Abstract
Background: Identifying markers of disease severity in patients with sickle cell anemia (SCA) could help to improve patient management and inform discovery of new therapies. Tanzania has one of the largest single-centre for clinical and research programs in the world. We observed that some individuals with SCA have splenomegaly that persists into adolescence and beyond. Palpable spleen in 10% of individuals attending the outpatient clinics at Muhimbili National Hospital has previously been described (Makani et al, 2010). Splenomegaly was palpable in more than one-third of 10-year olds in an observational study of children with SCA in Kilifi (Sadarangani et al, 2009). These individuals do not fit the natural history of the disease pathogenesis as most patients with SCA may have suffered splenic infarction leading to auto-splenectomy by the time they are adults. This study sought to better understand the clinical implications of persistent splenomegaly by investigating its prevalence and clinical correlates.
Methods: This was a descriptive cross-sectional study involving individuals with SCA aged ten years and older at steady-state who attended clinics in the Muhimbili Sickle Cell (MSC) program at Muhimbili National Hospital, Tanzania, between December 2015 and February 2016. Patients with SCA were screened for splenomegaly by physical exam. Abdominal ultrasound was done in all recruited individuals to document findings on the spleen, liver and biliary tree respectively. Splenomegaly was defined as any palpable spleen below the left coastal margin. Socio-demographic and clinical information were obtained using a structured questionnaire. Laboratory evaluation included automated complete blood count, reticulocyte count, peripheral smear for identification and quantification of Howell-Jolly bodies, rapid diagnostic test to detect malaria, and markers of hemolysis (lactate dehydrogenase and bilirubin). Records from the Muhimbili Sickle Cohort database were used to confirm the SCD status and obtain fetal hemoglobin levels. Chi-square test was used for analysis of categorical variables and independent student t -tests were used to compare sample means for continuous variables.
Results:A total of 194 individuals between the ages of 10 - 42 years (median 17 years) were recruited; 60.3% were females. Splenomegaly by palpation was observed in 9 individuals (5%) with a slight male predominance. Meanwhile, a spleen was present in 86 (44.3%) patients on abdominal ultrasound. There were no significant differences in frequency of hospital admissions, causes of admission, blood transfusions, or malaria episodes when comparing individuals with and without splenomegaly. However, patients with splenomegaly (n=9) had significantly higher levels of hemoglobin (P=0.02), haematocrit (P=0.003), and fetal haemoglobin (P=0.01). In addition, white blood cell counts (P=<0.001), platelets (P=<0.001), mean corpuscular hemoglobin (P=0.03) and mean corpuscular hemoglobin concentration (P=<0.001) were significantly lower in those with splenomegaly (Table 1). There were no differences in the levels of markers of hemolysis. Cholelithiasis was observed in 38 (20.5%) patients among those with no palpable splenomegaly and in only 1 (11.1%) patient out of those with splenomegaly (P=0.69). Howell-Jolly bodies were present in thin smears of all patients, with no significant difference between the two groups.
Conclusion:Persistent splenomegaly exists in SCA patients in Tanzania and is correlated with laboratory markers that signify less severe disease. Future work, including a matched case control study and assessment of splenic function, will help to identify causes of splenomegaly in patients with SCA and to determine if splenomegaly is a predictor of disease severity in SCA.
No relevant conflicts of interest to declare.
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