What is the best course of treatment for a patient with flank pain after trauma, considering potential internal bleeding or kidney injury?

Management of Flank Pain After Trauma

Hemodynamic status determines the treatment pathway: hemodynamically unstable patients require immediate operative management, while stable patients should undergo CT imaging with IV contrast followed by non-operative management with selective angioembolization for specific indications. 1

Initial Assessment and Hemodynamic Stratification

The first critical step is determining hemodynamic stability, as this dictates all subsequent management decisions. 1, 2

• Hemodynamically unstable patients (non-responders to fluid resuscitation) require immediate operative management 1
• Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) may serve as a bridge to definitive hemorrhage control in severely unstable patients 1, 2
• Hemodynamically stable or stabilized patients should proceed with diagnostic imaging 1

Diagnostic Imaging for Stable Patients

All hemodynamically stable patients with suspected renal injury require IV contrast-enhanced CT with immediate and delayed images to accurately grade injury severity and identify vascular complications. 2

• CT imaging identifies arterial contrast extravasation, pseudoaneurysms, arteriovenous fistulas, and extent of parenchymal injury 1
• Look specifically for disrupted Gerota's fascia with contrast extravasation, which increases the need for angioembolization 1
• Extended perirenal hematoma and progressive hemoglobin decrease during observation are additional indicators for intervention 1

Non-Operative Management Protocol

Non-operative management is the standard of care for hemodynamically stable patients, regardless of injury grade, including even Grade V devascularized kidneys. 1, 2

Key principles:

• The presence of devascularized kidney tissue alone does NOT mandate urgent surgical intervention in stable patients 1, 2
• Urine extravasation by itself is NOT an indication for operative management in the acute setting 1
• Success requires institutional capability for continuous monitoring, immediate operating room access, blood products, and trained surgeons 1

Common pitfall to avoid:

Do not rush to surgery for a devascularized or shattered kidney in a hemodynamically stable patient without other indications for laparotomy. 2 This is a critical error that increases morbidity without improving outcomes.

Indications for Angiography and Angioembolization

Angiography with super-selective angioembolization is indicated for hemodynamically stable or stabilized patients with specific findings on CT or clinical presentation. 1

Specific indications include:

• Arterial contrast extravasation on CT scan 1
• Pseudoaneurysms 1
• Arteriovenous fistula 1
• Non-self-limiting gross hematuria 1
• Progressive hemoglobin decrease during non-operative management 1

Technical considerations:

• Angioembolization should be performed as selectively as possible 1
• Blind angioembolization is NOT indicated when angiography shows no active bleeding, even if CT showed contrast extravasation 1
• Approximately 32% of blunt renal injuries with arterial contrast extravasation on CT have negative angiography and can be managed successfully without embolization 1
• If initial angioembolization fails, repeat angioembolization should be considered before proceeding to surgery 1

Special populations:

• For solitary kidney with moderate (AAST III) or severe (AAST IV-V) trauma and arterial contrast extravasation, angioembolization should be the first choice 1
• In children, angioembolization should be first-line even with labile hemodynamics, provided appropriate resources are immediately available 1

Absolute Indications for Operative Management

Proceed immediately to surgery for the following conditions: 1

• Hemodynamic instability unresponsive to resuscitation 1
• Uncontrollable life-threatening hemorrhage with avulsion of the renal pedicle 1
• Pulsating or expanding retroperitoneal hematoma discovered during laparotomy for other injuries 1
• Main renal vein injury without self-limiting bleeding (angioembolization is NOT effective for venous injuries) 1
• Penetrating injuries with retroperitoneal hematoma that have not been adequately studied, especially if entering the peritoneal cavity 1

Important caveat:

Arterial injuries or severe parenchymal injuries often result in nephrectomy when discovered intraoperatively, with arterial repair success rates only 25-35%. 1 Arterial repair should be attempted only in patients with solitary kidney or bilateral renal injuries 1

Management of Main Renal Artery Injury

For main renal artery injury, dissection, or occlusion in stable patients at specialized centers, consider angioembolization and/or percutaneous revascularization with stent/stent-graft if warm ischemia time is less than 240 minutes. 1

• Endovascular selective balloon occlusion of the renal artery can serve as a bridge to definitive hemostasis 1
• Do not attempt arterial repair with prolonged warm ischemia time (>240 minutes) 2

Long-Term Complications and Follow-Up

Monitor for renovascular hypertension with periodic blood pressure checks for up to one year. 2

Page kidney phenomenon:

• Some patients develop significant devascularization leading to renin-angiotensin-aldosterone cascade activation 1
• These patients present with flank pain and unrelenting persistent hypertension not responsive to antihypertensives 1
• In rare instances with uncontrollable hypertension and a functional contralateral kidney, delayed nephrectomy may be the only option if all other management strategies fail 1, 2

Urinary extravasation management:

• Initial observation is appropriate for stable patients 2
• If complications develop, drainage options include ureteral stent, possibly augmented by percutaneous urinoma drain or percutaneous nephrostomy 2

Critical Differential Diagnoses to Consider

While trauma is the presenting history, do not anchor solely on traumatic etiology if the clinical picture doesn't fit. 3, 4

• Spontaneous renal artery dissection or thrombosis can present with flank pain mimicking trauma 5, 6
• Polyarteritis nodosa can cause bilateral renal hemorrhage wrongly attributed to blunt trauma 3
• Page kidney from non-traumatic causes (renal cyst rupture, tumor, arteriovenous malformation) can present with flank pain and hematuria 4
• Always obtain contrast-enhanced imaging to avoid missing vascular pathology 5