Should a patient with suspected polycythemia vera, marked leukocytosis and new altered mental status who cannot see hematology promptly be transferred to the emergency department for admission, and what emergent interventions are indicated?

Emergency Transfer to Hospital is Mandatory for This Patient

A patient with suspected polycythemia vera, marked leukocytosis, and new altered mental status must be transferred immediately to the emergency department for admission, as altered mental status in this context signals potential life-threatening complications including thrombosis, hyperviscosity syndrome, or transformation to acute leukemia. 1, 2

Immediate Actions Required

Transfer Without Delay

• Transport the patient to the emergency department immediately with continuous monitoring, as altered mental status combined with hematologic abnormalities represents a high-risk clinical scenario requiring urgent evaluation and intervention 1
• Establish IV access during transport and provide supplemental oxygen only if oxygen saturation falls below 94% 1
• Do not delay transfer to obtain specialty consultation—the emergency department provides the necessary infrastructure for rapid diagnostic workup and immediate intervention if the patient deteriorates 1

Critical Differential Diagnoses to Exclude Emergently

The combination of altered mental status and marked leukocytosis in a patient with suspected polycythemia vera raises several life-threatening possibilities that require immediate hospital-based evaluation:

• Cerebrovascular thrombosis (stroke or TIA) is a leading concern, as arterial thrombosis occurs in 16% of PV patients at or before diagnosis, and altered mental status may represent acute cerebral ischemia 2, 3
• Hyperviscosity syndrome from extreme erythrocytosis can cause neurologic symptoms including confusion, dizziness, and transient visual changes, which occur in 14% of PV patients 2
• Transformation to acute leukemia must be excluded, as marked leukocytosis with altered mental status could signal blast crisis, which occurs in 6.8% of PV patients and requires immediate recognition 2
• Splanchnic vein thrombosis (portal, hepatic, or mesenteric) can present with altered mental status if hepatic encephalopathy develops; venous thrombotic events occur in 7% of PV patients and often involve unusual sites 2

Emergent Interventions in the Emergency Department

Immediate Diagnostic Workup

• Obtain complete blood count with differential, peripheral blood smear, and comprehensive metabolic panel to quantify the degree of erythrocytosis, leukocytosis, and thrombocytosis, and to assess for blast cells 2, 4
• Measure hematocrit immediately—if elevated above 45%, this confirms the need for urgent phlebotomy to reduce thrombotic risk 5, 2, 4
• Perform urgent head CT without contrast to exclude intracranial hemorrhage or acute stroke, as PV increases both thrombotic and hemorrhagic risk 2
• Check JAK2V617F mutation status if not previously documented, as it is present in more than 95% of PV patients and confirms the diagnosis 6, 2, 4
• Obtain coagulation studies including PT/INR and fibrinogen to assess for acquired von Willebrand disease, which can occur with extreme thrombocytosis (platelet count ≥1000 × 10⁹/L) and increases bleeding risk 2

Immediate Therapeutic Interventions

• Initiate therapeutic phlebotomy emergently if hematocrit is above 45%, removing 250-500 mL of blood to rapidly reduce hyperviscosity and thrombotic risk 5, 2, 4
• Administer low-dose aspirin (81 mg) immediately unless contraindications exist (active bleeding, extreme thrombocytosis >1000 × 10⁹/L with acquired von Willebrand disease, or recent hemorrhage) 5, 2, 4
• Provide aggressive hydration with isotonic crystalloid to reduce blood viscosity and improve cerebral perfusion 1

Risk Stratification for Cytoreductive Therapy

The patient's altered mental status and marked leukocytosis place them in the high-risk category for thrombotic complications, which mandates consideration of urgent cytoreductive therapy:

• High-risk criteria include age >60 years OR history of thrombosis—altered mental status may represent an acute thrombotic event, automatically qualifying this patient for cytoreductive therapy 5, 2, 4
• Hydroxyurea is the first-line cytoreductive agent and should be initiated in the hospital for high-risk patients to rapidly reduce cell counts and thrombotic risk 5, 2, 4
• Interferon-α or pegylated interferon represents an alternative first-line option, particularly in younger patients or those with contraindications to hydroxyurea 5, 4

Critical Pitfalls to Avoid

• Do not attribute altered mental status to "benign" causes (dehydration, medication effects) without excluding thrombotic or hemorrhagic complications—PV patients have a 16% rate of arterial thrombosis at diagnosis 2
• Do not delay phlebotomy while awaiting hematology consultation—maintaining hematocrit <45% is the single most important intervention to prevent thrombosis and should be initiated emergently in the ED 5, 2, 4
• Do not administer aspirin if platelet count exceeds 1000 × 10⁹/L without first checking for acquired von Willebrand disease, as this dramatically increases hemorrhagic risk 2
• Do not discharge the patient from the ED even if initial imaging is negative—altered mental status in PV requires hospital admission for serial neurologic assessments, repeated phlebotomy if needed, and initiation of cytoreductive therapy 1

Admission and Monitoring Requirements

• Admit to a monitored bed (telemetry or step-down unit) with capability for frequent neurologic assessments and immediate intervention if clinical deterioration occurs 1
• Perform serial hematocrit measurements every 12-24 hours and repeat phlebotomy as needed to maintain hematocrit <45% 5, 2
• Monitor for signs of hypoperfusion including oliguria, cold peripheries, elevated lactate >2 mmol/L, or metabolic acidosis, which would indicate need for ICU-level care 1
• Arrange urgent hematology consultation within 24 hours for definitive management planning, risk stratification, and long-term cytoreductive therapy decisions 5, 2