Shattered kidney after blunt abdominal trauma

Clinical History

A 32-year-old male patient was urgently transported to the emergency department after a motorcycle accident, complaining of pain in the right abdominal flank and shoulder. He was haemodynamically stable, eupnoeic and presented with a GCS 15. Plain X-rays, focused assessment sonography in trauma (FAST), and a head and abdominal computer tomography (CT) were performed.

Imaging Findings

Plain X-rays of the shoulder area revealed a clavicle fracture. The Head-CT excluded traumatic lesions of the skull and brain. On the FAST assessment, a moderate volume haemoperitoneum was visualised, as well as heterogeneity of the liver parenchyma and hyperechogenicity in the posterior inferior border of the right hepatic lobe. Also, marked heterogeneity of the right kidney was observed, with a large haematoma occupying most of the kidney. Abdominal contrast-enhanced CT was performed, revealing a massive retroperitoneal haematoma with extensive laceration of the right kidney with separation of upper and inferior poles with acute arterial haemorrhage at the middle kidney segment. There was normal enhancement of both kidney fragments. The veins were intact and there were no signs of urine extravasation on delayed images. Furthermore, a 7 cm laceration in the right hepatic lobe was also observed. The patient underwent exploratory laparotomy, which confirmed complete right kidney laceration and nephrectomy was performed.

Discussion

Renal and urinary tract injuries are seen in approximately 8–10% of patients presenting with abdominal trauma, the majority (80%) resulting from blunt trauma [1–3]. Isolated severe renal injuries are rare, as multiorganic involvement is present in 75% of renal trauma injuries [4].
The most commonly used organ injury classification is the American Association for the Surgery of Trauma (AAST) classification, consisting of five injury grades, primarily based on findings during surgery, ranging from mild (Grade I) to severe (Grade V). It has been shown to strongly correlate with contrast-enhanced CT findings, as well as with the clinical outcome of these patients. [3]. From the radiologist’s perspective, this classification is based on three main parameters: parenchymal, vascular and collected system injuries [3, 4]. The presence of active bleeding, a critical finding influencing acute management, is otherwise not contemplated.
FAST is done as part of the initial evaluation in all patients with traumatic abdominal injuries, with high sensitivity rates (80-90%) reported for detecting intraperitoneal fluid, but it is relatively insensitive to retroperitoneal haemorrhage and frequently underestimates parenchymal organ injury [5, 6]. Contrast-enhanced CT is considered the gold standard imaging modality for assessment of patients with suspected renal trauma, providing information relating to the degree of parenchymal injury, vascular and excretory system injuries, renal functional status, active haemorrhage, as well as associated traumatic lesions to other abdominal organs. [7]. In addition, CT can help delineate physiologic variants, important for potential surgical exploration and pre-existing pathologic processes that may predispose to posttraumatic haemorrhage. The CT protocol should include an arterial phase in order to access vascular injuries that may not be apparent on more delayed phases, a portal venous phase (early nephrographic phase), suited for detecting parenchymal injuries and potential devascularised segments and a 5-minute delayed phase, to exclude leakage of contrast-enhanced urine if renal pedicle injury or significant perirenal fluid is present. The delayed phase can be also important when contrast extravasation is observed, in order to distinguish between active bleeding and pseudo aneurysm [3].
The haemodynamic status remains the benchmark for management of suspected renal blunt trauma. Haemodynamically unstable patients require exploratory laparotomy. Haemodynamically stable patients should undergo a FAST and/or contrast-enhanced CT examination. Conservative management is advocated in grades I-IV renal injuries, and vascular lesions can be effectively treated with superselective angioembolisation. Extensive injuries with urinary extravasation, devitalised areas of renal parenchyma or associated high-grade injuries to other abdominal organs warrant operative management [8, 9].

Differential Diagnosis List

Final Diagnosis

AAST V renal and AAST III liver post-traumatic injuries

URL:	https://eurorad.org/case/15410
DOI:	10.1594/EURORAD/CASE.15410
ISSN:	1563-4086