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."

A common source of Difluoroethane

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

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

1. Sudden cardiac death from DFE abuse can occur in previously healthy individuals.
3. Always obtain an EKG and initiate cardiac monitoring.
5. Do not rely on routine tox screens—DFE often won’t show up.
7. Avoid exogenous catecholamines if arrhythmia risk is present.
9. Suspect DFE in cases of unexplained syncope, seizures, or cardiac arrest—especially in youth or with aerosol products nearby