About half a million people each year visit emergency rooms because of kidney stones. Symptoms include back and side pain (also called flank pain) that can come in waves, an urgent need to urinate, burning with urination, blood in urine, nausea, and vomiting. For many, kidney stones are a lifelong problem.

Kidneys are essential for maintaining the body’s fluid and chemical levels, filtering waste from blood, and removing it through urination. Kidney stones can interrupt that process, causing blockages, swelling, and pain in your urinary system. If you’ve ever passed a kidney stone, you know how painful it can be.

Here are eight other facts you should know about kidney stones:

1. Kidney stones are formed from minerals and salts in urine. Normally, those minerals and salts are dissolved in water and excreted during urination. Sometimes they clump together instead, forming small stones. Kidney stones usually range in size from small as a grain of sand to as large as a pea. They can be larger, however. Small stones can usually pass in urine. Stones too large to pass may need to be removed using sound waves or surgery.

2. You might not even know you have kidney stones. If a stone stays in the kidney, you might not have any symptoms. If it moves down the urinary tract instead, a kidney stone can get stuck and block the flow of urine. It becomes painful at that point, and very obvious that something is wrong that might require medical attention.

3. Kidney stones have many causes, including genetics, dehydration, diet, bowel conditions or surgeries, obesity, certain medical conditions, or even certain medications and supplements.

4. Treatment depends on the type of stone, its size, where it’s located, and how long you’ve lived with symptoms. There are four main types of stones – calcium-based, uric acid, struvite, and cystine. Treatments can range from drinking water and pain medications for stones small enough to pass in urine, to surgery for stones too large pass.

5. Certain lifestyle choices can help prevent kidney stones. Eating a healthy diet, drinking plenty of water, and reducing salt intake can help keep stones from forming.

6. A heart-healthy diet, like the DASH plan (Dietary Approaches to Stop Hypertension), can prevent kidney stones, too. Eating fruit, vegetables, whole grains, fish, low-fat dairy, and lean proteins – while limiting saturated fats, salt, and sugar – benefits your entire body.

7. Kidney stones are more common in hot weather because of the greater risk of dehydration. Heat and humidity can cause you to lose more fluid than you take in. By the time you notice feeling thirsty, you’re already dehydrated. Drinking water is especially important in the heat.

8. Nearly 1 in 10 people will have a kidney stone at some point in their life, and more of those will be men than women.

If you think you have a kidney stone, it’s important to get medical attention right away. The pain you feel is a sign that urine is backing up in your urinary tract. That can cause an infection or more severe complications. To discuss kidney stones with a doctor, schedule an appointment today.