What is a right flank hematoma?

What is a Right Flank Hematoma?

A right flank hematoma is a collection of blood in the retroperitoneal space on the right side of the body, located between the parietal peritoneum and the transversalis fascia, typically presenting with right-sided flank pain, abdominal distension, and potentially a palpable flank mass. 1

Anatomical Location and Clinical Significance

The flank hematoma occurs in the retroperitoneal space, which contains critical structures including:

• The right kidney and adrenal gland
• Proximal right ureter
• Portions of the duodenum
• Major vascular structures (abdominal aorta, renal vasculature)
• Pancreatic tissue 1

This anatomical location is particularly dangerous because the retroperitoneum is a potential space that can conceal significant blood loss, leading to hypovolemic shock without obvious external signs of bleeding 1.

Common Causes

Right flank hematomas can develop through several mechanisms:

Spontaneous bleeding (Wunderlich syndrome):

• Anticoagulation therapy complications
• Renal tumors (benign or malignant)
• Vascular abnormalities
• Renal infarction 2

Traumatic causes:

• Blunt abdominal trauma
• Pelvic or spine fractures
• Penetrating injuries 1

Iatrogenic causes:

• Transfemoral catheterization procedures
• Surgical complications
• Post-procedural bleeding 1

Vascular rupture:

• Aortic aneurysm rupture
• Visceral vessel rupture
• Pseudoaneurysms from pancreatic or duodenal inflammation 1

Clinical Presentation

Look for these specific findings:

• Right-sided flank or lower quadrant abdominal pain
• Back pain radiating to the right side
• Abdominal distension
• Palpable right flank mass
• Grey Turner sign (flank ecchymosis) indicating retroperitoneal hemorrhage 3
• Hemodynamic instability in severe cases
• Decreasing hematocrit without obvious bleeding source 2

Critical pitfall: These clinical findings are nonspecific and can be easily missed or attributed to more common conditions like nephrolithiasis, especially when hematuria is present 4. The diagnosis is frequently delayed because the retroperitoneum is not readily accessible to physical examination 1.

Diagnostic Approach

CT abdomen and pelvis is the appropriate initial imaging modality for suspected right flank hematoma due to its speed, high spatial resolution, and noninvasiveness 1.

CT findings that confirm the diagnosis:

• High attenuation on noncontrast CT indicates acute bleeding
• Mixed attenuation suggests acute-to-subacute bleeding or rebleeding
• Low attenuation indicates subacute-to-chronic blood products
• Sentinel clot may suggest bleeding source even without active extravasation 1

When to escalate imaging:

• CTA abdomen/pelvis if active bleeding is suspected (detects bleeding rates as low as 0.3 mL/min) 1
• Urgent aortography reserved for hemodynamically unstable patients with high suspicion for active arterial bleeding, as it allows simultaneous diagnosis and treatment via transcatheter arterial embolization 1

Clinical Implications

The volume of bleeding can be substantial and life-threatening because the retroperitoneal space can accommodate large amounts of blood before becoming clinically apparent. This necessitates:

• Aggressive fluid resuscitation
• Blood transfusions in significant hemorrhage
• Urgent intervention (angiographic embolization or surgery) in unstable patients 1

Management depends on:

• Hemodynamic stability
• Presence of active bleeding on imaging
• Size and cause of the hematoma
• Patient's overall clinical status 1