Skeletal Fluorosis Due to Fluorocarbon Inhalation from an Air Dust Cleaner

Skeletal fluorosis (SF) is an osteosclerotic metabolic bone disorder caused by excessive ingestion or inhalation of fluoride. SF is extremely rare in developed countries. We report a case of SF due to inhalational abuse from a fluoride-containing air dust cleaner. A 33-year-old man with no past medical history presented with progressively worsening low back pain for 2 years. Physical examination was notable for loss of lumbar lordosis and tenderness over the lumbar spine. Radiographs were notable for uniform generalized osteosclerosis in the long bones, entire spine, rib cage, and pelvic bones, and loss of the normal lumbar curvature. DXA scan showed Z-scores of +10.7 at the lumbar spine, +6.5 at the total hip, and +1.0 at the 1/3 radius. Laboratory studies were notable for elevated serum alkaline phosphatase (334 U/L, ref: 40-129 U/L) compared to a normal value 3 years prior, suggesting acquired osteosclerosis. Serum fluoride concentration returned elevated (2.8 mg/L, ref: 0.0-0.2 mg/L). Initially, the source of fluoride excess could not be identified. At a follow-up visit, he was found inhaling from a can of an air duster hidden in an inner pocket. He admitted "huffing" 2-7 cans weekly from a fluorocarbon-containing air dust cleaner for the past 3 years to achieve a euphoric feeling, explaining the source of his SF. Fluoride inhalation can be a potential source for SF, and should be suspected in patients with acquired osteosclerosis, as inhalant abuse is increasingly practiced in many countries.