Medical Emergencies, Toxicological and Environmental Conditions
Medical Emergencies
What to know
Medical emergencies reward systematic thinking about endocrine, metabolic, and infectious crises. Sepsis care emphasizes early recognition, lactate measurement, cultures before antibiotics when this does not delay therapy, broad-spectrum antibiotics within one hour for septic shock, and about 30 mL/kg crystalloid for hypotension or elevated lactate. DKA and HHS are treated with aggressive isotonic fluids first, then insulin once potassium is known to be adequate. Anaphylaxis is treated with intramuscular epinephrine 0.3–0.5 mg of the 1:1000 concentration into the lateral thigh, repeated as needed, along with fluids and adjuncts. Hyperkalemia with ECG changes receives intravenous calcium first to stabilize the myocardium, then insulin-dextrose, albuterol, and definitive removal.
Traps
Never start an insulin infusion in DKA when potassium is below 3.3 mEq/L; replace potassium first. Insulin before fluids worsens hypotension. Sodium bicarbonate is not routine. In anaphylaxis, epinephrine is first-line and must not be delayed for antihistamines or steroids. Correct sodium slowly to avoid osmotic demyelination.
Worked example
A patient in DKA has a glucose of 480 mg/dL and a potassium of 3.1 mEq/L. Hold insulin, give intravenous potassium, continue isotonic fluids, and recheck potassium before starting the drip. Rule of thumb: fluids first, potassium second, insulin third.
Toxicological and Environmental Conditions
What to know
Toxicology items test toxidrome recognition and antidote matching. Anticholinergic toxicity causes dry skin, flushing, mydriasis, urinary retention, and delirium. Cholinergic crisis causes salivation, lacrimation, urination, diarrhea, bradycardia, and bronchorrhea; organophosphate poisoning is treated with atropine plus pralidoxime. Opioids cause miosis and respiratory depression, reversed with naloxone titrated to breathing. Acetaminophen toxicity is treated with N-acetylcysteine, guided by a timed level and the Rumack-Matthew nomogram. Carbon monoxide poisoning leaves pulse oximetry falsely reassuring; use co-oximetry and give 100% oxygen. Methemoglobinemia responds to methylene blue and cyanide toxicity to hydroxocobalamin. Environmental emergencies include heat stroke, which requires rapid evaporative cooling, and hypothermia, which requires gentle handling and active rewarming.
Traps
Activated charcoal is avoided with caustic ingestion, altered mental status without airway protection, and late presentations. Flumazenil can precipitate seizures in mixed overdose or benzodiazepine-dependent patients. Do not rely on pulse oximetry in carbon monoxide or methemoglobinemia.
Worked example
Firefighters arrive confused after a basement fire with a normal SpO2 of 99%. Suspect carbon monoxide or cyanide; give 100% oxygen and consider hydroxocobalamin if there is profound lactic acidosis and smoke inhalation. Rule of thumb: a normal saturation in a fire victim is not reassuring.