What labs should be obtained for a patient with frequent and profuse epistaxis?

Laboratory Evaluation for Frequent and Profuse Epistaxis

For patients with frequent and profuse epistaxis, obtain a complete blood count (CBC) to assess hemoglobin levels and platelet count, along with coagulation studies including PT/INR and aPTT, particularly if the patient is on anticoagulation or has suspected bleeding disorders.

Essential Laboratory Tests

Hemoglobin and Hematocrit Assessment

• Obtain a CBC to evaluate for anemia and assess the severity of blood loss 1
• A hemoglobin drop ≥2 g/dL is associated with significantly increased mortality risk and indicates major bleeding requiring aggressive management 1
• Keep in mind that pre-resuscitation hemoglobin may be artificially elevated due to hemoconcentration, so serial measurements may be necessary 1
• Patients with cardiovascular disease (history of angina, myocardial infarction, heart failure, or peripheral artery disease) are at higher risk of mortality from significant hemoglobin drops 1

Coagulation Studies

• Request PT/INR and aPTT in all patients with clinically relevant bleeding, especially those on anticoagulation 1
• For patients on warfarin or other vitamin K antagonists, the INR guides perioperative and bleeding management decisions 1
• If a concomitant coagulation defect (such as disseminated intravascular coagulation) is suspected, additional specialized coagulation tests may be needed 1
• Document anticoagulant and antiplatelet medication use, as 15% of epistaxis patients are on long-term anticoagulation 2, 3

Platelet Count

• Include platelet count as part of the CBC to identify thrombocytopenia as a potential contributor 1
• This is particularly important in patients with suspected hematologic disorders or those on medications affecting platelet function 3

Additional Considerations Based on Clinical Context

When to Suspect Underlying Systemic Disease

• Consider additional workup if epistaxis is recurrent, bilateral, or refractory to standard treatment 2, 3
• Approximately 45% of hospitalized epistaxis patients have underlying systemic diseases contributing to bleeding 3
• Systemic causes include hematologic disorders (von Willebrand disease, hemophilia), liver disease, renal disease, and hereditary hemorrhagic telangiectasia 3

Assessment of Hemodynamic Stability

• Monitor vital signs closely: tachycardia may be the first sign of hemodynamic instability from blood loss 1
• Systolic blood pressure <90 mmHg, a decrease >40 mmHg, or orthostatic changes (systolic drop ≥20 mmHg or diastolic drop ≥10 mmHg) indicate hemodynamic instability 1
• Urine output <0.5 mL/kg/h serves as a surrogate marker for organ perfusion 1

Common Pitfalls to Avoid

• Don't rely solely on initial hemoglobin values in acute bleeding, as hemoconcentration can mask the true extent of blood loss 1
• Don't delay obtaining coagulation studies in patients on anticoagulation, as this information is critical for management decisions 1
• Don't overlook the need for serial hemoglobin measurements in patients with ongoing or recurrent bleeding 1
• Don't forget to assess for hereditary hemorrhagic telangiectasia in patients with recurrent bilateral epistaxis or family history, as this may require specialized testing 2

Risk Stratification Based on Laboratory Findings

High-Risk Features Requiring Aggressive Management

• Hemoglobin drop ≥2 g/dL or requirement for ≥2 units of packed RBCs transfusion 1
• Significantly elevated INR in anticoagulated patients 1
• Thrombocytopenia or abnormal coagulation studies suggesting bleeding disorder 1
• Evidence of hemodynamic instability with laboratory confirmation of significant blood loss 1