Kidney (Renal) Trauma

Your kidneys are generally well protected by muscles of the back and rib cage but injuries can occur as a result of blunt or penetrating trauma. The following information should help explain why timely evaluation and proper management are critical for the best outcomes.

What happens under normal conditions?

The kidneys are paired, bean-shaped solid organs located deep in the abdomen, protected by strong back muscles and separated from the front of the abdomen by the organs of the gastrointestinal tract. Their main function is to rid the body of harmful excretory substances in the form of urine. Therefore they are vital for normal function.

What types of trauma can occur?

The kidney is the most common organ in the urinary tract to be injured by severe trauma. "Trauma" is injury caused by an external force that may be either blunt-such as a car accident-or penetrating-such as a gunshot wound. Blunt trauma injuries to the kidney may show no evidence of external injury or bruises may appear over the back or abdomen where the kidney is located. Penetrating kidney injury may also be difficult to detect. For example, the external point of entry of the bullet may be small and at a distance far enough away from the location of the kidney for it not to be a consideration.

What are the signs and symptoms of kidney trauma?

Injury to the kidney can occur either as an isolated organ injury or may be associated with injury to other organ systems. Kidney injury has been classified into five grades based upon the severity of the injury. Grade one consists of low grade injury in the form of kidney bruising and grade five represents the most severe variety associated with shattering of the kidney and tearing its blood supply.

Blood in the urine (hematuria) is probably the best indicator of blunt kidney injury to the urinary system. Hematuria may be either visible to the naked eye or found only on microscopic examination of the urine. Microscopic hematuria is easily detected with high accuracy by means of a simple dipstick test.

How is kidney trauma diagnosed?

Once injury is suspected, it is important to perform imaging studies of both kidneys to confirm clinical suspicion and determine injury severity. In past years, an X-ray called an intravenous pyelogram (IVP) was used. This consists of injecting a dye and observing it as it is excreted through the kidneys. Today, a CT scan with contrast is the investigation of choice to obtain a reliable and quick way of assessing kidney injury. Ultrasonography is another effective tool that may be utilized in the diagnosis of kidney trauma. However, it may not provide the best details of the degree of injury and may need to be supplemented by either an IVP or a CT scan.

How can it be treated?

Treatment of kidney trauma depends upon the condition of the patient, the severity of kidney injury and the presence of other injuries. If the patient's condition is stable and injury to other organ systems has been ruled out, conservative, non-surgical treatment is an option. The patient needs hospital admission and bed rest until the blood in the urine clears. He/She is monitored closely for bleeding or other problems. Even after discharge from the hospital, the patient needs to be monitored for the possibility of late bleeding from the injured kidney or development of high blood pressure as the result of the kidney injury.

Surgical exploration of the injured kidney is indicated if the patient is clinically unstable and appears to be losing a lot of blood from the kidney. Patients with other significant abdominal injuries, such as injuries to the bowel, spleen or liver, who require open operation and repair may also, at the same time undergo surgical exploration and repair of the injured kidney. The aim of surgical management is to try to repair and preserve the injured kidney.

However, if it is not possible to save the kidney because it is too severely injured, surgical removal may be required. Today, most kidney injuries are managed without surgery. Even many serious injuries can be treated with minimally invasive techniques such as angiographic embolization, which accesses the arteries of the kidneys through large blood vessels in the groin, similar to a cardiac catheterization.

Are there any complications after kidney trauma?

The most common complications are urinary leakage or delayed bleeding from the damage. Treatment of these complications depends on the patient. They may require additional procedures including endoscopy (using telescopes to access the urinary tract), angiographic embolization, or surgical management (including the possible removal of the kidney) if more conservative treatment fails.

Other complications, such as the development of an abscess surrounding the kidney, can also occur. This is treated by drainage of the infection either non-surgically with a tube placed into the abscess collection or surgical evacuation. Finally, some patients develop hypertension after significant kidney trauma. This may be treated by medications, angiographically or surgically (including removal of the kidney) if conservative treatment fails.