(See also Overview of Poisoning.)
Pills containing iron are commonly used to treat certain kinds of anemia. Iron also is included in many multiple vitamin supplements. People—especially toddlers—who overdose on these pills may develop iron poisoning. Because many households contain adult multiple vitamin supplements that contain iron, iron overdose is common. However, children’s chewable iron-containing vitamins do not contain very much iron, so even a whole bottle does not provide enough iron to cause serious poisoning. Overdose of pure iron supplements, however, may cause serious iron poisoning. Prenatal vitamins contain a lot of iron and may poison a small child.
Iron poisoning is a potential cause of fatal poisoning in children younger than age 5. It first irritates the stomach and digestive tract, sometimes causing bleeding. Within hours, iron poisons the cells, interfering with their internal chemical reactions. Within days, the liver can be damaged. Weeks after recovery, the stomach, digestive tract, and liver can develop scars due to the previous irritation.
Serious iron poisoning usually causes symptoms within 6 hours of the overdose. The symptoms of iron poisoning typically occur in 5 stages:
Stage 1 (within 6 hours after the overdose): Symptoms include vomiting, vomiting blood, diarrhea, abdominal pain, irritability, and drowsiness. If poisoning is very serious, rapid breathing, a rapid heart rate, coma, unconsciousness, seizures, and low blood pressure may develop.
Stage 2 (6 to 48 hours after the overdose): The person’s condition can appear to improve.
Stage 4 (2 to 5 days after the overdose): The liver fails, and people may die from shock, bleeding, and blood-clotting abnormalities. Sugar levels in the blood can decrease. Confusion and sluggishness (lethargy) or coma may develop.
Stage 5 (2 to 5 weeks after the overdose): The stomach or intestines can become blocked by scars. Scarring in either organ can cause crampy abdominal pain and vomiting. Severe scarring of the liver (cirrhosis) can develop later.
The diagnosis of iron poisoning is based on the person’s history, symptoms, presence of metabolic acidosis (acid in the bloodstream released from the poisoned cells), and the amount of iron in the blood. If many pills have been swallowed, they can sometimes be seen on x-rays of the stomach or intestines.
People with significant symptoms or high levels of iron in the blood need hospitalization. A large amount of iron can remain in the stomach even after vomiting. A special solution of polyethylene glycol may be given by mouth or through a stomach tube to wash the contents of the stomach and intestines (whole-bowel irrigation), although its effectiveness is unclear. Deferoxamine, a drug that binds with the iron in the blood (called chelation therapy), allowing it to pass into the urine, is given by vein (intravenously) if poisoning is severe.