Background: Splenic function may be reduced or absent in a range of medical conditions in childhood, most prominently in homozygous sickle cell disease, celiac disease, or after total or partial splenectomy. In neonates and patients with malignant disease, transient hyposplenia has been reported as well. A simple method with reliable reference values is required to determine a patient's splenic function and thereby assess the risk of systemic infection.
Patients: Pitted erythrocytes (pitE) were determined semi-quantitatively in patients up to 20 years of age. This included splenectomized individuals, patients at risk for hyposplenia (homozygous sickle cell anemia (HbSS), leukemia, nephroblastoma and Hodgkin's disease after irradiation, patients after stem cell transplantation (SCT)), term and preterm neonates, and 90 controls (0-20 years of age, no neonates).
Method: A capillary blood sample was diluted in buffered glutaraldehyde. PitE were scored using differential interference contrast microscopy with Nomarski optics.
Results: PitE were <2% in all controls regardless of age, in splenectomized individuals >18%. In patients with HbSS, pitE scores ranged from 6.2 to 44%. Scores did not exceed 2% in patients after SCT, irradiation, or during chemotherapy for leukaemia. In term neonates, pitE were increased in the perinatal period only. The elevation in preterm neonates persisted up to 2 months after birth.
Conclusion: Serial measurement of pitE can be used to accurately and reliably assess splenic function in children. Except for neonates, pitE are consistently <2% in healthy individuals. For clinical purposes, the degree of hyposplenia can be determined to give an estimation of the risk of severe infection, e.g. in patients with HbSS or after partial splenectomy.