A broken kidney

 

A 17 year old man was brought in to the accident and emergency department in the early hours of the morning having sustained an obvious head injury. He had been found wanW, dering by the roadside, smelled of alcohol, was agitated, and could not remember what had happened.
On examination, doctors found a small scalp laceration and right flank bruising. No focal neurological signs could be elicited and no major musculoskeletal injuries were detected on examination. However, a urine specimen showed the patient had frank haematuria (blood in the urine altering its colour to the naked eye).

The consultant radiologist arranged urgent contrast enhanced computed tomography of the abdomen.

Questions

1.  What abnormality does the figure show?
2.  What other radiological test(s) could be useful to assess renal injury?
3.  What are the indications for further intervention?
4.  Apart from the loin injury, what else concerns you about the history and examination findings
    

Answers

1. Fractured right kidney with associated haematoma.
2. Intravenous urogram (IVU) gives information on whether the urine collecting system is intact, and renal angiography shows whether the blood supply to the kidneys is intact. CT, however, also provides accurate information on these and provides better definition than ultrasound examination.
3. Haemodynamic instability indicating continued haemorrhage.
4. The head injury combined with apparent retrograde amnesia may warrant CT of the head to assess for intracranial haemorrhage.

Discussion
Injuries to the kidney in the United Kingdom are most commonly the result of significant blunt trauma, often as part of polytrauma (multiple injuries to different parts of the body).¹ Elsewhere, penetrating injuries are more common, especially in war zones.

Trauma should always be managed in accordance with advanced trauma life support (ATLS) methods.² This gives priority to the airway with cervical spine control breathing, and circulation in that order (ABC), and is followed by a secondary survey, an examination from head to toe. This, of course, requires patient cooperation.

Victims of polytrauma often suffer devastating injuries that take priority over possible renal injuries, which may not be immediately evident. The presence of loin pain bruising, lower rib fractures, and haematuria are suggestive of renal trauma. Haemodynamic changes such as hypotension or unexplained tachycardia must also raise suspicion. Haematuria is never normal and indicates damage in the genitourinary tract between the kidney and external meatus. However, in renal trauma, frank haematuria may be delayed for some hours.³

Suspected renal trauma based on history and examination should be investigated with a urine dipstick for haematuria. A full blood count, urea, and electrolytes will demonstrate blood loss and give an indication of renal function.

Clinical suspicion of significant renal injury based on history and examination warrants investigation. The key to confirming renal damage of significance is imaging. The gold standard investigation of first choice is CT. It is non-invasive, gives excellent definition of kidney body (parenchymal) lacerations, and defines urine leaks and haematomas:' Contrast on scans will indicate whether portions of the kidney have a blood supply. Our scan shows the fractured portion of kidney still enhancing w contrast, indicating an intact blood supply.

An IVU can also be a useful first line investigation if CT is not immediately available. An IVU, where radio opaque dye is excreted from the kidneys into the urine collecting systems, shows if both kidneys are present defines their outlines, and outlines the collecting systems on subsequently timed x rays.⁴ The main aims of imaging are to assess the extent of injury and to see if the other kidney is functional. Failure of excretion on an IVU suggests renal pedicle damage.

Patients with no clinical signs of blood loss and only microscopic haematuria will not require an IVU or CT as the results will not alter management. Most patients fall into this group. Classification of injury is needed if there is concern about major renal damage, as in this case. Grading is made according to the Organ Injury Scaling Committee scale.⁵

Most injuries lie in class 1-2. In our case, however, the imaging indicates a class 4 injury with a major laceration urine leakage, and appreciable haemorrhage.

Management
Conservative management
Minor injuries are managed conservatively. Management however, begins before the injury is classified, and is synchronous with investigation if renal trauma is suspected Don't forget about the ATLS system, since renal injuries are rarely sustained in isolation.

The patient should have blood cross matched in case haemorrhage is severe and transfusion is necessary. Intra venous access should be established so that analgesia, antiemetics, and fluids can be given if necessary. Strict bed rest should be enforced to prevent putting stress on the renal hilum (where the main vessels and the collect ing system enter and exit the kidney). This is the main anchoring point of the kidney and may be damaged. Regular clinical observations will indicate if the body is compensating for the blood loss. By this time, imaging investigations will provide the information necessary for classification.

In our example, the patient sustained major injury, was found by the roadside, and had no recollection of the events. We must assume that he was hit by a vehicle at high speed until proved otherwise.

Surgery
If conservative measures fail, then surgery is indicated. There are only two indications for surgery, both signs of progressive blood loss. The first is shock, where the body fails to compensate for blood loss, and the second is an expanding mass in the loin or abdomen.³

The aims of surgery are to control haemorrhage and to preserve renal tissue. It is rarely indicated in blunt trauma and often results in nephrectomy (surgical removal of the kidney). If the patient is stable, even after major injury, then close observation is best. An operation could remove the tamponading effect of a haematoma and result in torrential haemorrhage. Surgery, however, is often life saving when indicated.

After careful consideration, our patient did not require surgery. Clinically, he stabilised and did not show signs of continued haemorrhage. After 10 days as an inpatient with strict bed rest he was discharged with advice to rest for another three weeks. He will be followed up with repeat ultrasound scans to ensure that the haematoma is resolving and will be checked for complications.

Complications
Late complications include hypertension from a scarred and stenosed renal artery, hydronephrosis from a scarred and stenosed collecting system, and loss of renal function from devascularisation.

With thanks to the radiology and medical photography departments of Pinderfields General Hospital.

1. Renal trauma. Surgical tutor: www.surgical-tutorial.org.uk/core/trauma/renal_trauma.htm
2. American College of Surgeons Committee on Trauma. Advanced trauma life support for doctors student course nun nail. 6th ed. Chicago, IL: American College of Surgeons, 2003.
3. Fowler CG. Ba97ey and Love,, short practice of surgery. 24th ed London: Arnold Publishing, 2004:1311-2.
4. Underwood M, Alexander R, Gurun M, ]ones G. Key topics in urology. 1st ed. Oxford: BIOS Scientific Publishers, 2003:108-9.
5. Trauma scoring. Organ injury scaling: kidney. www.trauma.org/scores/ois-renal.html