FM13.12 | Phosphorus, Iodine & Barium — Summary & Reflection

KEY TAKEAWAYS

Phosphorus, iodine, and barium (FM13.12) are three forensically distinct agents within the same competency framework:

• Yellow/white phosphorus: three-phase course (GI → latent → hepatorenal failure); garlic odour and phosphorescent liver are pathognomonic. No specific antidote; copper sulphate lavage; avoid all oils. Historically significant as homicidal poison in India.

• Iodine: blue-black mucosal staining; corrosive-systemic syndrome. Antidote: starch/milk orally; sodium thiosulphate lavage. Airway emergency from vapour inhalation.

• Barium (carbonate/chloride): blocks K_ir channels → intracellular K⁺ trapping → severe extracellular hypokalaemia despite normal total body K⁺ → ascending flaccid paralysis + cardiac arrhythmia. Decontamination: oral sulphate salts. Reversal: IV potassium chloride.

The general management framework — decontamination → supportive → antidote → enhanced elimination — applies to all three, with the specific modifications summarised above. Medicolegal inference must address mode of access, intent, and the timeline of the clinical course relative to when the victim could have sought help.

REFLECT

A rural community reports three family members dying within 24 hours of consuming a meal. Post-mortem of the first casualty (performed quickly due to community pressure) shows the liver glowing faintly in the dark, with a garlic smell. The family insists it was food poisoning. As the forensic medicine specialist called to advise the investigating magistrate: what questions would you ask about the source of the food, the presence of rat poison on the premises, and the symptom timeline? How does the three-phase clinical course of phosphorus poisoning affect your interpretation of why the family did not seek help earlier? What analytical samples would you prioritise?