Kidney pain: what is the cause behind it?

inflammation of the renal pelvis

If the kidney connective tissue is inflamed due to a bacterial infection, severe kidney pain occurs. Depending on whether only one or both kidneys are affected, the kidney pain occurs on the right, left or on both sides.

A typical sign of renal pelvis inflammation (pyelonephritis) is an abrupt onset of high fever, sometimes accompanied by chills. There is also an increased urge to urinate, which makes urination more difficult and accompanied by pain. A previous inflammation of the urethra or bladder often triggers an inflammation of the renal pelvis.

Since the urethra in women is significantly shorter (and therefore more susceptible to invading pathogens) than in men, women are also more often affected by renal pelvis inflammation.

Glomerulonephritis

In addition to renal pelvis inflammation, glomerulonephritis is one of the kidney inflammations. The inflammation affects the kidney corpuscles—these filter waste products from the blood. If glomerulonephritis is present, this function is impaired. Deposits of antibodies on the kidney corpuscles probably trigger the inflammation. The inflammation, therefore, often occurs as a result of a previous infection.

In addition to kidney pain, symptoms such as high blood pressure (often accompanied by headaches), blood in the urine, flu-like symptoms and fluid retention (oedema), especially in the calves and eyelids, can occur.

Acute renal failure

Acute kidney failure, also known as acute kidney failure, can be accompanied by kidney pain. Abdominal and pelvic pain are also common symptoms. Fatigue, fever and nausea with vomiting can also occur. Another common sign is decreased urine output. Less than 500 millilitres per day is called oliguria, and less than 100 millilitres is anuria. In some cases, there may be no urine production at all. This leads to water accumulation in the legs or, worst case, in the lungs.

Depending on the underlying cause, not all symptoms may appear. The intensity can also differ. In acute kidney failure, the symptoms develop within hours or days. If acute kidney failure is suspected, a doctor should be consulted as soon as possible, or if severe symptoms are already present, the emergency doctor should be called. However, acute renal failure often occurs in patients who are already in intensive care.

Chronic renal failure

In the case of chronic renal failure or renal insufficiency, renal function decreases over several years. A previous illness, such as high blood pressure or diabetes mellitus, triggers this. If, at the beginning of the disease, an increased urge to urinate (even at night) is the main symptom, symptoms such as kidney pain, a decrease in the amount of urine, tiredness, vomiting, nausea, and water retention (oedema) occur later in the disease. Diarrhea, itching or restlessness at night and restless legs syndrome can also occur.

Kidney stones and kidney gravel

The intensity with which kidney stones trigger kidney pain depends entirely on their size and location. If the stones are more minor, one speaks of kidney gravel. This can be noticed by slight pulling in the area of ​​the kidneys or small amounts of blood in the urine.

Larger kidney stones can cause severe pain if the stones block urine flow within the urinary tract. A renal colic can be the result. A doctor diagnoses kidney stones with an ultrasound.

renal colic

Larger kidney stones can cause renal colic if they block urine flow through the urinary tract. If renal colic occurs, sudden, wavy, stabbing and severe kidney pain occurs, which can radiate into the thighs.

In addition, those affected suffer from nausea, vomiting and anxiety. The symptoms can last only a few minutes, but they can also last for a few hours. If renal colic is suspected, a doctor should be consulted urgently to prevent permanent kidney damage.

kidney cancer

In rare cases, kidney pain can also be a symptom of kidney cancer. The kidney pain often occurs on one side, and (at a later stage) swelling in the affected area can be felt. Other signs of kidney cancer are blood in the urine, swollen legs or new high blood pressure. Unspecific symptoms such as tiredness, fever, night sweats and weight loss can also indicate kidney cancer.

Autosomal dominant polycystic kidney disease

Autosomal dominant polycystic kidney disease (ADPKD) is a genetic condition that causes fluid-filled cysts to form in the kidney. In most cases, it is diagnosed after birth or in early childhood.

Chronic kidney pain is a common symptom. Blood in the urine and high blood pressure can also be signs of ADPKD. Those affected also suffer more frequently from kidney stones and urinary tract infections, such as a bladder infection.

kidney pain in pregnancy

If kidney pain occurs during pregnancy, so-called kidney congestion can be behind it. The symptoms can be unilateral or bilateral. The trigger is the increased amount of body fluid during pregnancy, which, as urine, is only slowly passed on from the kidneys to the bladder. If a large amount of urine backs up into the renal pelvis system, this is called kidney congestion.

Lighter forms have no clinical significance and are often symptom-free. However, if the pain is severe and there is nausea, vomiting, fever or blood in the urine, a doctor should be consulted urgently.