Your kidneys are a pair of bean-shaped organs below the ribs, behind your belly, one on each side of your spine. Each kidney is about four inches long, almost the size of your fist. These organs are responsible for removing wastes, filtering your blood, controlling your body’s fluid balance, and maintaining the right levels of electrolytes.
Each kidney has a million small filters called nephrons. Your kidneys filter 120 to 150 quarts of blood every day, producing one to two quarts of urine, which is composed of wastes, minerals, salt, and extra fluid. The filtered blood circulates back into your body. Kidneys also help keep your blood healthy by producing erythropoietin (EOP), a hormone needed for making red blood cells.
Flank or kidney pain can be a sign of urinary tract infection or kidney infection. Other possible causes are kidney stones and cysts. If you are experiencing acute, sharp pain, it is best to see your doctor rule out any severe conditions.
Location of your kidneys
Kidneys are two organs that are shaped like a bean on either side of the spine. They are located below the rib cage, behind the abdomen, and under the liver. The right kidney sits a bit lower than the left one as the biggest part of the liver is on the right side of the abdomen.
Most problems or infections with your kidney cause middle back pain or flank pain. However, the pain is not always felt where the kidneys are located. According to Medicine Net, flank or renal pain can be felt anywhere between your lowest ribs and your buttocks. In some cases, the pain may radiate to your abdominal area.
The pain can be felt in just the right or left side of the back, depending on its underlying cause. But sometimes, kidney pain may affect both sides of your back. Although it can be hard to distinguish between back pain and kidney pain, kidney pain usually comes with other symptoms.
Common symptoms of kidney pain
Musculoskeletal problems are common causes of back pain. However, back pain can also be a sign of a kidney problem. In addition to the pain in your middle back, groin area, or abdomen, kidney pain also comes with other symptoms, including:
- Nausea and vomiting
- Fever and chills
- Burning sensation while urinating
- A strong urge to urinate but in small amounts
- Urine that is cloudy or has a foul odor
Different Causes of Kidney Pain
Most flank pain or kidney pain occurs around the location of your kidneys. The pain and location also depend on the underlying cause of kidney infections or disease that can cause pain in other body areas.
#1. Urinary Tract Infection
Urinary tract infection is an infection in any part of the urinary system – the urethra, bladder, ureters, and kidneys. In most cases, the infection involves the lower urinary tract, the urethra, and the bladder. This condition occurs when bacteria enter the urinary tract and start to multiply in the bladder.
The common signs and symptoms of UTI include a burning sensation when urinating, strong-smelling urine, persistent urge to urinate, urine that looks bright pink, red, or cloudy, and pelvic pain in women.
Doctors often treat this condition with antibiotics. Besides medications, it is also important to drink plenty of water, avoid drinks that irritate your bladder, and empty your bladder after intercourse. Avoid feminine products that can irritate the genital area.
#2. Kidney Stones
Kidney stones are hard deposits composed of salts and minerals that form in the kidneys. These stones occur when your urine becomes concentrated and allows minerals to stick together and crystallize.
Kidney stones may cause symptoms when moving around the kidney or passing into the ureter. You may experience severe pain below the ribs, foul-smelling or cloudy urine, nausea and vomiting, pain during urination, and pain that radiates to the groin and lower abdomen.
Other symptoms include fever and chills, urinating more often than normal and small amounts, and pink, brown or red urine. Small stones can be treated with pain relievers, drinking water, and medical therapy.
More extensive treatment may be required in cases of large stones, such as surgery, parathyroid gland surgery, and sound waves.
#3. Kidney Infection (Pyelonephritis)
Pyelonephritis is a urinary tract infection that starts in the bladder or urethra and travels to your kidneys. This condition requires immediate medical attention.
If not treated properly, it can damage the kidneys permanently. Bacteria can enter your bloodstream and may result in severe infection.
An infection’s signs and symptoms may include chills, fever, flank, groin or back pain, frequent urination, and abdominal pain. You may also experience pain or burning sensation when urinating, blood or pus in urine, nausea and vomiting, and urine that is cloudy or smells blood. Doctors may prescribe antibiotics as the first line of treatment. It is also vital to stay hydrated and avoid delaying urination.
#4. Kidney Cysts
Another possible cause of kidney pain is a kidney cyst around a pouch of fluid that develops on or in the kidney. Kidney cysts can be linked to other severe disorders that may damage the function of your kidneys.
But in most cases, these noncancerous cysts rarely cause further complications. Although the exact causes aren’t clear, its symptoms may include upper abdominal pain, fever, and dull pain in your side or back.
Kidney function and imaging tests are required to diagnose kidney cysts. If it doesn’t interfere with your kidney function and there are no symptoms, treatment may not be needed. For cysts that cause pain and other symptoms, procedures include puncturing and draining the cysts and surgery to eliminate the cyst.
#5. Blood Clots
Renal vein thrombosis is a blood clot that forms in one or both renal veins. The two renal veins are responsible for draining oxygen from your kidneys.
According to Medicine Net, blood clots can cause serious damage to your bean-shaped organs and may result in other life-threatening conditions.
The most common symptoms of renal vein thrombosis include lower back pain, decreased urine output, and bloody urine. Other symptoms include fever, hip pain, nausea, and vomiting.
Treatment for this problem depends on the size of the clot and its locations. For small blood clots, doctors may recommend rest until the clot goes away and symptoms improve. Your physician may also prescribe blood thinners or thrombolytic medication to prevent blood clots or dissolve existing clots. In cases of severe RVT, surgery may be required to remove clots.
#6. Chronic Kidney Disease
Also called chronic kidney failure, chronic kidney disease is the gradual loss of kidney function due to different conditions and diseases. Possible causes include high blood pressure, polycystic kidney disease, diabetes, kidney stones, enlarged prostate, vesicoureteral reflux, and recurrent kidney infection.
Symptoms of chronic kidney disease may include vomiting, nausea, sleep problems, chest pain, shortness of breath, decreased mental sharpness, fatigue, and weakness.
Other signs are hypertension, loss of appetite, swelling of ankles and feet, muscle twitches, and cramps. The treatment for this disease depends on the underlying cause. However, chronic kidney disease has no cure but can be treated.
If the kidneys can no longer keep up with fluid and waste clearance, dialysis or a kidney transplant will be required. Depending on your situation, doctors may recommend a special diet to limit the work of your kidneys.
Diabetic kidney disease is a complication that develops in individuals with diabetes. When this occurs, the filters of the kidneys become damaged.
Studies show that 1 out of 4 people with diabetes have kidney disease, making it difficult for the organs to filter blood. This causes toxins and wastes to build up in the body and may cause other health issues.
Having diabetes for a long time increases the risk of damaging your kidneys. People with diabetes are more likely to experience kidney disease if blood pressure or blood glucose is too high. Those who smoke, overweight, not active, have heart disease, don’t follow eating plans, and have a family history of kidney disease or failure are more likely to get this condition.
#8. Kidney Injury
A blow to your back might cause kidney pain if it injured your kidneys. But according to Mayoclinic, kidney injury may also occur after long-term use of certain medicines, a severe drop in blood flow to the kidneys, or ingesting poisons.  Kidney injuries may also reduce the amount of urine and cause nausea, vomiting, loss of appetite, and swelling in your legs.
#9. Kidney Cancer
Also called renal cancer, kidney cancer occurs when kidney cells become cancerous or malignant and grow out of control, developing a tumor. Most kidney cancers first appear in the lining of tubules (tiny tubes) in the kidney. With imaging techniques like CT scans, kidney cancers can be found easily before they spread to other organs. These allow patients to treat the disease successfully.
Kidney cancer may not cause any signs or symptoms during the early stages. But in later stages, you may experience loss of appetite, tiredness, blood in urine, unexplained weight loss, pain in the back or side, and fever. If you experience any symptoms that worry you, it is best to make an appointment with your doctor.
Pregnancy can also cause kidney pain as it increases the risk of developing blood clots or urinary tract infections, which can cause back pain. Because the uterus is growing, it may prevent the normal flow of urine and cause infections.
You can reduce kidney pain by drinking lots of water, consuming lemon juice, eating more fruits and vegetables, and basil leaves in your salad every day. Although UTIs are common among pregnant women, it is best to visit your doctor for a proper diagnosis.
Hydronephrosis is the swelling of one or both kidneys, which happens when urine cannot drain properly from a kidney and gathers in the organ. This condition does not always show any signs, but when they occur, symptoms of hydronephrosis may include fever, frequent need to urinate, pain in the back and side, nausea, and vomiting.
The common causes of hydronephrosis are vesicoureteral reflux and partial blockage in the urinary tract. Vesicoureteral reflux occurs when urine goes backward through the ureter from the bladder into the kidney. Doctors may require a blood test, urine test, ultrasound imaging exam, or X-ray to diagnose hydronephrosis.
Treatments will depend on the underlying cause, but many cases of this condition resolve on their own. In severe circumstances, surgery may be necessary to correct the reflux or remove the blockage.
When to See a Doctor
Pain in your middle back that radiates to your groin or abdomen is usually a sign of a serious health problem. It is important to visit your doctor immediately if you suspect kidney pain. The warning signs of kidney problems are:
- High blood pressure
- Swelling of your hands and feet
- Sudden sharp flank pain
- Blood in your urine
- A dull, constant one-sided pain in your side or back
- Painful and/or frequent urination
Call your doctor if you also experience fatigue, body aches, and fever. Seek medical attention if you have sudden, severe kidney pain, even if blood is not present in your urine.
Without kidneys, our bodies would not maintain healthy blood pressure, keep essential minerals and water balance in our bloodstream, activate vitamin D for bones, increase the production of red blood cells, and extract waste and chemicals.
However, some diseases can increase the risk of kidney diseases, such as hypertension and diabetes. Kidney pain can be on the right, left, or both sides. The causes are diagnosed with a physical examination, a person’s history, lab tests, CT scans, and MRI.
Treatment for the pain depends on the main cause, but in many cases, acetaminophen (Tylenol), ketorolac (Toradol), and ibuprofen (Motrin) are used to alleviate the pain. In cases of bacterial infections, antibiotics are prescribed by doctors. For symptoms that worry you, it is best to see a physician for proper diagnosis and prompt treatment.