What are kidney and bladder stones?
Your kidneys filter waste and excess fluid (urine) from your bloodstream. Urine produced in the kidneys travels through the ureters, into the bladder, and out of your body through the urethra.
Stones are hard clusters of minerals and other substances that are usually dissolved in urine. Under certain conditions, these substances can crystallize and form stones in the kidney or bladder.
Small stones may stay in place or pass from the urinary tract without any issues. Large kidney stones that pass into the ureter can get stuck, causing extreme pain and blocking the flow of urine. In the bladder, stones can obstruct urine flow, causing pain, frequent urination, and infections.
Kidney stones are more common than bladder stones. Nearly 10% of people will have a kidney stone at some point in their lives. Both kidney and bladder stones affect men more often than women.
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Understanding Kidney and Bladder Stones
Kidney Stone Symptoms
Kidney stones rarely cause symptoms until they move into the ureters. In these thin tubes, a stone can get stuck and block urine, causing severe pain called renal colic. The pain is typically sharp and located on one side of your back below your ribs. Pain can also radiate to your stomach or groin. In some cases, large stones in the kidney can also cause pain and repeat infections, even if they don't block urine flow.
Other kidney stone symptoms include:
- Blood in your urine
- Cloudy or foul-smelling urine
- Fever or chills, if there is an infection
- Nausea and vomiting
- Recurrent urinary tract infections (UTIs)
Bladder Stone Symptoms
Bladder stones may not cause any symptoms. When symptoms do occur, they may include:
- Blood in your urine
- Difficulty urinating
- Frequent urination
- Loss of bladder control (urinary incontinence)
- Pain when urinating
- Pelvic pain
- Recurrent urinary tract infections (UTIs)
Causes and Risk Factors of Kidney Stones
Kidney stones are usually caused by a combination of dietary, genetic, and health factors. Some factors that increase the risk of kidney stones include:
- Dehydration
- Diabetes
- Eating disorders
- Excess protein in your diet
- History of surgery to remove a portion of the intestine, including gastric bypass surgery for weight loss
- Hyperparathyroidism
- Inflammatory bowel disease
- Medications, including some antibiotics, aspirin, antacids, diuretics to reduce fluid retention, and certain antiseizure medicines
- Metabolic syndrome
- Personal or family history of stones
- Polycystic kidney disease (PKD)
- Urinary tract infections
Causes and Risk Factors of Bladder Stones
Bladder stones usually form when a health condition prevents your bladder from emptying fully. The most common causes are an enlarged prostate (benign prostatic hyperplasia) and bladder dysfunction due to nerve damage (neurogenic bladder). In some cases, bladder stones begin as kidney stones that have traveled to the bladder.
Other factors that increase bladder stone risk include:
- Bladder augmentation surgery to make the bladder larger
- Bladder infections
- Medical devices placed in your bladder, such as a tube (catheter) to drain urine
- Past radiation therapy
Types of Kidney Stones
Doctors classify kidney stones based on what they are made of. The main types are:
- Calcium stones: These stones can be made of calcium oxalate or calcium phosphate. Calcium oxalate stones are the most common type of kidney stone. They can be caused by many factors, including your diet, family history, and other diseases. Calcium phosphate stones form when your urine is less acidic than usual, usually because of certain medications or health conditions.
- Uric acid stones: Uric acid is a compound found in animal protein. You can develop uric acid stones if you eat too much red meat, poultry, or seafood. Diabetes can also increase your risk of these stones.
- Struvite stones: Struvite (magnesium ammonium phosphate) crystallizes from urine when the pH becomes less acidic, usually due to a bacterial infection. Struvite stones are more common in women and can grow quickly.
- Cystine stones: Cystine is an amino acid your body uses to make protein. Cystine stones are rare and occur in people with cystinuria, an inherited condition that affects how your body processes cystine.
Types of Bladder Stones
About half of all bladder stones are made of uric acid. Calcium oxalate, calcium phosphate, cystine, and struvite stones can also form in the bladder.
Kidney and Bladder Stone Prevention
You can’t always prevent kidney and bladder stones. The most important thing you can do is drink plenty of water. Fluids dilute your urine and reduce the chance that crystals will form. Doctors recommend drinking at least 2.5 liters of water every day.
Kidney and bladder stones are often diagnosed by primary care providers or in the emergency room when people develop symptoms and seek care. Diagnosis is based on a person’s medical history, an examination, and tests, such as:
- Urine tests to look for blood, urinary crystals, or signs of infection
- Imaging tests, such as a kidney-ureter-bladder (KUB) X-ray, CT scan, and ultrasound
Sometimes, radiologists find kidney and bladder stones on imaging tests done for other reasons.
Following diagnosis, your doctor will refer you to a urologist for further evaluation and treatment. They may order imaging or lab tests if you haven’t had them already.
For complex or recurrent kidney stones, our urologists work with nephrologists (kidney experts) to provide complete care. Nephrologists use in-depth evaluations to identify the underlying cause of kidney stones. Testing typically includes analyzing a urine sample you collect over 24 hours.
Kidney and Bladder Stones
We provide expert kidney and bladder stone treatment, including ongoing monitoring, removal procedures, and follow-up care to prevent new stones.
Kidney stones
Bladder stones
urinary stones
kidney stone surgery
bladder stone surgery
lithotripsy
percutaneous nephrolithotomy