Injury, Int. J. Care Injured 33 (2002) 265– 266 www.elsevier.com/locate/injury
Case report
Distal radius fracture in a premature infant with osteopenia caused by handling during intravenous cannulation S. Jones, M.J. Bell * Department of Orthopaedics, Sheffield Children’s Hospital, Western Bank, Sheffield S10 2TH, UK Accepted 8 November 2000
1. Introduction We present a case of an infant with osteopenia of prematurity who sustained a fractured radius whilst being gently held/handled during insertion of an intravenous cannula. Osteopenia of prematurity occurs when the bone mineral content is significantly decreased compared to that of an infant of comparable size or gestational age. It may occur in as many as half of all infants whose birth weight is less than 1000 g [1,2]. The clinical findings in preterm infants with osteopenia include a widened anterior fontanelle, craniotabes, bony expansion of the wrists, costochondral beading and rib fractures. The radiological features are generalised bone demineralisation, widening, cupping and fraying of the distal metaphyses [3]. Biochemical changes include persistently low serum inorganic phosphate and markedly elevated alkaline phosphates levels [3].
feeding supplemented with tube feeding using Aptamil which contained 2 g Calogen in every 100 ml. She was diagnosed as having osteopenia of prematurity when Serum alkaline phosphatase levels were elevated at 908 (normal range 70–330) and radiographs of her long bones showed osteopenia. Whilst still in hospital, 4 months postnatally (corrected age 1.5 weeks) she was noticed by her mother to have a swollen left distal forearm. This part of her forearm had been held on two occasions one day before during the siting of an intravenous cannula. On examination the left distal forearm was swollen and deformed. Radiographs of her forearm confirmed a volar displaced fracture of the left distal radius (Fig. 1). On further review there was no evidence of blue sclerae,
2. Case report A 25 week old baby (birth weight 650 g), delivered prematurely as a result of prolonged rupture of membranes, was admitted to the Special Care Baby Unit (SCBU) for ventilatory support and required ventilation for 39 days. Initially, she was given a week’s course of prophylactic broad spectrum antibiotics but required repeated courses (administered intravenously), for recurrent chest infections. In addition, due to chronic lung disease, a loop diuretic (Frusemide) was administered for prolonged periods. Nutritional support was carried out by bottle * Corresponding author. Tel.: + 44-114-2717367; fax: +44-1142768419.
Fig. 1. Radiographs showing a volar displaced fracture of the left distal radius.
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bowing or swelling of the other limbs. Chromosomal analysis was normal (46xx) A full skeletal survey revealed no other fractures or evidence of Wormian bones in the skull. The fracture healed satisfactorily following immobilisation of her forearm in a POP cast for a period of 4 weeks.
3. Discussion Preterm infants are particularly at risk of developing osteopenia. Osteopenia of prematurity occurs with an increasing incidence and severity with decreasing gestational age and birth weight [4]. The common underlying causes appear to be mineral dietary deficiency particularly of calcium and phosphate [5,3]. Eighty percent of bone mineralisation in the foetus occurs during the third trimester hence diets that are particularly low in mineral content may predispose preterm infants to osteopenia [4]. It is more common in ill preterm infants who require long term parenteral nutrition and medication such as diuretics (especially Frusemide) and corticosteroids that may affect mineral metabolism [2,6]. Isolated nutritional deficiency of copper and ascorbic acid have also been implicated [4,3]. The serum calcium, phosphate and copper levels were within normal limits in this case. The extent to which specific risk factors are responsible for the development of osteopenia in critically ill patients receiving multiple therapy and suboptimal nutritional support is difficult to define [3]. The mineral content of bone is responsible for its compressive strength [7]; in osteopenia of prematurity this is compromised. During cannulation with the wrist held flexed (as in this case) the resulting compressive
load on the volar aspect of the distal radius exceeds the compressive strength, resulting in fracture. The mainstay of therapy for osteopenia of prematurity is the provision of adequate calcium and phosphorus supplements, which can be achieved with high mineral containing formulas or human milk containing fortification products [5]. Treatment of fractures in these infants is conservative and a good outcome is expected [1]. Prolonged immobilisation would further deplete bone mass. This case highlights the risk of fracture arising from minimal trauma as occurs in day to day handling of ill preterm infants. Great care should be taken with all aspects of handling of these patients by health care professionals and family members alike to avoid this complication and possible medico-legal consequences.
References [1] Koo WWK, Sherman R, Succop P. Fractures and rickets in very low birth weight infants: conservative management and outcome. J Pediatr Orthop 1989;9:326. [2] Koo WWK, Tsang R. Bone mineralisation in infants. Prog Food Nutri Sci 1984;8:229. [3] Avery GB, Fletcher M, MacDonald MG. Neonatology, Pathophysiology and the Management of the Newborn. 4th edn. J.B. Lipincott 1994:599 – 560. [4] Taeusch HW, Ballard RA. Averys Diseases of the Newborn, 7th edn. Philadelphia, PA: Saunders, 1998:1202 – 3. [5] Taeusch HW, Ballard RA. Averys Diseases of the Newborn, 7th edn. Philadelphia, PA: Saunders, 1998:970 – 3. [6] Koo WWK. Parenteral nutrition-related bone disease. J Penj Parenter Enter Nutr 1992;16:386. [7] Nordin M, Frankel VH. Biomechanics of bone. In: Basic Biomechanics of the Musculoskeletal System. 2nd edn. Philadelphia: Lea and Febiger, 1989:3 – 29.