Toxicity can result from ingestion of as little as 200 mg of a barium salt. Oral lethal doses are reported to range from 1 to 30 g of a barium salt. Occupational exposure to barium fumes of greater than 0.02 mg/m3 are associated with health effects.36 Exposure to inhaled particulate barium may cause pulmonary baritosis, which consists of very fine punctate and annular lesions and some slightly larger nodular lesions.36
Following ingestion, 5% to 10% of soluble barium carbonate salts are absorbed,15 with the rate of absorption dependent on the degree of water solubility of the salt. The time to peak serum concentration is 2 hours.15
The toxicokinetics are characterized by a rapid redistribution phase, followed by a slow decrease of serum barium concentrations, with a reported half-life ranging between 18 and 85 hours.15,26 Renal elimination of the absorbed dose accounts for 10% to 28% of total barium excretion, with the predominant route of elimination through the gastrointestinal tract in the feces.
Serum barium concentrations range from 3.7 to 41.1 mg/L in published case reports of symptomatic patients.2,8,21,23,26,29,31 Death is uncommon following exposure but occurs most commonly following ingestion in clinical settings with limited health care resources.12 Death from an ingestion of barium chloride was associated with the following barium concentrations at autopsy: blood, 9.9 mg/L; bile, 8.8 mg/L; urine, 6.3 mg/L; and gastric contents, 10 g/L.16
Intravasation is a rare but serious complication of radiologic studies in which barium sulfate is administered under pressure, such as a barium enema. Following a small perforation, barium sulfate leaks into the peritoneal cavity or portal venous system.20 Although sudden cardiovascular collapse may occur, it is unclear whether this is the result of venous occlusion (pulmonary embolism), overwhelming sepsis, or barium toxicity.6,30,35 In at least one case report of intravasation, signs and symptoms were consistent with barium toxicity and elevated barium concentrations were confirmed.22 If hypokalemia is present, then barium toxicity should be assumed.
Additionally, intravenous administration of barium sulfate has occurred as the result of iatrogenic error. Rapid recognition followed by aspiration through a central venous catheter was associated with a good outcome.28