Iron Overdose in a Pregnant Patient

This case is written by Dr. Kate Hayman (@hayman_kate) and Dr. Dawn Lim (@curious doc). Dr. Hayman (MD MPH FRCPC) is an emergency physician at University Health Network and an Assistant Professor at the University of Toronto. Her interests are in health equity, advocacy education, and the use of simulation in low-resource settings.

Why it Matters

Iron toxicity is a relatively rare presentation to the ED. Familiarity with its presentation can be vital to recognizing this potentially lethal overdose. This case highlights the following:

  • The presenting features of moderate to severe iron toxicity
  • The fact that prenatal vitamins contain ferrous fumarate
  • When chelation therapy is indicated for an iron overdose

Clinical Vignette

You are working in a large community ED. You are called to a resuscitation room where EMS has just brought in a 29-year woman with altered mental status. Her boyfriend called 9-1-1 when he found her confused this morning. She is 10 weeks pregnant and had some vomiting and diarrhea yesterday. Her boyfriend is in the waiting room.

Case Summary

A 29-year old woman with a history of depression and an early unplanned pregnancy is found at home with decreased level of consciousness. She comes to the ED with EMS and her boyfriend. She remains altered in the resuscitation room and declines despite aggressive resuscitation.

After gathering history from the boyfriend, it seems likely that she has ingested a large quantity of pre-natal vitamins resulting in iron toxicity. This is confirmed on bloodwork and imaging. She will require airway management, hemodynamic support and specific chelation therapy.

Download the case here: Pregnant Iron OD

AXR for the case found here:

Toxicology_Iron_Tablets-936x1024

(AXR source: https://lifeinthefastlane.com/top-ten-foreign-bodies/)

CXR for the case found here:

post-ETT-CXR

(CXR source: http://jetem.org/ettcxr/)

Abdominal U/S showing IUP for the case found here:

IUP

(U/S source: https://radiologykey.com/first-trimester-pregnancy/)

FAST for the case found here:

Untitled

(U/S source: http://www.emergencyultrasoundteaching.com)

Pelvic U/S for the case found here:

Untitled2

(U/S source: http://www.emergencyultrasoundteaching.com)

2 thoughts on “Iron Overdose in a Pregnant Patient

  1. Was looking for an iron overdose case and came across this one. Thank you.
    I just wanted to check if the toxicologist in Canada calculate iron levels a bit differently than in Australia. The iron used in the case is 27mg of ferrous furamate. The elemental iron available from that is 27 divided by 3 so which is 9 mg. So a 100 tables makes it 900mg in a 55kg woman = 16mg/kg which would put her in the asymptomatic category. I looked up a few different formulations of pregnancy vitamins here in Australia and all of them have very low dose iron that even if you took the whole box of tablets you could not overdose. Iron supplement tables like ferro -grad c have 325mg of ferrous sulfate (which again needs to be divided by 3.3) so the whole box has close to 3g of elemental iron which would need the woman to be 50kg to make it to the 60mg/kg category for her to be a severe overdose. The only thing is that if you make the person also taking iron suppliment then the case becomes a little bit more obvious rather than the diagnostic dilemma it is at the moment. So don’t know best to tweak it. Either way thank you for great case and all the support media for it as well.

    Like

    • Hi Anu! Great thought. It turns out that the iron dosage on the prenatal vitamin bottles is actually the amount of elemental iron. The most common brand here in Canada contains exactly 27mg per tablet with 100 tablets per bottle. So 27mg x 100 tabs = 2700mg of elemental iron. In a 55kg woman, this means 49mg/kg, which is in the realm of moderate toxicity.

      Like

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