Kidney Stones: Causes, Symptoms, and Risks

Anyone who has had a kidney stone knows that the stone and you have the same goal: to get it out of the body. While that may be true, those who have passed a kidney stone may argue that they suffered more than the stone. Understanding how and why kidney stones occur is important, as is knowing what symptoms you may experience from these unwanted visitors.

Are kidney stones harmful?

Kidney stones can be harmful. They are common, occurring in both men and women. After passing a kidney stone, more than 10% of adults, and up to 50% of children, develop additional stones within 5 to 7 years. Kidney stones can cause considerable pain and infections and may injure the kidneys and urinary tract. These can cause long-term problems. They also may be due to other less common but sometimes serious diseases.

Once formed, a stone usually moves down the urinary tract into the ureter and bladder. Usually, tiny stones can pass out of the body in the urine without causing too much trouble. But stones that the body can’t pass may cause a great deal of pain and, often, back-up of urine in the kidney, ureter, or the bladder. In that case, several surgical procedures can safely remove the stone.

Signs and symptoms of kidney stones

• Blood in the urine: Visible blood in your urine suggests the presence of a kidney stone. It may have a red, pink, or brown discoloration. Sometimes the blood is only detected under the microscope or through a simple office test. Keep in mind that there are other potentially serious diseases of the kidney and bladder that cause blood in the urine. If there is doubt, a more thorough evaluation is often needed.
• Pain: The pain associated with a kidney stone is often severe, may come and go, and vary in intensity. It may be a throbbing sensation. More frequently, however, it abruptly starts and is sharp and crampy. When the kidney stone is in the upper part of the urinary system, the pain is on one side, toward the back, and under the ribs. As it moves through the lower portion of the ureter and into the bladder, the pain may move to the lower abdomen and groin. The pain ends fairly quickly when the stone passes out of the body. However, the pain also may resolve when the stone passes into the bladder. It is important to be certain that this is not the case while also determining whether any other stones are present.
• Cloudy or foul-smelling urine: These signs often signal the presence of infection. Bladder infections are common, particularly in women, but the presence of a stone increases the risk, especially if the stone causes inflammation, Incomplete urine drainage, or poor urine flow. Although often localized in the bladder, infections may easily spread into the kidney. Other symptoms that often occur with this type of infection include fever, nausea, vomiting, and a burning sensation during urination. The medical term for a bacterial infection of the kidney is pyelonephritis. This is a problem that often requires more intense antibiotic therapy and even hospitalization.

When to see a doctor

Although numerous symptoms often occur with a kidney stone, it is wise to see your doctor promptly if you develop:

• Unrelenting pain on one side under the ribs or in the pelvis.
• Blood in the urine.
• Fever or chills, especially with symptoms of urinary infection.
• Vomiting large amounts, especially if not offset by drinking enough fluids.
• Diminished urination.

Kidney stone symptoms also may also imitate other diseases, such as a right-sided stone and acute appendicitis.

Why and how do kidney stones form?

Kidney stones develop when there are more crystal-forming minerals and other substances that can remain dissolved in the urine. Since these minerals, mainly calcium, oxalate, and uric acid, are normally found in the urine, a number of other factors determine whether crystals form in the first place. These include structural abnormalities of the urinary system promoting poor urine drainage, inherited or acquired abnormalities of blood or urine metabolic balance, and several aspects of general health and lifestyle.

Stones do not develop overnight. Over a long period, when urinary drainage is poor, or the urine is very concentrated, crystal-forming substances are released and begin to form and grow in size. Kidney stone formation is caused by conditions in the urine that favor crystal formation.

Am I at risk of developing kidney stones?

Several factors are associated with a greater likelihood of kidney stones. Among these are:

• Inherited risk: If a family member has had a kidney stone, you are more likely to form one. In this case, there is a greater likelihood that your stone will have the same composition as your relative.
• Diet: In some kidney stone disorders, dietary modifications may decrease the amount of crystal-forming minerals excreted in the urine or make the urine more resistant to crystal formation. These changes depend on what kind of stone you have and explain the importance of capturing a passed kidney stone and bringing it to your doctor for further analysis.
• Bodyweight: Research shows that obese individuals have a greater risk of kidney stone disease.
• Metabolic causes: The chemistry of the urine is complex and important. In some conditions, the amount of crystal-forming minerals and other substances can be excessive. Both alkaline and acidic urine also can favor crystal and stone growth, depending on your type of stone. Some conditions raise the amount of uric acid or calcium in your blood, such as gout, excess or diminished amounts of certain hormones, hereditary disorders, and certain medications. Discuss risk factors with your physician. Many diseases are associated with the risks of stone formation.
• Urine volume: One of the factors contributing to kidney stone risk is straightforward: The amount of urine produced. Not drinking enough, vomiting, fever, excessive perspiration, and a hot or dry climate can lead to dehydration and decrease the amount of urine produced.
• Other factors: These may include kidney diseases, medications, hormonal disturbances, and metabolic diseases that can increase the risk of developing kidney stones.

Summary

• Most kidney stones develop when the amount of certain minerals in the urine is greater than what can remain dissolved. This leads to the development of mineral crystals that begin the stone formation process.
• The main kidney stone signs and symptoms include severe flank pain that may wax and wane, and blood in the urine. Other signs and symptoms, such as fever, chills, and cloudy, foul-smelling urine suggest a kidney infection with or without a kidney stone. Certain types of kidney disease may also promote the chances of forming a kidney stone.
• There are effective approaches for passing most kidney stones, although many of these depend upon the type of stone you have. If you pass one, try to collect it for your doctor to analyze.
• An underrecognized but impactful approach to preventing or decreasing the risk of almost all types of kidney stones is to drink plenty of fluids. A starting goal is at least 2 ½ to 3 quarts of fluid daily.
• If you pass a kidney stone, talk to your doctor about lifestyle modifications that can decrease your risk of another.