• Kidney Disease

Kidney Stones: What Do You Need to Know About the Causes and Symptoms?

Medically reviewed and edited by Rachel McLeod, NP

A kidney stone can be incredibly painful — we’ve all heard the stories from friends, relatives, and colleagues who’ve had this condition.

But did you know one in every 500 people in the U.S. get kidney stones each year? The good news is that kidney stones can be treated and prevented when you follow the right steps.

In this article, we’ll explain what a kidney stone is, what causes it, and which symptoms indicate that you may have this condition.

What is a Kidney Stone?

Kidney stones – often referred to as nephrolithiasis – are accumulations of mineral waste that stick together to form larger deposits that could cause obstructions within the kidney or further along the urinary tract.

The formation of kidney stones can occur gradually or swiftly, with their sizes ranging considerably.

Most kidney stones are small and typically pass through the body unnoticed and without discomfort. However, larger stones can inflict significant pain and may require hospitalization, and or surgical intervention.

What are the Different Types of Kidney Stones?

The type of kidney stone you have depends on underlying risk factors. There are four different types:

Calcium oxalate and calcium phosphate stones

Most kidney stones are classified as calcium stones, accounting for approximately 80% of all cases. These stones may be one of two types: calcium oxalate and calcium phosphate.

Conditions that lead to an increased amount of calcium in the urine, such as an overactive parathyroid gland, can heighten your risk of developing these stones.

Uric acid stones

Uric acid stones constitute approximately 5-10% of kidney stone cases.

These stones are associated with consuming high-purine foods, including organ meats (such as liver, kidneys, and brains), other types of meat, alcohol, and seafood.

The breakdown of these foods in our bodies results in the production of uric acid, which can accumulate in the kidneys and lead to the formation of stones. Additionally, this accumulation often triggers gout, a condition characterized by extremely painful joint inflammation.

Cancer and its treatment, including chemotherapy, can elevate uric acid levels in the body. This increase occurs as both normal and cancerous cells are converted into uric acid once they die.

A specific condition, known as tumor lysis syndrome, results from the rapid death of tumor cells, leading to a sharp rise in uric acid and a decrease in calcium levels.

In attempts to correct the calcium deficit, healthcare professionals may inadvertently cause calcium stones to form.

Acidic urine may also be a risk factor as uric acid stones do not readily dissolve in acidic environments. Obesity, chronic diarrhea, diabetes, and gout can all increase urine acidity.

Struvite stones

Struvite kidney stones (magnesium ammonium phosphate), often result from recurrent or persistent urinary tract infections (UTIs).

Bacteria involved in these infections alkalinize the urine, creating an environment conducive to the formation of struvite stones.

Struvite stones account for approximately 10% of all kidney stone types.

These stones typically grow quickly and can become quite large, sometimes evolving into a staghorn calculus — a branched structure that fills the kidney's internal space. Such extensive growth can lead to kidney failure.

Cystine stones

Cystine, an amino acid integral to protein structure, can lead to the formation of kidney stones in individuals with a genetic condition known as cystinuria.

In those affected by cystinuria, the body fails to eliminate excess cysteine properly, allowing it to accumulate in the kidneys and crystallize into stones.

These cystine stones are quite rare, representing less than 1% of kidney stone cases.

What are the Symptoms of Kidney Stones?

If you have kidney stones, you may experience one or more of the following symptoms:

• Pain: The pain from kidney stones can be severe, and it is often described as intermittent, shifting between sharp and dull. This results from the ureter muscles trying to push the stone through a narrow passage.

  The discomfort typically starts in the back, below the ribs, radiating down to the groin. Notably, a 2017 Journal of Pain Research study found that many women who have experienced both childbirth and kidney stones reported the latter to be more painful.

• Nausea and vomiting: The intense pain caused by kidney stones may result in nausea and vomiting for some people.

• Hematuria: Also known as blood in the urine, this is caused by injury to the walls of the urinary tract. This may go unnoticed and is often only detected when urine testing is done by a healthcare professional.

• Signs of infection: Symptoms such as fever, chills, and tenderness over the kidney area can indicate complications from kidney stones.

Blockage of the ureter or kidney may reduce urine flow, creating an environment conducive to infection.

An obstruction coupled with infection and fluid backpressure on the kidneys — urine flowing back into the kidneys — can escalate into a potentially life-threatening situation that requires immediate surgical intervention.

What Causes Kidney Stones?

The kidneys play a pivotal role in the urinary system by eliminating waste products from our bodies. They accomplish this by filtering this waste along with water from our blood.

When the body’s water reserves are low, the kidneys use less water to get rid of waste to prevent dehydration.

This conservation effort results in a higher concentration of waste products in the urine, often making it appear more yellow.

When the concentration of waste products exceeds the amount that can be diluted in urine, crystals may begin to form. Kidney stones develop when crystals stick to the kidney walls and keep growing as more crystals join them, making these stones larger.

Kidney Stone Risk Factors

Diet

Diet plays a major role in the development of kidney stones. According to the Journal of Clinical Medicine, stone prevention may be possible through diet changes alone.

They recommend the following dietary guidelines:

• Water intake: This is crucial for all types of stones to help prevent their formation.

• Lemon and orange juice: These juices contain citrate, which helps prevent calcium stone formation. However, go easy with juice if you have diabetes.

• Calcium: You should maintain a normal dietary calcium intake (1,000-1,200mg/day). Contrary to past advice, dietary calcium can help reduce stone formation by binding with oxalate in the intestines, preventing it from reaching the kidneys. Just avoid calcium supplements which may increase kidney stone risk.

• Salt intake: Limit salt to less than 3-5g per day to reduce kidney stone risk.

• Oxalate reduction: These natural compounds are found in certain vegetables and plant-based foods — such as spinach, beets, potatoes, avocados, chocolate, and nuts — and reducing intake can prevent stones.

• Dietary protein: Decreasing protein intake can lower the risk of stone formation.

Low urine volume

Low urine volume is a major risk factor for kidney stone formation. Maintaining good fluid intake is important for ensuring proper urine output.

According to the Urology Care Foundation, it is recommended that people who are at risk of stone formation should drink at least 100 ounces of fluid each day.

Digestive problems

Digestive issues such as chronic diarrhea can lead to increased fluid loss, heightening your risk of developing kidney stones.

Similarly, weight loss surgeries such as a gastric bypass may elevate the risk by enhancing the absorption of oxalate, a known contributor to stone formation.

Obesity

Obesity has been linked to the development of kidney stones; however, it is difficult to completely attribute kidney stone development to weight alone as those with obesity often have multiple other associated illnesses.

Calcium oxalate and uric acid stones are the most common in the context of obesity.

Certain medical conditions

Certain medical conditions are associated with an increased risk of developing kidney stones. These include:

• Hypercalciuria: Excess calcium in the urine

• Hyperparathyroidism: This is a condition characterized by an overactive parathyroid gland, which leads to elevated levels of calcium in the blood

• Abnormal kidneys or urinary tract: Such as polycystic kidney disease, horseshoe kidney, or ureteropelvic junction stenosis

• Cystinuria: This is the only condition in which cystine stones occur

• Inflammatory bowel disease (e.g., Crohn’s disease or ulcerative colitis)

• Recurrent UTIs

• Gout

Family history

Individuals with a close relative — such as a parent or sibling — who has experienced kidney stones, are at a higher risk of developing kidney stones themselves.

The exact cause — whether kidney stones primarily form due to genetic predispositions, shared environmental factors, or a mixture of both — is not fully understood.

When Should You See a Doctor for Kidney Stones?

You should consult your doctor if you have any of the symptoms or risk factors for kidney stones we’ve mentioned.

Kidney stones can cause extreme pain which can be alleviated with prompt treatment. If you’ve had a kidney stone before, you should consult your doctor regarding preventative measures.

Where Can You Learn More About Kidney Health?

Do you have pain or other symptoms that may indicate a kidney stone? LifeMD can help.

A dedicated team of healthcare professionals is equipped to diagnose your condition accurately and offer a comprehensive range of treatment options and prevention strategies to help you avoid kidney stones.

Book your appointment today to get started.

Rachel McLeod, NP

Rachel is a certified and licensed family nurse practitioner who has worked in the healthcare field for over 15 years. She graduated from South University with a Master’s of Science degree and a specialization in Family Nurse Practitioner. Rachel has experience in a variety of areas including Urgent Care, Primary Care, Mental Health, and Weight Management. In her free time, she enjoys traveling and spending time with family and friends.

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