Essential Thrombocytosis (ET)

Etiology

  • Primary bone marrow problem related to JAK2 mutation
  • Must r/o secondary (reactive) causes thrombocytosis, including: Iron deficiency; Inflammation--> RA, Stills dz, other; Chronic infection--> TB, other; Post splenectomy; Para-neoplastic; Hemolysis

Risk Factors

  • Average age 60
  • 20% of patients present at age < 40

Symptoms

  • Asx until platelets significantly elevated
  • Sx related to arterial or venous thrombotic events→ stroke, MI, dvt/pe
  • Interestingly, some patients have increased risk bleeding

Physical Exam Findings

  • Splenomegaly in 40% of those w/ET

Tests