Unexplained Fractures And Bone Fragility
Unexplained fractures in infancy: looking for fragile bones
Nick Bishop Alan Sprigg Ann Dalton
Author Affiliations
1Academic Unit of Child Health, University of Sheffield, Sheffield Children’s Hospital, Sheffield, UK
2Sheffield Children’s NHS Foundation Trust, Sheffield Children’s Hospital, Sheffield, UK
3Sheffield Molecular Genetics Service, Sheffield Children’s NHS Foundation Trust, Sheffield Children’s Hospital, Sheffield, UK
Correspondence to:
Dr N Bishop, Academic Unit of Child Health, University of Sheffield, Sheffield Children’s Hospital, Sheffield S10 2TH, UK; n.j.bishop@sheffield.ac.uk
- Accepted 13 October 2006
A fracture occurs when the force exerted on a bone exceeds the ability of the bone to absorb the force by deforming. Fractures in children are common—approximately one third of children will have a fracture by 16 years of age, with more boys experiencing fracture than girls.1 This differentiation in fracture risk is apparent from 2 years of age. Before the age of 2 years, fracture incidence is equal and occurs at a rate of approximately 80/10 000 person years. For the UK, therefore, approximately 4800 infants will have a clinically evident fracture before their first birthday each year.
Some long-bone fractures may occur at birth2 in association with events such as shoulder dystocia3; skull fractures may occur during forceps4 and ventouse delivery.5 Some may (uncommonly) occur as a result of clearly defined trauma such as road accidents.6 Most, however, fall into the “unexplained” category. This article reviews our current approach to identifying bone disease in the infant presenting with more than one unexplained fractures, and discusses the recognised disease processes that result in increased bone fragility.
The history should include inquiry into specific areas as listed in the box. The two most frequently recognised underlying disease processes causing bone fragility in infancy are metabolic bone disease of prematurity7 and osteogenesis imperfecta, and directed questioning is appropriate for these conditions. For premature infants, the features commonly associated with fracture are delivery at <28 weeks of gestation, necrotising enterocolitis, late (>30 days) establishment of full enteral feeds, conjugated hyperbilirubinaemia, chronic lung disease, and use of furosemide.8,9 For a proportion of infants with osteogenesis imperfecta, there will be a family history either of osteogenesis imperfecta itself or of features that suggest osteogenesis imperfecta. The other elements of the history relating to the …
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Reply
Differentiating osteopenia of prematurity from child abuse
- Chandan Gupta, Senior House Officer Neonates
Mayday University Hospital, Croydon CR7 7YE, United Kingdom
Dear Editor,
The review on fractures in infancy is brilliant and very informative. I would like to take this opportunity to stress the sensitive issue of fractures due to osteopenia of prematurity that many a times needs differentiating from child abuse.
Reports of osteopenia/rickets of prematurity are on the increase because of improved survival rates of low birthweight infants.2 The incidence of osteopenia among infants born before 28 weeks of gestational age are as high as 30%. 1 The contributory factors are prematurity, lack of activity, chronic lung disease, use of diuretics, prolonged parenteral nutrition and iatrogenic factors that are unavoidable in neonatal intensive care. Iatrogenic injuries are frequently the result of physiologic or anatomical response to proper and lifesaving treatment. The most serious of these are found in the premature infant, who may suffer chronic lung disease or, more seriously, brain damage.3
The diagnosis of osteopenia of prematurity remains difficult as there is no screening test which is both sensitive and specific.5 Such infants sometimes go undiagnosed of fractures from the neonatal unit and when they come back with reasons like excessive crying and the x-rays show multiple healing fractures, the differential of child abuse, unfortunately, tends to take the top position. Due to the obvious reasons and the sensitivity of the issue, clinicians have shown concerns about the mistaken diagnosis of child abuse.4
I agree with the authors that the plain film radiography is not the final arbiter of bone fragility in infancy; as with the other forms of investigation discussed in the article, it is a part of the overall approach to discriminating between a diagnosis of bone fragility and one of non-accidental injury.Dual energy X-ray absorptiometry and quantitative ultrasound has been employed by some neonatal units to determine the mineral density of the bone but it is still not universal due to the issues like ionising radiation and the difficulty to interpret data.5
As a result, the clinicians, especially the junior doctors who happen to be the first contact with the carers need to keep osteopenia of prematurity high on their list of differentials especially when a NICU graduate presents without an official diagnosis of it.
References
1. Kocsis I, Kis E, Szabó A, et al. Osteopenia of Prematurity. Orv Hetil. 2005; 146:2491-7.
2. Caksen H, Oztürk A, Kurtoðlu S, et al .Reports of osteopenia/rickets of prematurity are on the increase because of improved survival rates of low birthweight infants. J Emerg Med 2002; 23:305-6.
3. Singleton EB. Intentional and unintentional abuse of infants and children. Curr Probl Diagn Radiol 1986; 15:277-330
4. Blumenthal I. Osteogenesis imperfecta, non-accidental injury, and temporary brittle bone disease. Arch Dis Child 1996; 74:91
5. McDevitt H, Ahmed SF. Quantitative ultrasound assessment of bone health in the neonate. Neonatology 2007; 91:2-11.
Source:
http://adc.bmj.com/content/92/3/251.extract/reply#archdischild_el_3269
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