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Femoral Fracture as a Rare Presentation of Prepubertal Graves Disease

2012; Elsevier BV; Volume: 162; Issue: 2 Linguagem: Inglês

10.1016/j.jpeds.2012.10.036

1097-6833

Sunita Cheruvu, Brian Alverson, Jose Bernardo Quintos,

Bone health and osteoporosis research

A 3-year-old boy was admitted for a right oblique femur fracture after a fall from a bed (Figure 1). Non-accidental trauma was ruled out. On exam, his height was at the 90th percentile, weight at the 50th percentile, and body mass index at the 24th percentile for age and sex. He had normal sclerae and dentition. He had significant proptosis, a goiter measuring 3 times normal size and rubbery in texture, tongue fasciculations, and hand tremors (Figures 2 and 3). Laboratory values were consistent with hyperthyroidism: T3 816 ng/mL, Free T4 9 ng/dL, and thyroid stimulating hormone <0.03 IU/mL. Thyroid stimulating immunoglobulin was positive at 444% (normal <140%) with negative thyroid peroxidase and thyroglobulin antibodies. Laboratory evaluation for fracture showed vitamin D insufficiency with a 25-hydroxy vitamin D of 20.9 ng/mL and normal calcium and parathyroid hormone levels. Evaluation of markers of bone turnover showed osteocalcin of 165 ng/mL (normal for age) and urinary N-telopeptide of 2110 nmol bone collagen equivalents/mmol creatinine (age reference not available). Bone mineral density with hologic dual-energy X-ray absorptiometry scanner showed a total spine (L1-L4) of 0.337 g/cm2 with a Z-score −2.7, consistent with osteoporosis. He was started on vitamin D3 1000 units daily and methimazole, titrated to normalize thyroid function. Since initiation of treatment with methimazole 1.5 years ago, no further fractures occurred and repeat urinary N-telopeptide decreased to 50 nmol bone collagen equivalents/mmol creatinine.Figure 2Goiter.View Large Image Figure ViewerDownload Hi-res image Download (PPT)Figure 3Significant proptosis.View Large Image Figure ViewerDownload Hi-res image Download (PPT)Increased bone turnover in thyrotoxicosis is thought to be secondary to thyroid hormone's direct effects on osteoblasts and cytokine effects on bone resorption. Causes of secondary osteoporosis in children include inflammatory bowel disease, malabsorption, prolonged steroid treatment, metabolic/endocrine disorders, and decreased mobility.1Boyce A.M. Gafni R.I. Approach to child with fractures.J Clin Endocrinol Metab. 2011; 96: 1943-1952Crossref PubMed Scopus (36) Google Scholar Few cases of low bone mineral density in children with Graves disease have been reported but fracture is rare.2Lucidarme N. Ruiz J.C. Czernichow P. Leger J. Reduced bone mineral density at diagnosis and bone mineral recovery during treatment in children with Graves' disease.J Pediatr. 2000; 137: 57-62Abstract Full Text Full Text PDF Scopus (47) Google Scholar, 3Numbenjapon N. Costin G. Gilsanz V. Pitukcheewanont P. Low cortical bone density measured by computed tomography in children and adolescents with untreated hyperthyroidism.J Pediatr. 2007; 150: 527-530Abstract Full Text Full Text PDF PubMed Scopus (20) Google Scholar This case illustrates the importance of thyroid hormone on skeletal growth and bone remodeling and that untreated prepubertal Graves can result in fracture. A 3-year-old boy was admitted for a right oblique femur fracture after a fall from a bed (Figure 1). Non-accidental trauma was ruled out. On exam, his height was at the 90th percentile, weight at the 50th percentile, and body mass index at the 24th percentile for age and sex. He had normal sclerae and dentition. He had significant proptosis, a goiter measuring 3 times normal size and rubbery in texture, tongue fasciculations, and hand tremors (Figures 2 and 3). Laboratory values were consistent with hyperthyroidism: T3 816 ng/mL, Free T4 9 ng/dL, and thyroid stimulating hormone <0.03 IU/mL. Thyroid stimulating immunoglobulin was positive at 444% (normal <140%) with negative thyroid peroxidase and thyroglobulin antibodies. Laboratory evaluation for fracture showed vitamin D insufficiency with a 25-hydroxy vitamin D of 20.9 ng/mL and normal calcium and parathyroid hormone levels. Evaluation of markers of bone turnover showed osteocalcin of 165 ng/mL (normal for age) and urinary N-telopeptide of 2110 nmol bone collagen equivalents/mmol creatinine (age reference not available). Bone mineral density with hologic dual-energy X-ray absorptiometry scanner showed a total spine (L1-L4) of 0.337 g/cm2 with a Z-score −2.7, consistent with osteoporosis. He was started on vitamin D3 1000 units daily and methimazole, titrated to normalize thyroid function. Since initiation of treatment with methimazole 1.5 years ago, no further fractures occurred and repeat urinary N-telopeptide decreased to 50 nmol bone collagen equivalents/mmol creatinine. Increased bone turnover in thyrotoxicosis is thought to be secondary to thyroid hormone's direct effects on osteoblasts and cytokine effects on bone resorption. Causes of secondary osteoporosis in children include inflammatory bowel disease, malabsorption, prolonged steroid treatment, metabolic/endocrine disorders, and decreased mobility.1Boyce A.M. Gafni R.I. Approach to child with fractures.J Clin Endocrinol Metab. 2011; 96: 1943-1952Crossref PubMed Scopus (36) Google Scholar Few cases of low bone mineral density in children with Graves disease have been reported but fracture is rare.2Lucidarme N. Ruiz J.C. Czernichow P. Leger J. Reduced bone mineral density at diagnosis and bone mineral recovery during treatment in children with Graves' disease.J Pediatr. 2000; 137: 57-62Abstract Full Text Full Text PDF Scopus (47) Google Scholar, 3Numbenjapon N. Costin G. Gilsanz V. Pitukcheewanont P. Low cortical bone density measured by computed tomography in children and adolescents with untreated hyperthyroidism.J Pediatr. 2007; 150: 527-530Abstract Full Text Full Text PDF PubMed Scopus (20) Google Scholar This case illustrates the importance of thyroid hormone on skeletal growth and bone remodeling and that untreated prepubertal Graves can result in fracture.