Severe Megaloblastic Anaemia Secondary to Coeliac Disease Mimicking Multiple Life-Threatening Disorders: A Case Report

Background: Megaloblastic anaemia can present with severe clinical and biochemical derangements that mimic other life-threatening conditions, including sepsis, acute leukaemia, and hemophagocytic lymphohistiocytosis (HLH). Identifying the underlying aetiology requires a high index of suspicion, especially in resource-limited or peripheral settings.Case Presentation: A 26-year-old female patient with epilepsy on multiple antiepileptic drugs presented with exertional breathlessness, fever, and high-output heart failure. Investigations revealed macrocytic anaemia, bicytopenia, elevated lactate dehydrogenase levels, and high ferritin levels. A pruritic rash on her extensor elbows and a history of wheat intolerance led to the clinical suspicion of celiac disease, which was later confirmed by positive tissue transglutaminase antibodies. She was initiated on intramuscular vitamin B12, oral folate, and a strict gluten-free diet, resulting in rapid haematological and clinical recovery.Conclusions: This case highlights the "megaloblastic mimics." Severe B12 and folate deficiencies can masquerade as cytopenia, haemochromatosis, sepsis, or HLH due to ineffective erythropoiesis. Correctly interpreting the reticulocyte production index and recognising pathognomonic skin findings, such as dermatitis herpetiformis, are crucial for avoiding misdiagnosis.