Hydrocarbon Poisoning

Hydrocarbon poisoning follows ingestion, inhalation or skin contact with petroleum distillates (petrol or gasoline, kerosene, diesel, mineral spirits, lamp oil, turpentine), aromatic compounds (benzene, toluene, xylene), halogenated hydrocarbons (carbon tetrachloride, trichloroethylene, methylene chloride) and terpenes. Toddlers swallow kerosene and lamp oil stored in drink bottles, which is a major cause of childhood poisoning in low- and middle-income settings. Deliberate inhalation (volatile substance abuse, "huffing") also occurs.

Physical properties determine harm: low viscosity (under 60 Saybolt seconds universal), high volatility and low surface tension allow easy aspiration into the lungs with spread across the airway. Aspiration causes chemical pneumonitis, which is the main cause of morbidity. Gastrointestinal absorption is small for most aliphatic compounds, and systemic toxicity is limited, with some important exceptions.

Systemic hazards

• Halogenated hydrocarbons: hepatic and renal toxicity (carbon tetrachloride), and myocardial sensitization to catecholamines (arrhythmia and "sudden sniffing death")
• Aromatics: benzene causes bone marrow depression and leukemia on chronic exposure, and toluene causes renal tubular acidosis, hypokalemia and hypophosphatemia
• Camphor, and pesticide- or heavy-metal-containing products: seizures and other systemic effects after a small ingestion
• Methylene chloride: converted to carbon monoxide, with carboxyhemoglobin rising for hours

Complications: aspiration pneumonitis, acute respiratory distress syndrome, pneumatoceles, bacterial superinfection, arrhythmia, central nervous system depression, seizures and liver or kidney injury.

• Immediately after aspiration: coughing, choking, gagging, vomiting, then tachypnea, grunting, wheeze, cyanosis and fever within 30 minutes to 6 hours
• Central nervous system: drowsiness, euphoria, ataxia, headache, seizures and coma (hypoxia or direct effect)
• Cardiac: tachycardia and ventricular arrhythmia (halogenated hydrocarbons, toluene, and inhalant abuse), particularly with sudden exertion or stress
• Skin: dermatitis and chemical burns on prolonged contact
• Red flags: respiratory distress, hypoxia, coma, seizures, arrhythmia and ingestion of a hydrocarbon with systemic toxicity (camphor, halogenated or aromatic compounds, those with pesticides or heavy metals)

1. Clinical assessment: respiratory rate, oxygen saturation, auscultation, mental state and ECG. Identify the product (label or poison center) and any added toxic ingredients.
2. Chest radiograph at presentation and at 6 hours (and repeated at 24 hours if symptomatic): perihilar infiltrates, patchy or bilateral consolidation, which may appear within 30 minutes to 6 hours. A normal film at 6 hours in an asymptomatic patient is reassuring.
3. Pulse oximetry and arterial blood gas for respiratory distress.
4. ECG and continuous monitoring for halogenated hydrocarbons, toluene and inhalant abuse.
5. Blood tests when systemic toxicity is possible: electrolytes (potassium, phosphate), blood count, creatinine, liver tests, glucose, carboxyhemoglobin (methylene chloride) and methemoglobin.

Differentials: bacterial pneumonia, foreign body aspiration, bronchiolitis, other poisoning (organophosphates, opioids), asthma.

1. Do not induce vomiting. Avoid gastric lavage and activated charcoal for most cases (they raise the risk of aspiration). Consider careful nasogastric aspiration within 1 hour only for a large ingestion of a hydrocarbon with systemic toxicity, with a protected airway.
2. Decontamination: remove contaminated clothing and wash the skin and hair with soap and water. Irrigate eyes with saline.
3. Respiratory support: oxygen to maintain saturation over 94%, nebulized salbutamol 2.5 to 5 mg (children 2.5 mg) for wheeze, and continuous positive airway pressure or mechanical ventilation with positive end-expiratory pressure for respiratory failure. High-frequency oscillation and venovenous extracorporeal membrane oxygenation for refractory hypoxemia.
4. Avoid corticosteroids and prophylactic antibiotics (no benefit). Give antibiotics only for proven bacterial infection (usually after 48 hours, with fever and new infiltrate): amoxicillin-clavulanate 1.2 g IV every 8 hours (children 30 mg/kg every 8 hours) or ceftriaxone 1 to 2 g IV daily.
5. Arrhythmia from catecholamine sensitization: avoid epinephrine and other sympathomimetics. Use esmolol 500 micrograms/kg IV over 1 minute, then 50 to 200 micrograms/kg/min, or propranolol 1 mg IV every 5 minutes up to 5 mg, and lidocaine 1 to 1.5 mg/kg IV.
6. Seizures: lorazepam 4 mg IV (children 0.1 mg/kg, maximum 4 mg).
7. Specific poisons:
   • Methylene chloride: 100% oxygen (and hyperbaric oxygen for severe carboxyhemoglobin).
   • Carbon tetrachloride: N-acetylcysteine 150 mg/kg IV over 1 hour, then 50 mg/kg over 4 hours, then 100 mg/kg over 16 hours for hepatic and renal protection.
   • Toluene: replace potassium (potassium chloride 10 to 20 mmol IV over 1 to 2 hours with monitoring) and phosphate, and treat acidosis.
8. Observation: at least 6 hours, then discharge asymptomatic patients with a normal chest radiograph, a normal oxygen saturation and no respiratory symptoms. Admit for any symptoms, hypoxia or radiographic change.

Follow-up: chest radiograph and clinical review at 2 to 4 weeks in those who were symptomatic. Counsel on keeping kerosene and fuels in original, labeled, child-resistant containers, never in drink bottles, and on the danger of inhalant abuse.