Neobook — clinical reference

Mechanism of toxicity

Direct corrosive effects (GIT toxicity) & cellular toxicity (periportal liver damage, vasodilatation/ hypotension/ shock)

Toxic dose

Elemental iron:

Elemental iron content of ferrous salts
Ferrous salt	Amount	Elemental iron
Ferrous sulphate (dried)	200 mg	65 mg
Ferrous sulphate	300 mg	60 mg
Ferrous gluconate	300 mg	35 mg
Ferrous fumarate	200 mg	65 mg

Symptoms and signs of poisoning

	Time after ingestion	Clinical features
Phase 1	0.5–8 h	Vomiting, haematemesis, abdominal pain, diarrhoea, shock, acidosis, coagulopathy
Phase 2	6–12 h	Symptoms improve or disappear.
Phase 3	12–48 h	Haematemesis, melaena, GIT perforation, vascular collapse, severe acidosis, hypoglycaemia, cyanosis, pulmonary oedema, convulsions, coma, hepatorenal failure

Special investigations

Full blood count
Electrolytes and arterial blood gas
Iron levels: 4–6 h post ingestion and repeated after 2–4 h (useful within 12 h post ingestion only)
- Iron levels < 54 mcmol/L (< 300 mcg/dL) and/or asymptomatic: no antidote needed
- Iron levels > 54 mcmol/L (>300 mcg/dL) and symptomatic: administer antidote
Abdominal x-ray (iron = radiopaque): assess success/failure of GIT evacuation

Management

Intervention	Not effective	Consider	Indicated
Gastric lavage
Early post-ingestion activated charcoal
Multiple dose active charcoal
Whole-bowl irrigation
Dialysis
Charcoal haemoperfusion

Antidote: desferrioxamine

Indications:moderate/severe systemic toxicity (cardiovascular shock, gastrointestinal bleeding, lethargy,CNS depression, metabolic acidosis, iron-induced hepatotoxicity, iron levels > 90 mcmol/L
Contraindications: severe renal disease/anuria
Dosing: 15 mg/kg/hour continuous infusion (max total dose in 24 h: 80 mg/kg). Reduce rate after 4–6 h if hypotension occurs. End point = cessation of metabolic acidosis/clinical improvement. Generally moderate toxicity treated for 12h/ severe toxicity up to 24 h Prolonged therapy (>24h) associated with lung injury.

Symptomatic and supportive:

Iron Poisoning