{"title":"Tumor-Induced Osteomalacia in a Patient with Crohn's Disease: A Case Report and Approach to Investigating Hypophosphatemia.","authors":"Kate Hawke, Anthony Croft, Syndia Lazarus","doi":"10.1159/000536136","DOIUrl":null,"url":null,"abstract":"<p><strong>Introduction: </strong>Hypophosphatemia occurs commonly in inflammatory bowel disease (IBD) patients and can cause considerable morbidity. The differential diagnoses in IBD include nutritional causes and hypophosphatemia induced by some formulations of intravenous iron infusions.</p><p><strong>Case presentation: </strong>We present the case of a 37-year-old man with active Crohn's disease, presenting with difficulty walking and fractures of the vertebrae and calcaneus. He had long-standing hypophosphatemia. Nutritional causes for hypophosphatemia were considered in the first instance given the presence of chronic diarrhea and vitamin D deficiency; however, there was minimal response to appropriate supplementation with oral phosphorous and vitamin D. Iron infusion-induced hypophosphatemia was then considered, but the nadir phosphate level preceded any iron infusion. Therefore, work-up was undertaken for less common causes. He was ultimately diagnosed with tumor-induced osteomalacia, caused by excess fibroblast growth factor 23 (FGF23) secretion from a phosphaturic mesenchymal tumor about the knee. He had complete resolution of symptoms and biochemical abnormalities following successful resection of the tumor.</p><p><strong>Conclusion: </strong>This case illustrates the approach to investigation of hypophosphatemia in IBD patients. If the time course and response to phosphate supplementation are not as expected for nutritional or iron infusion-induced hypophosphatemia, less common causes should be considered.</p>","PeriodicalId":9614,"journal":{"name":"Case Reports in Gastroenterology","volume":null,"pages":null},"PeriodicalIF":0.5000,"publicationDate":"2024-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10896610/pdf/","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Case Reports in Gastroenterology","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1159/000536136","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2024/1/1 0:00:00","PubModel":"eCollection","JCR":"Q4","JCRName":"GASTROENTEROLOGY & HEPATOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Introduction: Hypophosphatemia occurs commonly in inflammatory bowel disease (IBD) patients and can cause considerable morbidity. The differential diagnoses in IBD include nutritional causes and hypophosphatemia induced by some formulations of intravenous iron infusions.
Case presentation: We present the case of a 37-year-old man with active Crohn's disease, presenting with difficulty walking and fractures of the vertebrae and calcaneus. He had long-standing hypophosphatemia. Nutritional causes for hypophosphatemia were considered in the first instance given the presence of chronic diarrhea and vitamin D deficiency; however, there was minimal response to appropriate supplementation with oral phosphorous and vitamin D. Iron infusion-induced hypophosphatemia was then considered, but the nadir phosphate level preceded any iron infusion. Therefore, work-up was undertaken for less common causes. He was ultimately diagnosed with tumor-induced osteomalacia, caused by excess fibroblast growth factor 23 (FGF23) secretion from a phosphaturic mesenchymal tumor about the knee. He had complete resolution of symptoms and biochemical abnormalities following successful resection of the tumor.
Conclusion: This case illustrates the approach to investigation of hypophosphatemia in IBD patients. If the time course and response to phosphate supplementation are not as expected for nutritional or iron infusion-induced hypophosphatemia, less common causes should be considered.
导言:低磷酸盐血症常见于炎症性肠病(IBD)患者,可导致相当高的发病率。IBD 的鉴别诊断包括营养原因和由静脉注射铁剂引起的低磷血症:本病例是一名患有活动性克罗恩病的 37 岁男子,表现为行走困难、椎骨和小腿骨骨折。他长期患有低磷血症。由于存在慢性腹泻和维生素 D 缺乏症,低磷酸盐血症首先考虑了营养原因;然而,对口服磷和维生素 D 的适当补充反应甚微。因此,医生又对一些不太常见的原因进行了检查。他最终被诊断为肿瘤诱发的骨软化症,原因是膝关节磷酸盐间质瘤分泌过多的成纤维细胞生长因子23(FGF23)。成功切除肿瘤后,他的症状和生化异常完全消失:本病例说明了检查 IBD 患者低磷酸盐血症的方法。如果营养或铁输注引起的低磷血症的时间过程和对磷酸盐补充剂的反应与预期不符,则应考虑不太常见的原因。