Clinical presentation

Systemic fluorosis

Systemic fluorosis is life threatening and can occur after dermal or inhalational exposure, or ingestion of hydrofluoric acid.

Clinical effects of systemic fluorosis include:

  • metabolic effects—electrolyte disturbances including hypocalcaemia and hypomagnesaemia and, in severe cases, metabolic acidosis and hyperkalaemia
  • cardiovascular effects
    • hypotension
    • QT-interval prolongation due to hypocalcaemia and hypomagnesaemia
    • ventricular arrhythmias, cardiac arrest
  • central nervous system (CNS) effects—CNS depression, tetany, seizures.

Hypocalcaemia, hypomagnesaemia and metabolic acidosis can occur within 1 to 2 hours and may lead to severe cardiovascular toxicity. Hypotension, seizures, QT-interval prolongation and arrhythmias indicate severe hypocalcaemia and hypomagnesaemia due to systemic fluorosis. In severe systemic fluorosis there have been reports of hyperkalaemia, but this is less common.

Note: Hypotension, seizures, QT-interval prolongation or arrhythmias indicate severe hypocalcaemia and hypomagnesaemia.

Dermal exposure

Most dermal exposures involve low-concentration hydrofluoric acid solutions (eg 4 to 10%) over extended periods of time. The most common presenting symptom after hydrofluoric acid exposure is pain at the exposure site. The degree of pain is associated with the concentration of solution. Low-concentration solutions cause delayed pain (8 to 24 hours after exposure) that can be severe and may last 12 to 48 hours. Exposure to high-concentration solutions cause more immediate pain with rapid tissue damage. Other local effects include pallor and blanching (first few hours), and blistering and tissue loss (days).

High-concentration hydrofluoric acid solutions (eg 50 to 100%) can cause life-threatening systemic fluorosis even when only a small surface area of the body has been exposed (eg death has been reported following exposure to hydrofluoric acid 100% solution exposure to 2.5% body surface area [BSA]). Exposure to low-concentration hydrofluoric acid solutions can cause systemic fluorosis if a large surface area of the body has been exposed (eg hydrofluoric acid 23% solution exposure to 11% BSA).

Inhalational exposure

Inhalational exposure to hydrofluoric acid can irritate the eyes, nose and throat. Respiratory effects include cough, wheeze, dyspnoea and, in severe cases, pulmonary oedema. Inhalational exposure can also cause systemic fluorosis.

Ingestion

Ingestion of high-concentration hydrofluoric acid solutions, or large volumes of any hydrofluoric acid solution, can cause local caustic injury and systemic fluorosis.

Ocular exposure

Ocular exposure is similar to dermal exposure in terms of causing severe pain, but with the additional risk of visual loss.