What are the delayed manifestations of iron poisoning?
October 11, 2024
Iron is an essential mineral for our body, helping in vital processes like carrying oxygen in the blood. It is found in everyday foods like fortified cereals, red meat, spinach, and even dark chocolate. It is also prescribed to treat iron deficiency anemia and found in a multitude of vitamins and supplements including prenatal vitamins. It can be severely toxic in overdose and in the 1990s, iron was the leading cause of poisoning deaths in small children in poison center data. Iron can directly harm cells, disrupt enzymes, and interfere with proteins in the blood, leading to significant morbidity and mortality. The referral amount for hospital care is 40 mg/kg of elemental iron.
Iron toxicity symptoms progress in 5 stages. The first stage occurs within 30 minutes to 6 hours after ingestion and is related to direct gastrointestinal injury. Symptoms include nausea, vomiting, diarrhea, abdominal pain. Hematemesis and bloody diarrhea can also occur. The second stage is when the gastrointestinal symptoms cease but the patient remains clinically ill and can have a metabolic acidosis. The third stage is shock which can result from volume loss, decreased cardiac output, and/or dilation of blood vessels. Metabolic acidosis can also occur in the third stage. The fourth stage is hepatic failure which occurs 2-3 days after ingestion.
The fifth stage is rare and is one of the delayed manifestations. This stage is gastrointestinal obstruction which can occur from strictures related to the initial injury from iron poisoning. Symptoms can occur 2-8 weeks after ingestion and manifest with vomiting, abdominal pain, and cessation of flatulence and bowel movements. Another delayed manifestation is Yersinia enterocolitica infection which occur after resolution of iron poisoning. Both iron poisoning and the chelator used to treat iron poisoning, deferoxamine, can result in Yersinia enterocolitica. If a patient develops bloody diarrhea, fever, and/or abdominal pain after iron poisoning, it is important to culture the stool. If Y. enterocolitica is identified, treatment is excellent supportive care and antibiotics and the organism is often susceptible to Trimethoprim-Sulfamethoxazole, fluoroquinolones, 3rd generation cephalosporins, and aminoglycosides.
Question prepared by: Bruno Bocchese da Cunha Lanca, G1, Vanderbilt Medical Scientist Training Program
Thankfully, iron poisoning is seen less frequently due to concerted public health efforts in the 1990s to reduce iron poisonings especially in small children. However, serious ingestions still occur especially with intentional overdoses. It is important to counsel patients and their families about symptoms of Y. enterocolitica infection and bowel obstruction after resolution of iron poisoning such that they are aware to return to medical care if they occur.
Rebecca Bruccoleri, MD, Medical Director, Tennessee Poison Center