SUN-723 Non-endemic Skeletal Fluorosis as a Result of Inhalant Abuse

Abstract Disclosure: E. Bosak: None. A. Alaasmi: None. E. Demirtas: None. D.A. Towler: None. Introduction: Skeletal fluorosis is endemic in areas with fluoride-contaminated waters, however, can also present in cases of excessive fluoride ingestion or inhalation. We present a rare case of skeletal fluorosis in a 50-year-old male with a history of dust cleaner inhalation. Case summary: Past medical history significant for sustaining third-degree burns on his body 25 years ago, from an explosion accident during work as a house painter. He had been in a coma for 2 months, requiring dialysis and multiple skin grafts (17 surgeries). COPD secondary to smoking. Coronary artery disease, pre-diabetes, hypertension and hyperlipidemia. On chest X-ray for workup of shortness of breath, found to have increased bone density. He attributes his generalized body aches and joint aches, especially on his arms and hands, to contraction scars from his burn injuries. History was taken by another provider a couple of years later and after further questioning the patient admitted to being addicted to amphetamine and inhaling dust cleaner almost 2-3 cans a day for 4 years, last used in 2019. He does not use or ingest fluids containing fluoride, black tea, or fluoride toothpaste. No history of fragility fractures, there was only a clavicula fracture from a motor vehicle accident. Dexa scan in 2021 showed increased bone density, with a Z-score of +9.1 in the lumbar spine. The latest Dexa scan in 2024 revealed a worsening lumbar spine Z-score to +9.8, although the offending agent was discontinued almost 5 years ago. Concern was raised for skeletal dysplasia and osteopetrosis; however, genetic panel was negative. Serum fluoride was elevated at 5.6 mcmol/L (Ref <4.1 mcmol/L) in 2024. Of note, he had elevated tryptase 14 ng/mL (Ref <11.5 ng/mL), elevated N-Terminal Telopeptide (NTX) 35.5 nM BCE (Ref 5.4 - 24.2 nM BCE), elevated alkaline phosphatase 287 units/L (Ref 40-129 units/L) in 2019 that normalized in 2021. Consistently normal calcium, phosphorus and PTH values, Vitamin D deficiency that was replaced, normal 1,25 Vitamin D, and extremely low urinary calcium (22mg/24 hours Ref 100-300mg) that is being managed with increased dietary and supplementary calcium. Conclusion: History taking is a fundamental element in medicine, as always. Although there is no specific therapy for skeletal fluorosis except removing the offending agent, calcium and vitamin D deficiency seems to worsen the condition. Efforts to understand the worsening of his Z-scores include repeating fluoride as well as NTX levels to observe a trend, and re-history taking to make sure nothing else is missed. Skeletal fluorosis is becoming increasingly common with increasing numbers of inhalant abuse and should be screened for in cases of known inhalant abuse and in increased bone density scans, such as this case. Presentation: Sunday, July 13, 2025