Acute Iron Overdose

1. THE IRON WOMAN
OVERDOSE
IMED Department Meeting Presentation
Dr Rajiv Lal

2. CASE HISTORY
• 21 year old female
36/40 gravid
• Persistent vomiting and diarrhea
• Abdominal pain
• Ingested Iron tabs 4 hours ago
• Nil known comorbidities
• Unemployed. stays with partner. Family issues…

3. EXAMINATION
Examination – actively vomiting. Weak looking
Hr 100. RR 24 bp 110/76 spo2 98% RA temp 36 cbg 6.8
Heent/chest exam essentially normal
Abdomen. Mild generalized tenderness.
Ext good perfusion

4. • Overview
• Risk assessment
• Clinical signs
• investigation
• Management

5. IRON SUPPLEMENTS IS NOT BENIGN
11000 cases annually under 6 years in USA. Accidental ingestion
These tablets appeal to children because they are often brightly colored, are
sugar coated, and have the appearance of candy.
Uncommon in adults. Intentional ingestion with fatal iron toxicity and deaths

6. Age Sex Year
1 M 2023
21 F 2023
3 M 2022
2 F 2022
4 M 2022
5 F 2021
4 F 2021
5 F 2021
20 F 2021
20 F 2020
6 F 2020
6 M 2019
7 M 2019
6 M 2019
8 F 2019
41 F 2019
CWMH admissions

8. Both cases had
severe GI
bleeding, hepatic
failure,
coagulopathy,
shock

10. MECHANISM OF TOXICITY
Ferric iron (Fe3+) is toxic to many cellular processes. The primary
mechanism for iron-induced tissue damage is free radical production and
lipid peroxidation. Toxic effects on cells include the following:
• Mucosal cell necrosis
• Impairment of capillary permeability
• Alteration of the lipid membrane of mitochondria
• Inhibition of enzymatic processes in the Krebs cycle
• Uncoupling of oxidative phosphorylation
• Direct vasodilation
• Inhibition of serum proteases (eg, thrombin)

11. Transferrin the chief iron-binding protein in plasma
Ferritin an iron-storage protein that sequesters iron intracellularly
protect cells by binding iron, limiting the amount that is circulating in the
ferric state. However, these protective mechanisms become quickly
overwhelmed with an acute intoxication.
• After iron ingestion, local toxicity (manifested as abdominal pain,
vomiting, diarrhea, and gastrointestinal [GI] bleeding) develops from
iron-induced damage to the GI mucosa.
• Systemic toxicity occurs as the result of injury to the cardiovascular
system and liver. The cause of death from iron poisoning is usually shock
or liver failure

13. • RISK ASSESSMENT
• Risk assessment according to dose is:
• <20mg/kg –– asymptomatic
• 20-60mg/kg –– GI symptoms only
• 60-120mg/kg –– potential for systemic toxicity
• >120mg/kg –– potentially lethal
• Peak SIL concentration >90mic/L (500mg/L)
• ALOC, hypotension or metabolic acidosis

14. • based on the amount of elemental iron ingested. This varies
considerably between different types of iron tablets, depending on the
type of ferrous or ferric salt:
• ferrous sulfate (dried) — divide dose by 3 (feso4 200mg = 65mg
elemental iron)
• ferrous sulfate (heptahydrate) — divide dose by 5 (feso4 325mg = 65mg
elemental iron)
• ferrous gluconate — divide dose by 9
• ferous fumarate — divide dose by 3
• ferric chloride — divide dose by 3.5
• ferrous chloride — divide dose by 4

15. CLINICAL FEATURES
Iron poisoning classically follows 5 stages, although the stages usually
overlap, reflecting the two important phases of toxicity:
• gastrointestinal
• systemic

16. Classic stages and time course of iron toxicity:
• 0-6 hours –– vomiting, diarrhoea, haemetemesis, melena, abdominal
pain. Significant fluid loseses may lead to hypovolemic shock
• 6-12 hours –– gastrointestinal symptoms wane and the patient appears
to be getting better. During this time iron shifts intracellularly from the
circulation
• 12-48 hours –– Cellular toxicity becomes manifest as vasodilative
shock and third-spacing, high anion gap metabolic acidosis (HAGMA)
and hepatorenal failure, coagulopathy, CNS dysfunction
• 2-5 days –– acute hepatic failure, coma although rare mortality is high
• 2-6 weeks –– chronic sequelae occur in survivors –– cirrhosis and
gastrointestinal scarring and strictures

17. INVESTIGATIONS
• In addition to the usual screening tests in suspected tox cases (BSL,
ECG) the following specific tests can be useful:
• serum iron concentration
• peak levels occur 4-6 hours following iron ingestion
• after 6 hours iron levels fall due to intracellular shift
• levels do not clearly correlate with clinical toxicity, but > 90 micromol/L (500
mcg/dL) is generally considered predictive of systemic toxicity (equivalent
to >60mg/kg)
• blood gas
• the presence of HAGMA is a useful marker of systemic toxicity
• abdominal X-ray — can be used to confirm ingestion
• LFTs, Coags — hepatic failure
• UEC — renal failure

18. Copyrights apply
Tabs causing radio opaque images
C – Calcium Carbonate, Chloral hydrate
H- Heavy metals – mercury, lead
I – Iron and iodine
P – Phenothiazines
E – Enteric coated pills
S – Sustained release preparations

19. MANAGEMENT
• Resuscitation:
• ABCs
• Priority is early restoration of circulating volume
• Fluid Resuscitation to prevent shock from gastrointestinal losses, vasodilation
and third spacing
• Ongoing assessment of response to resuscitation and antidotes

20. Decontamination
• Iron not adsorbed by activated charcoal
• Whole bowel irrigation indicated for confirmed ingestions > 60 mg/kg
(difficult and potentially hazardous in small children)
• Surgical or endoscopic removal of tablets if lethal ingestion (e.g.
>120mg/kg) or WBI not feasible
Antidotes
• Desferrioxamine chelation therapy
Enhanced elimination
• nil

21. DESFERRIOXAMINE
• Desferrioxamine chelation therapy is an option for severe iron toxicity –
the indications, duration and end-points of therapy are controversial.
• Indications (may also be used in chronic iron overload)
• level >90 micromol/L at 4-6 hours post-ingestion
• evidence of systemic toxicity
• shock
• metabolic acidosis
• altered mental status
Should Not Delay Treatment!!

22. Mechanism of action
• chelates free ferric and ferrous ions in the plasma resulting in water
soluble complexes that can be renally excreted
• ferrioxamine is excreted unchanged in the urine, which classically turns
a vin rose colour (although this is not a reliable indicator of chelation)

23. • initial IV infusion rate of 15 mg/kg/h, reduced if hypotension occurs,
titrated up to 40mg/kg/h in severe toxicity
• Maximum dose is 80mg/kg/24hrs
• cardiac monitoring is mandatory
• reconstitute the 500 mg powder with 5 mls sterile water and dilute
to 100 mls with 5% glucose or normal saline
• The infusion can be stopped when
the patient is clinically stable.

24. • Ingested 42 tabs of feso4 200mg = 2730mg elemental
iron
= 45.5mg/kg elemental iron. Toxic dose > 20mg/k
Serum iron on admission 59umol/l.
• Iv fluid. Antiemetic
• Desferoximine started within 4 hrs of presentation.
• Total 3100mg over 48hrs.
• Patient recovered well and discharged day 5 of
admission after counsellors and psychiatric team review
• 10days later ND