Kidney stones are hard crystal deposits that form in the urinary tract. They start when minerals and salts in urine come together and grow over time. Many small stones leave the body on their own. Some get stuck and cause strong pain. If a stone blocks the flow of urine, you may need a procedure to break it or remove it. With the right care, most people recover well and learn how to lower the chance of new stones.
This guide explains kidney stones in clear, simple language. You will learn symptoms, causes, types, tests, treatment options, and prevention steps. You will also find answers to common questions. Links to trusted sources are included for deeper reading.
Overview
Kidney stones form when urine has more crystal-forming material than the body can dilute. Common materials include calcium, oxalate, phosphate, uric acid, and cystine. When urine is very concentrated, crystals can grow and join together. A stone may be as small as a grain of sand or as large as a marble. Rarely, a stone grows bigger. The pain from kidney stones is strong because the urinary tract is narrow and the stone irritates the tissue as it moves.
Small stones can pass without surgery. Drinking enough water, taking pain relief as advised, and moving your body can help. When a stone gets stuck, urine can back up behind it. This can cause swelling in the kidney and severe pain. If fever develops, or if you cannot pass urine, it becomes an urgent medical issue. Doctors have safe ways to break stones into tiny pieces or remove them through small instruments. They also help you plan how to prevent new stones.
Kidney stones are common. Many people will have at least one stone in their lifetime. Once you have had one, your chance of another stone is higher, so prevention is important. The steps in this guide can lower that risk.
Symptoms
The main symptom of kidney stones is pain. The pain often starts suddenly. It may come in waves. It may move from the back to the side, down to the lower belly, or toward the groin. Other symptoms can include:
- Sharp or cramping pain in the back, side, or lower belly
- Pain or burning when passing urine
- Urine that looks pink, red, or brown
- Urine that looks cloudy or has a strong smell
- Feeling like you must pass urine often, but little comes out
- Nausea or vomiting
- Fever or chills, which can signal infection
Some very small kidney stones cause few symptoms and pass without you noticing. If you have pain with fever, if pain is not controlled, or if you cannot keep fluids down, seek medical care. If you have one kidney, are pregnant, or have a weak immune system, do not wait to call a doctor.
What causes kidney stones
Urine carries water, minerals, acids, and waste. When the balance changes, crystals can start to form. Causes and triggers for kidney stones include:
- Not drinking enough water, especially in hot weather or during hard work
- Diets high in sodium, animal protein, or added sugar
- Very high intake of vitamin C supplements in some people
- Low calcium intake from food, which can raise oxalate in the gut
- Metabolic issues that change the levels of calcium, oxalate, uric acid, or citrate
- Past bowel surgery or conditions that affect absorption
- Urinary infections that promote certain kinds of stones
- Family history of kidney stones
- Some medicines that increase stone risk
Stones often build over weeks or months. They sometimes form around a tiny “seed” crystal. Over time more crystals stick to the surface. The stone then moves with urine flow. If it reaches a narrow area, such as the ureter, it can get stuck. That is when the pain begins.
Types of kidney stones
Knowing the type of kidney stones you have helps guide treatment and prevention. The main types are:
Calcium oxalate stones
These are the most common. They form when calcium and oxalate join. Risk grows with high oxalate in urine, low urine volume, and low citrate. Too much sodium and animal protein can raise risk. A urine test and stone analysis help confirm this type.
Calcium phosphate stones
These can form in people with certain metabolic conditions or with urine that is more alkaline. They may occur with calcium oxalate stones. Prevention focuses on fluid intake, lower sodium, and managing the cause.
Uric acid stones
These stones form when urine is very acidic and concentrated. Diets rich in animal protein can contribute. Gout and some metabolic changes also raise risk. Making urine less acidic with diet and medicine helps dissolve and prevent these stones.
Struvite stones
These are linked to some urinary infections. They can grow quickly and become large. Procedures are often needed to remove them. Preventing new infections is part of the plan.
Cystine stones
These are rare. They happen in people with a genetic condition that causes cystine to build up in urine. Treatment aims to increase fluid intake and change urine chemistry. Some people need specific medicines to prevent new stones.
Who is at risk
Anyone can get kidney stones, yet some people have a higher chance. Risk rises if you:
- Do not drink enough fluids, or live in a hot climate without replacing fluids
- Eat a diet high in sodium, added sugar, or animal protein
- Have a family history of kidney stones
- Have gout, diabetes, obesity, or metabolic syndrome
- Have had bowel surgery or a condition that changes absorption
- Have repeated urinary infections
- Take certain medicines that change mineral levels
If you have had one stone, your chance of another stone is higher. This is why prevention steps matter. A 24-hour urine test can find your personal drivers. Your care team can then tailor advice to your results.
Possible complications
Most kidney stones leave the body without serious problems. Complications can happen when a stone blocks urine flow or when infection is present. Possible issues include:
- Severe pain and swelling in the kidney from backed-up urine
- Urinary infection or fever
- Blood in the urine
- Temporary drop in kidney function
- Repeat stones in the future
Call a doctor right away if you have fever with pain, cannot pass urine, or pain is severe and not controlled. These signs need urgent care.
Diagnosis and tests
Doctors diagnose kidney stones by listening to symptoms, doing an exam, and ordering tests. Common tests include:
- Urinalysis: Checks for blood, crystals, infection, and pH
- Blood tests: Check kidney function and mineral levels
- Imaging: Ultrasound, X-ray, or CT scan to see stone size and location
- Stone analysis: If you pass a stone, it can be sent to a lab to learn its type
- 24-hour urine test: Finds the drivers that caused your kidney stones
Imaging helps plan care. Ultrasound avoids radiation and is common during pregnancy. A CT scan is very accurate and helps when the diagnosis is not clear.
Management and treatment
Treatment depends on stone size, location, symptoms, and whether there is infection. The main goals are to relieve pain, clear the stone, and protect kidney function. Options include:
Conservative care for small stones
- Drink plenty of water unless your doctor says otherwise
- Pain relief as advised by your doctor
- Medicine that relaxes the ureter to help the stone move in some cases
- Strain your urine to catch the stone for analysis
Many small kidney stones pass on their own within days to weeks. Your care team will tell you what symptoms to watch for and when to return.
Procedures for larger or stuck stones
- Shock wave lithotripsy: Focused waves from outside the body break the stone into small pieces that pass more easily
- Ureteroscopy: A thin scope is passed through the urethra and bladder into the ureter to break and remove the stone
- Percutaneous nephrolithotomy: A small incision in the back lets the surgeon reach the kidney directly to remove large stones
Sometimes a temporary stent is placed to help urine flow and reduce swelling. Your doctor will explain how long it stays in and how it is removed.
Medicine for specific stone types
- Uric acid stones: Making urine less acidic can help dissolve them and prevent new stones
- Calcium stones: Some people benefit from medicine that lowers calcium in urine or raises citrate
- Cystine stones: Special medicines and high fluid intake help reduce new stones
If infection is present with a blocked stone, urgent care is needed. Doctors will drain the urine and treat the infection before breaking or removing the stone.
Prevention and daily habits
Prevention is the best treatment for kidney stones. The exact plan depends on your test results and stone type. These steps help many people:
Fluids
- Drink water through the day so urine stays light yellow
- Spread fluids across the day and with meals
- Drink more in hot weather or when active
Diet
- Limit sodium from salt, fast food, and packaged snacks
- Include normal calcium from food like yogurt or milk with meals
- Do not overuse vitamin C supplements unless your doctor advises
- Moderate animal protein. Enjoy beans, lentils, and plant protein too
- If you had oxalate stones, moderate high-oxalate foods and pair them with calcium foods at meals
- Eat more fruits and vegetables for potassium and citrate
- Cut back on added sugar in drinks and desserts
Weight, activity, and general health
- Stay active most days of the week
- Work toward a healthy weight with steady habits
- Manage conditions such as diabetes and gout with your care team
For an easy read on healthy weight habits, you may like our post: Top 13 natural ways to lose weight fast.
Living with kidney stones
Most people with kidney stones return to normal life. A first stone is a chance to reset habits. Keep a water bottle with you. Learn your personal risk from a 24-hour urine test. Make small changes you can keep. If you are prone to stones, routine follow-up helps catch problems early.
Stress is common during a stone episode. Short walks, slow breathing, and support from family can help. If you feel very anxious or low, speak with a professional. Healing takes time. Be kind to yourself as you recover.
FAQs
Can kidney stones go away on their own?
Yes. Many small kidney stones pass without surgery. Drink water as advised and use pain relief as directed. If pain is severe, if you have fever, or if you cannot pass urine, seek care at once.
How long does it take to pass a stone?
It depends on size and where the stone is stuck. A very small stone may pass in days. Some stones take longer. Your doctor will tell you when a procedure is safer than waiting.
What foods should I avoid?
Limit sodium, added sugar, and very large portions of animal protein. If you had oxalate stones, moderate high-oxalate foods and pair them with calcium foods at meals. Focus on water, fruits, vegetables, and balanced meals.
Why do kidney stones come back?
Risk is higher after a first stone. Causes include low fluid intake, diet patterns, and body chemistry. A 24-hour urine test helps find your drivers so you can reduce future kidney stones.
When should I go to the emergency department?
Go if you have fever with pain, cannot control pain, cannot keep fluids down, or cannot pass urine. People with one kidney, pregnancy, or weak immunity should seek care early.
Helpful resources
Medical disclaimer: This article is for education only and does not replace care from your own healthcare professional.
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