- Overview
- Kidney stones occur when minerals within the urinary collecting system crystalize and bind together. The lifetime incidence of kidney stones is about 10% and has been increasing over the last few decades.
- Causes
- Causes for kidney stones are multi-factorial – meaning many things contribute to their formation. Some of these causes include:
- Dehydration, family history/genetics, diet, lifestyle, obesity
- Signs/symptoms
- Many kidney stones stay in the kidney and don’t cause problems. However, these can continue to increase in size and make treatment more difficult than it otherwise would be.
- Kidney stones can also be a source of recurrent urinary tract infections or hematuria (blood in the urine).
- Large stones in the kidney can cause deterioration of renal function over time
- When kidney stones try to pass from the kidney to the bladder, they often get stuck in the ureter tube that connects the two organs. This results in pain, nausea/vomiting, voiding symptoms, renal dysfunction, and infections.
- Diagnosis
- Many kidney stones are found incidentally on imaging studies done for other reasons (ultrasound, X-ray, or CT scans).
- If you have signs/symptoms of kidney stones, your doctor will evaluate.
- Urinalysis – look for signs of blood and/or infection in the urine
- Blood tests – look for signs of kidney dysfunction and/or infection
- Imaging – CT scan is the gold standard for diagnosing kidney stones. Sometimes, ultrasound and/or X-ray is indicated to reduce radiation exposure.
- Treatment
- Observation – small stones that aren’t causing problems can be safely observed with serial imaging to ensure no growth
- Trial of passage – performed when small stones are passing in the ureter tube. Patient elects to attempt to pass stone on his/her own with close follow-up.
- Medical expulsive therapy – medications are given to facilitate passage of small stones.
- Extracorporeal shock wave therapy (ESWL) – high energy shock waves directed from the outside of the body towards the kidney stone with the intent to fragment into small pieces and facilitate the body’s own passage. Short, outpatient procedure requiring general anesthesia. Occasionally, your doctor may recommend a ureteral stent for 1-2 weeks to further aide in stone passage.
- Ureteroscopy – small, flexible camera is navigated into the ureter and up to the stone. Depending on the stone size and location, it is then fragmented with a laser and/or removed with a small basket. A ureteral stent is left in place for 1-2 weeks to allow healing and stone fragment passing. This is a short, outpatient surgery requiring general anesthesia.
- Percutaneous nephrolithotomy – Reserved for larger stones, typically >2cm. Small hole is made though the back and into the kidney. Larger instruments can then be inserted into the kidney to remove large stones in a single setting. Requires general anesthesia and an overnight stay in the hospital.
- Prevention
- Some patients are high risk kidney stone formers, meaning they make large or bilateral stones, frequent stones, or stones at a young age. Metabolic analysis is performed by analyzing 24 hour urine collection for certain minerals, metabolites, and volume. Treatment depends on the results of the evaluation. This can include dietary or lifestyle modifications, and/or medications.
