What is the appropriate workup for unexplained bruising in a 78-year-old female?

Workup for Unexplained Bruising in a 78-Year-Old Female

Begin with a focused bleeding history and initial laboratory screening including CBC with platelet count, peripheral blood smear, PT/INR, aPTT, and fibrinogen level 1, 2.

Initial Clinical Assessment

Critical History Elements

• Personal bleeding history: Prior surgeries, dental procedures, menstrual history (when applicable), previous unexplained bleeding episodes
• Medication review: Anticoagulants, antiplatelet agents, NSAIDs, SSRIs, herbal supplements that affect hemostasis
• Family history: Inherited bleeding disorders (von Willebrand disease, hemophilia carriers, platelet disorders)
• Onset timing: New-onset bruising in elderly patients raises concern for acquired disorders, particularly acquired hemophilia A 3, 4
• Associated symptoms: Mucosal bleeding (epistaxis, gingival bleeding), joint bleeding, or deep tissue hematomas

Physical Examination Focus

• Pattern and location of bruising: Spontaneous bruising in unusual locations (trunk, proximal extremities) is more concerning than bruising over bony prominences
• Size and severity: Large ecchymoses or expanding hematomas warrant urgent evaluation
• Mucocutaneous bleeding: Suggests platelet dysfunction or von Willebrand disease
• Joint swelling or deep hematomas: Suggests coagulation factor deficiency

Laboratory Workup Algorithm

First-Line Testing

Order simultaneously 1, 2:

• Complete blood count with platelet count
• Peripheral blood smear
• PT/INR
• aPTT
• Fibrinogen level

Interpretation and Next Steps

If PT and aPTT are both normal:

• Suspect platelet disorder (most commonly von Willebrand disease)
• Order von Willebrand panel (vWF antigen, vWF activity, Factor VIII level)
• Consider platelet function testing if von Willebrand testing is normal 5

If PT normal and aPTT prolonged:

• Indicates intrinsic pathway defect
• Perform mixing study (1:1 mix with normal plasma)
  • If corrects: Factor deficiency (check Factor VIII, IX, XI levels)
  • If does not correct: Consider acquired inhibitor, particularly acquired hemophilia A in elderly patients 3, 4
• Order Factor VIII level and Bethesda assay (inhibitor screen) given patient age

If PT prolonged and aPTT normal:

• Suggests Factor VII deficiency or early vitamin K deficiency
• Check vitamin K level or trial of vitamin K supplementation 2

If both PT and aPTT prolonged:

• Consider liver disease, vitamin K deficiency, or multiple factor deficiencies
• Check liver function tests, vitamin K level
• Consider DIC workup if clinically indicated (D-dimer, fibrin degradation products)

Critical Considerations for Elderly Patients

Acquired Hemophilia A

This is a particularly important diagnosis to consider in elderly patients with new-onset bruising 3, 4. The condition presents with:

• Spontaneous, extensive bruising without trauma history
• Markedly prolonged aPTT that does not fully correct with mixing studies
• Profoundly low Factor VIII levels
• Positive Bethesda assay showing Factor VIII inhibitor

This requires urgent hematology consultation and specialized treatment (immunosuppression, bypassing agents).

Medication-Related Causes

Elderly patients frequently take multiple medications affecting hemostasis. Review for:

• Direct oral anticoagulants (DOACs)
• Warfarin
• Antiplatelet agents (aspirin, clopidogrel)
• SSRIs (impair platelet function)
• Corticosteroids (cause vascular fragility)

When to Consult Hematology

Immediate consultation indicated for 1, 2:

• Abnormal initial laboratory results
• High clinical suspicion despite normal initial testing
• Severe or progressive bruising
• Evidence of deep tissue or mucosal bleeding
• Suspected acquired inhibitor (non-correcting mixing study)

Common Pitfalls to Avoid

• Do not dismiss senile purpura: While common in elderly patients, extensive or atypical bruising requires workup 6
• Specimen handling matters: aPTT is sensitive to collection technique; false prolongation occurs with underfilled tubes or delayed processing 5
• Do not overlook acquired disorders: Unlike congenital bleeding disorders, acquired hemophilia A presents later in life without prior bleeding history 3, 4
• Mixing studies are essential: When aPTT is prolonged, mixing studies differentiate factor deficiency from inhibitors—critical for elderly patients at risk for acquired hemophilia A

If initial workup is unrevealing but clinical suspicion remains high, proceed with hematology referral for specialized testing including platelet aggregation studies, specific factor assays, and consideration of rare disorders 6, 7.