Transient Haemolytic Anaemia and Thrombocytopenia in a Healthy Young Adult Following Influenza a Infection

Influenza A can trigger rare haematologic complications such as immune thrombocytopenia (ITP) and haemolytic anaemia, most commonly in paediatric or immunocompromised populations. We describe a case of post-influenza immune cytopaenias in a previously healthy adult.

A 22-year-old male presented with fever, haematuria and malaise after influenza A infection. Laboratory workup revealed severe thrombocytopenia, anaemia (haemoglobin 11.7 g/dl, haematocrit 34.1%), elevated reticulocyte count (3.7%, absolute 99 ×10⁹/l), acute kidney injury (serum creatinine 2.44 mg/dl), markedly elevated LDH (1,991 U/l), ferritin (6,016 ng/ml), low haptoglobin (<30 mg/dl) and iron saturation of 60%. A peripheral smear showed anisopoikilocytosis with fragmented red blood cells, including schistocytes. He was treated with oseltamivir and a four-day course of dexamethasone. Platelets normalised and renal function improved.

The patient demonstrated an Evans-like presentation likely triggered by post-viral immune dysregulation. Although schistocytes raised concern for thrombotic microangiopathy (TMA), the absence of neurologic findings, progressive renal failure, and the need for plasma exchange or complement blockade made TMA unlikely. Unlike most similar reports requiring IVIG or plasmapheresis, this case resolved fully with steroids.

This case highlights the need to consider immune cytopaenias in otherwise healthy individuals following influenza A and supports early steroid intervention.

Influenza A can precipitate Evans-like immune cytopaenias even in previously healthy young adults, a population not typically considered at risk for such haematologic complications.The presence of schistocytes can raise concern for thrombotic microangiopathy, but the absence of progressive renal or neurologic involvement should prompt consideration of immune-mediated cytopaenias.Early recognition and corticosteroid initiation can result in complete recovery without intravenous immunoglobulin (IVIG), rituximab or plasmapheresis, underscoring the importance of maintaining diagnostic vigilance in post-viral cytopaenias.