Difluoroethane
Introduction
Difluoroethane (DFE) is a hydrofluorocarbon (HFC) commonly used as a propellant in aerosol products, including computer keyboard cleaners and refrigerants. Though considered non-toxic for industrial use, DFE is increasingly recognized as a substance of abuse, especially among adolescents and young adults, due to its rapid-onset euphoric effects when inhaled—a practice known as "huffing."
Pathophysiology
DFE is rapidly absorbed through the lungs and acts primarily as a CNS depressant. Its volatile properties and lipid solubility allow it to penetrate the brain quickly, producing an intoxicating effect within seconds of inhalation.
Key pathophysiologic effects:
- Sensitization of myocardium to catecholamines → increased risk of fatal arrhythmias ("sudden sniffing death")
- Hypoxia and asphyxia due to displacement of alveolar oxygen
- Central nervous system depression, including coma and seizures
- Pulmonary injury: inflammation, hemorrhage, and edema
- Hepatic and renal injury with chronic or massive exposure
Clinical Features
Acute Presentation:
- Euphoria, dizziness, slurred speech
- Confusion, ataxia, lethargy
- Nausea, vomiting
- Seizures, particularly in high-dose exposure
- Syncope or cardiac arrest (especially with exertion or catecholamine surge)
Cardiac Effects
- Palpitations
- Premature ventricular contractions (PVCs)
- Ventricular tachycardia/fibrillation
- QT prolongation, possibly torsades de pointes
Pulmonary Effects
- Cough, dyspnea
- Chemical pneumonitis
- Pulmonary hemorrhage (in rare cases)
Chronic Use
- Cognitive decline
- Peripheral neuropathy
- Hepatotoxicity or nephrotoxicity
- Dermal frostbite or oronasal irritation from direct contact with aerosol can
Evaluation
History & Exam: Consider DFE toxicity in any young patient with sudden unexplained arrhythmia, altered mental status, or seizure
Ask about recent use of aerosol sprays, cleaning products, or refrigerants
Look for signs of inhalant abuse:
Chemical odor on breath
Perioral or hand burns
Empty aerosol cans
Skin frostbite
Recommended Workup: EKG: assess for QT prolongation, PVCs, ventricular arrhythmias
Cardiac monitoring
Chest X-ray if respiratory symptoms are present
Basic labs:
CBC, BMP, troponin
Creatinine kinase (CK)
ABG if hypoxia suspected
Urine toxicology screen: may not detect difluoroethane but can help rule out co-ingestions
Management
Supportive Care is the Mainstay: Airway, breathing, circulation (ABCs)
Supplemental oxygen as needed
Continuous cardiac monitoring due to risk of arrhythmia
Avoid catecholamines (e.g., epinephrine, norepinephrine) unless absolutely necessary—may precipitate fatal arrhythmias
Treat Complications as They Arise: Ventricular arrhythmias → defibrillation, amiodarone (avoid lidocaine in some cases)
Seizures → benzodiazepines
Respiratory failure or chemical pneumonitis → consider intubation and supportive ventilation
Skin or mucosal injury → treat as chemical burns or frostbite
Disposition
Admission Criteria: Persistent arrhythmias or EKG abnormalities
Seizure activity
Altered mental status or respiratory compromise
Suspicion of recurrent or chronic use (requires observation)
Discharge Criteria: Normal mental status
Normal EKG and cardiac monitoring for at least 4–6 hours post-exposure
No signs of pulmonary or neurologic complications
Referral Considerations: Substance abuse counseling or addiction medicine
Consider social work consult for adolescents or vulnerable individuals
Outpatient follow-up with primary care or mental health services
Key Pearls
Sudden cardiac death from DFE abuse can occur in previously healthy individuals.
Always obtain an EKG and initiate cardiac monitoring.
Do not rely on routine tox screens—DFE often won’t show up.
Avoid exogenous catecholamines if arrhythmia risk is present.
Suspect DFE in cases of unexplained syncope, seizures, or cardiac arrest—especially in youth or with aerosol products nearby