Kidney Contusion

A crushed kidney is an injury to the kidney caused by blunt force trauma. It is one of the most common renal trauma.

Kidney Contusion

What is kidney contusion?

In medicine, a kidney contusion is also referred to as a kidney bruise or kidney contusion. A single kidney or both organs can be affected by blunt force trauma.

According to the definition of the AAST (American Association for the Surgery of Trauma), kidney contusion is the lightest form of kidney trauma. With a share of about 70 percent, it is also the most common type of renal trauma. Contusion of the kidneys is accompanied by bruising (hematoma), swelling and pain in the flank region. See etaizhou for What does Hematochezia Mean.


If the kidney is crushed, there is often a connection with polytrauma. Those at risk include people suffering from kidney malformations and children. Men are up to four times more likely to suffer from a kidney contusion than women.

In about 80 to 90 percent of all cases, kidney contusions are caused by traffic accidents or sports injuries. Sometimes, however, a physical injury can also be the reason for the contusion. The medicine divides kidney contusion into several different degrees of severity. They range from grade I to grade V.

Around two thirds of all kidney injuries correspond to grade I. This is a contusion of the kidney with a hematoma inside the connective tissue capsule that surrounds the human kidney. The hematoma does not expand as it progresses. Although the functional tissue of the kidney is displaced, it is not damaged.

In grade II, there is a tear in the renal parenchyma of less than one centimeter. A perirenal hematoma can also exist. Grade III is when the parenchymal tear is more than one centimeter. Grades II and III can usually still be treated conservatively.

Severe kidney injuries and damage to the urinary tract are present in cases of severity IV and V. Part of the kidney function tissue may have been destroyed. It is even possible for the urinary tract to be torn off. Therefore, an operation is considered necessary for treatment.

Symptoms, Ailments & Signs

The symptoms of a kidney contusion can be different and sometimes non-specific. Symptoms do not always appear immediately after the accident, but only appear a little later. Most patients suffer from severe pain on the affected side of the flank.

This is usually boring, dull or stinging and appears on the back at the level of the navel. Sometimes the pain radiates to the back or abdomen. For example, some patients suffer from intense back pain and tension when they have a kidney contusion.

This is due to a pronounced networking of the nerve plexuses, which lead to cramping of the back muscles. Another typical symptom of kidney contusion is the formation of a bruise with swelling. Hematuria, which is blood in the urine, is also important. Physicians distinguish between microhematuria and macrohematuria.

Microscopic hematuria is when the urine is hardly discolored by the blood, while macroscopic hematuria is when the affected person can see the reddish discoloration with their eyes. In addition, complete red blood cells that have remained intact can be detected in the urine. But even if the urine is normal in color, kidney bleeding cannot be ruled out.

However, hematuria is considered an indication of numerous other diseases such as urinary stones or urinary tract infections, so that it cannot in principle be assigned to kidney contusion. Some patients also experience nausea and vomiting associated with renal contusion. If the symptoms do not improve or even worsen, a visit to the doctor is recommended.

Diagnosis & course of disease

The doctor first records the medical history in order to identify possible accidents as a trigger. A physical examination will then take place. Determining a crushed kidney is not considered difficult. However, it is important to rule out severe kidney damage that could necessitate an operation.

The doctor feels the injured area and looks for swelling, redness and bruising. Pressure pain is a typical sign of kidney contusion or kidney contusion. The doctor will also take a urine sample to check for bleeding.

Special test strips are used to detect microhematuria. In addition, imaging examination methods are available to rule out possible uncertainties. These include sonography (ultrasound examination), computed tomography (CT) and magnetic resonance imaging (MRI), which can be used to determine the exact extent of the kidney injury.

Although a kidney contusion is very painful, it rarely results in long-term damage. As a rule, the contusion heals by itself after a few days, so that a positive prognosis can be made.


Due to the kidney contusion, those affected usually suffer from severe pain in the area of ​​the kidneys and flanks. It is not uncommon for this pain to spread to other regions of the body, such as the back or hips. In the worst case, the person concerned dies from the kidney contusion if kidney failure occurs.

Patients are then usually dependent on dialysis or a kidney transplant. Abdominal pain can also occur as a result of kidney contusion and tension in the back. The urine may be red in color from bleeding. The risk of urinary stones or infections of the urinary tract can also increase significantly as a result of kidney compression. In some cases, those affected also suffer from vomiting or nausea.

Kidney contusion pain can be treated with common painkillers. There are no particular complications. In serious cases, however, surgical interventions are necessary to prevent the patient from dying. The life expectancy of the patient may be reduced due to the kidney crush.

When should you go to the doctor?

A kidney contusion can be present in different degrees of severity, so that medical or even inpatient treatment is not always mandatory. In most cases, such a bruise is caused by brute force, so that those affected complain of severe pain on the respective side. At the first sign of kidney pain, a doctor should definitely be consulted to avoid serious complications. In particularly bad cases, the pain can even spread to the back. Anyone who consults a doctor early can count on a full and speedy recovery.

If you do not visit a doctor, the pain is likely to increase significantly. In the worst case, the kidneys can even fail completely, posing an acute threat to life. There may be blood in the urine, which is a sign of bleeding in the kidney. At the latest when this symptom occurs, a doctor should be consulted immediately. A visit to the doctor can be dispensed with if the kidney is slightly bruised. The pain subsides on its own after a few days, so that no medical or drug treatment is necessary.

Treatment & Therapy

Treatment for a crushed kidney consists of several days of bed rest and gentle cooling of the crushed area. The application of the so-called PECH rule is recommended. In addition, the patient should be given plenty of fluids. In this way, the healing process can be well supported.

Drugs such as ibuprofen or diclofenac are suitable for treating the pain. Kidney contusion can almost always be treated conservatively. Surgeries are only performed for serious kidney injuries. In order to safely rule out worse impairments, ultrasound check-ups and a urine test must be carried out.

Outlook & Forecast

The prognosis for a crushed kidney depends on the extent of the trauma suffered. In the case of a slight bruise, freedom from symptoms can be documented after just a few weeks. There is pain, swelling and bruising. However, if there is no impairment of the functioning of the kidneys, the human organism often regenerates itself with sufficient rest and protection. Depending on the general state of health, the symptoms improve after just a few days. For some sufferers, the effects can affect everyday life for a few months.

In the case of a severe kidney contusion, further secondary disorders are to be expected. In addition to tension and internal bleeding, irreversible organ damage can occur. In addition, the risk of secondary diseases increases. The affected person is susceptible to infections and can therefore develop other health disorders.

If a severe kidney contusion is detected, an operation must be performed. Possible internal bleeding must be stopped as soon as possible so that a life-threatening condition due to bleeding can be ruled out. In addition, it is necessary to check how severe the injuries to the tissue are. If irreversible damage to the organ occurs, long-term therapy is required. In addition to drug treatment, dialysis may be required. If the course of the disease is unfavorable, the need for a donor organ can become relevant to ensure survival.


Preventive measures against kidney contusion are not known. Sometimes it can make sense to avoid aggressive contact sports.


In most cases, those affected have only very few and very limited options for aftercare in the event of a kidney contusion. For this reason, the sufferer should ideally see a doctor at the first signs and symptoms of the disease to prevent the onset of other ailments and complications. The further course of kidney contusion depends very much on the time of diagnosis, so that life expectancy cannot be predicted.

The person affected should drink a lot of fluids if they have a crushed kidney. In general, a healthy lifestyle with a healthy diet can have a very positive effect on the further course, although the person concerned should refrain from smoking and alcohol.

In many cases, it is also necessary to take various medications to alleviate and limit the symptoms. The patient should always pay attention to regular intake and to the prescribed dosage of the medicine. If anything is unclear or if you have any questions, consult a doctor first. As a rule, regular check-ups by a doctor are also very important in the case of kidney contusion.

You can do that yourself

In the case of a kidney contusion, the person concerned needs sufficient rest and protection. Physical exertion or sporting activities should be avoided. The movements should be performed slowly and evenly so that the organism is not exposed to further overload.

In the regeneration and healing phase, situations associated with stress and hectic have to be avoided. In addition to physical stress, emotional excitement must be kept to a minimum. The organism needs a sufficient amount of oxygen every day and a healthy and balanced diet. The consumption of harmful substances such as nicotine or alcohol must be completely avoided. Since a lack of exercise is initiated in the healing phase, the diet should not be too fatty. The number of calories consumed should be adjusted to the needs of the organism so that obesity does not develop.

The affected person often adopts a relieving posture due to the symptoms. Compensatory movements or lying positions should be used to prevent muscle problems or poor posture. The body can be supported with a sufficient supply of heat so that possible tension can be reduced or avoided. Since kidney contusion is associated with severe pain, those affected can use mental techniques to promote their well-being. Autogenic training or meditative states help to establish inner balance and support mental strength.