Pseudomicroangiopathic Thrombotic Syndrome: Unveiling the Vitamin B12 Deficiency Connection.

Pernicious anemia, a manifestation of vitamin B12 deficiency, can present with a spectrum of hematological abnormalities, sometimes mimicking more severe conditions such as thrombotic microangiopathy (TMA). This case report details a 53-year-old female who presented with significant weight loss, watery diarrhea, and jaundice. Laboratory investigations revealed pancytopenia, hemolysis, and schistocytes, initially suggesting a diagnosis of microangiopathic hemolytic anemia (MAHA). However, significantly low vitamin B12 levels and subsequent bone marrow examination confirmed pernicious anemia with megaloblastic changes. This case underscores the importance of considering vitamin B12 deficiency in the differential diagnosis of patients presenting with TMA-like symptoms. Early recognition and treatment with vitamin B12 supplementation led to rapid clinical improvement and the resolution of symptoms. This report highlights the need for heightened clinical awareness of atypical presentations of pernicious anemia to prevent misdiagnosis and ensure timely, effective treatment.