Most of us are familiar with normal bruising, specifically when the skin becomes discolored and painful to the touch. What many individuals do not know, however, is that you can bruise your internal organs. More specifically, you can injure your kidneys due to trauma. A bruised kidney can be severe, requiring careful medical management. To help understand this injury, this article will discuss bruised kidneys and how they are managed.
What is a bruised kidney?
Your kidneys are two bean-shaped organs belonging to your renal (urinary) system that serve various functions throughout the body. They are positioned in the middle of your back, right below the ribs. A single kidney sits on either side of the spine.
The kidneys execute several bodily functions. Their roles include:
- Filtering blood. The kidneys filter blood by removing waste and excess water, which exit the body as urine.
- Maintaining a balance between fluid and electrolyte levels. The kidneys help support equilibrium within the body by promoting the proper levels of fluid and electrolytes. Electrolytes include minerals such as sodium, calcium, potassium, and magnesium.
- Regulating blood pressure and red blood cell counts in the body.
Because the kidneys support several critical bodily functions and processes, they must work properly and be healthy. Certain conditions, such as diabetes and high blood pressure, can adversely affect the kidneys. Additionally, trauma from an external force can also injure the kidneys. When this occurs, you may experience what is called a bruised kidney1.
Injuries to the urinary system are uncommon and account for only 10 percent of traumas. When trauma does occur in this area, however, the kidneys are most likely to be damaged2. Having a bruised kidney can prevent your kidneys from working correctly, affecting things such as your blood pressure and fluid and electrolyte levels. Therefore, if you experience an injury to this area, it is vital to seek medical treatment to ensure proper healing and functioning1.
How does a bruised kidney happen?
Usually, your back muscles and ribs protect the kidney from external force. Occasionally, these barriers cannot guard against significant trauma, which can damage the renal system and bruise the kidneys. Trauma to the body, specifically the kidneys, is categorized as being either blunt or penetrating in nature.
- Blunt trauma. Blunt trauma refers to an injury from an object that does not penetrate the skin. In these instances, an external force strikes the organ and pushes it against the muscles. Car accidents, falls, hard hits to the renal area, or stopping too fast can cause blunt injury. Such situations can damage the kidney but may not cause the skin to break. Between 80 to 90 percent of bruised kidneys are due to blunt abdominal trauma.
- Penetrating trauma. Penetrating trauma is an injury that breaks the skin and enters the body. Likewise, gunshot and stab wounds are the most common causes of penetrating kidney damage. Penetrating renal trauma accounts for up to 20 percent of bruised kidney cases1,2.
Is a bruised kidney serious?
Most bruised kidney cases are minor; however, some injuries can be severe. If left untreated, renal injury can lead to complications like bleeding, infection, high blood pressure, kidney failure, or kidney loss3. Therefore, if you experience trauma in this area, it is best to seek medical attention.
The American Association for the Surgery of Trauma (AAST) developed a classification system to categorize bruised kidneys. These categories communicate how serious a kidney injury is and how to proceed with treatment. Based on your presentation, your provider can classify your bruised kidney into one of the five grades. A grade I bruised kidney is the least severe type of injury, while a grade V injured kidney is the most severe4.
Bruised kidney symptoms
What does a bruised kidney feel like?
You should understand the signs and symptoms associated with kidney injury to know when to seek medical attention. Patients with renal bruising commonly experience feelings of pain and tenderness located in their back or abdomen. However, not all individuals will have symptoms of a bruised kidney2.
Bruised kidney signs?
The symptoms you experience due to an injured kidney may vary depending on thetype of trauma you experienced (blunt or penetrating). The most common sign of kidney injury is blood in the urine. Other common bruised kidney symptoms include:
- Back pain
- Abdominal pain and swelling
- A bump in the back or abdomen
- Bruising or discoloration of the skin
- Wounds near the kidneys
- Muscle spasms
- Nausea and vomiting2,5
In some cases, a bruised kidney can cause more severe complications such as:
- Low blood pressure
- Trouble urinating
- Internal bleeding (can manifest as fatigue, dizziness, nausea, vomiting, or low blood pressure)
- Kidney failure
How to treat a bruised kidney?
There are a few ways to treat a bruised kidney, and how your provider treats it will depend on the injury’s severity. Experts categorize renal injury treatment in two ways: non-operative or operative. Non-operative approaches do not involve surgery and sometimes include minimally invasive procedures. Operative approaches involve surgery. The types of bruised kidney treatment are detailed below.
Non-operative management (NOM) is best for patients with blunt grade I or grade II renal trauma, meaning that the injury is only mild or moderate. If clinically indicated, some grade III, IV, or V patients can also be managed using NOM. Patients receiving NOM, however, must be hemodynamically stable. Hemodynamically stable means that your blood flow is steady and your blood pressure is normal. In studies, NOM was successful in up to 95 percent of kidney trauma cases4.
NOM involves supportive care measures, typically provided in the intensive care unit (ICU). Additionally, providers will execute routine clinical assessments, regularly measure hematocrit levels, and transfuse blood products as needed. As you heal, you can receive less frequent labs, step-down from the ICU unit, and eventually go home2.
For some patients, NOM may entail angiographic embolization. Angiographic embolization is a procedure that helps to control bleeding experienced due to pelvic trauma. It is a minimally invasive procedure that successfully stops bleeding up to 88 percent of the time. Providers typically prefer angioembolization over surgery as it lowers your risk of kidney loss and helps to preserve your kidney function2,4.
Some patients with bruised kidneys will require operative management, meaning that they will need surgery. Typically, you will need surgery if:
- Your blood flow/circulation is unstable
- You are not successful using non-operative treatment alone
- You continue to have persistent bleeding requiring blood transfusions or angioembolization
Surgery aims to stop bleeding and to save the kidney. In some instances, the kidney may not be salvageable, and the surgeon would need to perform what is known as a nephrectomy. A nephrectomy involves the removal of the kidney. Kidney bruising due to penetrating trauma is more likely to require a nephrectomy than bruising due to blunt trauma2,4.
Bruised kidney recovery time
The bruised kidney recovery time will depend on if the injured kidney was treated non-operatively or if it was fixed or removed. Additionally, your kidney will take longer to heal if you experience complications associated with the injury or surgery. If you have no difficulties, recovery can last up to three weeks.
There are a few complications that can occur after treatment, including:
- An abscess (a puss pocket)
- Urinary leaking
- High blood pressure2
Most complications can be managed without surgery via minimally invasive procedures.
When should you see a doctor?
While a bruised kidney can usually be managed without complications, it still requires proper treatment in order to heal correctly. Therefore, if you think you may have a bruised kidney, you should see a doctor right away.
Get help from an online doctor
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The kidneys are essential to many bodily functions, so damage to them can affect your overall health and wellbeing. Key points to remember about bruised kidneys include:
- Blunt or penetrating trauma can bruise your kidneys, although blunt trauma is more common.
- Symptoms of renal injury include blood in the urine, nausea, vomiting, back and abdominal pain, and bruising.
- Proper treatment of a bruised kidney is essential. Most cases can be managed via non-surgical methods such as supportive care and angioembolization.
- More severe cases of kidney injury may require surgery in which the kidney is fixed. Sometimes the kidney will need to be removed via a nephrectomy.
- Recovery from a bruised kidney will depend on the severity of the injury, complications, and treatment.
- Immediate and adequate intervention is essential to treating a bruised kidney. Therefore, contact a doctor right away if you think you may have a bruised kidney.
- Kidney (Renal) trauma: Symptoms, diagnosis & treatment—Urology care foundation. (n.d.). Retrieved June 22, 2022, from https://www.urologyhealth.org/urology-a-z/k/kidney-(renal)-trauma
- Singh, S., & Sookraj, K. (2022). Kidney trauma. In StatPearls. StatPearls Publishing. http://www.ncbi.nlm.nih.gov/books/NBK532896/
- Kidney injuries—Injuries and poisoning. (n.d.). Merck Manuals Consumer Version. Retrieved June 22, 2022, from https://www.merckmanuals.com/home/injuries-and-poisoning/injury-to-the-urinary-tract-and-genitals/kidney-injuries
- Erlich, T., & Kitrey, N. D. (2018). Renal trauma: The current best practice. Therapeutic Advances in Urology, 10(10), 295–303. https://doi.org/10.1177/1756287218785828
- Bruised kidney (Kidney contusion): Symptoms and treatment. (2018, February 26). Healthline. https://www.healthline.com/health/bruised-kidney
- Belval, L. (2015, March 4). Kidney injury | korey stringer institute. https://ksi.uconn.edu/emergency-conditions/internal-trauma/kidney-injury/