Medicine 216.444.6771