Severe Cobalamin Deficiency Disguised as Schistocytes: A Case Report

Area of Science:

• Hematology
• Neurology
• Endocrinology

Background:

• Vitamin B12 (cobalamin) is essential for red blood cell production and nerve myelination.
• Deficiency can lead to bone marrow failure and demyelinating disease, severity dependent on duration and extent.
• Severe deficiency may cause ineffective erythropoiesis and hemolysis, potentially linked to elevated homocysteine levels.

Observation:

• A middle-aged man presented with fatigue, pallor, and dyspnea due to macrocytic anemia.
• The anemia was associated with intravascular hemolysis and hypothyroidism, in the context of Hashimoto's thyroiditis.
• Marked vitamin B12 deficiency ( < 100 pg/mL) was identified.

Findings:

• Vitamin B12 replacement therapy led to the reversal of anemia and hemolysis.
• Hemoglobin levels improved significantly following treatment.
• The patient experienced resolution of symptoms and hematological abnormalities.

Implications:

• Severe vitamin B12 deficiency, though rare, can manifest as life-threatening hemolysis and anemia.
• Timely diagnosis, appropriate lifelong replacement, and identification of underlying causes are critical for management.
• Excluding other hemolytic disorders is essential, as the exact mechanism of hemolysis in B12 deficiency remains under investigation.