What are Urinary Calculi?

Urinary calculi are hard masses, commonly referred to as stones — the word “calculi” literally means “pebbles” in Latin — that are found anywhere in the urinary tract. They are made up of mineral salts, primarily calcium oxalate in most cases, and are typically formed in the kidneys. Vesical, or bladder, calculi are those found in the urinary bladder. If they are found in the kidney or pelvic area, they are called renal or kidney calculi.

The symptoms of urinary calculi can vary quite a bit, depending on their size, but some of the more common signs are blood or pus in the urine; a severe pain that comes and goes, usually in the groin and lower back area; nausea and vomiting; and less urine output because the calculi are blocking the urinary passages. If the calculi cause infection, there might be a burning sensation when urinating. There might be no symptoms at all, which is the case most of the time, if the calculi are small and they can be seen only as a result of some type of scan being done.

Urinary calculi are caused by an imbalance of fluids and certain mineral salts in the body. When certain mineral salts are in excess, calculi are formed. There usually is an underlying metabolic disorder that causes the imbalance, and the disorders are associated with the predominant mineral involved in the formation of the calculi. For instance, in the case where the stone is made up mostly of calcium oxalate — which is approximately 85 percent of calculi found — a common disorder underlying it is hyperparathyroidism, the parathyroid being the gland responsible for controlling the amount of calcium in the body and “hyper” meaning that it is in excess.

Calculi are further tested for chemical makeup when they have been passed or have been extracted surgically. Depending on what mineral is found to be predominant in the makeup of the calculi, a follow up test or tests might be performed. Tests can help determine what the underlying disorder is.

The most common, and most reliable, diagnostic test performed to either look for or confirm urinary calculi is the computed tomography (CT) scan; only very rare types of stones miss detection by CT scan. CT scans are expensive, though, and they cause radiation, an acute danger in certain cases such as pregnancy. Other tests are available, including X-rays, ultrasound and tests of the urine and/or blood. They are either less expensive than CT scans, as in the case of X-rays, or don’t cause radiation, as in the case of ultrasound, blood tests and urine tests.

Urinary calculi are usually treated by encouraging them to be passed, or pushed through the urinary tract, usually by increasing the amount of liquids consumed and in some cases with the help of certain medications. If the calculi are too large to pass, or if they don’t pass after a month or so, they can be either surgically extracted or treated with shock-wave lithotripsy. This treatment sends sound waves through the body and breaks up the calculi so they can be passed.