Retrospective Study
Copyright ©The Author(s) 2023. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Clin Cases. Nov 16, 2023; 11(32): 7785-7794
Published online Nov 16, 2023. doi: 10.12998/wjcc.v11.i32.7785
Adult-onset hypophosphatemic osteomalacia as a cause of widespread musculoskeletal pain: A retrospective case series of single center experience
Sungwon Kim, Sun Woong Kim, Byung Chan Lee, Du Hwan Kim, Duk Hyun Sung
Sungwon Kim, Department of Physical and Rehabilitation Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, South Korea
Sun Woong Kim, Department of Physical and Rehabilitation Medicine, Jungdap Hospital, Suwon 16480, South Korea
Byung Chan Lee, Physical Medicine and Rehabilitation, Chung-Ang University Hospital, Seoul 06973, South Korea
Du Hwan Kim, Physical Medicine and Rehabilitation, Chung-Ang University, Seoul 06973, South Korea
Duk Hyun Sung, Department of Physical and Rehabilitation Medicine, Samsung Medical Center, Seoul 06351, South Korea
Author contributions: Kim SW, Kim DH and Sung DH contributed to the conceptualization of this study; Kim S, Lee BC, and Kim SW involved in the investigation and data curation of this manuscript; Kim S and Kim SW wrote the original draft; Lee BC, Kim DH, and Sung DH participated to the writing - review & editing; and all authors have read and agreed to the published version of the manuscript.
Institutional review board statement: All procedures performed in this study involving human participants were in accordance with the ethical standards of the institutional review board and have therefore been performed in accordance with the ethical standards laid down in the 1964 Declaration of Helsinki and its subsequent amendments. This study was approved by the Institutional Review Board of Samsung Medical Center (approval number: 2020-09-027-001).
Informed consent statement: Informed consent was waived by the Institutional Review Board because of the retrospective nature of the study and the analysis used anonymous clinical data.
Conflict-of-interest statement: All the authors report no relevant conflicts of interest for this article.
Data sharing statement: The datasets generated for this study are available on request to the corresponding author.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Duk Hyun Sung, MD, PhD, Professor, Department of Physical and Rehabilitation Medicine, Samsung Medical Center, 81 Irwon-ro, Gangnam-gu, Seoul 06351, South Korea. yays.sung@samsung.com
Received: October 4, 2023
Peer-review started: October 4, 2023
First decision: October 9, 2023
Revised: October 14, 2023
Accepted: October 30, 2023
Article in press: October 30, 2023
Published online: November 16, 2023
Processing time: 42 Days and 20.4 Hours
Abstract
BACKGROUND

Osteomalacia (OM) is frequently confused with various musculoskeletal or other rheumatic diseases, especially in patients with adult-onset widespread musculoskeletal pain because of its low prevalence and non-specific manifestations.

AIM

To facilitate the early diagnosis and etiology-specific treatment of adult-onset hypophosphatemic OM.

METHODS

A retrospective review of medical records was performed to screen adult patients who visited a physiatry locomotive medicine clinic (spine and musculoskeletal pain clinic) primarily presenting with widespread musculoskeletal pain at a single tertiary hospital between January 2011 and December 2019. We enrolled patients with hypophosphatemia, high serum bone-specific alkaline phosphatase levels, and at least one imaging finding suggestive of OM.

RESULTS

Eight patients with adult-onset hypophosphatemic OM were included. The back was the most common site of pain. Proximal dominant symmetric muscle weakness was observed in more than half of the patients. Bone scintigraphy was the most useful imaging modality for diagnosing OM because radiotracer uptake in OM showed characteristic patterns. Six patients were diagnosed with adefovir (ADV)-induced Fanconi syndrome, and the other two patients were diagnosed with tumor-induced OM and light-chain nephropathy, respectively. After phosphorus and vitamin D supplementation and treatment for the underlying etiologies, improvements in pain, muscle strength, and gait were observed in all patients.

CONCLUSION

Mechanical pain characteristics, hypophosphatemia, and distinctive bone scintigraphy patterns are the initial diagnostic indicators of adult-onset hypophosphatemic OM. ADV-induced Fanconi syndrome is the most common etiology of hypophosphatemic OM in hepatitis B virus-endemic countries.

Keywords: Hypophosphatemia, Osteomalacia, Widespread musculoskeletal pain, Bone scintigraphy, Hepatitis B virus, Phosphaturic mesenchymal tumor

Core Tip: This retrospective study assessed the clinical manifestations as well as laboratory, and imaging findings of patients with adult-onset hypophosphatemic osteomalacia (OM) to highlight the importance of early diagnosis and etiology-specific treatment. Physicians should consider OM as a possible cause of widespread musculoskeletal pain in adult patients. Mechanical pain characteristics, insufficiency fracture sites, distribution of muscle weakness, hypophosphatemia, and distinctive patterns on bone scintigraphy can be the initial diagnostic indicators. Adefovir-induced Fanconi syndrome, phosphaturic mesenchymal tumors, and light-chain nephropathy can cause hypophosphatemic OM.