II. Background: Hydrogen Sulfide

  1. Hydrogen Sulfide is a Sulfur-Based Toxic Gas
    1. Flammable, colorless gas
    2. Poisonous
    3. Malodorous (rotten egg smell)
    4. Air Pollutant
  2. Manufacturing reagent
    1. Chemical manufacturing
    2. Petroleum processing
    3. Sewage processing
    4. Metallurgy
    5. Agriculture
    6. Analytical Chemistry
  3. Intentional Poisoning (Suicide attempt)
    1. Acid (e.g. toilet bowl cleaner) combined with sulfur-containing molecule (e.g. Pesticides, fungicide, lime sulfur)
    2. Results in release of Hydrogen Sulfide (H2S)

III. Pathophysiology: Hydrogen Sulfide Toxicity

  1. Toxicity
    1. Cytochrome C Oxidase inhibition
    2. Neuronal Potassium channels hyperpolarized
    3. Oxygen radicals form
    4. Corrosive at mucous membranes
  2. Concentrations <100 ppm will be detectable as a rotten egg smell
    1. Prolonged exposure at lower levels may result in loss of olfactory detection
  3. Concentrations >100 ppm result in Loss of Smell by olfactory paralysis (no rotten egg smell detected)
  4. Concentrations >500 ppm are rapidly lethal by inhalation

IV. History

  1. Sudden collapse in an enclosed work area such as a sewer (esp. if rotten egg smell was reported)

V. Signs

  1. Ocular ("gas eye")
    1. Conjunctivitis
    2. Photophobia
    3. Lacrimation
  2. Cardiopulmonary
    1. Dyspnea
    2. Cyanosis
    3. Rales
    4. Acute Respiratory Distress Syndrome (ARDS)
  3. Gastrointestinal
    1. Nausea
    2. Vomiting
  4. Neurologic
    1. Headache
    2. Syncope
    3. Loss of consciousness ("Knockdown gas")
    4. Seizures

VI. Labs

  1. See Poisoning
  2. Sulfide concentrations
    1. Blood sulfide concentration
    2. Blood and urine thiosulfate concentration
  3. Venous Blood Gas (or Arterial Blood Gas)
    1. Metabolic Acidosis (due to Lactic Acidosis)

VII. Imaging

  1. Head MRI or Head CT
    1. As indicated for neurologic findings

VIII. Management

  1. Immediately remove patient from Hydrogen Sulfide source
    1. Patients may start to improve in open air once removed from source
  2. ABC Management
  3. Respiratory Management
    1. Nonrebreather 100% oxygen
    2. Noninvasive Positive Pressure Ventilation (e.g. BiPap) or Mechanical Ventilation with PEEP
  4. Hypotension management
    1. Intravenous Fluids
    2. Vasopressors
  5. Sulfide Antidotes
    1. Sodium Nitrite 3% 0.2 ml per kg (children) up to 10 ml or 300 mg in adults IV over 2-4 min
    2. Hydroxycobalamin (cyanokit) 2.8 ml/kg or 70 mg/kg (children) up to 200 ml or 5 g in adults over 15 min
      1. May reduce Hydrogen Sulfide Toxicity
      2. Also indicated if co-exposure to Cyanide is suspected
    3. Cobinamide (experimental)
  6. Disposition
    1. Admit all patients with respiratory of neurologic signs or symptoms
    2. Patients with only mild mucosal irritation (e.g. Conjunctivitis) may be discharged home

IX. Complications

  1. Neurologic and psychiatric sequelae may be longstanding

X. Resources

  1. Hydrogen Sulfide (OSHA)
    1. https://www.osha.gov/hydrogen-sulfide
  2. Hydrogen Sulfide Toxicity (Stat Pearls)
    1. https://www.ncbi.nlm.nih.gov/books/NBK559264/

XI. References

  1. Swadron and Nordt (2022) EM:Rap 22(6): 5-7
  2. Tomaszewski (2017) Crit Dec Emerg Med 31(10): 24

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Ontology: Hydrogen Sulfide (C0020282)

Definition (CSP) toxic gas, H2S.
Definition (MSH) A flammable, poisonous gas with a characteristic odor of rotten eggs. It is used in the manufacture of chemicals, in metallurgy, and as an analytical reagent. (From Merck Index, 11th ed)
Concepts Hazardous or Poisonous Substance (T131) , Indicator, Reagent, or Diagnostic Aid (T130) , Inorganic Chemical (T197)
MSH D006862
SnomedCT 27390006
LNC LP15644-5, MTHU011758
English Hydrogen Sulfide, Sulfide, Hydrogen, Hydrogen sulfide (H2S), Hydrogen Sulfide [Chemical/Ingredient], hydrogen sulfide, hydrogen sulphide, Hydrogen sulfide, Sulfur hydride, Hydrogen sulphide, Hydrogen sulfide (substance), Sulphur hydride
French Sulfure d'hydrogène, H2S, Hydrogène sulfuré, Sulfure de dihydrogène
Swedish Svavelväte
Czech sirovodík, sulfan
Finnish Rikkivety
Japanese 硫化水素
Polish Siarkowodór
Norwegian Hydrogensulfid
Spanish Ácido Sulfhídrico, hidrógeno azufrado, sulfuro de hidrógeno (sustancia), sulfuro de hidrógeno, ácido sulfhídrico, Sulfuro de Hidrógeno
Portuguese Ácido Sulfídrico, Sulfeto de Hidrogênio
German Schwefelwasserstoff
Italian Solfuro di idrogeno

Ontology: Hydrogen sulfide poisoning (C0274947)

Concepts Injury or Poisoning (T037)
SnomedCT 2443003
English poisoning hydrogen sulfide (diagnosis), poisoning hydrogen sulfide, Hydrogen sulfide poisoning, Hydrogen sulfide poisoning (disorder), Hydrogen sulphide poisoning
Spanish intoxicación por ácido sulfhídrico (trastorno), intoxicación por ácido sulfhídrico