Case Presentation: A 20-year-old Guyanese female of Indian descent presented with a five-day history of fever and left upper quadrant abdominal pain, associated with abdominal distension. Physical examination was remarkable for fever of 103F, conjunctival icterus, left upper quadrant tenderness, and splenomegaly. Laboratory data revealed hemoglobin (Hb) of 6.5g/dl, mean corpuscular volume (MCV) 64.8fl, mean corpuscular hemoglobin (MCH) 22.2pg and an elevated leukocyte count of 14.72 x 10^9 with a left shift. Lactate dehydrogenase (LDH) was elevated (3420 u/l) with decreased haptoglobin <15. Reticulocyte count was 7.5%. Liver function test revealed hyperbilirubinemia. Peripheral blood smear showed markedly hypochromic microcytic red blood cells with target cells and increased reticulocytes. Computed tomography (CT) scan of the abdomen with contrast showed massive splenomegaly (22 cm), consisting of circumferential peripheral and centrally diffuse infiltrative cystic attenuation within the parenchyma. Data was consistent with an acute hemolytic anemia. Coomb’s test, osmotic fragility test and G6PD assay were negative. Sickling test done was positive, Hb electrophoresis revealed sickle cell trait (AS) with Hb percent consisting of HbA-48%, HbS-26.8% and Hb F-24.0% with normal HbA2 (1.2%). DNA test for beta globin gene mutation was pending. She was transfused 2 units of packed red cells, and received empiric antibiotics and supportive care, however, symptoms persisted therefore splenectomy was performed. Pathologic examination of the spleen demonstrated massive splenomegaly with peripheral serpiginous yellow infarcts, surrounded by acute inflammation and small capillaries plugged with sickle cell shaped red blood cells consistent with splenic sequestration. Postoperatively, there was defervescence of fever and improvement of Hb to 10.6g/dl, and she was discharged home. At follow-up two weeks later, she was completely asymptomatic. DNA test revealed beta-globin mutations consistent with sickle-beta-thalassemia.

Discussion: Acute splenic sequestration syndrome and acute splenic infarction are sequelae of sickle hemoglobin disorders. According to various case reports the association of S-β thalassemia with splenic sequestration crisis is uncommon [1]. There are no apparent precipitating factors for S-β thalassemia associated ASSC in adults [2], even though some hypothesize that high altitude and infections can precipitate the crisis. Transfusion of blood products and supportive care can reduce the severity of the crisis. Splenectomy can be considered in cases with recurrent splenic sequestration crisis, or those with double heterozygous sickle hemoglobinopathies with acute splenic sequestration syndrome who fail to show clinical improvement [3].

Conclusions: This case highlights the wide variety of clinical phenotype encountered with S-β+ thalassemia. A high index of suspicion should be maintained to minimize unnecessary testing and ensure prompt and appropriate management.