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Abstract
Background:
Megaloblastic anemia, most commonly due to vitamin B₁₂ deficiency, is associated with ineffective erythropoiesis and significant hematological and clinical consequences. Initiation of parenteral vitamin B₁₂ therapy leads to rapid marrow recovery, which may result in early metabolic shifts, including a decline in serum potassium levels with potential cardiac implications. This study aims to evaluate early potassium changes and their association with electrocardiographic abnormalities to inform safer monitoring practices, particularly in resource-limited settings.
Materials and Methods:
This prospective observational study enrolled patients with newly diagnosed megaloblastic anemia to evaluate early biochemical and electrocardiographic changes following initiation of parenteral vitamin B₁₂ therapy. Serum potassium levels and ECG findings were assessed at baseline and on Day 3. Statistical analyses were performed to determine the magnitude of potassium changes, association with anemia severity, and correlation with cardiac electrophysiological alterations.
Results:
A total of 200 patients with megaloblastic anemia were included, with a mean age of 42.6 ± 14.2 years and slight male predominance (54%). A significant decline in serum potassium was observed by Day 3 following vitamin B₁₂ therapy (4.12 ± 0.42 to 3.78 ± 0.51 mmol/L; p <0.001), with a greater reduction in patients with severe anemia and a higher incidence of hypokalemia. ECG abnormalities were noted in 31% of patients and were strongly associated with hypokalemia (p <0.001).
Conclusion:
Parenteral vitamin B₁₂ therapy in megaloblastic anemia is associated with a significant early decline in serum potassium, particularly in patients with severe anemia, increasing the risk of hypokalemia. These changes are closely linked to electrocardiographic abnormalities, highlighting the need for early electrolyte and cardiac monitoring during treatment.