Blister chemical agents

Background

• Highly persistent
• Skin primary route of exposure when in liquid form; pulmonary and GI tracts as routes in vapor form

Types

• Lewisite (L)
• Sulfur mustard (H)
• Phosgene oxime (CX)

Pathophysiology

• Alkylation of DNA, RNA, and protein causing cell death
• Depletes glutathione causing cellular membrane breakdown

Clinical Features

• Skin – Initially pruritus and stinging pain, superficial bullae appear over 24 hours. Blisters do not contain toxin
• GI – abdominal pain, nausea, vomiting, diarrhea, and weight loss
• Respiratory –
  • Usually only upper respiratory tract affected
  • Sinus congestion, sore throat, hoarseness. Rarely pulmonary edema
  • Epithelial sloughing and pseudomembranes causing inability to clear pathogens and dead tissue.
• Mucous membranes and actively reproducing cells most vulnerable to severe damage
• Ocular damage – occurs within 4-8 hours
  • conjunctivitis, chemosis, blepharospasm, and corneal perforation at even low level exposures
• Bone Marrow – Leukopenia first (3-5 days), followed by anemia and thrombocytopenia

Bullae formation after blister chemical agent exposure (Wikimedia Commons).

Differential Diagnosis

Chemical weapons

• Blister chemical agents (Vesicants)
  • Lewisite (L)
  • Sulfur mustard (H)
  • Phosgene oxime (CX)
• Pulmonary chemical agents
  • Ammonia
  • Methyl isocyanate
  • Methyl bromide
  • Hydrochloric acid
  • Chlorine gas
  • Phosgene
  • Pepper spray
• Incendiary agents
  • Agent orange
  • White phosphorus
• Cyanide chemical weapon agents
  • Hydrocyanic acid
  • Formonitrile
  • Prussic acid
• Nerve Agents
  • Acetylcholinesterase inhibitors
  • Includes household and commercial pesticides (diazinon and parathion)
  • G-series (sarin, tabun, soman) and V-series (VX)
  • V-series high viscosity with oily consistency

Management

• Immediate decontamination, 0.5% hypochlorite solution will inactivate sulfur mustard but not appropriate for pediatric patients
• Supportive care, ABCs
• Thermal burn-type care
• Fluid losses less than with thermal burns
• No antidotes for mustard agents
• N-acetylcysteine, glutathione
• G-CSF for patients with bone marrow suppression
• British antilewisite (BAL) – chelating agent to reduce systemic effects from lewisite exposure.
  • Won’t alter the blistering effects on skin or airway.
  • Only used for patients with shock or severe pulmonary injury given BAL side effect
  • Relative contraindications to BAL: Renal disease, pregnancy

See Also

• Chemical weapons

Authors

Ross Donaldson, Rafael Caban, Kevin Lu, Claire, Daniel Ostermayer, Neil Young