TOXICOLOGYMECHANISM/TOXICITY
■ Absorbed through skin and mucous membranes →free fluoride ion avidly
binds extracellular Ca++and Mg+→pain
■ Systemic hypocalcemia and hypomagnesemia may occur with inges-
tion or heavy dermal exposure.
■ Hyperkalemia may be delayed in onset due to cellular breakdown,
acidosis and direct fluoride effects on K+efflux.
■ HF is a weak acid and exposure to low-concentration (< 10%) solutions
does not produce caustic injury.
■ High-concentration solutions can produce direct tissue injury similar to
other strong acids.
SYMPTOMS/EXAM
■ There is a direct relationship between solution concentration and symp-
tom onset.
■ Concentrated solutions produce symptoms earlier.
■ Onset can be delayed up to 24 hours after exposure to a dilute solution.
■ Dermal exposure to low concentrations:
■ Local pain, erythema, swelling, and a white-blue discoloration (espe-
cially subungual)
■ Pain “out of proportion” to skin findings
■ Oral ingestion or large dermal exposure to concentrated solutions:
■ Local pain of direct tissue injury
■ Systemic hypocalcemia →tetany, weakness, Chvostek’s sign, dysrhyth-
mias, and sudden death.
DIAGNOSIS
■ Usually determined from the patient’s history and examination
■ ECG findings with severe hypocalcemia include prolonged QT interval
and peaked T waves.
■ Direct measurement of total or ionized Ca++confirms severe toxicity.
TREATMENT
■ Copious water irrigationfor surface decontamination
■ Calcium gluconateadministration (to bind fluoride ions):
■ Topical paste
■ Subcutaneous and intradermal injections
■ Regional intraarterial infusion
■ Nebulized (for inhalation exposure)
■ Systemically ill patients should be monitored carefully and aggressively
treated with intravenous calcium.
■ Avoid calcium chlorideinjection,which can cause skin necrosis.
Lead
Lead is a heavy metal used extensively in commercial products and manufac-
turing processes. Adult lead exposure is primarily occupational (construction,
mining, welding, smelting, manufacture of batteries, plastic and rubber,
“moonshine”). Pediatric exposure usually results from accidental ingestion of
lead-containing material, especially paint chips.
Onset of symptoms from
dermal exposure to low
concentrations of HF may be
delayed up to 24 hours.Calcium gluconate paste,
injection, and arterial infusions
are key to treating ongoing
pain and toxicity from dermal
HF exposure.