What is a bruised kidney?

A bruised kidney, also known as a renal haematoma, is an injury caused by trauma to the kidney. In most cases, this is due to a road traffic accident or sports accidents. The trauma results in bleeding inside the kidney, which can be serious. 10 per cent of people with abdominal traumatic injury have renal haematoma and about three per cent of hospital stays for traumatic injury are due to traumatic injury to the kidney.

What are the symptoms?

Following the incident that resulted in injury, a bruised kidney may cause the following symptoms:

• Ache or pain in the abdomen or lower back
• Skin bruising/discolouration
• Nausea
• Vomiting
• Muscle spasms in the back
• Blood in the urine

Serious cases involving substantial damage to the kidney can cause the following:

• Low blood pressure
• Anaemia
• Internal bleeding
• Inability to pass urine
• Shock
• Kidney failure

Severe damage can even be fatal.

What are the causes of renal haematomas?

The main cause of a bruised kidney is blunt force trauma to the abdomen or back. This can be from an unfortunate accident, such as a fall or a car crash, an injury sustained while playing sport, or the result of a violent incident, such as being kicked in the back.

How is a bruised kidney diagnosed?

A bruised kidney can be a serious injury and can even be fatal if severe and left untreated. If you suspect a bruised kidney, you should seek medical attention immediately.

Doctors will usually order scans such as MRI and CT scans to assess the damage and check for internal bleeding, while X-rays may be used to check for further injuries sustained at the same time, such as fractured ribs.

What can happen if a bruised kidney is left untreated?

If a kidney is seriously bruised, or has an acute injury, the most serious complications if it goes untreated can be: 

• Muscle weakness, paralysis and heart rhythm problems due to high levels of potassium in the blood
• Build-up of fluid in the arms and legs, or in the lungs. This is also known as pulmonary oedema
• Chronic kidney disease
• Nausea, vomiting, drowsiness and breathlessness due to metabolic acidosis (acidic blood). 

How long does it take for a bruised kidney to heal?

Mild cases tend to heal on their own, although patients are often kept under observation during this time. Bed rest may be recommended during this time. It can take around two weeks for a bruised kidney to heal by itself.

More serious injuries may require controlling fluid intake, with doctors administering fluids to keep the patient’s blood pressure stable. If internal bleeding cannot be controlled, the patient may need surgery.

Which specialist treats a bruised kidney?

Nephrologists are the specialists that treat bruised kidneys. However, many bruised kidney cases may need immediate attention without time to see a specialist so, emergency doctors and surgeons are also likely to treat a bruised kidney.