Cornelia McDonald MD., Joel Butler MD., William Rushton MD
UAB Office of Toxicology
A 45-year-old male presented to the Emergency Department complaining of severe pain and swelling to his second and third digits that started 20 hours prior. He first noticed his symptoms after getting home from work the day before which continued to progress rapidly over the next three hours. He reported having used an industrial wheel cleaning solution bare handed prior to onset of symptoms.
Upon arrival to the emergency department, his vital signs were within normal limits. Physical exam revealed swelling and severe tenderness to palpation isolated to the 2nd and 3rd digits of his right hand distal to the PIP joint. His presentation was consistent with hydrofluoric acid burn and he was treated with calcium gluconate topical gel within a glove in addition to intravenous opioid pain medication. He was subsequently admitted to the burn service for further pain control and observation for burn progression.
He remained an inpatient for 3 days on the burn service for dressing changes with reapplication of the calcium paste glove for pain control. He followed up in burn clinic roughly one week post later and reported compliance with his glove and calcium gel, which he applied and changed daily. While he still had some mild residual pain, he reported full function of his entire affected hand.
Hydrofluoric acid (HF)is commonly found in automotive cleaning solutions and is also used in the production of etching glass. Direct dermal exposure to HF acid at high concentrations or for prolonged time can result in severe chemical burns and extreme pain. Hydrofluoric acid causes direct damage when free fluoride ions attempt to scavenge cations (calcium and magnesium) intracellularly, thereby disrupting cellular membranes. The severe pain that occurs with this type of acid burn is a result of the direct spontaneous depolarization caused by the free fluoride ions on nerve tissue. Treatment therefore should target free fluoride ions that are responsible for the tissue damage; therapy aims to neutralize the fluoride ions with elemental calcium, limiting ongoing tissue destruction and alleviating severe pain.
Several recipes exist for making the calcium preparation as commercially grade products often have concentrations that are insufficient in elemental calcium. A common preparation (see: https://www.aliem.com/2012/09/tricks-of-trade-calcium-gel-for/) that has successfully been employed requires only two ingredients: calcium carbonate (TUMS) and 5 ounces of water-soluble jelly. After manually crushing up 10 grams of calcium carbonate tablets (or 20 tabs), mix with water-soluble jelly to make a paste. Coat the affected area with the paste and place in a glove; the patient should wear for at least 30 minutes. Repeated application may be required for severe burns. Although some references suggest intradermal calcium gluconate injection for severe symptoms, most patients have gross improvement with topical treatment alone. Patients should all have rapid follow-up or evaluation with a burn or hand specialist following disposition from the emergency department.
Clinicians should consider mixing their own topical calcium carbonate paste for the treatment of hydrofluoric acid. While messy, the highly concentrated calcium paste can reduce further tissue damage and improve pain. The Regional Poison Control Center of Children’s at Alabama (1-800-222-1222) can further aid in guiding management of these patients.