Case 20 – An Upset Stomach

Case #20: An Upset Stomach
Author: Michael Gottlieb, MD
Peer Reviewer: Patrick Lank, MD

A 22 year old G1P0 at 30 weeks gestational age presents with mild, diffuse abdominal pain and intermittent non-bilious, non-bloody vomiting over the past few hours. Her review of systems is otherwise unremarkable. She has no past medical history and only takes prenatal vitamins. On further prompting, she endorses taking “half of the bottle” after a fight with her boyfriend four hours prior to arrival.

Vitals: Temp: 98.6, HR: 76, RR: 10, BP: 118/76, O2 Sat: 97% on RA

What is the most likely etiology of this patient’s presentation?
Although the differential diagnosis for abdominal pain is extremely broad, given her history (and that this is a toxicology website), iron toxicity is the most likely culprit.
What other clinical symptoms might you expect to see with this patient?
Iron toxicity occurs in five stages:

Stage 1 (0-6 hours): Abdominal pain, vomiting, and diarrhea.
Stage 2 (6-24 hours): Latent stage; GI symptoms may improve while the organ damage and metabolic acidosis worsens. Note: This stage may not always occur.
Stage 3 (6-48 hours): Systemic toxicity; Symptoms range from return of GI symptoms to multi-organ failure with seizures and/or coma.
Stage 4 (2-5 days): Fulminant liver failure.
Stage 5 (4-6 weeks): Delayed effects of mucosal injury (rare) causing bowel obstruction due to Iron’s corrosive damage to the stomach/intestine.

In general…

Clinical Effects Elemental Iron Dose Serum Iron Concentration
Non-Toxic/Mild Ingestion <20 mg/kg <300 mcg/dL
Moderate Toxicity 20-60 mg/kg 300-500 mcg/dL
Severe Toxicity >60 mg/kg >500 mcg/dL

Note: FeSO4 325 mg = 65 mg elemental Iron

What is the initial treatment for this patient?
Consider whole bowel irrigation if there was a significant ingestion or increasing serum iron levels. Activated charcoal has not been shown to improve outcomes as it poorly adsorbs ions such as Iron. Otherwise, fluid resuscitation and supportive care are the initial interventions.

Consider deferoxamine if peak Fe levels are > 500 mcg/dL (regardless of whether they are downtrending), metabolic acidosis is present, or there are signs of systemic toxicity. The initial dose is 5 mg/kg/hr IV titrated up (as tolerated) to 15 mg/kg/hr (Max Dose: 1 g/hr) with no more than 6 g given during the first 24 hours. Side effects include hypotension (assoc with fast administration rates), red (‘vin rosé’) urine, pulmonary toxicity (if given for > 24 hours), and risk of Yersinia bacteremia. Deferoxamine is safe in pregnancy. Deferoxamine should be stopped when the patient shows signs of clinical recovery with the guidance of a regional poison control center.

What further work-up is required?
Obtain an initial Iron level (and consider serial Iron levels if you suspect a significant ingestion). Also check a venous blood gas (for pH), complete blood count, electrolytes, kidney and liver function tests, and coagulation factors. Consider abdominal x-rays.

Note: Not all iron supplements are radiopaque, so a negative x-ray does NOT rule out ingestion.

What is the disposition for these patients?
Patients with mild ingestions and who remain minimally symptomatic (mild nausea and vomiting) may be discharged home or transferred to psychiatry after six hours of observation. All other patients should be admitted to the hospital. Anyone with significant ingestion, increasing levels, and/or given Deferoxamine should be considered for admission to the ICU.

References:

Madiwale T, Liebelt E. Iron: not a benign therapeutic drug. Curr Opin Pediatr 18: 174, 2006.

Singhi SC et al. Acute iron poisoning: clinical picture, intensive care needs and outcome. Indian Pediatr 40: 1177, 2003.

Chyka PA, Butler AY. Assessment of acute iron poisoning by laboratory and clinical observations. Am J Emerg Med 11: 99, 1993.

Baranwal AK, Singhi SC. Acute iron poisoning: management guidelines. Indian Pediatr 40: 534, 2003.

Manoguerra AS, Erdman AR, Booze LL, et al: Iron ingestion: an evidence-based consensus guideline for out-of-hospital management. Clin Toxicol (Phila) 43: 553, 2005.

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