What is the most common cause of acquired platelet dysfunction?

Most Common Cause of Acquired Platelet Dysfunction

Drugs, especially aspirin, are the most common cause of acquired platelet dysfunction in our society. 1, 2

Understanding Acquired Platelet Dysfunction

Acquired platelet dysfunction refers to abnormal platelet function that develops during a person's lifetime rather than being inherited. It can manifest as:

• Mucocutaneous bleeding
• Epistaxis (nosebleeds)
• Superficial epidermal bleeds
• Prolonged bleeding after procedures

Causes of Acquired Platelet Dysfunction (In Order of Frequency)

1. Medications (Most Common)

• Antiplatelet drugs:

  • Aspirin (acetylsalicylic acid) - inhibits cyclooxygenase, preventing thromboxane A2 production 3
  • ADP receptor antagonists (clopidogrel, prasugrel) 3
  • GPIIb-IIIa receptor blockers (abciximab, eptifibatide, tirofiban) 1

• Other medications that affect platelet function:

  • NSAIDs (non-steroidal anti-inflammatory drugs)
  • Antibiotics (particularly β-lactams and 3rd generation cephalosporins) 3
  • Cardiovascular and lipid-lowering drugs
  • Selective serotonin reuptake inhibitors (SSRIs)
  • Volume expanders 1

2. Medical Conditions

• Renal failure - uremic toxins affect platelet function 4
• Liver disease - impaired thrombopoietin production
• Myeloproliferative neoplasms (MPNs) - abnormal platelet production 4
• Myelodysplastic syndromes - dysfunctional platelets 4
• Paraproteinemias - coating of platelets by abnormal proteins 4

3. Procedures

• Cardiopulmonary bypass - mechanical damage to platelets 4
• Extracorporeal membrane oxygenation (ECMO) - mechanical platelet damage 4

4. Other Factors

• Dietary supplements with platelet-inhibitory effects 4
• Alcohol consumption - direct toxic effect on platelets

Diagnostic Approach

Despite newer platelet function assays, light transmission aggregometry (LTA) remains the preferred diagnostic test for acquired platelet dysfunction 5. The diagnostic approach should include:

1. Medication review - most critical step given drugs are the most common cause
2. Laboratory testing:
   • Complete blood count with platelet count
   • Peripheral blood smear examination
   • Platelet function tests (aggregometry with various agonists)
   • Flow cytometry for specific receptor abnormalities in selected cases

Management Strategies

Management of acquired platelet dysfunction depends on the underlying cause:

1. Drug-induced platelet dysfunction:

   • Withdrawal of the offending drug when possible
   • For aspirin-induced bleeding, desmopressin (0.3 μg/kg) may be administered 3
   • For severe bleeding, platelet transfusions may be required

2. Medical condition-related platelet dysfunction:

   • Treatment of the underlying disorder
   • Dialysis for uremic platelet dysfunction
   • Erythropoietin for renal failure-associated platelet dysfunction 4

3. Supportive measures:

   • Antifibrinolytic agents (e.g., tranexamic acid)
   • Desmopressin for selected cases 3
   • Recombinant factor VIIa for severe bleeding 3

Clinical Pearls

• Patient compliance is critical - non-compliance with antiplatelet medications may be as high as 18% 3
• Combination of aspirin and clopidogrel increases bleeding risk significantly
• Platelet dysfunction may remain compensated until challenged by surgery, trauma, or additional medication
• The presence of platelet dysfunction may be the first sign of an underlying hematologic disorder

In conclusion, while there are multiple causes of acquired platelet dysfunction, medications—particularly aspirin and other antiplatelet drugs—represent the most common etiology in clinical practice.