Household Chemical Exposure

Common Agents - Culprit Chemicals

• Corrosives:
  • Acids (e.g., HCl, $H_2SO_4$ in toilet/battery cleaners): Coagulative necrosis (limits penetration).
  • Alkalis (e.g., NaOH, KOH in drain/oven cleaners): Liquefactive necrosis (deep penetration). 📌 Alkali = Liquefactive, Looser tissue.
• Hydrocarbons:
  • Kerosene, turpentine, gasoline, petroleum distillates.
  • Mechanism: CNS depression, pulmonary aspiration leading to chemical pneumonitis.

  ⭐ Kerosene aspiration pneumonitis is often more severe than systemic toxicity from ingestion.

• Pesticides:
  • Organophosphates (e.g., Malathion, Chlorpyrifos): Irreversible acetylcholinesterase (AChE) inhibition.
  • Carbamates (e.g., Carbaryl, Propoxur): Reversible AChE inhibition.
  • Pyrethroids (e.g., Permethrin, Allethrin): Sodium channel modulation (prolonged opening).
  • Rodenticides:
    • Zinc phosphide: Releases phosphine ($PH_3$) gas (mitochondrial toxin).
    • Warfarin-type (Superwarfarins): Anticoagulant (Vitamin K epoxide reductase inhibition).
• Cleaning Agents:
  • Bleach (Sodium hypochlorite, $NaOCl$): Oxidizing agent, irritant. Mixing with acids releases $Cl_2$ gas. $Cl_2 + H_2O \rightleftharpoons HOCl + HCl$.
  • Detergents (Anionic, Cationic, Non-ionic): GI upset. Cationic (e.g., benzalkonium chloride) can be corrosive.
  • Disinfectants (e.g., Phenols, Cresols): Cellular toxicity, neurotoxicity, hepatotoxicity.
• Medications (Accidental Ingestion):
  • Paracetamol (Acetaminophen): Hepatotoxicity via NAPQI metabolite.
  • Iron tablets: Direct GI corrosive effects, systemic iron toxicity (mitochondrial damage).

Clinical Features & Diagnosis - Toxic Tell-Tales

• General: ABCDE, history (source, amount, time), vital signs.

• Key Toxidromes & Features:

  Toxin	Clinical Features	Diagnostic Pointers
  Corrosives	Oral/pharyngeal burns, dysphagia, drooling, stridor, hematemesis, chest/abdominal pain. Signs of perforation (rigid abdomen, shock).	Endoscopy (within 6-24h, ideally 12h); Zargar classification (Grade 0-IV).
  Hydrocarbons	Coughing, choking, dyspnea, grunting, tachypnea. Chemical pneumonitis (fever, hypoxia). CNS: lethargy, seizures.	Kerosene/gasoline odor. CXR for pneumonitis.
  Organophosphates	Cholinergic crisis: 📌 DUMBBELS (Diarrhea, Urination, Miosis, Bronchospasm/Bronchorrhea, Bradycardia, Emesis, Lacrimation, Salivation/Sweating) / SLUDGE. Muscle fasciculations, weakness.	Garlic-like odor. ↓RBC/Plasma cholinesterase.
  Carbamates	Similar to OPs (cholinergic), but generally shorter duration and less severe. Reversible cholinesterase inhibition.	Clinical diagnosis.
  Bleach (NaOCl)	Irritant: oral, esophageal, gastric. Nausea, vomiting. Mixing with acid → $Cl_2$ gas (lung injury); with ammonia → chloramine gas.	History of exposure/mixing.

• Other Clues: Specific odors (e.g., bitter almonds - cyanide), skin changes, pupillary signs.

• Investigations: CBC, electrolytes, LFTs, RFTs, ABG, ECG. Chest X-ray (hydrocarbons). Specific toxin levels if available.

• Corrosive Ingestion Management Flowchart:

⭐ Absence of oral burns does not rule out significant esophageal injury, especially with alkali ingestion (e.g., drain cleaners).

Management Principles - Toxin Takedown

Core Principles (📌 ABCDE):

• Airway, Breathing, Circulation: Prioritize supportive care.
• Decontamination: Skin, eye, GI.
• Antidotes: Specific, if available.
• Enhanced Elimination: Rarely for common household chemicals.

Decontamination Strategies:

• Skin/Eye: Copious irrigation immediately.
• GI Decontamination:
  • Emesis: ⚠️ Contraindicated: Corrosives, hydrocarbons, ↓LOC.
  • Gastric Lavage: Limited utility; ⚠️ Contraindicated: Corrosives, hydrocarbons, >1 hr post-ingestion.
  • Activated Charcoal: Ineffective for corrosives, hydrocarbons, metals, alcohols. Consider for specific pesticides/medications.

Specific Poisoning Management:

• Corrosives (Acids/Alkalis):
  • ⚠️ DO NOT neutralize, induce emesis, or perform lavage.
  • Supportive care, NPO, early endoscopy (<24 hrs).
• Hydrocarbons (Kerosene, Petrol):
  • ⚠️ DO NOT induce emesis. Risk of aspiration pneumonitis.
  • Supportive care, manage pneumonitis (monitor CXR).
• Organophosphates (OP)/Carbamates:
  • Full decontamination. Atropine (2-5 mg IV, repeat PRN). Pralidoxime (OPs only: 1-2 g IV).

⭐ Pralidoxime is most effective if given early in organophosphate poisoning (ideally <24-48 hours), before "aging" of the enzyme-phosphate complex.

High‑Yield Points - ⚡ Biggest Takeaways

• Organophosphates: Cholinergic crisis (DUMBELS). Antidotes: Atropine, Pralidoxime.
• Caustics: Acids cause coagulation, Alkalis liquefaction necrosis. No emesis. Early endoscopy.
• Hydrocarbons (Kerosene): Risk chemical pneumonitis. Avoid emesis/lavage (low viscosity). CXR key.
• Carbon Monoxide: Tissue hypoxia, cherry-red skin (late). Dx: COHb levels. Treat: 100% O2, HBOT.
• Methanol/Ethylene Glycol: High AGMA, ↑ osmolar gap. Methanol: visual loss. EG: renal failure. Antidote: Fomepizole.
• Paracetamol: Hepatotoxicity. Antidote: N-acetylcysteine (Rumack-Matthew nomogram).
• Iron: GI bleed, shock, metabolic acidosis. Chelator: Deferoxamine.