Bismuth toxicity

Background

  • Heavy Metal
  • Available in two forms
    • Elemental
      • Nontoxic
    • Bismuth Salts
      • Uses
        • Oral preparations for traveler's diarrhea, nausea, and vomiting
        • Bismuth-impregnated surgical packing pastes for ileostomies and colostomies
        • Gastric ulcers
      • Cause toxicity

Toxicokinetics

  • Poorly understood due to lack of data
  • Low absorption in the GI tract, approximately 0.2% is systemically absorbed [1]
  • 90% excreted from kidneys
  • Levels may be increased in those taking PPI
    • Ranitidine does not alter the absorption of bismuth

Clinical Features

Acute

Chronic

  • Diffuse progressive encephalopathy
  • Neurobehavioral changes
    • Apathy
    • Irritability
    • Poor concentration
    • Worsened short term memory
    • Visual hallucinations
  • Movement disorders
  • Pigmentation of skin and oral mucosa
  • Seizure
  • Coma and death

Differential Diagnosis

Heavy metal toxicity

Encephalopathy

Evaluation

  • Need to have high index of suspicion
  • BMP
  • CBC
  • Urinalysis
  • CT head for cases of encephalopathy
    • May show diffuse cortical hyperdensity of the grey matter
  • Salicylate level
    • In the United States bismuth subsalicylate is the most common oral compound, and up to 90% of salicylate is absorbed [2]
  • EEG

Management

  • Supportive care
  • Consider whole bowel irrigation
  • Chelation
    • Limited data to support its use
    • Exact timing and dosages are unknown
    • British anti-Lewisite (BAL)
      • Undergoes biliary elimination which is useful in those with renal insufficiency
      • Benefits shown in experimental models

Disposition

  • Admission if evidence of renal failure or encephalopathy manifestations
  • Consult Toxicology or poison control

References

  1. Hundal O, Bergseth M, Gharehnia B, et al. Absorption of bismuth from two bismuth compounds before and after healing of peptic ulcers. Hepatogastroenterology. 1999;46:2882-2886.
  2. Pickering LK, Feldman S, Ericsson CD, Cleary TG. Absorption of salicylate and bismuth from a bismuth subsalicylate containing compound (Pepto- Bismol). J Pediatr. 1981;99:654-656.

Rao, R. Bismuth. In: Goldfrank's Toxicologic Emergencies. 9th Ed. New York: McGraw-Hill; 2011: 1233-1236