L4: Iron Flashcards
Manner of Poisoning by Iron Toxicity
- Iron toxicity typically occur in children, 3-5 tablets may induce significant toxicity according to amount of elemental iron contained in ingested preparation.
Toxic Action of Iron Toxicity
Distribution of Iron
Transferrin Carier
- Iron is transported in the blood by transferrin.
- When binding sites on transferrin are saturated, Unbound iron reacts with blood vessels and platelets.
Absorbtion of Iron
Elimination of Iron
- There is no significant natural route of elimination other than by Gastrointestinal cell loss & blood loss.
1st GI Phase of Iron Toxicity
CP of Iron Toxicity
Severe iron poisoning may proceed in four phases
- 1st Gastrointestinal phase (Gastrointestinal effects)
- 2nd Window phase
- 3rd Multi-organ failure phase
- Late complications phase
2nd window Phase of Iron Toxicity
3rd Multi-Organ Failure phase of Iron Toxicity
Late Complications phase of Iron Toxicity
Investigations in Iron Toxicity
- Blood Iron Level
- Abdominal X-ray
- Electrolytes, Arterial blood gases & Blood glucose level & Full blood count
- Renal and Liver functions & Coagulation studies.
Blood Iron level investigations
What Might Abdominal X-Ray show in cases of Iron Toxicity?
- To identify radio-opaque tablets
- however their absence does not exclude iron overdose.
Determination of severity of Iron Toxicity
- Clinical Evaluation.
- Blood Iron Level.
- Dose of Ingested Elemental Iron
Dose of Ingested elemental Iron
TTT aspects of Iron Toxicity
- Emergency and supporlive
- Decontamination
- Antidote: (Desferrioxamine)
Emergency & Supportive TTT of Iron Toxicity
- Severe poisoning requires close monitoring (ABC, CVP line, regular electrolytes, blood gases and blood sugar monitoring)
- Volume replacement may be required (blood, fresh frozen plasma or crystalloids)
- Correction of acidosis.
Decontamination options in Iron Toxicity
- Activated Charcoal
- Gastric Lavage
- Whole bowel irrigation
Is Activated Charcoal effective in Iron Toxicity?
- Not effective.
- Iron is not adsorbed to charcoal.
Gastric Lavage in Iron Toxicity
- Limited value
- Intact tablets may not pass via lavage tube
What is the Method of choice of decontamination in Iron Toxicity?
Whole bowel irrigation
Indications for WBI
- Ingestions >60 mg/kg confirmed on X-ray.
- Un-dissolved tablets were detected on abdominal x-ray.
- Sustained release or enteric coated iron tablets were reported.
Antidote in Iron Toxicity
(Desferrioxamine)
Dose & Route of Desferrioxamine
- Desferrioxamine is given intravenously at a rate of 15 mg/kg body. weight/hour.
- Reduce dose by 50% in severe renal impairment.
- The urine will often (but not always) change to vin rose color.
MOA of Desferrioxamine
- It chelates ferric iron and causes redistribution of iron from tissue sites back into plasma.
- The iron- desferrioxamine complex is renally eliminated.
SE of Desferrioxamine
- Desferrioxamine infusion for greater than 24 hours may result in Non-cardiogenic pulmonary edema.
End point of therapy by Desferrioxamine
- Treatment should be continued until serum iron concentrations fall below 60 micromol/ L
- The urine (if it changed color) has returned to normal.
- This normally takes 6-8 hours of treatment but may be longer in severe poisoning.
Indications of Desferrioxamine
When to Cease Desferrioxamine?
