What is the most likely diagnosis for a patient with a hemoglobin level of severe anemia, who develops shortness of breath and fever after starting a blood transfusion?

Transfusion-Related Acute Lung Injury (TRALI)

The most likely diagnosis is D - Transfusion-Related Acute Lung Injury (TRALI), based on the characteristic presentation of acute dyspnea and fever developing 2 hours after transfusion initiation in a severely anemic patient. 1, 2

Clinical Reasoning

Why TRALI is the Correct Answer

TRALI presents with the classic triad of hypoxemia, dyspnea, and fever occurring 1-2 hours after transfusion, which precisely matches this patient's timeline and symptoms. 3, 1 The mechanism involves donor leukocyte antibodies (HLA class I, class II, or granulocyte-specific antibodies) interacting with recipient neutrophils, causing non-cardiogenic pulmonary edema and acute respiratory distress. 1, 2

• Timing is diagnostic: Signs and symptoms appear within 1-2 hours after transfusion and reach maximum intensity within 6 hours. 3, 1
• Key distinguishing feature: TRALI causes hypotension (not hypertension), which differentiates it from transfusion-associated circulatory overload (TACO). 1, 2
• TRALI is a leading cause of transfusion-related mortality despite being underdiagnosed and underreported. 1, 4

Why Other Options Are Incorrect

Option A (Allergic Reaction): Allergic reactions typically present with urticaria, pruritus, and bronchospasm, but not with the severe hypotension and profound hypoxemia seen in this case. 1 The presence of fever and acute respiratory distress 2 hours post-transfusion points away from simple allergic reaction. 4

Option B (Anaphylactic Reaction): Anaphylaxis occurs within the first minute of transfusion, not 2 hours later. 4 The first 10 minutes of infusion are critical for immediate reactions. 4

Option C (Febrile Non-Hemolytic Reaction): While this can cause fever, it does not cause the acute respiratory distress and dyspnea that are prominent in this patient. 3 Febrile reactions are generally benign and self-limited without significant pulmonary involvement. 5

Immediate Management Protocol

Critical First Steps

1. Stop the transfusion immediately and maintain IV access with normal saline - this is the single most critical intervention. 1, 4, 2

2. Administer 100% oxygen to address severe hypoxemia. 1, 2

3. Call for help and prepare for potential intubation and mechanical ventilation. 1

4. Maintain blood pressure with IV fluid resuscitation using normal saline or lactated Ringer's solution. 1

Critical Pitfall to Avoid

DO NOT administer diuretics - this is the most dangerous error in TRALI management. 1, 4, 2 TRALI causes non-cardiogenic pulmonary edema from immune reactivity, not fluid overload. Diuretics are ineffective and potentially harmful. 1, 2 This distinguishes TRALI from TACO, which would present with hypertension and cardiovascular changes suggesting fluid overload requiring diuretic therapy. 4, 2

Post-Stabilization Actions

• Report the reaction to the blood bank immediately to remove the implicated donor from the pool, as this is required by the FDA. 1, 4

• Continue observation for at least 24 hours, as TRALI can evolve over the first 6-12 hours post-transfusion. 1

• Send post-reaction blood samples for complete blood count, direct antiglobulin test, repeat crossmatch, PT, aPTT, and fibrinogen to exclude hemolytic reaction. 1, 4

• Monitor vital signs every 5-15 minutes including heart rate, blood pressure, temperature, respiratory rate, and oxygen saturation. 4

Prognosis

Most patients recover within 96 hours with appropriate supportive care, although TRALI remains one of the top three most common causes of transfusion-related deaths. 3, 1