Clinico-laboratory Profile and Outcomes of Megaloblastic Anemia presenting as Severe Pyrexial Illness mimicking Tropical Infection

Background: Anemia-causing fever has been described in patients with megaloblastic anemia. Although the exact mechanism of this is unknown, high-grade fever is relatively less reported. Materials and methods: This prospective observational study included all new cases of megaloblastic anemia presenting with febrile illness (>101°F) during a 3-year period. Patients with existing anemia, comorbidities, and other causes of macrocytosis were excluded. A detailed evaluation for megaloblastic anemia and workup for excluding tropical infections was done. The patients were treated with parenteral vitamin B12, folic acid, and other hematinics. Results: Around 24 cases of megaloblastic anemia presenting with high-grade fever were included, with 14 (58.3%) males, mean duration of fever 7.7 days (4–18 days), and 09 (37.5%) having temperature >103°F. The mean hemoglobin (Hb) was 8.15 g/dL (3.7–11.1 g/dL), the mean corpuscular volume (MCV) was 111 ± 7.8 fL, 18 (75%) had unconjugated hyperbilirubinemia, the mean lactate dehydrogenase (LDH) was 814 ± 24 IU/L, and 21 (87.5%) had low B12 or folate levels. Most showed good therapeutic response to B12 or folic acid with defervescence in 1–5 days (mean 2.6 days) and improvement in lab parameters in 1 week. The study population was divided into those with temperature ≥103°F, and temperature <103°F it was seen that there was a significant association (p < 0.05) with leucocyte count of ≤3000/cumm, and MCV ≥110 fL, in patients with temperature ≥103°F. Conclusion: Megaloblastic anemia should be considered in the differentials of a patient presenting with a febrile illness with no clinical localization and a negative initial fever workup. Early identification and prompt therapy of this easily treatable disorder are very essential.