Bone Abstracts

Background: Chronic recurrent multifocal osteomyelitis (CRMO) is a rare inflammatory bone disease characterized by chronic non-infectious osteomyelitis. Spinal involvement has been reported in up to 26% of patients (1). Three studies evaluated the effect of Pamidronate (PAM) on spinal lesions in pediatric patients with CRMO (1, 2, 3) and showed partial or complete resolution of vertebral hyperintensities on MRI (1). However, the effect of Zoledronic acid (ZOL) in pediatric patients with CRMO with spinal involvement has not been previously reported.

Presenting problem: We report a case series of 3 patients seen at a tertiary pediatric center between March 2014 and January 2016 with CRMO and vertebral spine involvement, treated with ZOL 0.025 mg/kg every 3 months. We performed full body MRI before and 6 to 12 months after ZOL. A 14-year-old girl had hyperintense vertebral lesions which completely resolved after 6 months, while a 10-year-old girl with a diagnosis of William syndrome also had hyperintense vertebral lesions which significantly improved within one year. Both patients reported back pain before initiating ZOL, which completed resolved within 3 months with concomitant use of NSAIDs. The third case, a 4½ year old girl, did not have hyperintense vertebral lesions or back pain, but rather a Genant grade 3 vertebral compression fracture. Her fracture did not progress further after 6 months of treatment. ZOL was well tolerated with no significant adverse effects in all patients.

Discussion: This case series is the first to document the effect of ZOL on spinal involvement in pediatric CRMO patients. The positive effect of ZOL in our patients is concordant with the reported effect of PAM in CRMO patients treated for spinal involvement and back pain. One of our patient had a severe vertebral compression fracture, possibly due to a previous and inactive spinal lesion from CRMO. Follow-up imaging in this patient only 6 months after treatment might explain the absence of improvement in her vertebral fracture. In conclusion, our data shows that ZOL can be useful in treating vertebral hyperintensities and back pain in pediatric CRMO. Further experience with the use of ZOL in this context is needed to confirm these findings.

Disclosure: The authors declared no competing interests.

References:
1. Hospach T, Langendoerfer M, Von Kalle T, Maier J, & Dannecker GE. Spinal involvement in chronic recurrent multifocal osteomyelitis (CRMO) in childhood and effect of pamidronate. Eur J Pediatr 2010 169 (9) 1105–1111.

2. Miettunen PM, Wei X, Kaura D, Reslan WA, Aguirre AN & Kellner JD. Dramatic pain relief and resolution of bone inflammation following pamidronate in 9 pediatric patients with persistent chronic recurrent multifocal osteomyelitis (CRMO). Pediatr Rheumatol Online J [Internet]. 2009 Jan 12 [cited 2017 Feb 3] 7 2. Available from: http://www.ncbi.nlm.nih.gov/pubmed/19138427

3. Gleeson H, Wiltshire E, Briody J, Hall J, Chaitow J, Sillence D, et al. Childhood chronic recurrent multifocal osteomyelitis: pamidronate therapy decreases pain and improves vertebral shape. J Rheumatol [Internet]. 2008 Apr [cited 2017 Feb 3] 35 (4) 707–712. Available from: http://www.ncbi.nlm.nih.gov/pubmed/18381777