Contrastes baritados: a toxicologia experimental como ferramenta no estabelecimento de nexo causal de intoxicação maciça por bário

Abstract

On April, 2003, the Sanitary Surveillance of the State of Goiás (VISA-GO) started to receive notifications concerning possible poisoning Barium-containing contrast pharmaceutical products of brand A, B and C. These contrast solutions should be barium sulphate suspensions in water (BaSO4 1 g/ml), which is not absorbed by the gastrointestinal tract. Two hundred twenty three (223) cases were investigated, in which 44 patients (20%) were considered poisoning. Of these, 11 (26%) were hospitalized and 9 (21%) died due to the brand A contrast solution, 24 h after the exposition. The main signals and symptoms were: nausea, abdominal pain, diarrhea, vomiting, cardiac arrhythmias, chronic headache, dyspnea, and agitation. Of the three brand contrast solution, brand A was associated to 89% of the deaths. In the present work, we investigated the acute toxicity (hippocratic screening and lethality) of the brand A contrast solution, containing 13,8% of barium carbonate, in comparison to soluble barium nitrate, Ba(NO3)2 and barium carbonate Ba(CO3)2) and, insoluble (pure barium sulphate). Material and Methods: in was used in the experiments male Swiss mice, weighing 25 g (n=10 mice/group) and male Wistar rats, (300-430 g) (n=2 or 3 rats/dose) kept in polypropylene box with chow and drinking water ad libitum. All animals were observed for 14 days; the survivors were sacrificed and anatomopathologic investigated. Control animals received saline solution only. Results: treatment with Ba(NO3)2, Ba(CO3)2 and brand A produced poisoning signals, in a dose-dependent manner: tremors, rhinorrhea, cardiac arrhythmias, piloerection, diarrhea, decrease in motor activity and respiratory rate, paralysis of skeletal muscle, inflammation of penis and testicles, death (50% of the animals treated with brand A). When the animals were treated with pure barium sulphate no toxic effects were observed. Lethality: Ba(NO3)2 (800 mg/kg), Ba(CO3)2 (2000 mg/kg) and brand A (2000 and 4000 mg/kg). No death was observed for BaSO4. Mice treated with the doses of 1000, 2000 and 4000 mg/kg, 10, 10 and 50% of the animals died, respectively.