Heavy Metal Poisoning - Metal Mayhem
| Metal | Source(s) | Key Clinical Features | Diagnosis | Management / Antidotes |
|---|---|---|---|---|
| Lead | Paint, batteries | Burton's line, basophilic stippling, foot/wrist drop, anemia, encephalopathy | BLL | EDTA, DMSA, BAL. Chelate: BLL > 45 µg/dL (child) |
| Arsenic | Pesticides, water | Aldrich-Mees lines, garlic breath, rain-drop skin, neuropathy | Urine As | BAL, DMSA. Supportive care. |
| Mercury | Fish, dental | Minamata (neuro), acrodynia, tremor, nephrotoxic | Blood/Urine Hg | DMSA, DMPS, Penicillamine. Remove source. |
Pesticide Poisoning - Pest Patrol
-
Organophosphates (OP)
- Mechanism: Irreversible Acetylcholinesterase (AChE) inhibition. $Acetylcholine + AChE \rightarrow Choline + Acetic \ Acid$; OP blocks AChE.
- Symptoms: Cholinergic crisis. 📌 DUMBELS: Diarrhea/Diaphoresis, Urination, Miosis, Bronchospasm/Bronchorrhea, Emesis, Lacrimation, Salivation.
- Management:
- Atropine: 2-5 mg IV, repeat every 5-15 min until atropinization (↓secretions, ↑HR, mydriasis).
- Oximes: Pralidoxime (PAM) 1-2 g IV. Reactivates AChE.
- OP Poisoning Management Flowchart:
-
Carbamates
- Mechanism: Reversible AChE inhibition.
- Symptoms: Similar to OP, but shorter duration, less severe. CNS effects less common.
- Management: Atropine. Oximes usually not needed/contraindicated (except Physostigmine).
-
Organochlorines (e.g., DDT, Lindane, Endosulfan)
- Mechanism: CNS stimulation (Na+/K+ channel & GABA disruption).
- Symptoms: Seizures, tremors, paresthesias, ataxia.
- Management: Supportive care, Diazepam for seizures. Decontamination.
⭐ Pralidoxime (PAM) is most effective in organophosphate poisoning if administered within 24-48 hours, before 'aging' of the phosphorylated acetylcholinesterase enzyme occurs.
Toxic Gases & Inhalants - Airy Agony
| Feature | Carbon Monoxide (CO) | Cyanide (CN) | Methemoglobinemia |
|---|---|---|---|
| Source | Incomplete combustion (fires, heaters) | Fires (plastics, wool), industrial | Nitrites, dapsone, local anesthetics |
| MOA | Binds Hb ($Hb(Fe^{2+}) + CO \rightarrow COHb$), ↓O₂ delivery | Inhibits cytochrome oxidase, ↓ATP | Oxidizes Hb iron ($Fe^{2+} \rightarrow Fe^{3+}$), ↓O₂ carrying capacity |
| Key Features | Headache, cherry-red skin (late, unreliable), ↑COHb | Bitter almond smell (inconsistent), rapid collapse, ↑lactate | Chocolate-brown blood, cyanosis unresponsive to O₂ |
| Antidote | 100% O₂; Hyperbaric O₂ (COHb >25%, >15% pregnant, or neuro/cardiac signs) | Amyl nitrite, sodium nitrite, sodium thiosulfate; OR Hydroxocobalamin | Methylene blue 1-2 mg/kg IV |
⭐ Pulse oximetry is unreliable in carbon monoxide poisoning as it cannot differentiate carboxyhemoglobin from oxyhemoglobin, often showing falsely normal saturation.
Industrial & Plant Toxins - Factory & Flora Foes
- Hydrocarbons (Kerosene, Petrol)
- Risks: Aspiration pneumonitis (key), CNS depression, arrhythmias.
- Management: Supportive care; AVOID emesis.
- Corrosives
- Acids: Coagulation necrosis.
- Alkalis: Liquefaction necrosis (deeper injury).
- Key: Esophageal/gastric injury; endoscopy within 12-24 hrs.
- Management: AVOID neutralization/emesis.
⭐ In corrosive ingestion, alkalis typically cause more severe and deeper esophageal injury (liquefaction necrosis) compared to acids (coagulation necrosis).
- Plant Toxins
- Datura (Anticholinergic): Mydriasis, delirium, dry skin. Antidote: Physostigmine.
- 📌 Mnemonic: "Blind as a bat, mad as a hatter, red as a beet, hot as a hare, dry as a bone".
- Oleander (Cardiac Glycoside): Hyperkalemia, arrhythmias. Antidote: Digibind.
- Datura (Anticholinergic): Mydriasis, delirium, dry skin. Antidote: Physostigmine.
High‑Yield Points - ⚡ Biggest Takeaways
- Organophosphate poisoning: SLUDGE + Killer B's (bradycardia, bronchospasm). Antidotes: Atropine, Pralidoxime (enzyme reactivator).
- Carbon Monoxide: Cherry-red skin (rare), headache, confusion. Diagnosis: ↑COHb. Treatment: 100% O2, hyperbaric O2.
- Lead poisoning: Burton's line (gums), wrist drop, microcytic anemia with basophilic stippling. Chelation: EDTA, BAL, Succimer.
- Arsenic poisoning: Mees' lines (nails), garlic odor (breath), raindrop pigmentation. Chelation: BAL, DMSA.
- Cyanide poisoning: Bitter almond breath, rapid cellular hypoxia (normal PaO2). Antidotes: Nitrites, Thiosulfate, Hydroxycobalamin.
- Paraquat: Causes severe lung fibrosis ("Paraquat lung") and acute renal failure. Often fatal.
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