special subjects
Hydrofluoric Acid Exposure
Symptoms and Signs of Hydrofluoric Acid Exposure
Symptoms and signs of hydrofluoric acid exposure vary depending on the route of exposure. Pain is typically the first symptom to manifest after dermal exposure and precedes signs of chemical burns, such as erythema (1st degree), edema and bullae formation (2nd degree), or gray-white discoloration (3rd degree). Pain is often more severe than expected based on apparent dermal involvement. If the fingers and nail beds are burned, the nails may remain intact, and pain may be severe despite apparent absent or minimal involvement of the nails and skin. Oral occupational exposure to HF is less common but may occur when aqueous solution containing HF is stored in unmarked containers (eg, water bottles). Nonoccupational oral HF exposure may result from attempts at self-harm or exploratory ingestion by young children. Ingestion of dilute HF solution may result in oropharyngeal erythema and edema and gastrointestinal irritation; ingestion of a small volume may be asymptomatic. Ingestion of concentrated HF solution results in hemorrhagic gastritis and pulmonary toxicity similar to inhalational exposure. Inhalational exposure to HF most commonly results in upper airway and chest pain (described as burning), cough, and shortness of breath. Patients may also report nausea, vomiting, and headache and a burning sensation in skin exposed to HF vapor. Time to symptom-onset is inversely proportional to the airborne concentration of HF. Pharyngeal erythema and edema may be present, as may wheezing, rales, and respiratory distress. With more severe inhalational exposure, patients may develop hemorrhagic alveolitis with Hemoptysis or Dermal, oral, or inhalational HF exposure may result in systemic fluoride toxicity (ocular exposure has not been implicated in systemic toxicity). Onset of systemic toxicity is more rapid after oral HF exposure because systemic absorption is more rapid after oral exposure than dermal exposure. Dermal exposure to concentrated HF solution may result in systemic fluoride toxicity even when the body surface area involved is small. Systemic fluoride toxicity is marked by Hypocalcemia , Ocular exposure to HF may result from a splash injury involving an aqueous solution or from gaseous HF. Mild (more dilute) exposure may cause eye pain, conjunctival injection, and chemosis and may not manifest for hours after the exposure. If the exposure is more concentrated, onset of symptoms is more rapid; corneal coagulative necrosis may occur, and the globe may rupture. 