Kidney stones, also known as renal calculi, nephrolithiasis, or urolithiasis, are hard deposits of minerals and salts that form inside your kidneys. They can affect any part of your urinary tract, from the kidneys to the bladder. Often, kidney stones develop when the urine becomes concentrated, allowing minerals to crystallize and bind together.
Alt text: Diagram of the female urinary system showing kidneys, ureters, bladder, and urethra.
While passing kidney stones can be very painful, they typically don’t cause permanent damage if identified promptly. Treatment options range from pain management and increased water intake to surgery, depending on the severity and location of the stones. If you are at increased risk of developing kidney stones again, your doctor may recommend preventive treatment.
Symptoms of Kidney Stones
A kidney stone may not cause symptoms until it moves within the kidney or passes into the ureters, the narrow tubes connecting the kidneys and bladder. When a kidney stone becomes lodged in the ureters, it can block urine flow, causing the kidney to swell and the ureter to spasm. This obstruction can lead to intense pain and other symptoms, including:
- Severe Pain: Sharp pain in the side and back, below the ribs, often radiating to the lower abdomen and groin. The pain may come in waves and fluctuate in intensity.
- Painful Urination: Pain or a burning sensation while urinating.
Other signs and symptoms of kidney stones may include:
- Pink, red, or brown urine (hematuria)
- Cloudy or foul-smelling urine
- A persistent urge to urinate, frequent urination, or small urine volume
- Nausea and vomiting
- Fever and chills, indicating a possible infection
It’s important to note that pain caused by kidney stones can shift location or change in intensity as the stone moves through the urinary tract.
Alt text: Illustration of kidney stones forming in the kidney and moving into the ureter.
When to Seek Medical Attention:
Consult your doctor if you experience any worrying signs or symptoms. Seek immediate medical care if you have:
- Intense pain that makes it impossible to sit still or find a comfortable position
- Pain accompanied by nausea and vomiting
- Pain accompanied by fever and chills
- Blood in your urine
- Difficulty passing urine
Causes of Kidney Stones
Often, there isn’t one specific cause of kidney stones. However, several factors can increase your risk. Kidney stones form when your urine contains more crystal-forming substances – such as calcium, oxalate, and uric acid – than the fluid in your urine can dilute. Simultaneously, your urine may lack substances that prevent crystals from sticking together, creating an ideal environment for kidney stone formation.
Types of Kidney Stones
Identifying the type of kidney stone you have can help determine its cause and provide insights into preventing future occurrences. If you pass a kidney stone, try to save it for analysis by your doctor. Common types of kidney stones include:
- Calcium Stones: The most common type, usually composed of calcium oxalate. Oxalate is produced daily by your liver and absorbed from your diet. Certain foods like fruits, vegetables, nuts, and chocolate are high in oxalate. High doses of vitamin D, intestinal bypass surgery, and some metabolic disorders can increase calcium or oxalate concentrations in urine. Calcium stones can also form as calcium phosphate, more common in metabolic conditions like renal tubular acidosis and associated with medications like topiramate.
- Struvite Stones: These form in response to urinary tract infections (UTIs). Struvite stones can grow rapidly and become quite large with minimal warning.
- Uric Acid Stones: These stones can develop in individuals who lose too much fluid due to chronic diarrhea or malabsorption, consume high-protein diets, or have diabetes or metabolic syndrome. Genetic factors may also play a role.
- Cystine Stones: These stones occur in people with cystinuria, a hereditary disorder that causes the kidneys to excrete excessive amounts of specific amino acids.
Alt text: Diagram of the male urinary system, showing the kidneys, ureters, bladder, and urethra.
Risk Factors for Kidney Stones
Several factors can increase your risk of developing kidney stones:
- Family or Personal History: A family history of kidney stones increases your likelihood of developing them. If you’ve had kidney stones before, you’re at a higher risk of recurrence.
- Dehydration: Insufficient water intake can increase the risk of kidney stones. People in warm, dry climates or those who sweat excessively are particularly vulnerable.
- Diet: A diet high in protein, sodium (salt), and sugar can increase the risk of certain types of kidney stones, especially high-sodium diets that increase the amount of calcium the kidneys must filter.
- Obesity: High body mass index (BMI), large waist size, and weight gain have been linked to an increased risk of kidney stones.
- Digestive Diseases and Surgery: Gastric bypass surgery, inflammatory bowel disease, or chronic diarrhea can alter digestive processes, affecting calcium and water absorption, and increasing stone-forming substances in urine.
- Other Medical Conditions: Renal tubular acidosis, cystinuria, hyperparathyroidism, and recurrent UTIs can also increase your risk.
- Certain Supplements and Medications: Vitamin C, dietary supplements, excessive laxative use, calcium-based antacids, and certain medications for migraines or depression can increase the risk.
Understanding the causes, symptoms, and risk factors associated with kidney stones is essential for prevention and early detection. If you suspect you may have kidney stones, consult a healthcare professional for proper diagnosis and treatment.
