Professor Craig Munns
Defining bone fragility in children from infants to adolescents goes well beyond bone density and must also include fracture characteristics, risk factors and the clinical context.
According to an article in the Journal of Clinical Endocrinology and Metabolism, the definition of paediatric osteoporosis needs to be updated in line with advances in diagnostic tools and treatments.
The article highlighted that low trauma fractures of the vertebra, femur, humerus and flat bones require much less evidence to trigger a bone health evaluation than low trauma fractures of the lower leg, forearm, fingers, toes and clavicle.
“Even a single, low-trauma long bone fracture can represent a major osteoporotic event in children with first presentations of osteogenesis imperfecta (OI), and in children with risk factors such as Duchenne muscular dystrophy (DMD),” the article said.
“Comminuted fractures and those with atypical displacement are also significant regardless of long bone site, especially when they occur in the absence of trauma.”
And they noted that even children with high-trauma fractures – either accidental or non-accidental – may also have an underlying bone fragility condition.
The article includes a comprehensive diagnostic pathway guiding an initial work-up for primary and secondary osteoporosis.
It includes early exploration of disorders of mineral metabolism such as rickets, serious acute conditions such as leukaemia and underlying chronic conditions such as IBD and juvenile arthritis.
“The fact that vertebral fractures (VFs) can be a presenting sign of serious systemic diseases like leukemia and inflammatory disorders underscores the importance of the 2013 ISCD recommendation that even a single VF can be a manifestation of osteoporosis in children,” the article said.
Co-author of the paper Professor Craig Munns, told the limbic that more clinicians were starting to appreciate the need to look for osteoporosis in children with underlying conditions.
“Often you have the underlying inflammatory disorder mucking up the bones – conditions like arthritis or IBD – and then those conditions are treated with chronic steroids. So you’ve got two things together.”
Professor Munns, from The Children’s Hospital at Westmead and the University of Sydney, said a big difference between adult and paediatric osteoporosis was that it was assumed an adult had first achieved proper bone development before bone was then lost.
“Whereas in paediatric osteoporosis, it’s a failure to make and develop appropriate bone in the first place.”
This led to another major difference between adult and paediatric osteoporosis – whether to treat or not.
“Sometimes the best thing to do in a child is to do nothing. Because they are growing and making bone all the time, they can sometimes get better themselves. For example, with osteoporosis associated with cancer, you cure their cancer, then the best thing to do is nothing because three to four years down the track of being completely well and free of cancer, they would have made a brand new skeleton themselves over that time. And so their osteoporosis may have gone away.”
“Whereas if you have someone with a chronic condition that is not going to get better by itself, say DMD, and they have vertical compression fractures, that’s not going to get better by itself so you do need to sometimes jump in with a bisphosphonate.”
And there were grey areas in between.
“For example with OI, if they are really severe then it’s a no brainer. But if it’s mild, again sometimes the best thing you can do is let them go through puberty and let themselves get better.”
“In adults it’s a little more cut and dried because without the pharmaceutical intervention the chances of them improving substantially is low.”
Professor Munns said vertebral fractures in children had probably been previously overlooked.
“Vertebral compression fractures in children equal osteoporosis unless they have fallen out of a tree or been in a major motor vehicle accident,” he said.
“And unlike adults, vertebral fractures in children often don’t cause severe pain so unless you actually look for them, you won’t know they are there.”
He said it was now safer to look for these fractures in children as vertebral fracture assessment involved very low radiation doses.
However he advised caution with interpreting bone density results in children because it was less straightforward than in adults.
“…making sure that when you do use bone density as one of the tools to assess a child’s overall bone health, you are using the appropriate Z-score which is used for children and not the T-core which is used for adults.”
He said the more nuanced understanding of paediatric osteoporosis would hopefully translate into improved care.
“As we have got new treatments along the way, we need to best define the children who would benefit from those therapies and really that is what this is trying to do.”