Immediate Management: Stop Enoxaparin and Transfuse
With hemoglobin 72 g/L and platelets 77 × 10⁹/L, enoxaparin must be immediately discontinued, and the patient requires urgent blood product transfusion and investigation for the underlying cause of cytopenias. 1, 2
Critical First Steps
Discontinue enoxaparin immediately - The FDA label explicitly states that enoxaparin should be discontinued if platelet count falls below 100,000/mm³ (100 × 10⁹/L), and your patient is already below this threshold at 77 × 10⁹/L. 2 Additionally, severe anemia (Hgb 72 g/L) represents a significant bleeding risk that contraindicates continued anticoagulation. 1
Urgent heparin-induced thrombocytopenia (HIT) workup - Send HIT antibodies immediately, as enoxaparin can cause HIT with thrombosis, which paradoxically increases both bleeding and clotting risk. 3, 2, 4, 5 HIT typically develops 5-9 days after heparin initiation with platelet drops >50% from baseline or counts <100,000/μL. 3
Transfuse blood products now:
- Red blood cells to target Hgb >80 g/L given the severe anemia (Grade 3 by CTCAE criteria) 3
- Platelet transfusion is indicated if active bleeding is present or invasive procedures are needed 1
Diagnostic Workup Required
Assess for active bleeding sources:
- Check stool for occult blood, examine skin for petechiae/purpura, assess for mucosal bleeding 1
- Obtain coagulation studies (PT/INR, aPTT, fibrinogen, D-dimer) to rule out disseminated intravascular coagulation 3
- Monitor hemoglobin/hematocrit daily to detect ongoing blood loss 6
Evaluate etiology of cytopenias:
- Complete blood count with differential and peripheral blood smear 1
- Direct Coombs test to evaluate for hemolytic anemia 3
- Bone marrow biopsy if unexplained and not responding to initial management 3, 1
- Rule out infection, malignancy, nutritional deficiencies, and medication effects 1
When to Resume Anticoagulation (If Still Indicated)
The International Society on Thrombosis and Haemostasis provides clear platelet count-based thresholds for restarting anticoagulation: 1, 7
- Platelets ≥50 × 10⁹/L: Resume full therapeutic-dose enoxaparin without platelet transfusion support 1, 7, 6
- Platelets 25-50 × 10⁹/L: Use 50% therapeutic dose or prophylactic-dose enoxaparin only if thrombosis risk is high; consider platelet transfusion support to maintain platelets ≥40-50 × 10⁹/L 1, 7, 6
- Platelets <25 × 10⁹/L: Anticoagulation remains contraindicated 1, 7
Critical caveat: If HIT is confirmed, never restart any heparin product (including enoxaparin). Switch to direct thrombin inhibitors like argatroban or bivalirudin instead. 3, 6, 2
Alternative Anticoagulation Strategy
If anticoagulation is absolutely necessary before platelets recover:
- Low molecular weight heparin (LMWH) remains preferred over direct oral anticoagulants (DOACs) in thrombocytopenia, as DOACs lack safety data at platelet counts <50 × 10⁹/L 1, 7, 6
- Consider reduced-dose LMWH (50% therapeutic) with platelet transfusion support only for high-risk thrombosis (proximal DVT, pulmonary embolism, cardiac thrombus) 1, 7, 6
- One small case series suggests reduced-dose enoxaparin may be used relatively safely during severe thrombocytopenia with close monitoring, though this represents low-quality evidence 8
Common Pitfalls to Avoid
Do not continue enoxaparin based solely on "needing anticoagulation" - The bleeding risk with Hgb 72 g/L and platelets 77 × 10⁹/L far outweighs thrombosis risk in most clinical scenarios. 1, 2
Do not assume immune thrombocytopenia (ITP) without excluding drug-induced causes - Enoxaparin itself can cause thrombocytopenia through HIT or non-immune mechanisms. 2, 4, 5
Do not add antiplatelet agents (aspirin, clopidogrel) in this setting, as they dramatically increase bleeding risk. 6
Do not delay transfusion while waiting for diagnostic workup - Grade 3 anemia (Hgb <80 g/L) requires immediate transfusion support. 3