FLUORIDE TOXICITY
Fluoride toxicity is characterized by a variety of signs and symptoms. Poisoning most commonly follows ingestion (accidental or intentional) of fluoride- containing products. However, in many parts of the world (eg, region of India and China), elevated levels of fluoride in groundwater result in chronic fluoride toxicity (fluorosis). Potentially toxic levels of fluoride have also been found in well water in the US.
Fluoride is found in many common household products, including the following
Toothpaste (eg, sodium monofluorophosphate)
Vitamins
Dietary supplements (eg, sodium fluoride)
Glass-etching or chrome- cleaning agents (eg, ammonium bifluoride)
Insecticides and rodenticides (eg, sodium fluoride)
Historically, most cases of serious acute fluoride toxicity have followed accidental ingestion of insecticides or rodenticides.
Symptom onset usually occurs within minutes of exposure, but may be delayed. Manifestations of fluoride toxicity are predominantly gastrointestinal (GI), but neurologic and cardiovascular effects also occur. Tests for measuring fluoride levels are not available in the emergency department. Assessment of patients with suspected fluoride toxicity is directed toward the consequences of the toxicity, and may include the following:
Electrocardiogram
Electrolyte levels
Fingerstick glucose assay
No antidote for fluoride toxicity exists, and fluoride does not absorb to activated charcoal. Treatment includes gastric aspiration and lavage, and correction of electrolyte abnormalities.
PATHOPHYSIOLOGY:
Fluoride has several mechanisms of toxicity. Upon ingestion, the GI tract is the earliest and most commonly affected organ system. Ingested fluoride can form hydrofluoride acid in the stomach, which leads to GI irritation or corrosive effects.
Once absorbed, fluoride binds calcium ions and may lead to hypocalcemia. Fluoride also has direct cytotoxic effects and interferes with a number of enzyme system: it disrupts oxidative phosphorylation, glycolysis, coagulation, and neurotransmission ( by binding calcium).
Fluoride inhibits Na+/K+ - ATPase, which may lead to hyperkalemia by extracelluar release of potassium. Fluoride inhibits acetycholinesterase, which may be partly resposible for hypersalivation, vomiting, and diarrhea( cholnergic signs). Seizures may result from both hypomagnesemia and hypocalcemia.
Severe fluoride toxicity will result in multiorgan failure. Central vasomotor depression as well as direct cardiotoxicity also may occur. Death usually results from respiratory paralysis, dysrhythmia, or cardiac failure.
ETIOLOGY:
The most common type of exposure is ingestion of products that contain fluoride. To obtain the exact name of the product and how much was ingested is extremely important.
Toothpaste contain 1 mg/g of fluoride as sodium monofluorophosphate. This fluoride formulation has low solubility and is generally nontoxic. The toxic effects following large ingestions of the following products usually are limited to GI discomfort:
Toothpaste
Oral hygiene products
Insecticide
Rodenticide
Dietary supplements
Automobile wheel-cleaning products
Glass -etching products
Over 95% of the toothpaste sold in the U.S now contains fluoride. The use of fluoride toothpaste, particularly during early childhood, presents health risks. This is why the FDA requires a poison warning on every tube of fluoride toothpaste now sold in the US.
Risks from ingesting fluoride toothpaste include permanent tooth discoloration ( dental fluorosis), stomach ailments, acute toxicity, skin rashes (perioral dermatitis ), and impairment in glucose metabolism. All of these have been unnecessarily increased by the marketing practices of toothpaste manufacturers, who use cartoon packaging and candy-flavors to target 'adult-strength' fluoride toothpaste to young ' children.' The dental community's failure
