The kidneys are fist-sized organs shaped like beans. They’re located at the back of the middle of your torso, in the area called your flank. They’re under the lower part of your ribcage on the right and left sides of your backbone.
The main job of the kidneys is to filter waste out of your blood and produce urine to remove that waste — along with extra fluid — from your body.
When your kidney hurts, it usually means there’s something wrong with it. It’s important to determine whether your pain is coming from your kidney or from somewhere else so that you receive the right treatment.
There are muscles, bones, and other organs around your kidney, so it’s sometimes hard to tell if your kidney or something else is causing your pain. The type and location of the pain and any other symptoms can help point to your kidney as the source of your pain.
Kidney pain typically feels like a constant dull ache deep in your right or left flank, or both flanks, that often gets worse when someone gently hits the area.
Most conditions usually affect only one kidney, so you typically feel pain on only one side of your back. If both kidneys are affected, the pain will occur on both sides.
Symptoms that may accompany kidney pain include:
Kidney pain is a sign that there’s something affecting one or both of your kidneys. Your kidney may hurt for these reasons:
- Kidney stones. Kidney stones may occur in either or both kidneys, and they usually do not hurt until they pass into the tube connecting your kidney and bladder. You may pass a small stone without noticing it, but when it does hurt, it causes severe, sharp pain. You may also experience nausea or vomiting.
- Pyelonephritis (kidney infection). Pyelonephritis is an infection that can occur in one or both kidneys. The cause is a UTI that has spread. Pyelonephritis can result in fever, nausea, a burning feeling when urinating, and flank pain and tenderness.
- Hemorrhage. Bleeding in either or both kidneys can have a variety of causes, including injury, infection, and certain diseases. You’ll likely have blood in your urine along with pain in your abdomen or lower back.
- Renal vein thrombosis. In renal vein thrombosis, there’s a blood clot in either or both of the renal veins connected to your kidneys. There may be no symptoms if the clot develops slowly. With a sudden clot, you may feel extreme pain in your flank and soreness around your ribs.
- Hydronephrosis. A blockage called hydronephrosis can cause your urine to back up and fill one of your kidneys with water, making it swell. Hydronephrosis usually affects only one kidney, but in some cases it can affect both. You may feel persistent dull pain with occasional bouts of severe pain. Symptoms may also include nausea and painful urination.
- A mass or cancer. You can have a benign, noncancerous mass or kidney cancer in one or both kidneys. It may cause you to feel tired, have swelling in your kidney area, and experience persistent pain in your lower back or side.
- Cyst. A sac of fluid may form in either or both kidneys. Kidney cysts do not usually cause symptoms, but sometimes the cysts can get bigger and press against your organs, resulting in abdominal pain. If the cyst ruptures, you may feel extreme pain in your side.
- Polycystic kidney disease (PKD). In this inherited condition, many cysts grow in both kidneys and can damage them. As PKD progresses and the cysts grow, you may sometimes have periods of intense pain in your back and sides. You may also have kidney stones, high blood pressure, and blood in your urine.
- Renal artery aneurysm. In this rare condition, there’s a small, weakened section of the artery wall in one or both of your kidneys. Typically, there are no symptoms. If the aneurysm tears, you may feel pain in your flank.
- Atheroembolic renal disease. If plaque breaks off from a larger artery, it can block small arteries to either kidney. You may experience abdominal pain along with other symptoms, such as diarrhea and fever.
Depending on the condition that’s causing your kidney pain, you may be able to treat it with home remedies, medications, or surgery.
Conditions such as kidney stones and cysts sometimes resolve on their own.
Drinking lots of water is one of the main treatments for smaller kidney stones.
A doctor may prescribe medications to treat different conditions. These can include:
- antibiotics for pyelonephritis or other kidney infections
- anticoagulants, or medications to prevent blood clots, for conditions such as renal vein thrombosis
- targeted cancer medications such as sunitinib (Sutent) and sorafenib (Nexavar) to stop tumor growth
- blood pressure medications to help with PKD
- cholesterol medications to help with atheroembolic renal disease
In some cases, surgery may be necessary to treat your kidney condition. For example, renal artery aneurysms may require surgery if the weakened part of the artery wall is expanding or tearing.
With the help of a thin, lighted microscope, a surgeon can create a small incision and remove kidney cysts. In ureteroscopy, a thin telescope passes up through your bladder and into your kidney. A surgeon can use this technique to remove larger kidney stones.
If a kidney has been significantly damaged, such as from hydronephrosis or cancer, it may need to be removed entirely. For most people, the remaining kidney is enough on its own.
A surgeon may also remove only the section of kidney with a tumor, or use cryotherapy to freeze and destroy the tumor alone.
Tips for preventing kidney pain
You may be able to use home remedies to prevent some of the conditions that cause kidney pain. To reduce your risk of developing bladder infections that can lead to kidney infections, it’s best to take these steps:
- Drink plenty of water.
- Urinate as soon as you feel the urge to go.
- Urinate after sexual intercourse.
- Wipe from front to back when using the restroom, if you have a vulva.
Note that if you have kidney failure, you may need to limit the amount of water you drink.
You can also reduce your risk of kidney cancer by taking these steps:
Below are a few questions that people often have about kidney pain.
How do I know if it’s kidney pain?
It can be hard to distinguish between kidney pain and back pain.
Back pain is more common than kidney pain. In general, back pain will be related to your muscles, occurs lower in your back, and causes a consistent ache.
If it’s kidney pain, it’ll likely be higher, near your ribs. You may feel waves of severe pain and possibly have a fever. The pain may also be stronger on one side.
What should I do if my kidneys hurt?
If you think you’re experiencing kidney pain, it’s important to talk with a doctor.
Kidney pain is almost always a sign that something is affecting your kidney. If you have kidney pain, contact a doctor as soon as possible to determine the cause of your pain.
If the condition that caused your kidney pain isn’t treated promptly and appropriately, you may experience kidney failure, where your kidneys stop working.
It’s especially important to contact a doctor right away if your pain is severe and started suddenly. This is often caused by a serious problem — such as renal vein thrombosis or bleeding into your kidney — that needs emergency treatment.