Environmental, Toxicological, and Infectious Disease Emergencies
Pattern recognition and antidote pairs
Environmental emergencies reward rapid physiology correction. Heat stroke is core temperature above 40°C with central nervous system dysfunction; cool aggressively and immediately. Hypothermia demands gentle handling to avoid arrhythmia, plus warmed fluids and active rewarming. In drowning, the priority is rescue breathing and ventilation, since the insult is hypoxic; do not attempt to drain the lungs or perform abdominal thrusts.
Toxicology is largely pattern recognition. Anticholinergic toxicity gives dry skin, flushing, mydriasis, urinary retention, agitation and hyperthermia. Cholinergic (organophosphate) toxicity gives salivation, lacrimation, urination, diarrhoea, bronchospasm and bradycardia; treat with atropine plus pralidoxime and decontaminate. Opioid toxicity gives pinpoint pupils and respiratory depression, reversed with naloxone titrated to breathing rather than to full consciousness. Sympathomimetic toxicity gives tachycardia, hypertension, agitation and dilated pupils without dry skin.
Know the antidote pairs: N-acetylcysteine for paracetamol, fomepizole for methanol or ethylene glycol, hydroxocobalamin for cyanide, sodium bicarbonate for tricyclic overdose with a widened QRS, glucagon for beta-blocker overdose, and 100% oxygen with co-oximetry for carbon monoxide. Standard precautions apply to every patient; transmission-based precautions are added on suspicion, not on confirmation. Sepsis is recognised with a screening tool and treated with cultures, lactate and antibiotics within one hour for septic shock.
Worked example: a patient with a widened QRS after a tricyclic overdose receives sodium bicarbonate.
Trap: trusting pulse oximetry in carbon monoxide poisoning - it reads falsely normal.