Kidney Stone Symptoms & Diagnosis

Causes, Symptoms & Diagnosis of Kidney Stones

What is a Kidney Stone?

A kidney stone is a solid concretion of minerals that forms in a kidney. Kidney stones vary in size and may stay in the kidney or travel down the urinary tract. Urinary stone disease is one of the most common urological conditions in the United States and throughout the world.

What Causes Kidney Stones?

When substances in the urine—such as calcium, oxalate, and phosphorus—become highly concentrated, kidney stones can form. People who do not drink enough fluids may also be at higher risk, as their urine is more concentrated. Kidney stones often do not have one specific cause, although some factors may increase your risk.

Types of Kidney Stones

Identifying the type of kidney stone can help determine the cause and treatment protocol, as well as how to best reduce your risk of getting future kidney stones.

• Calcium-based stones. The most commonly found kidney stones are calcium stones, usually in the form of calcium oxalate. Oxalate is a naturally occurring substance found in some foods such as leafy green vegetables, certain nuts, and chocolate. Dietary modifications and certain medications can help reduce the risk of developing calcium-based stones.
• Struvite stones. This type of stone is composed of magnesium ammonium phosphate and occur most often in patients with chronic bacterial urinary tract infections. The best way to manage these stones is to remove them completely while treating the infection. 
• Uric acid stones. Uric acid stones occur when the urine is highly acidic, and can be caused by not drinking enough fluids, eating a high protein diet, and from disorders such as gout. These stones can sometimes be dissolved with medications.
• Cystine stones. This type of kidney stone usually forms in patients who have an underlying genetic condition that affects the kidney’s ability to process amino acids. These stones can be prevented with high fluid intake and specialized medications.

Who Gets Kidney Stones? What are the Risk Factors?

Kidney stones are common. According to the most recent data from the National Institute of Diabetes and Digestive and Kidney Diseases, about 11% of men and 7% of women in the United States have kidney stones at least once during their lifetime. Once you have a kidney stone, you are also more likely to develop future kidney stones.

Risk factors include:

• Age – older people are more commonly affected
• Race – Caucasians are at higher risk
• Family History – kidney stones frequently run in families
• Certain medications – including, indinavir (to treat HIV), acyclovir (anti-viral), diuretics (to rid your body of water), sulfadiazine (antibiotic)
• Associated conditions – including, obesity, diabetes, inflammatory bowel disease, gout, hyperparathyroidism
• Anatomic conditions – urinary obstruction, UPJ obstruction, urinary stasis

What are the Symptoms of Kidney Stones?

People with kidney stones may not experience symptoms until the stone moves from the kidney into your ureter (the tube connecting your kidney and bladder), at which point you may experience one or more of these symptoms:

• Flank Pain (discomfort in your upper abdomen or back and sides)
• Hematuria (blood in your urine)
• Nausea and/or vomiting
• Urgency to urinate
• Urinating more frequently than usual
• Pain when urinating
• Fever

Symptoms are often unrelated to stone size. The smallest stones can cause the most discomfort, while large stones may sit quietly in the kidney causing only a dull ache.

How are Kidney Stones Diagnosed?

Diagnosing a kidney stone requires a detailed history, physical exam, and diagnostic imaging. The current gold imaging modality is a non-contrast CT scan of the abdomen and pelvis. At UCLA Urology, we offer state-of-the-art low-dose CT imaging to minimize radiation exposure for our patients. Once a stone is detected, size and location are key determinants of the most appropriate management options.

For an appointment with a kidney stone specialist, please call 310-794-7700.