Overview
Bromide is a halide ion chemically similar to chloride and is distributed mainly in plasma and extracellular fluid. Historically, bromide salts such as sodium bromide and potassium bromide were widely used as sedatives and antiepileptic agents in the 19th and early 20th centuries.
Because bromide has a long biological half-life and slow renal elimination, it can accumulate in the body with chronic use. Measurement of bromide levels is mainly relevant today in cases of suspected bromide toxicity, known as bromism, and in selected clinical, toxicological, and veterinary settings.
Symptoms
Bromide excess does not cause symptoms initially, but chronic accumulation leads to bromism. Common symptoms include fatigue, headache, dizziness, memory impairment, confusion, irritability, and depression.
Neurological manifestations such as tremors, ataxia, hallucinations, psychosis, and delirium may occur in severe cases. Gastrointestinal symptoms like nausea, vomiting, abdominal pain, and anorexia can also be seen. Advanced toxicity may progress to coma.
Causes
Elevated bromide levels are caused by chronic exposure or ingestion of bromide-containing compounds. Historically, this was due to prolonged therapeutic use of bromide salts. In modern practice, causes include the use of certain sedatives, herbal or alternative remedies containing bromide, occupational exposure, or accidental ingestion.
Bromide interferes with chloride measurement in some assays, leading to falsely elevated serum chloride and a low or negative anion gap, which can complicate diagnosis.
Risk Factors
Risk factors for bromide toxicity include long-term or high-dose bromide intake, dehydration, renal insufficiency, and low-chloride diets. Elderly individuals and patients with impaired kidney function are particularly susceptible due to reduced bromide clearance.
Misinterpretation of laboratory results, especially unexplained hyperchloremia without metabolic acidosis, increases the risk of delayed diagnosis.
Prevention
Prevention of bromide toxicity relies on avoiding unnecessary exposure to bromide-containing medications and supplements. Awareness of bromide’s effect on electrolyte measurements helps prevent diagnostic errors. Early recognition of neurological or psychiatric symptoms with unexplained laboratory findings allows timely testing and intervention. Adequate hydration, chloride supplementation, and discontinuation of bromide sources are key to preventing accumulation and complications.
