Post-infectious dengue cerebellitis in a patient with transfusion-dependent β-thalassaemia major: A case report

Dengue fever is endemic in Sri Lanka and can rarely cause neurological complications, including post-infectious cerebellitis. Although patients with β-thalassaemia major have altered immune profiles, the intersection of expanded dengue syndrome with underlying haematological disorders is poorly documented. We report a 22-year-old woman with optimally managed, transfusion-dependent β-thalassaemia major who developed progressive cerebellar dysfunction eleven days after the onset of dengue haemorrhagic fever. Neurological examination revealed characteristic cerebellar signs, and the magnetic resonance imaging of the brain was normal. A clinical diagnosis of post-infectious dengue cerebellitis was made. Intravenous methylprednisolone led to rapid and complete resolution of symptoms.
This case highlights a rare neurological sequela of dengue and underscores the need for vigilance for post-infectious autoimmune complications in multiply transfused patients, even when iron overload is minimal. We propose that chronic alloantigen exposure from lifelong transfusions establishes a constitutively dysregulated adaptive immune state, characterised by expanded Tregs and elevated IL-6, IL-10, and TGF-β, which may amplify post-viral autoimmune responses irrespective of iron overload status. This case emphasises the importance of early recognition and immunosuppressive treatment of immune-mediated neurological complications in optimally managed, multiply transfused patients.