Splenic Infarction Induced By Epstein-Barr Virus Infection in a Patient with Sickle Cell Trait

Introduction

Although sickle cell trait (SCT) is considered a benign condition, evidence has been accumulating for related complications, including isothenuria, hematuria, exercise-induced death and splenic infarction.Most splenic infarctions are reported during a hypoxic state.Non-hypoxic related splenic infarction in a patient with SCT and EBV infection has been reported once.Here we present the second case of such association.

Case Report

An otherwise healthy 7-year-old African American male presented with worsening LUQ abdominal pain associated with emesis, dark-colored urine and low-grade fever. There was no history of trauma. Family history was positive for SCD.

On presentation, the patient had a temperature of 38.2 °C and was tachycardic. Physical examination revealed scleral icterus and conjunctival pallor. Abdomen was soft, but the spleen was tender and palpable 6 cm below the costal margin.

Laboratory studies showed hemoglobin of 7.2 g/dL, MCV 72.6 fL, leukocytes 14 X 10⁹/L with 73% neutrophils, platelet count 136 X 10⁹/L, and reticulocyte count 8%. Peripheral blood smear didn't reveal sickling, spherocytosis nor elliptocytosis. Total bilirubin was 3.5 mg/dL, direct bilirubin 0.6 mg/dL, ALT 13 U/L, AST 57 IU/L, LDH 476 IU/L. The Direct Coombs were negative. The D-dimer was positive. The Abdominal X-ray was negative, however abdominal ultrasound showed an enlarged spleen, 13.1 cm in longitudinal diameter.

An Abdominal MRI showed splenic enlargement, 13 cm in longitudinal diameter, with non-enhancing 4 cm density in anterior aspect and minimal left pleural effusion.

The thrombophilia work-up was negative. EB VCA IgG and IgM antibodies levels were high (> 8 and 1 AI, respectively), consistent with late acute infection. The CMV serology was negative. G6PD screening was negative. Hemoglobin electrophoresis revealed HbA 63.9%, HbA2 3.1%, HbF 0.0%, and HbS 33%. Patient was managed conservatively with RBCs transfusion, hydration and pain control and discharged home once stable.

Discussion

SCT is generally considered a benign hematological condition, still evidence has been accumulating for related complications. In United States, SCT affects 6-9% of the African American population, and 0.01-0.05% of the remaining population.

Splenic infarction is commonly associated with SCD, but rarely with SCT. Reported cases of splenic infarction in SCT have been predominantly related to hypoxic states, primarily in a high altitude setting. Still there have been limited reports in non-hypoxic conditions. (Kark JA and Ward FT Semin Hematol1994).One case of non-hypoxic related splenic infarction in a patient with SCT and acute EBV infection was reported (Symeonidis A et al Acta Haematol 2001). Here we report the second case.

We present a non-obese, previously healthy male with no evidence of hypoxia, high altitude setting, or intensive exercise. He suffered a splenic infarction during the acute phase of EBV infection. His initial presentation was consistent with hemolytic anemia and indirect hyperbilirubinemia, which led to further work-up and the diagnosis of SCT. We postulate that hemolysis resulted from hypersplenism.

Possible factors leading to infarction in SCT are the induction of sickling and the presence of a hypercoagulable state. The exposure of these HbAS erythrocytes to lower pH and hypoxia in the splenic circulation likely promotes sickling and, as a consequence, splenic infarcts. Subjects with HbAS have significantly increased levels of D-dimer, thrombin-antithrombin TAT complexes, prothrombin fragment 1.2 (F1.2) and absolute monocytosis. The African American population has a 7% risk of VTE attributable to HbAS compared to an attributable risk of 3% for prothrombin G20210A mutation in the Caucasian population.

Contributing factors to splenic infarction in the presence of acute EBV infection can be thrombophilia, thrombotic microangiopathy and rapid splenic enlargement. Moreover, during an EBV infection, acute expansion of splenic red and white pulp, as well as increased blood flow and loosening of the reticular network, make the organ friable. HbS existing under such conditions may be quite unstable, which can induce sickling.