Toxin

Methanethiol

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Methanethiol, Methanethiol Poisoning, Methanethiol Toxicity, Methyl Mercaptan, Methyl sulfhydrate, Mercaptomethane

  • Background
  1. Organosulfur gas that is colorless, but has a putrid odor, and is highly toxic when concentrated (industrial use)
  2. Naturally occurring
    1. Found in natural gas, coal tar, decaying material in marshes, and sea algae breakdown products
    2. Occurs in mammal feces (contributes to the foul odor)
  3. Industry
    1. Production of plastics, Pesticides, jet fuel and farm feed
    2. By product in wood pulp processing
  4. Toxicity
    1. Blocks Electron Transport Chain
    2. Primary toxicity is via inhation
    3. Other exposures include skin contact and mucosal irritation
  5. Exposure Levels
    1. Odor present: 0.002 ppm
    2. Permissible exposure level: 10 ppm
    3. Human health hazard level: 150 ppm
  • Adverse Effects
  1. Respiratory
    1. Cough
    2. Respiratory distress
    3. Apnea (severe cases)
  2. Cardiac
    1. Tachycardia
    2. Hypotension
    3. Acute Coronary Syndrome
  3. Gastrointestinal
    1. Nausea
    2. Vomiting
  4. Neurologic
    1. Confusion
    2. Seizure
    3. Coma
  • Labs
  1. Serum Electrolytes
  2. Venous Blood Gas
    1. Metabolic Acidosis
  3. Lactic Acid
    1. Lactic Acidosis
  • Imaging
  1. Chest XRay
  • Management
  1. Move patient to fresh air
  2. Decontamination (remove contaminated clothing, wash skin)
  3. Eye Irrigation for 15 minutes (if contact exposure)
  4. Treat bronchospasm (e.g. Nebulized Albuterol)
  5. Seizure Management (start with Benzodiazepines)
  6. Antidotes
    1. Consider hydroxycobalamin 5 g IV
  • Resources
  1. Methanethiol (Wikipedia)
    1. https://en.wikipedia.org/wiki/Methanethiol
  2. Methanethiol (PubChem)
    1. https://pubchem.ncbi.nlm.nih.gov/compound/methanethiol
  • References
  1. Tomaszewski (2020) Crit Dec Emerg Med 34(12): 28