Hydrocarbons Toxicity 

Exposure to hydrocarbons is common in modern society. Hydrocarbons are easily accessible in products such as gasoline, turpentine, furniture polish, household cleansers, propellants, kerosene, and other fuels. Although hydrocarbons include all compounds composed predominantly of carbon and hydrogen, the compounds of interest are derived from petroleum and wood. Most of the dangerous hydrocarbons are derived from petroleum distillates and include aliphatic (straight-chain) hydrocarbons and aromatic (benzene-containing) hydrocarbons. Other hydrocarbons such as pine oil and turpentine are derived from wood.

Types of exposure include unintentional ingestion, intentional recreational abuse, unintentional inhalation, and dermal exposure or oral ingestion in a suicide attempt. The highest rates of morbidity and mortality result from accidental ingestion by children younger than 5 years. Aspiration pneumonitis is the most common complication of hydrocarbon ingestion, followed by CNS and cardiovascular complications.

The toxic potential of hydrocarbons is directly related to their physical properties. Viscosity refers to the compound's resistance to flow; as the viscosity increases, the aspiration potential decreases. Volatility refers to the compound's ability to vaporize. Highly volatile compounds with low viscosity are more likely to be inhaled or aspirated into the respiratory system.

Pulmonary effects

Pulmonary toxicity is the result of hydrocarbon aspiration. The lower the viscosity and higher the volatility, the greater the risk of pulmonary aspiration. The hydrophobic nature of hydrocarbons allows them to penetrate deep into the tracheobronchial tree, producing inflammation and bronchospasm. The volatile chemical may displace alveolar oxygen, leading to hypoxia. Direct contact with alveolar membranes can lead to hemorrhage, hyperemia, edema, surfactant inactivation, leukocyte infiltration, and vascular thrombosis. The result is poor oxygen exchange, atelectasis, and pneumonitis.

Respiratory symptoms generally begin in the first few hours after exposure and usually resolve in 2-8 days. Complications include hypoxia, barotrauma due to mechanical ventilation, and acute respiratory distress syndrome (ARDS). Prolonged hypoxia may result in encephalopathy, seizures, and death.

GI effects

Local irritation is the usual GI manifestation of hydrocarbon ingestion. Abdominal pain and nausea are common complaints. Vomiting increases the likelihood of pulmonary aspiration.

CNS effects

Hydrocarbon toxicity produces various CNS effects. Initial effects are similar to the disinhibition observed in patients with alcohol intoxication. Narcoticlike depression may also be observed. Euphoria may develop, as in alcohol or narcotic toxicity. Eventually, lethargy, headache, obtundation, and coma may follow. Seizures are uncommon and are believed to be due to hypoxia.

Cardiac effects

Dysrhythmias are a major concern. Etiologies include hypoxia, myocardial sensitization to catecholamines, and direct myocardial damage. Sudden death has been reported as a result of coronary vasospasm due to hydrocarbon inhalation.

Other effects

Hydrocarbons are reported to cause bone marrow toxicity and hemolysis. Chlorinated hydrocarbon toxicity may cause hepatic and renal failure, and toluene toxicity may lead to renal tubular acidosis. Direct contact with the skin and mucous membranes may cause effects ranging from local irritation to extensive chemical burns.

Frequency

United States

An estimated 80,000 hydrocarbon exposures are reported to poison centers annually. Most exposures are unintentional and involve young children.

Mortality/Morbidity

Pulmonary toxicity is the major cause of morbidity and mortality. Approximately 20 deaths per year result from hydrocarbon poisoning; most of these deaths occur in children younger than 5 years. Long-term exposure may result in significant morbidity. Cardiomyopathy, cerebellar atrophy, dementia, cognitive deficits, and peripheral neuropathy have all been reported with long-term hydrocarbon inhalant abuse. Sudden death has been reported as a result of coronary vasospasm due to hydrocarbon inhalation.

Age

Unintentional ingestion usually occurs in children younger than 5 years.^[1] Improper storage and mislabeled containers of hydrocarbons are common contributing factors. Abuse by inhalation is most common in adolescents and young adults.