Kidney pain

and Sabine Schrör, medical journalist

Hanna Rutkowski is a freelance writer for the medical team.

More about the experts

Sabine Schrör is a freelance writer for the medical team. She studied business administration and public relations in Cologne. As a freelance editor, she has been at home in a wide variety of industries for more than 15 years. Health is one of her favorite subjects.

More about the experts All content is checked by medical journalists.

Kidney pain is often mistaken for back pain. The reason for this is the location of the kidneys in the upper back of the abdomen, on the right and left of the spine. Diseased kidneys make themselves felt as stabbing flank pain or dull pain in the lower back. Read here what can be behind kidney pain and what you can do about it yourself.

Brief overview

Description: Kidney pain is stabbing or dull pain that is independent of movement, to the side of the vertebral column in the lower back, possibly spreading to the lower abdomen and groin.
Causes: inflammation of the renal pelvis (pyelonephritis), kidney stones, glomerulonephritis (inflammation of the kidney corpuscles), kidney tumor, cyst kidney, acute or chronic kidney failure (acute or chronic kidney failure)
When to the doctor Always have kidney pain clarified by a doctor. Untreated kidney diseases can lead to permanent kidney damage and secondary diseases such as edema, high blood pressure and anemia.
Diagnostics: physical examination, blood and urine samples, imaging procedures such as ultrasound (sonography), computed tomography (CT), magnetic resonance tomography (magnetic resonance tomography, MRI).
Treatment: Depending on the cause, e.g. shock wave lithotripsy for kidney stones, antibiotics for inflammation, blood washing (dialysis) or kidney transplantation for kidney failure. Self-treatment for acute kidney pain (until you can reach a doctor) in the form of warmth and hydration.
Prevention: Kidney stones can be prevented with a low-salt diet and with 2-3 liters of fluid per day.

Kidney pain: description

The kidneys are embedded in protective fat capsules to the right and left of the spine, roughly at the level of the two lowest ribs. On top of each kidney is a hormone-producing adrenal gland. Because of the close proximity of the kidneys to the spine, kidney pain is often confused with back pain. The discomfort manifests itself as flank pain or pain in the lower back. In addition, there are usually painful complaints in the lower abdomen.

This is where the kidneys are:

What are the kidneys doing?

The kidneys filter the blood: Millions of tiny, sieve-like vessels (kidney corpuscles, glomeruli) extract excess fluid, salts and toxins from the body's juice. The filtered substances enter the urinary bladder via the renal pelvis and ureter. Around 180 liters of fluid are filtered out every day. Around 1.5 liters of this so-called primary urine remain and are excreted as urine.

But the kidneys not only regulate the water and salt balance, they also produce and activate important hormones: the so-called renin is involved in regulating blood pressure, while erythropoietin promotes the formation of new red blood cells in the bone marrow.

Kidney pain: causes

Kidney pain is mostly based on inflammation caused by kidney stones or ascending bladder infections. Women are affected far more often than men because of their shorter urinary tract.

The main causes of kidney pain are:

Renal pelvic inflammation: This so-called pyelonephritis usually occurs when bacteria rise into the kidneys as a result of a bladder infection. Typical symptoms are severe, sudden flank pain, fever, chills, vomiting and abdominal cramps, blood in the urine and frequent urination.

Kidney stones: They are formed from deposits of salt in urine. If they slide from the renal pelvis through the narrow urinary tract to the bladder or even clog the ureters (urine congestion!), Severe, cramp-like pain can occur. Men are significantly more likely to develop kidney stones than women.
Inflammation of the kidney corpuscles: The kidney corpuscles (glomeruli) can become inflamed as a result of autoimmune diseases or medication. This glomerulonephritis can lead to kidney failure. Typical signs are blood in the urine, frequent urination and protein in the urine.
Kidney tumor: In advanced stages, a kidney tumor can cause severe kidney pain. Other symptoms include blood in the urine and a palpable swelling.
Cyst kidneys: Mostly hereditary disease in which numerous fluid-filled cavities (cysts) form in the kidneys. This is often associated with flank pain, frequent urinary tract infections and high blood pressure. In the long term, a cyst kidney can lead to kidney failure.

How kidney pain can arise

Kidney pain can be caused by inflammation, among other things. Most commonly affected: the renal cortex or medulla and the renal pelvis.

In addition, the following ailments and diseases can be associated with kidney pain:

Chronic kidney failure: The kidneys slowly lose their ability to function, for example as a result of diabetes mellitus (diabetes), high blood pressure, untreated kidney stones, cyst kidneys or medication. The first possible warning signs include mild high blood pressure, foamy or red urine, and water retention in the legs. Later signs are increased infections, anemia, decreased performance and pale skin. However, kidney failure can also be completely symptom-free.
Acute kidney failure: The kidneys can lose their functionality within a short time due to vascular occlusions, burns or large blood loss, medication or kidney stones. The symptoms are not always clear. However, if acute kidney failure is not treated immediately, there is a risk to life!
Menstrual pain: some women experience menstrual pain before or during their period, which can manifest itself as (supposed) kidney pain, among other things.

Consequences of kidney dysfunction

If the kidneys do not work properly, there is a risk of secondary diseases:

Water retention in the tissue (edema): When the kidneys are weak, the tissue increasingly stores water. Water retention in the legs is typical.
High blood pressure: The blood pressure regulating hormone renin is produced in the kidneys. An undersupply of the kidneys with oxygen therefore leads to high blood pressure. A narrowing of the renal artery (renal artery stenosis) is usually responsible for this.
Anemia: In chronic kidney failure, the kidneys release a smaller amount of the hormone erythropoietin, which stimulates the production of red blood cells. The result is anemia.

Kidney pain: symptoms

Kidney pain can be recognized by the fact that, unlike back pain, it is not dependent on movement. In addition, they are usually not persistent, but occur in a convulsive manner. They spread laterally along the spine to the lower abdomen and the groin - on one side if only one kidney is damaged or sick, and on both sides if both kidneys are affected.

Kidney pain: when do you need to see a doctor?

Kidney pain should always be clarified by a doctor, unless it is due to menstrual cramps or harmless kidney stones. Because bacterial infections that have risen from the urinary tract or the bladder and cause kidney inflammation cannot be brought under control with home remedies alone. In the worst case, the symptoms are alleviated, but the pathogen is not eliminated and the foundation for chronic kidney disease is laid.

Kidney pain often only occurs when the kidney is already damaged. To prevent worse damage, you should therefore always consult a doctor in the event of pain in the kidney area.

A doctor's visit is particularly urgent if:

the kidney pain persists for several days
the urine is red in color (hematuria)
Fever, chills, and spasmodic kidney pain occur together
Vomiting and diarrhea are added
no more urine is produced (lack of urination), or the urine can no longer be excreted (urinary retention)
the heartbeat slows, dizziness and loss of consciousness occur
water collects in the legs or other parts of the body

Kidney pain: that's what the doctor does

Kidney pain does not go away on its own. Only when a kidney stone passes can the colic-like symptoms subside spontaneously as soon as the kidney stone has passed the ureter. As a rule, however, an examination and treatment by the doctor is necessary to determine the cause of the kidney pain and to eliminate it.

Kidney Pain: Finding the Cause

The doctor will first ask you carefully about your medical history (anamnesis). Among other things, he will have your complaints detailed, ask how long they have existed and whether there are any illnesses (acute cystitis, diabetes mellitus, high blood pressure, etc.). How often and how much water you urinate is also important for the diagnosis.

The anamnesis is followed by a physical examination. This enables the doctor to recognize other symptoms such as fever, high blood pressure, water retention or abnormal heart sounds.

A blood test can provide evidence of inflammation. In the case of kidney pain, a urine sample is also mandatory, as changes in the urine can indicate kidney disease early on. For example, foamy urine indicates that there is protein in the urine (proteinuria), which can indicate a kidney dysfunction, for example. Red colored urine (hematuria), on the other hand, can indicate kidney inflammation, kidney tumor or kidney failure.

Conclusions about the functionality of the kidneys can also be drawn from certain blood and urine values:

Urea, creatinine, and cystatin C are normally filtered out of the blood by the kidneys. If the kidney function is impaired, however, the concentration of these substances in the blood increases. The concentration of the substances in the urine is also measured and then compared with the blood values. From this, the filter performance of the kidneys can be calculated (creatinine clearance).
Uric acid is produced when dead body cells are broken down and is excreted via the kidneys. Elevated uric acid levels can indicate, among other things, severe kidney dysfunction.

In addition, the PAH clearance can be used to check how well the kidneys are supplied with blood. To do this, the substance para-aminohippuric acid is injected and then measured in blood and urine. The inulin clearance makes it possible to measure the filtration capacity of the kidney corpuscles (glomeruli). Here, too, the amount of substance in blood and urine is determined and calculated after intravenous injection.

If the cause of the kidney pain cannot be clearly identified by these examinations, further diagnosis is made with the help of imaging tests. The doctor can use ultrasound (sonography) to assess the shape of the kidneys and identify any pathological changes (such as cysts or tumors). Sometimes more imaging tests are needed. These include, for example, computed tomography (CT), magnetic resonance imaging (MRT) and x-ray examinations of the lower urinary tract using a contrast agent (urography).

Treatment of kidney pain

Which therapy the doctor prescribes depends on the cause of the kidney pain. Some examples:

Kidney stones often go off on their own. If this does not happen, the doctor can use shock waves to shatter them (shock wave lithotripsy). Pressure waves are generated on the surface of the skin, which continue into the kidney stone and break it up. Kidney stones rarely have to be removed surgically.

The doctor combats bacterial urinary tract infections and inflammation of the renal pelvis with a suitable antibiotic. This means that the kidney pain will quickly subside. Even so, antibiotics must be taken for as long as prescribed by the doctor. Otherwise, not all pathogens may be killed.

Kidney failure is an absolute emergency! It is treated with blood washing (dialysis). Sometimes a kidney transplant may also be necessary.

Kidney pain: you can do it yourself

The following tips will help you to relieve kidney pain in the short term before you see a doctor:

Keep yourself warm: a hot water bottle or a thick woolen scarf around the kidneys relax the muscles.
Drink a lot: Diuretic teas made from nettle or dandelion flush the kidneys and flush out bacteria.
You can force the removal of kidney stones by drinking a lot, bathing warmly or using a warming pillow. Hopping movements can also help the stone get through the urinary tract faster.

Important: These tips are not a substitute for a visit to the doctor! Always take kidney pain seriously and have it checked out by a doctor.

Prevent kidney stones

If you eat a low-salt diet and drink at least two to three liters of fluid a day, you can prevent kidney stones and the associated kidney pain. This is especially important for people who have had kidney stones before. You are more prone to getting some again.

Tags: organ systems therapies stress