What is Iron Toxicity?
Iron is a component often found in many everyday multivitamins that you can buy without a prescription. However, too much iron from intentional or accidental consumption is a common cause of poisoning. Swallowing too much iron is especially dangerous for children. Taking a large dose can be life-threatening, especially for children who accidentally consume strong adult formulations, such as prenatal vitamins. In adults, serious iron ingestion is typically associated with attempts to harm oneself.
Unintentional swallowing of iron is more prevalent in children under the age of six. Also, iron poisoning can occur after receiving multiple blood transfusions in individuals with chronic conditions like thalassemia, sickle cell disease, and blood cancers.
What Causes Iron Toxicity?
If you swallow less than 20 mg/kg of pure iron, it’s usually not harmful. However, swallowing between 20 mg/kg and 60 mg/kg can cause moderate symptoms. If more than 60 mg/kg of pure iron is swallowed, it can lead to serious health issues and can even be fatal.
The amount of pure iron you actually ingest depends on the specific type of iron supplement you take. Some common types include:
- 325 mg ferrous sulfate tablets, which contains about 20% pure iron (or 65 mg per tablet)
- 300 mg ferrous gluconate tablets, which contain about 12% pure iron (or 36 mg per tablet)
- 100 mg ferrous fumarate tablets, which contain about 33% pure iron (or 33 mg per tablet)
Prenatal vitamins often contain between 60 to 90 mg of pure iron in each tablet. Children’s vitamins contain less, usually between 5 to 19 mg of pure iron per tablet.
Risk Factors and Frequency for Iron Toxicity
In 2015, the Annual Report of the American Association of Poison Control Centers totaled 4,072 exposures to iron or iron salts. Most of these (3,211 cases) were accidental ingestion, with more than half (2,036 cases) occurring in children under the age of five. Over a thousand cases required treatment in a healthcare facility and there was one death reported.
- In 2015, 4,072 exposures to iron or iron salts were reported by the American Association of Poison Control Centers.
- Most of these exposures (3,211 cases) were due to accidental ingestion.
- Children under 5 years old accounted for more than half of the cases (2,036 cases).
- Over a thousand cases (1,161) required treatment in a healthcare facility.
- Unfortunately, one death was reported.
Signs and Symptoms of Iron Toxicity
Iron toxicity, which involves severe harm due to excessive iron amounts, can progress through five stages. However, patients do not always go through all of these stages. These stages can progress quickly, and the symptoms a patient experiences may change rapidly.
- Stage 1 (0.5 to 6 hours): The patient primarily deals with digestive issues like abdominal pain, vomiting, diarrhea, and passing blood in vomit or stool.
- Stage 2 (6 to 24 hours): The patient may feel like they’re getting better as their digestive symptoms might seem to improve, even though they have still absorbed harmful amounts of iron.
- Stage 3 (6 to 72 hours): The digestive symptoms come back accompanied by shock, imbalanced body pH, coagulation problems, liver issues, heart muscle disease, and kidney failure.
- Stage 4 (12 to 96 hours): This stage often involves a rise in enzyme levels related to liver health, potentially leading to liver failure.
- Stage 5 (2 to 8 weeks): This final stage shows the results of healing in the digestive tract, which might result in scarring and blockage near the stomach or in the upper bowel.
Whether a patient experiences or skips a stage depends on their specific symptoms and clinical signs, not the time since they ingested the iron.
Testing for Iron Toxicity
Diagnosing iron poisoning or iron toxicity is usually based on the patient’s symptoms and medical history. A blood test that measures iron levels in the body is typically used to understand the severity of the condition. The best time to perform this test is 4 to 6 hours after the suspected iron ingestion.
If the patient has taken a prolonged-release or an enteric-coated iron supplement – which gets absorbed more irregularly – a second blood test may be required 6 to 8 hours after ingestion.
The level of iron in the blood can give an idea of the toxicity. If peak iron levels are below 350 micrograms/dL, the toxicity is likely to be minimal. If they range between 350 to 500 micrograms/dL, it signifies moderate toxicity. Any reading above 500 micrograms/dL may indicate severe systemic toxicity, which can cause damage to major body organs. Please note that the body tends to clear iron from the bloodstream very quickly and stores it in the liver. So, if this blood test is done after the peak time, it can give a false low reading.
The doctor may also order other blood tests to track your electrolyte levels, kidney and liver functions, blood sugar levels, coagulation or clotting ability of the blood, and complete blood count.
X-ray imaging may sometimes show the presence of iron pills in the digestive tract, but many iron supplements do not show up on x-rays. Therefore, a normal x-ray does not completely rule out iron poisoning. X-rays can show the iron pills for about 2 to 6 hours after ingestion. However, the density of the supplement on the X-ray image does not always correlate with the severity of poisoning.
Treatment Options for Iron Toxicity
If you did not ingest a potentially toxic amount of iron, or if you don’t show any symptoms 4 to 6 hours after ingestion, you typically won’t need any treatment for iron poisoning.
Individuals who experience gastrointestinal symptoms that subside quickly and have normal vital signs usually just need supportive care and an observation period. This could indicate the second stage of iron poisoning.
Patients demonstrating symptoms, or those experiencing instability of their heart and blood vessels, will require more intensive care and may need to be admitted to an Intensive Care Unit (ICU).
To treat iron toxicity, various methods are available:
– IV (intra-venous) fluid treatment is provided to correct reduced blood volume and low blood flow.
– Deferoxamine, a drug that can remove iron from your body, is usually given to patients with systemic toxicity (when toxin affects your whole body), metabolic acidosis (too much acid in your body fluids), worsening symptoms, or elevated serum iron levels predicting moderate to severe poisoning. This drug is often given as a continuous infusion. Consulting with a toxicologist (a doctor specialized in poison treatment) is highly recommended for proper administration of deferoxamine.
Cleaning the gastrointestinal tract with a solution of polyethylene glycol may be used to remove iron pills before they’re absorbed by the body.
Gastric lavage, which is a method to clean your stomach, is only chosen if the X-ray shows significant amounts of visible pills. The benefits of the procedure usually need to outweigh the potential risks as it can be invasive.
Activated charcoal, a treatment often used for other types of poisoning, does not effectively remove iron from the body.
If you show gastrointestinal symptoms or signs of dehydration, or if you’re receiving deferoxamine treatment, hospital admission may be necessary. Admission to an ICU is required if you are unconscious, in shock, or have a high level of iron in your blood. If you’ve intentionally taken excess iron, you may need to see a psychiatrist.
Patients can usually safely leave the hospital if they don’t experience any symptoms after being watched for 6 to 12 hours and the radiograph (X-ray image) doesn’t show any iron, or if they only had mild gastrointestinal symptoms that has resolved, also without any signs of acid buildup in the body and normal iron levels after an observation period of 6 to 12 hours.
In some cases, especially if there’s a large hard mass of iron (bezoar) present, surgery may be required. In very severe instances, hemodialysis (a type of treatment to purify your blood) can also be effective.
What else can Iron Toxicity be?
Iron toxicity can often be confused with other health conditions that display similar symptoms. Here are some of those conditions:
- Sepsis
- Acetaminophen toxicity
- Other toxic ingestions that cause a specific type of metabolic acidosis (high acid levels in your body) such as salicylate, cyanide, methanol, and ethylene glycol toxicity
- Mushroom ingestion
- Heavy metal toxicity
- Theophylline toxicity (A drug used to treat lung diseases such as asthma)
- Gastrointestinal bleeding from other causes
Possible Complications When Diagnosed with Iron Toxicity
- Death of liver cells
- Heart failure leading to shock
- Heart muscle impairment
- Deep state of unconsciousness (coma)
- Seizures
- Blood clotting disorders
- Inflammation of the esophagus
- Low red blood cell count (anemia)
- Acute lung injury (ARDS)
- Narrowing of the intestine due to scar tissue
- Rupture in the stomach