The Development of Acquired Amegakaryocytic Thrombocytopenia in a Patient with Idiopathic Thrombocytopenic Purpura

Abstract

A 67-year-old Japanese male patient with Helicobacter pylori infection developed severe thrombocytopenia and was diagnosed with primary immune thrombocytopenia (ITP) on December 22, 2021. He was treated with Helicobacter pylori eradication therapy, corticosteroids, and eltrombopag (ELT). The platelet count (PLT) improved rapidly; however, after ELT cancellation and corticosteroid reduction, the PLT swiftly decreased. When the corticosteroid dose was increased, the PLT rapidly increased. The corticosteroid dose was reduced immediately; however, the patient presented with subacute arterial obstruction in the right leg and ultimately underwent surgical thrombectomy and transmetatarsal amputation. After corticosteroid cancellation, the PLT again decreased swiftly. Corticosteroids and ELT were thus re-administered. The PLT showed a tendency to recover temporarily, although the drug reaction was not gradual and showed a tendency to decrease. After a repeated BM aspiration, only megakaryocytes were not detected. We determined that the pathogenesis of the severe thrombocytopenia converted from ITP to acquired amegakaryocytic thrombocytopenia (AAMT). Cases of a conversion from ITP to AAMT are extremely rare, and the mechanism underlying this conversion is not well understood. Herein, we report the first case, to the best of our knowledge, in which transmetatarsal amputation triggered the progression of ITP to AAMT.