Prolonged Pyrexia: Kikuchi-Fujimoto Disease in a Patient With Hb H-Constant Spring Thalassemia

INTRODUCTION: Haemoglobin H (Hb H) disease is an alpha thalassemia characterised by either 3 alpha-globin gene deletions (deletional type) or 2 alpha-globin gene deletions with 1-point mutation (nondeletional type). Haemoglobin H-Constant Spring thalassemia is the most common Hb H disease in Asia. Kikuchi-Fujimoto disease (KFD) is an important cause of prolonged fever in thalassemia and is often self-limiting. CASE PRESENTATION: A 30-year-old women of Malay ethnicity presented to the thalassemia unit with a month history of prolonged fever, headache, and painful enlarged neck lymph nodes. She is known to have Hb H-Constant Spring thalassemia, in which she is on 3-monthly blood transfusion. Physical examination revealed persistent pyrexia of 38°C. She had multiple tender bilateral cervical lymphadenopathies with the largest measuring 4 × 4 cm. The complete blood count revealed hypochromic microcytic anaemia with leucopenia and a normal platelet count. She had hyperferritinemia of 3500 ng/mL. The DNA analysis of alpha-globin gene showed heterozygosity for alpha zero thalassemia South East Asian deletion with termination codon mutation (TAA-CAA) which was consistent with Hb H-Constant Spring thalassemia. Numerous investigations for her prolonged fever including cultures did not yield any positive results. Whole-body computed tomography (CT) imaging showed diffuse lymphadenopathies and hepatosplenomegaly. Finally, a left cervical lymph node biopsy was performed which was consistent with KFD. She was treated with oral prednisolone which was gradually tapered based on response. Currently, she is asymptomatic and is in complete remission. CONCLUSION: Kikuchi-Fujimoto disease should be considered as a cause for prolonged pyrexia in a patient with thalassemia. An early diagnosis of KFD would avoid an unnecessary battery of investigations. This case highlights the importance of clinicopathological correlation in managing patients with thalassemia as these patients often have other associated morbidities.