What is the most likely cause and appropriate immediate management of chills (rigor) and headache that occur during or shortly after a platelet transfusion?

Post-Platelet Transfusion Rigors and Headache

Most Likely Diagnosis

The most likely cause is febrile non-hemolytic transfusion reaction (FNHTR), but you must immediately rule out life-threatening bacterial contamination, which is the leading cause of transfusion-related death from platelet products. 1

Immediate Management Algorithm

Step 1: Stop and Assess (First 60 Seconds)

• Stop the platelet transfusion immediately and maintain IV access with normal saline 2
• Check vital signs: heart rate, blood pressure, respiratory rate, oxygen saturation, and temperature 2
• Verify patient identification and blood component compatibility labels for clerical errors 2
• Notify the transfusion laboratory/blood bank immediately 2

Step 2: Risk Stratification (Next 2-3 Minutes)

High-Risk Features Requiring Aggressive Management:

• Fever with hypotension or tachycardia = bacterial contamination or hemolytic reaction (life-threatening) 1
• Fever with respiratory symptoms within 1-6 hours = possible TRALI 1
• Dark urine or oliguria = hemolytic reaction with renal involvement 2
• Back pain accompanying fever = acute hemolysis 1

Lower-Risk Features Suggesting FNHTR:

• Isolated fever (≥38°C or rise ≥1°C) with rigors/chills and headache 3
• Hemodynamically stable 2
• No respiratory distress 1

Step 3: Diagnostic Workup

For ALL reactions (even if appears benign):

• Send the blood component bag with administration set back to transfusion laboratory 2
• Collect post-reaction blood samples for repeat crossmatch and direct antiglobulin test (Coombs test) 2
• Complete blood count 2
• Visual inspection of plasma for hemolysis 2
• Urine analysis for hemoglobinuria 2

If ANY high-risk features present:

• Blood cultures immediately (before antibiotics) 2
• Initiate broad-spectrum antibiotics immediately after cultures for suspected bacterial contamination 2
• Aggressive fluid resuscitation to maintain urine output >100 mL/hour if hemolysis suspected 2

Step 4: Symptomatic Treatment (Only After Ruling Out High-Risk Features)

• Acetaminophen 650-1000 mg orally or IV for fever control 2
• Continue monitoring vital signs 2

Critical Pitfalls to Avoid

• Never assume "just fever" is benign—platelets stored at room temperature (20-24°C) provide ideal bacterial growth conditions, making them the highest-risk component for fatal bacterial contamination 1
• Never restart the transfusion before laboratory clearance, even if symptoms improve, as the reaction may worsen with continued exposure 2
• Do not give preemptive acetaminophen or antihistamines routinely, as they mask early warning signs of serious reactions 4
• General anesthesia and critical illness can mask early signs of serious reactions 2

Pathophysiology Context

FNHTR mechanism: Most platelet FNHTRs are caused by cytokines (not antibodies) that accumulate during storage from leukocyte apoptosis and monocyte activation 5. This explains why rigors, chills, and headache occur even with leukoreduced products 6, 3.

Why platelets are highest risk: The room temperature storage required for platelet viability creates optimal bacterial growth conditions, making bacterial contamination a leading cause of transfusion-related mortality 1.

When to Suspect FNHTR vs. Bacterial Contamination

FNHTR is a diagnosis of exclusion that can only be made after ruling out bacterial contamination and hemolysis 2, 1. The clinical presentations overlap significantly, so laboratory confirmation is mandatory before attributing symptoms to benign FNHTR 7.