Clinical significance of urinary fluoride levels in patients with hydrofluoric acid burns

Objective

We investigated the urinary fluoride level in patients with hydrofluoric acid (HF) burns of different severities and explored the clinical significance of these levels in the diagnosis of acute HF burn.

Methods

Data from 260 patients with HF burns were collected from the Department of Burns, Zhejiang Quhua Hospital, between July 2006 and June 2016. According to burn severity, patients were divided into non-poisoning, mild poisoning, moderate poisoning, and severe poisoning groups. In addition, 25 healthy controls were recruited from fluorine chemical companies. The urinary fluoride level was measured using a fluoride-selective electrode and values were compared amongst groups. The urinary fluoride level was also measured periodically after exposure to investigate dynamic changes in the moderate and severe poisoning groups.

Results

Urinary fluoride levels were 0.32–520.0 mg/L (n = 260) on admission to the emergency department, and 182 patients had levels >1.7 mg/L. The levels in controls and the non-poisoning group were lower than in the other two groups, and increased significantly with an increase in severity. Thirty-three patients were admitted 4 h after injury; of these patients, fluoride levels were significantly higher in those with severe poisoning than in those with moderate poisoning. Levels peaked 4 h after injury and then dropped and returned to normal 6 days after injury.

Conclusion

Urinary fluoride level can be used for the early diagnosis of HF burns and to determine the severity of fluoride poisoning, which is crucial for early treatment.