Hypersplenism Affects Growth and Haematology in HbSS: Observations from the Jamaican Birth Cohort

In 296 patients with homozygous sickle cell disease (HbSS) detected during the screening of 100,000 deliveries between 1973-1981, chronic hypersplenism defined as a spleen measuring ≥4 cm below the costal margin with evidence of prolonged red cell sequestration occurred in 30 (10.1%) subjects, 23 resolved by splenectomy and 7 resolved spontaneously. Median age at splenectomy was 4.8 years and following splenectomy, median values for hemoglobin increased by 2.3 g/dL, reticulocytes fell by 8.3%, total nucleated cells fell by 2.2%, and platelets increased by 29,813 × 10⁹/dL. Mean splenic weight at splenectomy was 340 g representing 0.5%-4.9% of post-splenectomy body weight. Following splenectomy, height increased at a greater rate than in a matching period for controls (95% CI 0.11-4.06. p = 0.04). Risk factors for hypersplenism, did not differ among commonly used determinants of sickling, fetal hemoglobin (HbF), α globin gene number, or β globin haplotype. A history of acute splenic sequestration preceded hypersplenism more commonly among splenectomized cases (20/23 compared with 0 of 7 resolving spontaneously (Fishers exact test p < 0.001). Factors causing hypersplenism remain largely unknown but splenectomy after a period of monitoring for spontaneous regression, improves hematology and growth.