[Osteofluorosis caused by excess use of toothpaste]

Non-endemic skeletal fluorosis: Causes and associated secondary hyperparathyroidism (case report and literature review)

Skeletal fluorosis (SF) is endemic primarily in regions with fluoride (F)-contaminated well water, but can reflect other types of chronic F exposure. Calcium (Ca) and vitamin D (D) deficiency can exacerbate SF. A 51-year-old man with years of musculoskeletal pain and opiate use was hypocalcemic with secondary hyperparathyroidism upon manifesting recurrent long bone fractures. He smoked cigarettes, drank large amounts of cola beverage, and consumed little dietary Ca. Then, after 5 months of Ca and D₃ supplementation, serum 25(OH)D was 21 ng/mL (Nl, 30-100), corrected serum Ca had normalized from 7.8 to 9.4 mg/dL (Nl, 8.5-10.1), alkaline phosphatase (ALP) had decreased from 1080 to 539 U/L (Nl, 46-116), yet parathyroid hormone (PTH) had increased from 133 to 327 pg/mL (Nl, 8.7-77.1). Radiographs revealed generalized osteosclerosis and a cystic lesion in a proximal femur. DXA BMD Z-scores were +7.4 and +0.4 at the lumbar spine and "1/3" radius, respectively. Bone scintigraphy showed increased uptake in two ribs, periarticular areas, and proximal left femur at the site of a subsequent atraumatic fracture. Elevated serum collagen type I C-telopeptide 2513 pg/mL (Nl, 87-345) and osteocalcin >300 ng/mL (Nl, 9-38) indicated rapid bone turnover. Negative studies included hepatitis C Ab, prostate-specific antigen, serum and urine electrophoresis, and Ion Torrent mutation analysis for dense or high-turnover skeletal diseases. After discovering markedly elevated F concentrations in his plasma [4.84 mg/L (Nl, 0.02-0.08)] and spot urine [42.6 mg/L (Nl, 0.2-3.2)], a two-year history emerged of "huffing" computer cleaner containing difluoroethane. Non-decalcified histology of a subsequent right femur fracture showed increased osteoblasts and osteoclasts and excessive osteoid. A 24-hour urine collection contained 27 mg/L F (Nl, 0.2-3.2) and <2 mg/dL Ca. Then, 19 months after "huffing" cessation and improved Ca and D₃ intake, yet with persisting bone pain, serum PTH was normal (52 pg/mL) and serum ALP and urine F had decreased to 248 U/L and 3.3 mg/L, respectively. Our experience combined with 15 publications in PubMed concerning unusual causes of non-endemic SF where the F source became known (19 cases in all) revealed: 11 instances from high consumption of black tea and/or F-containing toothpaste, 1 due to geophagia of F-rich soil, and 7 due to "recreational" inhalation of F-containing vapors. Circulating PTH measured in 14 was substantially elevated in 2 (including ours) and mildly increased in 2. The severity of SF in the cases reviewed seemed to reflect cumulative F exposure, renal function, and Ca and D status. Several factors appeared to influence our patient's skeletal disease: i) direct anabolic effects of toxic amounts of F on his skeleton, ii) secondary hyperparathyroidism from degradation-resistant fluorapatite bone crystals and low dietary Ca, and iii) impaired mineralization of excessive osteoid due to hypocalcemia.

Skeletal Fluorosis Due To Inhalation Abuse of a Difluoroethane-Containing Computer Cleaner

Skeletal fluorosis (SF) is endemic in many countries and millions of people are affected worldwide, whereas in the United States SF is rare with occasional descriptions of unique cases. We report a 28-year-old American man who was healthy until 2 years earlier when he gradually experienced difficulty walking and an abnormal gait, left hip pain, loss of mobility in his right wrist and forearm, and progressive deformities including enlargement of the digits of both hands. Dual-energy X-ray absorptiometry (DXA) of his lumbar spine, femoral neck, total hip, and the one-third forearm revealed bone mineral density (BMD) Z-scores of +6.2, +4.8, +3.0, and -0.2, respectively. Serum, urine, and bone fluoride levels were all elevated and ultimately explained by chronic sniffing abuse of a computer cleaner containing 1,1-difluoroethane. Our findings reflect SF due to the unusual cause of inhalation abuse of difluoroethane. Because this practice seems widespread, particularly in the young, there may be many more such cases. © 2016 American Society for Bone and Mineral Research.

Skeletal fluorosis due to excessive tea and toothpaste consumption

We describe the case of a 53-year-old woman who presented with a metatarsal fracture and was found to have a bone mineral density (BMD) T-score of +11 in the lumbar spine and +7.6 in the hip. Subsequent investigation revealed very high serum, urine and tissue fluoride levels, associated with excessive tea and toothpaste consumption. The case emphasises the need to exclude fluorosis in individuals with unexpectedly high BMD levels.

Skeletal fluorosis from instant tea

INTRODUCTION

Skeletal fluorosis (SF) can result from prolonged consumption of well water with >4 ppm fluoride ion (F(-); i.e., >4 mg/liter). Black and green teas can contain significant amounts of F(-). In 2005, SF caused by drinking 1-2 gallons of double-strength instant tea daily throughout adult life was reported in a 52-yr-old woman.

MATERIALS AND METHODS

A 49-yr-old woman developed widespread musculoskeletal pains, considered fibromyalgia, in her mid-30s. Additionally, she had unexplained, increasing, axial osteosclerosis. She reported drinking 2 gallons of instant tea each day since 12 yr of age. Fluoxetine had been taken intermittently for 5 yr. Ion-selective electrode methodology quantitated F(-) in her blood, urine, fingernail and toenail clippings, tap water, and beverage.

RESULTS

Radiographs showed marked uniform osteosclerosis involving the axial skeleton without calcification of the paraspinal, intraspinal, sacrotuberous, or iliolumbar ligaments. Minimal bone excrescences affected ligamentous attachments in her forearms and tibias. DXA Z-scores were +10.3 in the lumbar spine and +2.8 in the total hip. Her serum F(-) level was 120 microg/liter (reference range, 20-80 microg/liter), and a 24-h urine collection contained 18 mg F(-)/g creatinine (reference value, <3). Fingernail and toenail clippings showed 3.50 and 5.58 mg F(-)/kg (control means, 1.61 and 2.02, respectively; p(s) < 0.001). The instant tea beverage, prepared as usual extra strength using tap water with approximately 1.2 ppm F(-), contained 5.8 ppm F(-). Therefore, the tea powder contributed approximately 35 mg of the 44 mg daily F(-) exposure from her beverage. Fluoxetine provided at most 3.3 mg of F(-) daily.

CONCLUSIONS

SF from habitual consumption of large volumes of extra strength instant tea calls for recognition and better understanding of a skeletal safety limit for this modern preparation of the world's most popular beverage.

Recovery from skeletal fluorosis (an enigmatic, American case)

A 52-year-old man presented with severe neck immobility and radiographic osteosclerosis. Elevated fluoride levels in serum, urine, and iliac crest bone revealed skeletal fluorosis. Nearly a decade of detailed follow-up documented considerable correction of the disorder after removal of the putative source of fluoride (toothpaste).

INTRODUCTION

Skeletal fluorosis, a crippling bone disorder, is rare in the United States, but affects millions worldwide. There are no data regarding its reversibility.

MATERIALS AND METHODS

A white man presented in 1996 with neck immobility and worsening joint pains of 7-year duration. Radiographs revealed axial osteosclerosis. Bone markers were distinctly elevated. DXA of lumbar spine (LS), femoral neck (FN), and distal one-third radius showed Z scores of +14.3, +6.6, and -0.6, respectively. Transiliac crest biopsy revealed cancellous volume 4.5 times the reference mean, cortical width 3.2 times the reference mean, osteoid thickness 25 times the reference mean, and wide and diffuse tetracycline uptake documenting osteomalacia. Fluoride (F) was elevated in serum (0.34 and 0.29 mg/liter [reference range: <0.20]), urine (26 mg/liter [reference range: 0.2-1.1 mg/liter]), and iliac crest (1.8% [reference range: <0.1%]). Tap and bottled water were negative for F. Surreptitious ingestion of toothpaste was the most plausible F source.

RESULTS

Monitoring for a decade showed that within 3 months of removal of F toothpaste, urine F dropped from 26 to 16 mg/liter (reference range: 0.2-1.1 mg/liter), to 3.9 at 14 months, and was normal (1.2 mg/liter) after 9 years. Serum F normalized within 8 months. Markers corrected by 14 months. Serum creatinine increased gradually from 1.0 (1997) to 1.3 mg/dl (2006; reference range: 0.5-1.4 mg/dl). Radiographs, after 9 years, showed decreased sclerosis of trabeculae and some decrease of sacrospinous ligament ossification. DXA, after 9 years, revealed 23.6% and 15.1% reduction in LS and FN BMD with Z scores of +9.3 and +4.8, respectively. Iliac crest, after 8.5 years, had normal osteoid surface and thickness with distinct double labels. Bone F, after 8.5 years, was 1.15% (reference range, <0.1), which was a 36% reduction (still 10 times the reference value). All arthralgias resolved within 2 years, and he never fractured, but new-onset nephrolithiasis occurred within 9 months and became a chronic problem.

CONCLUSIONS

With removal of F exposure, skeletal fluorosis is reversible, but likely impacts for decades. Patients should be monitored for impending nephrolithiasis.