- Kidney pain is often felt in the lower back or side and may affect one or both sides.
- Common causes include kidney stones, infections, cysts, hydronephrosis, tumors, trauma, and spine problems.
- Seek medical care for severe pain, fever, blood in the urine, reduced urination, or pain when urinating.
Kidney pain is usually felt in the lower back or along one or both sides of the body, just below the ribs. It can be caused by kidney stones, kidney infections, hydronephrosis, kidney cysts or tumors, trauma, or even conditions affecting the spine.
Depending on the cause, kidney pain may occur with fever, chills, blood in the urine, changes in urine color, pain or burning when urinating, frequent urination, or nausea and vomiting. The pain may be sharp and severe or constant and may spread to the groin or abdomen.
Treatment for kidney pain depends on the underlying cause and may include pain medication, antibiotics, dietary changes, surgery, or other specialized treatments. Severe kidney pain or pain accompanied by fever, blood in the urine, or reduced urine output requires prompt medical evaluation.
What it feels like
Kidney pain is usually felt in the lower back or along the side of the body. It may affect one or both sides.
The pain is often sharp, severe, and cramp-like and may spread to the groin or abdomen. It may also feel like constant pain in the upper abdomen and back that does not improve when changing positions.
Kidney pain may occur with pain or burning when urinating, frequent urination, reduced urine output, or blood in the urine. According to the National Institute of Diabetes and Digestive and Kidney Diseases, kidney stones may also cause cloudy or foul-smelling urine, fever, chills, nausea, and vomiting.
Seek immediate medical attention if kidney pain develops. A healthcare provider can identify the cause, begin the most appropriate treatment, and help prevent complications such as a severe kidney infection, kidney abscess, or kidney failure.
Main causes
The main causes of kidney pain are:
1. Kidney stones
Kidney stones can cause severe pain that may spread to the abdomen, groin, or genital area. They may also cause pain when urinating and pink, red, or brown urine due to small amounts of blood.
What to do: Treatment depends on the type of kidney stone. It may include pain medication, dietary changes, or laser lithotripsy, which breaks the stone into smaller pieces that can pass more easily through the urine.
2. Pyelonephritis
Pyelonephritis is a kidney infection that can cause severe lower back pain, fever, and chills. Other symptoms may include pain or burning when urinating, frequent urination, and very strong-smelling urine.
What to do: Drinking plenty of water may be recommended to help the body clear the microorganism causing the infection. A primary care provider or nephrologist may also prescribe antibiotics and medication to relieve symptoms, such as acetaminophen.
3. Kidney cysts or polycystic kidney disease
Kidney cysts are fluid-filled sacs that develop in the kidneys. A person may have one cyst or several cysts, and multiple cysts may be associated with polycystic kidney disease.
Large or numerous cysts may cause blood in the urine, lower back pain, high blood pressure, and frequent urinary tract infections (UTIs).
What to do: Treatment should be guided by a nephrologist. It may involve medication when the cyst is small or surgery to remove larger cysts.
4. Hydronephrosis
Hydronephrosis is swelling of one or both kidneys caused by a buildup of urine that cannot drain properly into the bladder. It may cause lower back pain, difficulty urinating, a low-grade fever, nausea, and vomiting.
What to do: Medical care is needed to drain the accumulated urine and identify the cause of the blockage. Possible causes include kidney stones, a severe UTI, or a kidney tumor.
5. Renal vein thrombosis or renal ischemia
Renal vein thrombosis occurs when a blood clot blocks a vein that carries blood away from the kidney. This can disrupt blood flow in the kidney and may lead to kidney cell damage and acute kidney failure.
This condition is very rare and can be difficult to detect because it may not cause symptoms. When symptoms occur, they may be mistaken for more common conditions and can include kidney pain, blood in the urine, and decreased urination.
What to do: It is important to seek medical care so imaging tests can be performed to identify the problem. Treatment generally involves anticoagulant medication, surgery, or both, depending on the severity of the condition.
6. Trauma
An injury or blow to the back, especially around the waist, can cause inflammation and pain in the kidney area.
What to do: Place a warm compress on the back and rest. Pain relievers or anti-inflammatory medications may also be used as directed by a healthcare provider.
7. Kidney cancer
Kidney cancer generally does not cause symptoms during its early stages. Symptoms may develop as the disease advances.
Possible symptoms include blood in the urine, pain on one side of the abdomen or in the lower back, unexplained weight loss, and fatigue.
What to do: Treatment is provided by an oncologist and depends on the stage of the tumor. It may include surgery, radiofrequency ablation, radiation therapy, immunotherapy, chemotherapy, or medication to relieve symptoms.
8. Spine problems
Spine problems such as poor posture, repetitive strain, a herniated disk, or irritation of the sciatic nerve can cause pain in the lower back, where the kidneys are located.
What to do: A primary care provider should assess the symptoms and perform a physical examination.
Diagnostic tests, such as a spinal X-ray, may be ordered when necessary to identify the cause and determine the most appropriate treatment.
Online symptom checker
Select the symptoms you are experiencing to find out whether you may have a kidney problem:
The kidney problem symptom checker is only a guidance tool. It does not provide a diagnosis or replace an appointment with a nephrologist, urologist, or primary care provider.
Kidney pain during pregnancy
Kidney pain during pregnancy is often caused by changes in posture and the added strain of the baby's growing weight on the back.
However, it may also be caused by a kidney condition. The normal physical changes that occur during pregnancy make pregnant people more susceptible to urinary tract and kidney infections.
What to do: Contact your healthcare provider if you have severe back pain, pain or burning when urinating, blood in the urine, changes in urine color, fever, or chills. These symptoms may be signs of a kidney infection and should be evaluated promptly to help prevent complications.
If the pain is related to the weight of the growing abdomen, applying a warm compress to the painful area may help. Sitting in a comfortable chair with the feet elevated can also help relieve back pain and reduce swelling in the feet.