ESPE Abstracts

Children with sickle cell disease (SCD) often suffer from back pain and present with vertebral changes, but the use of bisphosphonates is poorly reported. We present our experience on treating six children with SCD with Zoledronate in a tertiary paediatric endocrinology and haematology centre.

Population: Six children with SCD were treated with zoledronate infusions between the years 2016-2021. All children had a history of significant mid or lower back pain and vertebral abnormalities.

Methods: Bone mineral density (BMD) was recorded in whole body less head (WBLH), lumbar spine (LS) by dual energy X-ray absorptiometry (DXA) and bone mineral adjusted density (BMAD) of the LS was calculated. A z-score <-2 was considered to be low. 4/6 had magnetic resonance imaging (MRI) of the spine. Zoledronate was given at 0.05 mg/kg/dose every six months as an intravenous infusion.

Results: Six children (age 12-17years, females=3) received treatment. 5/6 were given > 3 doses of zoledronate. All had vertebral changes, the morphologies consisted of loss of vertebral height or biconcavities. MRI confirmed vertebral plate depressions, but there was no increased STIR signal indicating acute vertebral fracture. 4/6 children reported reduction in back pain, while pain remained unchanged in 2/6. Three children had at least one abnormally low BMD parameter at the start of treatment, of which one had also chronic kidney disease (CKD) and another had parathyroid adenoma and 2/6 had delayed puberty. After 1 year of treatment BMD z-score normalised in two of them and improved in the third. Also, the vertebral changes remained stable and there was remodelling in 1 vertebrae.

Conclusion: The diagnosis of osteoporosis in children with SCD is complicated by multiple factors. Back pain could be due to sickle cell crisis and vertebral compressions due to infarcts causing avascular necrosis or may represent osteoporotic changes. Pain improved in the majority of our cohort. Excluding the two children with CKD and parathyroid adenoma, BMD z-scores were within normal or only slightly reduced. Despite at least a year on Zoledronate, vertebral changes remained stable and only 1 vertebral shape improved, indicating that they are most likely features of the underlying SCD and not osteoporotic fractures.