Hydrocarbon poisoning may result from ingestion or inhalation. Ingestion, most common among children 5 years, can result in aspiration pneumonitis. Inhalation, most common among adolescents, can result in ventricular fibrillation, usually without warning symptoms. Diagnosis of pneumonitis is by clinical evaluation, chest x-ray, and oximetry. Gastric emptying is contraindicated because aspiration is a risk. Treatment is supportive.
(See also General Principles of Poisoning.)
aspiration pneumonitis. Toxic potential mainly depends on viscosity, measured in Saybolt seconds universal (SSU). Hydrocarbon liquids with low viscosity (SSU < 60), such as gasoline and mineral spirits, can spread rapidly over large surface areas and are more likely to cause aspiration pneumonitis than are hydrocarbons with SSU > 60, such as tar. Hydrocarbons, if ingested in large amounts, may be absorbed systemically and cause central nervous system (CNS) or hepatic toxicity, which is more likely with halogenated hydrocarbons (eg, carbon tetrachloride, trichloroethylene).
Recreational inhalation of halogenated hydrocarbons (eg, glues, paint, solvents, cleaning sprays, gasoline, hydrocarbons and hydrofluorocarbons used as propellants in aerosols—see Volatile Solvents), called huffing or bagging, is common among adolescents. It can cause euphoria and mental status changes and can sensitize the heart to endogenous catecholamines. Fatal ventricular arrhythmias may result; they usually occur without premonitory palpitations or other warning, often when patients are startled or chased.
Chronic toluene ingestion can cause long-term CNS toxicity, characterized by periventricular, occipital, and thalamic destruction.
Symptoms and Signs of Hydrocarbon Poisoning
After ingestion of even a very small amount of liquid hydrocarbon, patients initially cough, choke, and may vomit. Young children may have cyanosis, hold their breath, and cough persistently. Older children and adults may report burning in the stomach.
Aspiration pneumonitis causes hypoxia and respiratory distress. Symptoms and signs of pneumonitis may develop a few hours before infiltrates are visible on x-ray. Substantial systemic absorption, particularly of a halogenated hydrocarbon, may cause lethargy, coma, and seizures. Nonfatal pneumonitis usually resolves in about 1 week; mineral or lamp oil ingestion usually resolves in 5 to 6 weeks.
Arrhythmias usually occur before presentation and are unlikely to recur after presentation unless patients have excessive agitation.
Diagnosis of Hydrocarbon Poisoning
Chest x-ray and oximetry done about 6 hours after ingestion
If patients are too obtunded to provide a history, hydrocarbon exposure may be suspected if their breath or clothing has an odor or if a container is found near them. Paint residue on the hands or around the mouth may suggest recent paint sniffing.
Diagnosis of aspiration pneumonitis is by symptoms and signs as well as by chest x-ray and oximetry, which are done about 6 hours after ingestion or sooner if symptoms are severe. If respiratory failure is suspected, arterial blood gases are measured. Acute ingestion of hydrocarbons causes CNS depression and coma primarily. Chronic exposure to certain hydrocarbons (n-hexane, MnBK) causes demyelinating peripheral neuropathy. Strength is severely affected but sensation and reflexes may be minimally affected.
Central nervous system toxicity is diagnosed by neurologic examination and MRI. Major MRI findings include atrophy, white matter T2-weighted hyperintensity, and basal ganglia and thalamic T2-weighted hypointensity.
Treatment of Hydrocarbon Poisoning
Supportive care
Avoidance of gastric emptying
Any contaminated clothing is removed, and the skin is washed. (CAUTION: Gastric emptying, which increases risk of aspiration, is contraindicatedaspiration pneumonitis or other symptoms after 4 to 6 hours are discharged. Patients who have symptoms are admitted and treated supportively; antibiotics and corticosteroids are not indicated.
Pearls & Pitfalls
|
