Kidney Stone Symptoms & Diagnosis

Kidney stones often move through the urinary tract and leave the body without any symptoms at all. Such stones are referred to as "silent" stones, and are usually very small (under four millimeters).

Larger calculi cannot be excreted and even small stones can cause problems by becoming lodged in the ureter, the long narrow tube that carries urine from the kidney to the bladder. One of the typical symptoms of kidney stones is severe pain.

Symptoms of Kidney Stones: Renal Colic & Hematuria

When kidney stones become lodged in the urinary tract, they can cause irritation or blockages. The stones cause the urinary tract to go into spasm, a condition known as renal colic. Renal colic causes a severe cramping pain felt in the back and the side, and sometimes in the lower abdomen. Eventually, pain may spread to the groin. Pain is not only the most common of the symptoms of kidney stones, but also an important indicator that something is obstructing the urinary tract.

Irritation of the urinary tract often causes frequent urination. Blockages may result in difficulty urinating. Hematuria, or blood in the urine, is also common. Blood in the urine may indicate that a stone is trying to move through the narrow ureter. As the urinary tract attempts to pass the stone, the stone causes bleeding that appears as hematuria. Blood in the urine may be visible to the eye, or may require detection by urinalysis.

In addition to renal colic, hematuria, and frequent urination, other symptoms of kidney stones include:

nausea
vomiting
a burning sensation while urinating
fever
chills.

Diagnosis: Urinalysis & X-Ray Imagery

The diagnosis usually begins with a medical history. Your doctor will ask about current suspected kidney stone symptoms, whether you have a personal or family history of kidney stones, and will determine whether you have an existing medical condition that predisposes you to stone formation. A physical examination will be attempted, although renal colic pain may make a physical exam impossible.

Urinalysis and blood tests will be performed to evaluate kidney function and hydration levels. A urinalysis can detect bacteria and microscopic hematuria. Blood tests measure calcium levels in the body to determine whether this common mineral may be accumulating in the kidneys.

If urinalysis and blood work results indicate the likelihood of an obstruction, an x-ray of the kidney will locate the stone. A standard x-ray is often used, although an intravenous pyelogram (IVP) may also be required. An intravenous pyelogram injects a dye into the bloodstream. This dye appears on the x-ray and builds up in the kidney before being excreted, allowing any obstruction caused by a kidney stone to become visible.

A retrograde pyelogram also uses dye that appears on an x-ray. However, for this procedure, a narrow, hollow tube called a cystoscope is inserted through the urethra to the bladder, and dye is injected through the tube.

Ultrasound is also used to locate stones that may not show up on regular x-rays. A CT scan may be required to locate them. A CT scan takes multiple x-ray "slices" of an organ, which are then compiled into 3-dimensional computerized images.

Differential Diagnosis: Ruling Out Pancreatitis & Other Causes

A number of other conditions mimic kidney stone symptoms, including appendicitis, cholecystitis, peptic ulcers, pancreatitis and ectopic pregnancy. These conditions must be ruled out in the course of a diagnosis.

Appendicitis: The extreme renal colic pain can sometimes be similar to the pain of appendicitis, an inflammation of the appendix.
Cholecystitis: Renal colic-type pain can also be caused by cholecystitis, which is an inflammation of the gall bladder.
Ectopic Pregnancy: An ectopic pregnancy is a pregnancy that occurs outside the uterus. An ectopic pregnancy may involve the fallopian tubes or the peritoneal cavity in the abdomen.
Pancreatitis: An inflammation of the pancreas, the symptoms of pancreatitis may be confused with kidney stone symptoms.
Peptic Ulcer: A peptic ulcer occurs when gastric juices attack the mucous membrane of the stomach or duodenum.

Resources

Beers, M. H., & Berkow, R. (ed). Urinary calculi. The Merck Manual of Diagnosis and Therapy, 17th Edition. Merck Research Laboratories, NJ, 1999.

Browne, G. & Plant, L. (updated 2004). Kidney stones. Renal Unit of the Royal Infirmary of Edinburgh.

Fauci, A., Braunwald, E., Isselbacher, K., Wilson, J., Martin, J., Kasper, D., Hauser, S., & Longo, D. (ed.). Harrison's Principles of Internal Medicine, 14th Edition. McGraw-Hill, NY, 1998.

Carson-Dewitt, R.S. (1999). Kidney stones. Gale Encyclopedia of Medicine.

Kidney Stone Treatment and Prevention Centers. (nd). About kidney stones. LithoLink.com.