Cause:Ferric or ferrous iron; sx if >20 mg/kg, serious if >40 mg/kg, potentially lethal if >60 mg/kg
Pathophys:Direct corrosive effect on gi mucosa causes markedly increased absorption of iron salts, which are hepatotoxic; subsequently iron and ferritin are released from periportal cells leading to vasodepressor effect and shock
Sx:Nausea, vomiting, abdominal pain, diarrhea. Seizures, then 2-3 h respite, then fatal seizures
Si:GI bleeding
Stage 1 (0.5-6 h postingestion) = nausea, vomiting
Stage 2 (6-24 h) = latent, though may be absent in severe OD
Stage 3 (4-40 h) = systemic toxicity including shock, seizures, and death
Stage 4 (2-5 wk) = late cmplc like gi strictures/obstruction
Gastric perforation, later strictures, intestinal obstruction; shock, coma, coagulopathy, hepatic failure, acidosis
Lab:
Chem:Serum iron level 4-6 h after ingestion, not later because redistribution will falsely depress levels, then at 10 h in case delayed absorption; within 1-2 h if chewable/liquid forms ingested; >300 µgm % causes mild toxicity; >500 µgm % causes serious toxicity; >1000 µgm % often fatal
Glucose often >150 mg %
Hem:WBC often >15 000; TIBC no help
Urine: Deferoxamine challenge test occasionally used, urine may be rose-colored if serum-free iron is present
Xray:KUB, iron tablets often apparent unless ingested liquid, chewable or multivitamin preparations
Rx:Perhaps ipecac prehospital; lavage stomach w saline, although there is danger of perforating an already eroded stomach, or lavage whole bowel w PEG; fluids for shock. No charcoal
Deferoxamine 1 gm stat, 0.5 gm q 4-12 h up to 6 gm qd im, or iv if in shock, at 10-15 mg/kg/h (higher doses precipitate shock) up to 6 gm qd total; cannot use via gastric lavage; may have cytoprotective effects independent of chelation.
Maybe someday L1, an oral iron chelator, 1st choice (Clin Pharmacol Ther 1991;50:294)