Predictors of splenic size in children with Sickle Cell Anaemia in Steady-state using ultrasonography in Maiduguri, Nigeria

Abstract

Background: North-eastern Nigeria has the second-highest regional prevalence of sickle cell gene in the country after the South-west. This high prevalence has been believed to be sustained by the high rates of consanguineous marriages and intermarriages between the ethnic group in this region particularly the Kanuris and Shuwa Arabs. The dearth of data on splenic sizes among these patients living in this malaria-endemic sub-region. Narrative reports from the African region in general, have suggested that splenomegaly tends to persist to a comparatively much older age in these patients, attributed to the effect of recurrent malaria infection and/or hyperactive malarial splenomegaly syndrome. Objectives: This study was aimed to determine the sizes of the spleen in children with homozygous sickle cell disease using ultrasonography and the variations that occur in advancing age, and to compare it with foetal haemoglobin levels (HbF). Methods: Children with homozygous sickle cell disease aged 5-15 years, attending the Paediatric Haematology clinic of the University of Maiduguri Teaching Hospital (UMTH) were consecutively selected over six months. Demographic data, clinical details of previous crises and transfusions were recorded and had their foetal haemoglobin (HbF) quantified for all the subjects with the use of the Betke method of Alkali denaturation. Splenic sizes were determined using an ultrasound scanner (Aloka SSD 3500, Japan) with a 3.5 MHz sector transducer and ultrasound gel was used to optimize the image. A slightly lateral decubitus position during deep inspiration was used to expose the area of interest appropriately. Longitudinal size measurement was taken in the oblique plane between the most superior medial and the most inferior lateral borders of the spleen and the coronal size were determined along with the eleventh intercostal space. Values obtained was correlated with the height, a standard in assessing the longitudinal dimension of the spleen. Results: A hundred and twenty children with SCA in steady-state were evaluated, comprising 59 boys and 61 girls. Their ages ranged from 5-15 years, with a mean of 10.1 ± 3.5 years. Autosplenectomy was seen in 12 (10%) of our patients who were seven years and above while seven (5.83%) had splenomegaly. The mean HbF of the total population studied was low 6.2% ± 0.98 and the difference in the mean HbF level of patients with autosplenectomy (6.6% ± 0.96) compared to those with splenomegaly (6.1% ± 0.54) was not statistically significant (p-value = 0.28) Conclusion: The Foetal haemoglobin level was not significantly related to the presence or absence of splenomegaly in these children, although those with splenomegaly had lower mean HbF than those with autosplenectomy. It is recommended that early determination of HbF and possibly commencing hydroxyurea may improve the care of children with HSCD.