Hydrogen sulfide toxicity
- Colorless, flammable gas
- Encountered in following industries: oil, gas, organic decomposition (sewer and manure), roofing asphalt tanks
- Most common fatal gas exposure
- “Rotten egg” smell which diminishes with high concentrations or prolonged low concentration exposure
- Often used in suicide attempts: acidic detergent (toilet bowl cleaner) is mixed with bath salts or pesticides
Mechanisms of toxicity
- Highly lipid soluble
- Disrupts oxidative phosphorylation by inhibiting cytochrome oxidase aa3 (toxicity through cellular asphyxia and impairs ATP production) => lactate accumulation and metabolic acidosis
- Causes hyperpolarization of potassium-mediated channels in neurons
- Potentiates neuronal inhibitory mechanisms
- Alters brain neurotransmitter content and release
- Respiratory: dyspnea, cyanosis, hemoptysis, rales, delayed pulmonary edema
- Ophthalmic: conjunctivitis, corneal ulceration, corneal scarring
- Central nervous system: headache, weakness, disequilibrium, intention tremor, muscle rigidity, loss of consciousness, seizures, coma
- Gastrointestinal: green-gray line on gingiva, nausea, vomiting
- Cardiovascular: chest pain, bradycardia
- Neuropsychiatric: amnesia, lack of insight, disorientation, delirium, dementia
- No single test to verify exposure or levels
- ABG Interpretation: metabolic acidosis and normal oxygen saturation (unless pulmonary edema present)
- Elevated lactate
- Discolored copper coins found on patient may be helpful in diagnosis
- Removal from source
- 100% oxygen
- Hydroxocobalamin (Cyanokit)
- Can give nitrite component of cyanide antidote kit (do NOT give the thiosulfate portion):
- Hyperbaric oxygen therapy (though not proven to have any benefit)
- Admission, likely to MICU
- Toxicology consult
- Tintinalli et. al. Hydrogen Sulfide. In: Tintinalli et. al. Emergency Medicine A Comprehensive Study Guide. New York, NY: McGraw Hill. 2011. 1320.
- Haouzi P et al. High-dose hydroxocobalamin administered after H2S exposure counteracts sulfide-poisoning-induced cardiac depression in sheep. Clin Toxicol (Phila). 2015 Jan;53(1):28-36.
- Jiang J et al. Hydrogen Sulfide—Mechanisms of Toxicity and Development of an Antidote. Nature. Scientific Reports 6, Article number: 20831 (2016).
- Brenner M et al. The vitamin B12 analog cobinamide is an effective hydrogen sulfide antidote in a lethal rabbit model. Clin Toxicol (Phila). 2014 Jun;52(5):490-7.
- Goldfrank et. al. Hydrogen Sulfide Poisoning. In: Goldfrank et. al. Goldfrank’s Toxicologic Emergencies. New York, NY: McGraw Hill. 2002. 1504-1507.