A 35-year-old healthy woman presents with two weeks of easy bruising and an isolated platelet count of approximately 45 ×10⁹/L with normal hemoglobin, normal International Normalized Ratio, and normal fibrinogen; what is the appropriate initial evaluation and management?

Immune Thrombocytopenia (ITP): Initial Management

This 35-year-old woman with isolated thrombocytopenia (platelets 45,000/μL), normal coagulation studies, and easy bruising most likely has primary immune thrombocytopenia (ITP), and should be started on corticosteroid therapy immediately given her symptomatic bleeding and platelet count below 50,000/μL. 1

Immediate Diagnostic Workup

Before initiating treatment, confirm true thrombocytopenia and exclude secondary causes:

• Repeat the platelet count in a heparin or sodium citrate tube to exclude pseudothrombocytopenia from EDTA-dependent platelet clumping, which occurs in approximately 0.1% of adults 2
• Review peripheral blood smear to confirm isolated thrombocytopenia, look for platelet clumping, schistocytes, giant platelets, or leukocyte abnormalities 2
• HIV and Hepatitis C serology – these are the most common secondary causes of ITP and must be excluded urgently 2
• Antiphospholipid antibody panel (lupus anticoagulant, anticardiolipin antibodies, anti-β2-glycoprotein I) – antiphospholipid syndrome is a critical secondary cause 2
• Thyroid function tests and quantitative immunoglobulins to screen for autoimmune associations 2
• Bone marrow examination is NOT indicated in this patient with typical ITP features (isolated thrombocytopenia, age <60 years, no systemic symptoms) 2

First-Line Treatment Options

Corticosteroids are the standard initial therapy and should be started immediately given symptomatic bleeding (easy bruising) at a platelet count of 45,000/μL 1:

• Prednisone 1-2 mg/kg/day orally (approximately 60-120 mg daily for a 60 kg woman) 1, 2
• Expected response rate: 50-80% with platelet recovery within 1-7 days 1, 2
• Taper rapidly after platelet count reaches 30-50 × 10⁹/L, typically over 4-6 weeks 1
• Maximum duration 6-8 weeks – prolonged use causes severe adverse events (hyperglycemia, hypertension, osteoporosis, infections, mood changes) that outweigh benefits 1, 2

Alternative first-line option – High-dose dexamethasone:

• Dexamethasone 40 mg daily for 4 days produces 50% sustained response rate and may be superior to prednisone 1
• Can repeat for up to 4 cycles given every 2-4 weeks 1
• Consider this if more rapid response desired or to minimize cumulative steroid exposure 1

Intravenous immunoglobulin (IVIg) – reserve for specific situations:

• IVIg 0.8-1 g/kg as single dose achieves platelet response in 1-7 days 1, 2
• Use when more rapid platelet increase needed (pre-procedure, worsening bleeding) 1
• Can be added to corticosteroids if platelet count continues to decline 2
• More expensive than corticosteroids; not superior as monotherapy 1

IV anti-D is NOT appropriate for this patient because she has active bleeding (easy bruising) and decreased hemoglobin risk 2

Treatment Threshold Justification

Treatment is indicated at platelet count 45,000/μL with symptomatic bleeding (easy bruising) 1:

• Treatment rarely indicated above 50,000/μL unless bleeding, trauma risk, surgery planned, or mandatory anticoagulation 1
• Observation alone is NOT appropriate at this platelet level with active bleeding manifestations 2
• The combination of platelets <50,000/μL plus symptomatic bleeding mandates therapy 1, 2

Critical Management Pitfalls to Avoid

• Do NOT normalize platelet counts as treatment goal – target is ≥50,000/μL to reduce bleeding risk, not 150,000/μL 2
• Do NOT continue corticosteroids beyond 6-8 weeks – if no response by 4 weeks, taper and stop; switch to second-line therapy rather than prolonging steroid exposure 1, 2
• Do NOT assume ITP without excluding secondary causes – HIV, Hepatitis C, antiphospholipid syndrome, and medications must be ruled out 2
• Do NOT hospitalize unless platelet count drops below 20,000/μL or bleeding intensifies 2

Supportive Measures

• Discontinue NSAIDs and antiplatelet agents (aspirin, ibuprofen) that impair platelet function 2
• Control blood pressure to reduce bleeding risk 2
• Menstrual suppression with hormonal therapy if menorrhagia present 2
• Activity restrictions – avoid contact sports and high-risk activities until platelet count >50,000/μL 3

Monitoring Strategy

• Weekly platelet counts for at least 2 weeks after starting treatment 2
• If platelet count drops below 20,000/μL or bleeding worsens, consider hospitalization and add IVIg to corticosteroids 2
• If no response after 4 weeks of corticosteroids, taper and transition to second-line therapy (thrombopoietin receptor agonists, rituximab, or splenectomy) 2

When to Refer to Hematology

• Immediate referral if platelet count <20,000/μL, active significant bleeding, or rapid decline 2
• Routine referral for all new ITP diagnoses to establish etiology and coordinate long-term management 2
• Urgent referral if no response to first-line therapy by 4 weeks 2