Summary
Hydrocarbons are a large class of organic compounds found in many common products, such as fuels, solvents, and cleaning supplies; they can also be released from industrial and environmental sources. Acute poisoning can occur through ingestion, inhalation, or dermal absorption. Common sources of hydrocarbon poisoning include accidental ingestion by children, occupational exposure, and recreational inhalant use. Clinical features vary by substance and route of exposure but commonly include neurological symptoms (e.g., CNS depression), respiratory distress due to aspiration, and gastrointestinal symptoms following ingestion. Halogenated and aromatic hydrocarbons are particularly toxic, as they can sensitize the myocardium to catecholamines and cause fatal cardiac arrhythmias, a phenomenon known as "sudden sniffing death syndrome." Diagnosis is primarily clinical, supported by a chest x-ray to assess for chemical pneumonitis and an ECG to monitor for arrhythmias. Additional laboratory studies and imaging may be required to evaluate for organ damage and rule out comorbid poisoning. Supportive care is the cornerstone of management, as there are no specific antidotes. Treatment involves immediate decontamination of the skin and respiratory and hemodynamic support. Gastrointestinal decontamination is avoided due to the risk of aspiration. Adrenergic agents and unnecessary stimulation must be avoided to prevent fatal arrhythmias. Chronic hydrocarbon exposure can lead to severe long-term complications, including cognitive impairment, peripheral neuropathy, organ damage, and malignancy.
See also "Inhalant-related disorders" and "Inhalant intoxication" for the identification, diagnosis, and management of recreational inhalant use.
Overview
Definitions [1][2]
- Hydrocarbons: organic compounds composed of hydrogen and carbon, most commonly derived from crude oil and plants
- Aliphatic hydrocarbons: joined in a linear chain or by a nonaromatic ring
- Aromatic hydrocarbons: contain at least one aromatic ring
- Halogenated hydrocarbons (aliphatic or aromatic): contain fluorine, chlorine, bromine, or iodine
-
Volatile organic compounds (VOCs): organic compounds with high vapor pressure at room temperature
- May be hydrocarbons or nonhydrocarbons
- Can be emitted from solids and liquids
Etiology [3]
Poisoning by patient demographic [1]
- Children: most commonly due to accidental ingestion of household hydrocarbons
- Adolescents and young adults: usually due to recreational inhalant use (see "Inhalant use disorder")
- Workers: usually due to accidental dermal or inhalation occupational exposures
- General population: exposure to environmental pollutants
Industrial and environmental sources of hydrocarbons [4][5]
The risk of occupational poisoning and environmental contamination is highest in the following occupational settings:
- Occupational settings with high CO2 emissions
- Petroleum, oil, gas, coke, and coal refinery and processing
- High-combustion environments (e.g., firefighting, incineration)
- High engine exhaust emissions (e.g., automotive repair)
- Aluminum and/or silicon production (e.g, metal and glassworks)
- Paving and roofing with bitumen or asphalt
Commercial, household, and recreational sources of hydrocarbons [3][6]
The following products are widely available and may be used recreationally because of the intoxicating effects of their hydrocarbon content (see "Inhalant use disorder"):
- Aerosols: e.g., hairspray, air freshener, deodorant, fire extinguishers, cooking spray
- Paints (especially spray paint), polishes, varnishes, lacquers, and resins
- Office supplies: e.g., markers, correction fluid
- Cleaning supplies: e.g., cleansers, degreasers, paint thinners, varnish or polish remover
- Fuel: e.g., lighter fluid, gasoline
- Glues, adhesives, and cements
- Inhalational anesthetics
Hydrocarbons are commonly used as solvents and spray propellants in household and commercial products. [3]
Pathophysiology [1][2]
Toxicity depends on chemical properties.
- Low viscosity and/or surface tension: risk of aspiration, chemical pneumonitis, and acute lung injury due to surfactant disruption and direct alveolar injury
- High volatility: risk of asphyxia through oxygen displacement
- Lipophilicity: risk of neurotoxicity (e.g., CNS depression, peripheral neuropathy)
- Halogenated and aromatic hydrocarbons: risk of arrhythmias and sudden death due to myocardial sensitization to catecholamines
Clinical features
- Clinical features of hydrocarbon poisoning depend on the:
- Route of exposure (e.g., oral, inhalational, or dermal)
- Onset and duration of exposure
- Chemical structure of the hydrocarbon
- See the following sections for details:
- "Acute hydrocarbon intoxication and poisoning"
- "Chronic hydrocarbon poisoning"
- "Aliphatic hydrocarbons"
- "Aromatic hydrocarbons"
- "Halogenated hydrocarbons"
- Recreationally inhaling hydrocarbons can cause intoxication: See "Inhalant intoxication" for details.
Management
- For a general approach (including stabilization, decontamination, and disposition), see:
- For details on specific substances and their toxicities, see:
Acute hydrocarbon intoxication and poisoning
This section reviews acute hydrocarbon poisoning, including inhalant overdose. For more information on inhalant misuse and inhalant intoxication (including nonhydrocarbon inhalants), see "Inhalant-related disorders."
Clinical features [1][2]
-
Inhalation
- Neurological
- Headache, blurred vision
- Euphoria, agitation, hallucinations, seizures
- CNS depression, sedation, coma
- Cardiac: ventricular dysrhythmias, cardiac arrest, sudden sniffing death syndrome
- Pulmonary: cough, wheezing, dyspnea, hypoxia
- Other
- Neurological
-
Ingestion: Severe poisoning is usually caused by aspiration of ingested content.
- Abdominal pain, nausea, vomiting, diarrhea
- Clinical features of aspiration (common in children): cough, dyspnea, bronchospasm, hypoxia, features of chemical pneumonitis
- Signs of systemic toxicity (uncommon): e.g., CNS symptoms, hepatic injury, kidney injury
-
Dermal absorption
- Localized pain
- Signs of chemical burns: e.g., erythema, swelling, blistering
Patients with acute hydrocarbon poisoning may present with comorbid traumatic injuries and/or thermal burns. [3]
Initial management [1][2][3]
Approach
- Follow the ABCDE approach adapted to poisoning.
- Call poison control immediately for patients with any of the following:
- Severe CNS impairment
- Respiratory distress or failure
- Hemodynamic instability or cardiac arrest
- Provide aggressive supportive care for symptomatic and/or unstable patients.
There are no antidotes or specific treatments for hydrocarbon intoxication or poisoning.
Decontamination
- Perform body surface decontamination by removing contaminated clothing and irrigating the skin.
- Avoid GI decontamination due to the risk of aspiration. [2]
Respiratory support
- Secure the airway: Plan for early intubation and mechanical ventilation in patients with aspiration, CNS depression, or significant hypoxia.
- Prepare for management of a difficult airway if there are signs of burns or angioedema.
- Begin pulse oximetry and supplemental oxygen.
- Consider portable CXR, ABG, and CO-oximetry.
- Consider inhaled bronchodilators.
Hemodynamic support
- Provide IV fluid resuscitation.
- Obtain ECG and begin continuous cardiac monitoring.
- Avoid IV adrenergic agents and unnecessary stimulation, as they can trigger fatal cardiac arrhythmias.
- Consider short-acting beta blockers (e.g., esmolol ) for refractory tachyarrhythmias. [2][7]
- Cardiac arrest: Start ACLS, omitting epinephrine; see "Management" in "Sudden sniffing death syndrome."
Avoid catecholamine surges in patients with hydrocarbon exposure to prevent sudden sniffing death syndrome. [3][6]
Other supportive care
- Manage burns, if present.
- Consider benzodiazepines for the treatment of agitation and the management of acute seizures. [1]
Diagnosis [2][3][6]
Clinical diagnosis
- Established via clinical evaluation and toxicological risk assessment
- Obtain collateral history from EMS providers and witnesses.
- For occupational exposures, obtain relevant material safety data sheets.
- Consider investigations for:
- Severity assessment
- Comorbid poisoning, injuries, and/or differential diagnoses
Visible residue or odor of spray paint, solvents, or glitter on a patient's skin and/or clothing can indicate inhalant misuse. [3][6]
Laboratory studies and imaging
-
Severity and risk assessment
- CXR
- ECG, cardiac enzymes
- CBC, CMP, liver chemistries, CPK
- Blood gas analysis: typically shows metabolic acidosis
- Trauma diagnostics
- Pregnancy test
- Consider neuroimaging for new or unexplained neurological symptoms.
- Screening for comorbid intoxication or poisoning [3]
-
Urine screening [3][6]
- To assess for hydrocarbon metabolites
- Not useful for diagnosing acute intoxication, overdose, or poisoning
- Typically used to monitor long-term use in addiction treatment plans
Measure carboxyhemoglobin levels in patients with methylene chloride poisoning. [3]
Differential diagnosis [2]
- Other causes of dyspnea
- Other causes of altered mental status
- Other reversible causes of cardiac arrest: e.g., Hs and Ts
Ongoing management [1][2][3]
Aggressive supportive care is the mainstay of treatment for acute hydrocarbon poisoning, as there are no antidotes (see "Initial management").
- Tailor ongoing supportive care and monitoring based on the toxicological risk assessment, which integrates exposure, clinical features, and poisoning severity.
- Consult a medical toxicologist and any relevant and available material safety data sheets if the substance is identified.
- Consult pulmonology for consideration of surfactant administration in patients with severe pneumonitis.
- See "Aliphatic hydrocarbons," "Aromatic hydrocarbons," and "Halogenated hydrocarbons" for details on specific substances (e.g., vinyl chloride).
Disposition [2][6]
Patients with severe poisoning
- Admit to hospital.
- Consider ICU admission for unstable patients and/or patients with:
- Significant CNS depression
- Respiratory distress or respiratory failure requiring assisted ventilation
- Cardiac dysrhythmias or hemodynamic instability
Stable patients with mild poisoning
- Observe and provide supportive care.
- Consider admission vs. treat and release based on individual risk.
- Observe patients for at least 6 hours. [2]
- Admit for at least 24 hours if any of the following are present: [2]
- Cough, tachypnea, or hypoxia
- Evidence of chemical pneumonitis on CXR
- Ongoing mild CNS depression
Patients with inhalant use disorder
- Refer for substance use disorder management.
- Consider social work consultation and specialty referrals.
- See also "Management" in "Inhalant-related disorders."
Some types of poisoning (e.g., aromatic hydrocarbon poisoning) have a higher risk of significant systemic toxicity. Determine disposition in consultation with poison control based on clinical status and substance data. [2]
Sudden sniffing death syndrome
- Definition: sudden cardiac death associated with inhalant intoxication or other exposure to volatile hydrocarbons [6][7]
-
Pathophysiology: poorly understood [3][6][7]
- Cardiac sensitization mechanism
- Sodium, potassium, and calcium channels in cardiac myocytes are sensitized by hydrocarbons.
- Fatal cardiac tachyarrhythmias (e.g., VT, VF, or unstable SVT) can be triggered by:
- Catecholamine surges
- Hypoxia
- Hypocalcemia (from fluorinated hydrocarbons)
- Vagal mechanism
- Cardiac sensitization mechanism
-
Clinical diagnosis [6][7]
- Cardiac arrest in the context of inhalant intoxication or other exposure to volatile hydrocarbons
- Often preceded by a catecholamine surge (e.g., due to physical exertion or being startled)
-
Management [2][7][8]
- Follow the ACLS algorithm, but withhold epinephrine, as it can worsen hydrocarbon-associated arrhythmias.
- Consider beta blockers (e.g., esmolol ) for tachyarrhythmias refractory to standard ACLS. [2][7]
- Consider ECLS for refractory cardiac arrest, arrhythmias, and/or cardiogenic shock.
- Prevention: Avoid sympathomimetics and overstimulation in patients with hydrocarbon intoxication or poisoning. [3][6]
Consider alternative causes of inhalant-associated cardiac arrest (e.g., asphyxia, trauma, drowning, hypothermia, other poisoning) in patients with suspected sudden sniffing death syndrome. [3][6]
Chronic hydrocarbon poisoning
Chronic hydrocarbon poisoning is a clinical diagnosis and usually occurs in individuals with chronic occupational exposure or habitual inhalant misuse.
Toxicity [1][6][8]
-
Neuropsychiatric
- Cognitive impairment
- Nystagmus, tremor, ataxia
- Irritability, apathy, mood disturbances
- Speech and sleep disturbances
- Visual and auditory impairment
- Chronic toxic encephalopathy
- Sensorimotor polyneuropathy
- Pulmonary
- Cardiac: myocardial fibrosis, congestive heart failure
- GI
-
Kidney
- Renal tubular acidosis (e.g., Fanconi syndrome)
- Urinary calculi
- Muscle weakness due to severe hypokalemia in individuals with chronic toluene misuse
- Hematologic: aplastic anemia, leukemia, bone marrow suppression
-
HEENT
- Glue sniffer's rash: characteristic perioral eczema after prolonged use of inhalants
- Lip and upper airway edema
- Obstetric and gynecologic
Management [1][6][8]
Consider specialty referral (e.g., toxicology, neurology, pulmonology) as appropriate.
-
Chronic occupational exposure
- Consult poison control and obtain material safety data sheets if available.
- Modify activity to limit ongoing exposure.
- Refer to an occupational health specialist and/or medical toxicologist.
- Habitual inhalant misuse: See "Management" in "Inhalant-related disorders."
Subtypes and variants
The class of hydrocarbon influences the sources and routes of exposure, as well as the toxicokinetics and toxicodynamics of individual substances. Whenever possible, identify the hydrocarbon class to tailor the patient's toxicological risk assessment and management.
Aliphatic hydrocarbons
Overview [2][3]
- Hydrocarbons joined in a linear chain or by a nonaromatic ring
- Also referred to as petroleum distillates
-
Found in:
- Fuels: natural gas, gasoline, kerosene, lighter fluid, lamp oil
- Solvents, degreasers
- Furniture polishes
- Paraffin wax: used in scented candles, crayons, cosmetics, and certain food coatings (e.g., cheese) [9][10][11][12]
- Liquid paraffin (mineral oil): used as a laxative and/or enema [13]
- Exposure can be accidental, occupational, or recreational (e.g., inhalants).
Examples [3]
- Fuels
- n-Hexane
- Heptane
- Methane
- Ethane
- Propane
- Butane
- Octane
-
Terpene hydrocarbons: hydrocarbons containing isoprene building blocks
- Turpentine: used in the rubber, painting, and welding industries (in the form of pine turpentine oil)
- Camphor: a terpene derivative used in vapor rubs, mothballs, and air fresheners [14]
Poisoning [2]
- Usually ingested, aspirated, or inhaled
- Toxicity depends on chemical properties.
- Lung injury is common following accidental or intentional ingestion of low-viscosity aliphatic hydrocarbons (e.g., fuels).
- Exposure to leaks or spills of high-volatility aliphatic hydrocarbons can cause life-threatening asphyxia from oxygen displacement, especially in confined spaces.
- All aliphatic hydrocarbons are lipophilic enough to be systemically absorbed and cause CNS effects, irrespective of the route of exposure. [15]
- Camphor poisoning: most commonly occurs in children due to accidental ingestion; can manifest with seizures [14]
- See "Acute hydrocarbon intoxication and poisoning" and "Chronic hydrocarbon poisoning" for more details on clinical features and management.
Inhalant intoxication with aliphatic hydrocarbons can cause sudden sniffing death syndrome. [2]
Aromatic hydrocarbons
Overview
- Hydrocarbons containing at least one aromatic ring
- Found in solvents, glues, nail polish, cigarette smoke, car emissions, and paints
-
Polycyclic aromatic hydrocarbons [4][16]
- Contain at least two fused aromatic rings
- Found in natural sources (e.g., coal, bitumen) but also form during incomplete combustion (e.g., of wood, garbage, tobacco, fossil fuels and their derivatives)
- Ubiquitous contaminants in the environment
- Exposure via the respiratory tract (e.g., breathing in cigarette smoke or vehicle exhaust fumes), digestive tract (e.g., intake of charcoal-grilled meat), and skin (e.g., coal, tar)
- Many are classified as possibly carcinogenic to humans (group 2B carcinogens)
Exposure to polycyclic aromatic hydrocarbons most commonly occurs through occupational and environmental sources. [4]
Examples [3]
- Benzene
- Benzene derivatives
-
Polycyclic aromatic hydrocarbons
- Naphthalene
- Anthracene
- Benzo[a]pyrene
- Chlorinated aromatic hydrocarbons
- Chlorobenzene
- Chlorophenol
Polycyclic aromatic hydrocarbon poisoning [4]
Features of acute poisoning [4]
- Irritant and asphyxiant features (especially eyes and skin)
- Inhalant intoxication features: e.g., confusion
- GI features: e.g., nausea, vomiting, diarrhea
- See "Acute hydrocarbon intoxication and poisoning" for more details on clinical features and management.
Sequelae of chronic poisoning [4]
- Cancer: especially lung, skin (chimney sweeps' carcinoma), esophagus, colon, pancreas, bladder, and breast [17]
- Hepatotoxicity, nephrotoxicity
- Cataracts
- Inflammatory skin disorders
- Immunodeficiency
- Chronic lung disease
Chlorobenzene poisoning [18][19]
- Acute poisoning: loss of consciousness, muscle spasms
- Chronic poisoning: neurotoxicity (e.g., numbness, hyperesthesia, muscle spasms)
Other poisonings [2]
- Phenols (e.g., chlorophenol): very corrosive; dermal exposure causes chemical burns
- Toluene: renal tubular acidosis
- Benzene: bone marrow toxicity and leukemia
Halogenated hydrocarbons
Overview [2][3][20][21]
- Fluorinated, chlorinated, brominated, or iodinated hydrocarbons created through:
- Industrial manufacturing and/or byproducts thereof
- Combustion and decomposition of organic material
- Can be inhaled, dermally absorbed, or ingested due to their lipophilic and volatile properties
- Absorbed by microplastics and accumulate in fatty tissue
- Frequently carcinogenic, cardiotoxic, and hepatotoxic
Halogenated hydrocarbons are associated with a higher risk of cardiotoxicity (e.g., dysrhythmias) than other hydrocarbons. [2]
Exposure
-
Occupational or environmental: can be inhaled, dermally absorbed, or ingested [20][21]
- Industrial accidents, pollution, contamination of food (e.g., oils, dairy products) or water supplies
- Products or byproducts in the manufacturing of:
- Paints, plastics, solvents, lubricants, and hydraulic fluid
- Herbicides and pesticides
- Industrial or agricultural combustion and/or incineration
-
Recreational: typically inhaled (see "Inhalant-related disorders") [3]
- Cleaning products: cleansers, dry cleaning agents, degreasers, stain removers, paint thinners
- Aerosol propellants: spray paint, hairspray, spray deodorant, air freshener, fire extinguishers
- Adhesives
Examples [3]
-
Commercial and industrial chemicals
- Chloroform
- Carbon tetrachloride (CCl4): formerly widely used in fire extinguishers, refrigerants, dry cleaning fluids, and propellants
- Refrigerants
- Chloroflurocarbons
- Hydofluorocarbons (e.g., difluoroethane)
-
Anesthetic agents
- Ethyl chloride: topical anesthetic
- Halogenated inhalational anesthetics
- Persistent organic pollutants: See "Dioxins and dioxin-like compounds."
-
Chlorinated alkenes [3]
- Chloroethylene (vinyl chloride): a byproduct of polyvinyl chloride plastic manufacturing
- Trichloroethylene
- Tetrachloroethylene
- Methylene chloride
Methylene chloride can cause chemical burns after dermal exposure and can metabolize to carbon monoxide when ingested, causing delayed carbon monoxide poisoning. [2]
Carbon tetrachloride forms free radicals and is hepatotoxic, causing fatty liver, cell necrosis, and hepatocellular carcinoma. [2][22]
Dioxins and dioxin-like compounds [20]
Examples
-
Polychlorinated dibenzodioxins (dioxins)
-
2,3,7,8-tetrachlorodibenzodioxin (TCDD)
- A contaminant in the herbicide Agent Orange used by the US military during the Vietnam War
- Released in high quantities in an industrial accident in Seveso, Italy, in 1976
-
2,3,7,8-tetrachlorodibenzodioxin (TCDD)
- Polychlorinated dibenzofurans (PCDFs; flurans): e.g., 2,3,7,8-tetrachlorodibenzofuran
-
Polychlorinated biphenyls (PCBs): used in building materials (e.g., sealants), electrical equipment, lubricants, and hydraulics [21]
- 3,3′,4,4′-Tetrachlorobiphenyl
- 3,3′,4,4′,5-Pentachlorobiphenyl
Acute and subacute poisoning
- Features of inhalational exposure: See "Inhalation" in "Acute hydrocarbon intoxication and poisoning."
-
Chloracne [23]
- Mild: increased oiliness of the skin, large number of blackheads around the eyes, fluid-filled cysts, hirsutism and hair thickening [24]
- Severe: acneiform eruptions of pustules, cysts, and blackheads, mainly behind the ears and on the cheeks; possible scarring
- Treatment: exposure avoidance; typically resistant to treatment
- Prognosis: symptoms may take years to resolve after exposure cessation.
Chloracne is a hallmark manifestation of dioxin poisoning.
Chronic poisoning [20][21]
- Cancer: especially blood cancers such as leukemia, Hodgkin lymphoma, and non-Hodgkin lymphoma
- Birth defects [25]
- Endocrinologic dysregulation: thyroid disturbances, altered testosterone levels, pathological glucose tolerance
- Neurotoxicity
- Cardiotoxicity
- Nephrotoxicity (e.g., nephritis, nephrosis, kidney failure) [26]
- Hepatotoxicity
Yusho disease [20][27]
- Acute poisoning by food contaminated with PCBs and PCDFs
- Clinical features
- Chloracne
- Ocular discharge
- Decreased immune response
- Menstrual irregularities
- Numbness of limbs
- Developmental delay
Vinyl chloride poisoning [28]
Acute poisoning
Acute poisoning is usually due to accidental industrial exposure.
- Inhalant toxicity features: e.g., dizziness, headache, lightheadedness, drowsiness, loss of consciousness, ataxia
- Irritant and asphyxiant features: lung and mucosal irritation, death
- Dermal: frostbite from liquid vinyl chloride exposure
Chronic poisoning (vinyl chloride disease)
Chronic poisoning is usually due to long-term occupational or environmental exposure.
- Hepatotoxicity
- Kidney impairment
-
Connective tissue and bones
- Scleroderma-like skin changes
- Acro-osteolysis
- Raynaud phenomenon
- Hepatic angiosarcoma
- Peripheral neuropathy