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Hydrogen Sulfide
From WikEM
Contents
Background
General Information
- 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[1]
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
Clinical Features
- 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
- Death
Differential Diagnosis
- Carbon Monoxide Toxicity
- Cyanide Toxicity
- Hydrocarbons Toxicity
- Smoke Inhalation Injury
Evaluation
- 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
Management
- Removal from source
- 100% oxygen
- Hydroxocobalamin (Cyanokit)
- 5 g over 15 min to start, followed by a second dose prn
- If given as early as possible, has been shown in animal models to prevent PEA[2]
- Cobinamide, a vitamin B12 analog, shows promise as first line for H2S toxicity[3][4]
- Can give nitrite component of cyanide antidote kit (do NOT give the thiosulfate portion):
- Theoretically increasing methemoglobin formation in blood will cause conversion of sulfide to sulfmethemoglonin (less toxic)
- Amyl nitrite
- Sodium nitrite (3% NaNO2) IV over 2-4 minutes; adult dose 10 mL
- Obtain methemoglobin level 30 minutes after dose (desired level < 30%)
- Hyperbaric oxygen therapy (though not proven to have any benefit)[5]
Disposition
- Admission, likely to MICU
- Toxicology consult
References
- ↑ 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.
Authors
Catherine Neal, Kevin Lu, Jordan Swartz, Neil Young, Alex Koyfman, Daniel Ostermayer, Claire
