What are the signs and symptoms of a blood transfusion reaction?

Signs and Symptoms of Blood Transfusion Reactions

Blood transfusion reactions present with overlapping and often nonspecific symptoms that require immediate recognition and action—the key warning signs include tachycardia (>110 bpm), fever, hypotension, breathlessness, rash, and back or chest pain, with the critical understanding that stopping the transfusion immediately at the first sign of any suspected reaction is the single most important intervention to prevent progression to severe morbidity or mortality. 1, 2, 3

Cardinal Signs Requiring Immediate Transfusion Cessation

Cardiovascular Manifestations

• Tachycardia (heart rate >110 beats/min) is one of the most common early warning signs across all reaction types 1, 3
• Hypotension (systolic BP <90 mmHg) suggests serious reactions including hemolytic reaction, septic transfusion, anaphylaxis, or TRALI 1, 2, 4
• Hypertension with respiratory distress suggests transfusion-associated circulatory overload (TACO) rather than TRALI 4, 3
• Bradycardia may occur in anaphylactic reactions 1

Respiratory Symptoms

• Breathlessness or dyspnea developing within 1-6 hours suggests TRALI, one of the top three causes of transfusion-related deaths 2, 4, 3
• Tachypnea is a typical early symptom of serious transfusion reactions and should trigger immediate assessment 4
• Hypoxemia with respiratory distress within 1-2 hours after transfusion is the hallmark of TRALI 4, 3
• Respiratory symptoms with hypertension suggest TACO, while those with hypotension indicate TRALI 4, 3

Fever and Temperature Changes

• Fever occurring during or within 6 hours of transfusion, particularly with platelets, may indicate bacterial contamination—a leading cause of transfusion-related death 2, 3
• Fever with hypotension or tachycardia suggests hemolytic reaction or septic transfusion rather than simple febrile non-hemolytic reaction 2
• Isolated fever without hemodynamic instability may represent febrile non-hemolytic reaction (the most common type, 63.6% of acute reactions) 5

Cutaneous Manifestations

• Rash or urticaria indicates allergic reaction 1, 3
• Pruritus suggests allergic or hypersensitivity reaction 4

Pain Symptoms

• Back pain or chest tightness are critical warning signs that should never be ignored 3
• These symptoms may indicate acute hemolytic transfusion reaction 6

Renal and Hematologic Signs

• Dark urine or hemoglobinuria suggests intravascular hemolysis from acute hemolytic reaction 2, 6
• Oliguria (decreased urine output) with fever indicates hemolytic reaction with renal involvement 2, 6

Critical Timing Considerations

Immediate Reactions (Within Minutes to Hours)

• First 10 minutes are critical—immediate reactions typically occur within the first minute of infusion 3
• Within 1-2 hours: TRALI characteristically presents with the hallmark triad of hypoxemia, dyspnea, and hypotension 4, 3
• Within 6 hours: Bacterial contamination from platelets can present with isolated fever and is potentially fatal 2, 3
• Within 24 hours: Acute hemolytic transfusion reactions typically manifest during or within this timeframe 6

Delayed Recognition

• Up to 12 hours: TACO can occur during or up to 12 hours after transfusion 3
• TRALI can evolve over the first 6-12 hours post-transfusion, requiring continued observation for at least 24 hours 4

Premonitory Symptoms Often Overlooked

Patients may feel "odd" or "uncomfortable" or express a need to urinate or defecate before an infusion reaction becomes clinically apparent—these vague symptoms should be taken seriously and prompt immediate vital sign assessment. 1

Distinguishing Features Between Major Reaction Types

TRALI vs. TACO

• TRALI: Hypotension + hypoxemia + dyspnea within 1-2 hours, with non-cardiogenic pulmonary edema 4, 3
• TACO: Hypertension + respiratory distress + evidence of fluid overload (now the most common cause of transfusion-related mortality) 3

Hemolytic Reaction vs. TRALI

• Hemolytic reaction: Fever, back pain, hemoglobinuria, oliguria, microvascular bleeding—lacks the prominent respiratory distress of TRALI 2, 4, 6
• TRALI: Prominent hypoxemia and respiratory distress without hemolytic signs 4

Anaphylaxis vs. Allergic Reaction

• Anaphylaxis: Hypotension, bronchospasm, severe urticaria, potential bradycardia—requires immediate epinephrine 1
• Mild allergic: Isolated urticaria or pruritus without hemodynamic compromise 4

Critical Pitfalls to Avoid

• Never continue the transfusion despite "just fever"—general anesthesia and critical illness can mask early signs of serious reactions 2
• Never assume fever is always febrile non-hemolytic reaction—bacterial contamination from platelets can present with isolated fever within 6 hours and is potentially fatal 2
• Never restart the transfusion before laboratory clearance, even if symptoms improve, as the reaction may worsen with continued exposure 2
• Never administer diuretics for TRALI thinking it is fluid overload—TRALI requires supportive care with oxygen therapy, not volume removal 4, 3
• Never assume behavioral changes are purely psychiatric—they can signal life-threatening complications such as TACO, TRALI, or acute hemolytic reaction 3
• Never wait to confirm the reaction type before stopping the transfusion—immediate cessation is required at the first sign of any suspected reaction 3, 7

Monitoring Requirements

Minimum Vital Sign Assessment

• Pre-transfusion baseline: Heart rate, blood pressure, temperature, respiratory rate 1, 3
• 15 minutes after starting transfusion (critical early detection window) 3
• At completion of transfusion 3
• 15 minutes post-transfusion 1, 3
• Every 5-15 minutes during suspected reaction until resolution 3

Additional Parameters During Reaction

• Oxygen saturation monitoring 3
• Urine output (maintain >100 mL/hour for suspected hemolytic reaction) 2
• Assessment of consciousness level 1

Special Populations at Higher Risk

• Patients with previous transfusion history: 3.3 times greater odds of acute transfusion reaction 5
• Women with abortion history: 4.2 times greater odds of reaction 5
• Multi-unit transfusions (≥3 units): 3.9 times greater odds of reaction 5
• Older patients (age >70 years) at increased risk for TACO 3
• Patients with heart failure, renal failure, or hypoalbuminemia at increased risk for TACO 3
• Neutropenic patients: Fever may be masked by scheduled NSAIDs/acetaminophen, requiring high suspicion even with subtle signs 2