497 Infantile Blount’s disease: a case report of 3 years old female baby of Zhob, Pakistan

• Published in: Archives of disease in childhood Vol. 107; no. Suppl 2; p. A217
• Main Author: Akram, Sumera
• Format: Journal Article
• Language: English
• Published: London BMJ Publishing Group Ltd and Royal College of Paediatrics and Child Health 17-08-2022; BMJ Publishing Group LTD
• Subjects: Abstracts; Age; Alkaline phosphatase; Body Composition; Body mass index; Calcium (blood); Case reports; Diagnosis; Etiology; Genetics; Growth plate; Limbs; Obesity; Pediatrics; Rickets; Scientific Concepts; Tibia; Tribes; Vitamin D; Wrist; Pakistan
• ISSN: 0003-9888; 1468-2044
• DOI: 10.1136/archdischild-2022-rcpch.348

AimsBlount’s disease is a rare developmental disorder of children which causes progressive bowing of lower limbs. The term ‘Blount’ was named after American orthopedic surgeon ‘Walter Putnam Blount’ who first described this condition. The etiology of Blount’s disease is unknown but believed to be multifactorial. Various predisposing factors have been attributed including obesity, early walking, race, pre-existing varus, increased pressure on growth plate and nutrition. Blount’s disease has been suggested to be more frequent in African, Afro-american populations. Blount’s disease has to be differentiated from physiological bowing (physiologic genu varum) and rickets. Early diagnosis and treatment of Blount’s disease is essential as the disease process is reversible in early stage.MethodsA three years old female child was brought by her mother with complaint of progressive bowing of both lower limbs for last one year. She achieved her milestones at appropriate age and started walking at 11 months of age without support. On examination, her height was 90 cms (at 10th centile) and weight was 17 kgs (at 90th centile). BMI (body mass index) was 20.9 (obese). There were no clinical signs or symptoms of rickets i.e frontal bossing, wide wrist, rachitic rosary, carpopedal spasm, fits or muscle weakness etc. Roentgenogram showed tibia in varus with a peculiar beak at metaphysic and raised metaphyseal-diaphyseal angle (>16 degrees). Serum calcium and serum vitamin D (25-hydroxy vitamin D) were normal. Serum alkaline phosphatase level was raised. Keeping in view typical history, examination findings and radiological epiphyseal beaking along with raised metaphyseal-diaphyseal angle, diagnosis of Infantile Blount’s disease was made.ResultsMany cases of this disease have been reported worldwide since it was first invented by Walter Putnam Blount3. Prevalence of Blount’s disease remains unknown. Jensen N. et al. studied 139 cases of Blount’s disease in Ghana from 2010 to 2018. 90% of cases belonged to a particular tribe known as ‘Akan Tribe’. Familial predisposition (positive family history) was seen in 62% of cases. Jansen et al have reported the highest number of cases of Blount’s disease so far.ConclusionThe clinicians should have a high suspicion of infantile blount’s disease when a child, more than 3 year’s age presents with severe varus deformity at proximal tibia with typical radiological findings. Characteristic radiologic findings along with history and examination help to distinguish it from physiologic bowing (physiologic genu varum) and rickets.