What imaging should be ordered for a patient with spleen pain after transfusion of Packed Red Blood Cells (PRBC)?

Imaging for Splenic Pain Post-Transfusion of PRBCs

For a patient with splenic pain after PRBC transfusion, contrast-enhanced CT scan of the abdomen and pelvis is the first-line imaging modality of choice.

Diagnostic Approach

Initial Imaging

• CT abdomen and pelvis with IV contrast is the gold standard for evaluating splenic pathology with sensitivity and specificity approaching 96-100% 1
• IV contrast is crucial for proper evaluation as non-contrast CT has significantly lower sensitivity for detecting visceral organ and vascular injuries 1
• Delayed-phase imaging helps differentiate active bleeding from contained vascular injuries 1

Specific Considerations for Post-Transfusion Splenic Pain

When evaluating splenic pain after PRBC transfusion, the CT should focus on:

1. Splenic enlargement/rupture: Transfusion-related complications may include splenic enlargement
2. Vascular abnormalities: Look for:
   • Active contrast extravasation
   • Pseudoaneurysms
   • Arteriovenous fistulas
   • Contrast blush (occurs in ~17% of cases and predicts failure of non-operative management) 1

Alternative Imaging Options

If CT with contrast is contraindicated:

1. Ultrasound (US):

   • Can be used as an initial screening tool
   • Less sensitive than CT but can detect free fluid and gross splenic abnormalities
   • When used without contrast, has lower sensitivity but can identify "suspicious" findings with 93% sensitivity for splenic injury 2
   • Contrast-enhanced US (CEUS) increases visualization of splenic injuries and complications 1

2. MRI:

   • Consider when CT is contraindicated and detailed tissue characterization is needed
   • On T1-weighted images, normal splenic signal intensity is less than hepatic tissue
   • On T2-weighted images, spleen shows higher signal intensity than liver 3

Clinical Considerations

Warning Signs Requiring Urgent Imaging

• Hemodynamic instability
• Decreasing hematocrit
• Worsening abdominal pain
• Left shoulder pain (referred pain from diaphragmatic irritation)

Common Pitfalls to Avoid

1. Relying on non-contrast CT: Without IV contrast, CT has significantly reduced sensitivity for detecting splenic injuries (only 38% of parenchymal injuries visible) 2

2. Overlooking delayed complications: Some splenic complications may develop hours to days after the initial event

3. Inadequate follow-up: For patients with identified splenic abnormalities, appropriate follow-up imaging may be needed:

   • For low-grade injuries (AAST grade I-II), routine post-discharge follow-up CT is not necessary 1
   • For higher-grade injuries, follow-up imaging may be warranted, particularly with decreasing hematocrit 1

Management Implications

The imaging findings will guide management decisions:

• Normal imaging: Conservative management with observation
• Splenic injury without active bleeding: May be managed non-operatively with close monitoring
• Active extravasation or vascular abnormalities: May require angiography/angioembolization or surgical intervention

In summary, contrast-enhanced CT of the abdomen and pelvis remains the cornerstone of evaluation for splenic pain following PRBC transfusion, providing detailed information about splenic architecture, vascular integrity, and potential complications.