Acute massive splenic infarction with complete liquefaction of the spleen in sickle cell disease.

To the Editor: The link between splenic sequestration and massive infarction has been noted by several authors.1,2 Large splenic infarcts have been reported in sickle cell trait patients with normal sized spleens, an event precipitated by hypoxia during high altitude flights in an unpressurised aircraft or during mountain climbing. Massive splenic infarction has also been reported in patients with other sickle cell variants, where splenomegaly is common mainly in Hb sickle cell disease (SCD), in Sβ+ thalassaemia and Hb SE disease.3 Many of these patients start with splenic sequestration syndrome, followed by clinical deterioration leading to splenic infarction. In SCD, infarction is reportedly induced by stressful conditions including severe generalized painful crisis, septicemia, the postoperative period, strenuous exercise and in the postpartum state. It has also been reported following high altitude travel, including flying in modern pressurized aircraft. Hence SCD patients with splenomegaly are advised against air travel when possible, and if deemed unavoidable, they are advised to have a pre-travel simple or exchange transfusion in addition to adequate hydration. In a study of 134 SCD patients who underwent splenectomy in Saudi Arabia, only two patients (1.49%) had massive splenic infarction.3 Repeated attacks of vaso-occlusion, which are usually small and often asymptomatic leading to splenic infarction, often occur in children and result in autosplenectomy. However a significant number of SCD patients in Oman (60%) have preserved splenic function with some splenomegaly, well into adulthood, making them liable for splenic complications including sequestration and infarction.4,5 The preserved spleen is due in part at least to the high prevalence of both alpha-thalassaemia (48%), and betathalassaemia (2.6%) in the country.5 Similar results in the temporal sequence of splenic dysfunction in SCD have been reported by others in the region.6 While splenic infarction is a well recognized complication of SCD, massive splenic infarction with complete liquefaction of the spleen is rarely reported.7 We report our experience with three patients with SCD who had massive splenic infarction among a large number of patients with SCD who had splenectomy (Table 1, 2). All our patients with splenic sequestration had elevated HbF at a mean of 7.1% in general and 22% among the three patients with massive infarction. Noticeably, patients with massive splenic infarction had a significantly elevated HbF (P=.0001, unpaired t test). Although elevated HbF is usually compatible with a milder course for SCD, and in association with thalassaemia, helps to preserve the spleen into adulthood, high Hb F in these patients did not seem to protect them from getting splenic infarction or sequestration.8 On the contrary, this study suggest that a significantly elevated HbF may indeed be a predictor of high risk for massive splenic infarction when the spleen is preserved into adulthood, and under conditions that may lead to tissue hypoxia like stress, infections, hypoxia, strenuous exercise and high altitude. Sickling of erythrocytes occurs in efferent channels of the spleen, which sets a chain of reactions that progressively involves more efferent channels culminating in a large splenic infarction. Studies of blood flow through the spleen done during periods of acute splenic sequestration, verify that blood flow is greatly retarded and sluggish.7 Therefore, in the presence of the above precipitating factors, patients with SCD who develop acute splenic sequestration are at risk of Table 1. laboratory test results in sickle cell disease patients, including three patients with massive splenic infarction.