Complications of Ingesting Metallic Objects and a Magnet

MAY 25, 2007


Scott F. Reed, MD
Trauma Fellow Eastern Virginia Medical School Norfolk, VA Locum Tenens Department of Surgery Warren Memorial Hospital Front Royal, VA

General surgeons are often faced with foreign-body ingestion, es?pecially in the pediatric population. Most of these pass through the gastrointestinal (GI) tract without difficulty or need for surgical intervention. This case illustrates a unique type of ingestion of multiple small metal objects in conjunction with a magnet. Although either of these objects would likely have passed without incident when ingested separately, together they created a unique surgical situation, which required close clinical monitoring and surgical intervention.

Case report
A previously healthy 11-year-old boy came to the emergency department with his mother because of right lower quadrant pain of approximately 12 hours' duration, new-onset nausea, and one episode of emesis. After the initial evaluation and blood work done in the emergency department, the surgery department was consulted for what appeared to be a case of appendicitis.

On further questioning about dietary habits, the boy confessed to having swallowed several small nuts and bolts 3 days earlier. The day after ingesting these, the child had some nausea and vomiting, and the next evening he experienced some abdominal pain. When the pain did not resolve by the next day, the child's mother brought him in for evaluation. She did not know about the foreign body ingestion at that time.

Physical examination revealed a well-developed child who was resting comfortably. His temperature was 98.9?F, al?though his mother stated he had a fever at home of 103?F. His heart rate was 117 beats per minute and his blood pressure was 111/85 mm Hg. He had been eating well and had daily bowel movements up to and including the day of presentation. The only significant finding was moderate tenderness to palpation in the right lower quadrant, but no rebound, guarding, or distension. The remainder of the physical examination was unremarkable. His white blood cell (WBC) count was 11,700/?L, with a hemoglobin of 18.1 g/dL and a hematocrit of 49.1%. Electrolytes were within normal limits.

Abdominal radiographs showed a mass of several nuts and bolts, which appeared to be impacted in the right lower quadrant around the area of the ileocecal valve (Figure). There were some dilated loops of small bowel with air-fluid levels, but no evidence of free air.

It was thought that the foreign objects were swallowed individually, thus it was surprising that they had not passed, especially since he had been eating normally and continued to have regular bowel move?ments. Because of the abdominal pain, dilated loops of bowel on abdominal radiographs, and slightly elevated WBC count, the child was admitted for observation. Plans were made for frequent clinical examinations, which in?cluded repeated abdominal radiographs and blood chemistries in the morning. He was told to take nothing by mouth and was maintained on intravenous fluids.

The following morning, the abdominal radiographs were unchanged. The child's abdominal condition worsened and ex?amination demonstrated rebound and guarding on palpation. Based on these findings, he was prepared for abdominal exploration.

The child was given 500 mg of cefoxitin preoperatively, and general anesthesia was administered. A lower midline incision was made. Upon entering the abdomen, a mass was noted in the right lower quadrant and a moderate amount of GI fluid was observed in the ileocecal area. The mass consisted of three discrete loops of small bowel tightly adhered in the right lower quadrant. When these loops were carefully separated, four small metallic nuts were found outside of the ileum, approximately 2 cm from the cecum. Attempts to pick up the small nuts proved difficult because they seemed stuck to the area. Metal forceps were also attracted to the site and became stuck. After a moment of confusion, we deduced the child must also have swallowed a magnet. Inspection of the small bowel revealed more nuts and bolts in the bowel lumen and four small perforations were found. Two perforations were 20 cm proximal to the ileocecal valve and two others were 50 cm proximal to the ileocecal valve. All perforations ap?peared to have been caused by the nuts and bolts being pulled through the bow-el wall. The distal ileum was inflamed, with a necrotic area underlying where the nuts were found. The inflammation had nearly obstructed the segment of ileum. Al?though the metal objects appeared to be in one collection on the abdominal radiographs, they were actually located in three separate locations within the small bowel.

The nuts and bolts were very small and difficult to palpate in the small bowel lumen. The objects that could be felt were manipulated through the small perforations. At this point, a sterile magnet used to turn implantable defibrillators on and off was used to run the bowel, which revealed more nuts and bolts. On removing the metal objects, an enterotomy was made and a 1-cm round magnet was removed from the distal ileum. After an intraoperative abdominal radiograph confirmed that no metal objects were left behind, the small perforations were closed primarily. The area where the magnet had caused necrosis of the ileum was resected, and a side-to-side ileocolic anastomosis was made. The abdomen was then irrigated and closed. The child was discharged to home on postoperative day 4 and made a full recovery. He later confessed to swallowing the magnet.

Children have been known to swallow a number of small objects, such as toys and coins, and most pass without incidence. Magnets are common in children's toys, jewelry, and for holding art on refrigerators, and several cases of children swallowing multiple magnets are re?ported in the literature.1-3 Each of these cases had a similar pattern of bowel necrosis, perforation, obstruction, and even fistula formation. Although not widely reported, if only one magnet is ingested along with another metal object, a similar risk appears to exist.

Even if most of the ingested magnets are small, they can be very powerful. These magnets can attract each other from distances as much as 5 cm apart and exert up to 2,500 g of force.2,3 With that much force, magnets or a magnet and another metal object can stick together even though they are in distinctly dif-ferent parts of the GI tract. The interposed walls of bowel, stomach, or colon can undergo pressure necrosis leading to perforation or fistula formation. If the area becomes twisted on itself or if severe inflammation results, an obstruction can occur.

The time required for an object to travel through the GI tract is variable, with one study quoting 3.8 days. Also, having parents check a child's stools to determine whether the object has passed is unreliable, with 50% to 66% of objects missed.4 In this case, having objects in the small bowel 3 days after ingestion should have been an indication that other factors were present.

Foreign bodies swallowed by children are found in the oropharynx (5%-10%), esophagus (20%), stomach (60%), and small bowel (10%). These objects are radio?paque 60% to 90% of the time. They pass spontaneously in 80% to 90% of cases that are evaluated medically. Perforation occurs in less than 1% of all cases, with the most common site of perforation being the ileocecal area (75%).4

Although there does not appear to be a standard protocol for managing foreign- body ingestion, there are some common recommendations throughout the literature. Objects impacted in the esophagus should be removed because of the high risk of ulceration and necrosis. Objects trapped in the oropharynx (usually fish or chicken bones) almost always cause symptoms, whereas objects in the esophagus may remain asymptomatic. There?fore, if ingestion is suspected, or if other nonspecific symptoms are present, such as excessive salivation, nausea, vomiting, or respiratory difficulty, imaging should be used to determine whether a foreign body is present. Most objects in the stomach and small bowel may be observed because they pass spontaneously; however, long, sharp objects such as pins and needles have a much higher chance of becoming im?pacted or causing a perforation and should be removed. Small button-type batteries should also be removed because they can leak caustic material, causing erosions. Most of these can be removed endoscopically with a magnetic probe.4,5

Despite the fact that most ingested foreign bodies pass spontaneously and a large portion can be removed endoscopically, about 1,500 people in the United States die annually from complications of foreign- body ingestion.6 Most cases of ingested objects occur in children, but adults can also be involved. This usually involves mentally challenged or intoxicated individuals, or prisoners hiding items such as drugs. Although rare, cases of foreign- body ingestion have also been described in healthy adults, usually when the object is within food and eaten accidentally.7

The ingestion of magnets or a magnet with other metallic objects should be considered an impending surgical emergency. If a magnet or metal ingestion is suspected, magnetic resonance imaging should be avoided.8

Children presenting with abdominal pain should be questioned about possible foreign-body ingestion, and abdominal radiographs are an excellent tool for finding most of these objects. When a metallic object remains in the GI tract for an extended period of time or does not move on serial films, ingestion of a magnet should also be suspected. Based on the case reports in the literature, there is little chance of these objects passing on their own. These cases require close attention and most often result in laparotomy.

1. Cauchi JA, Shawis RN. Multiple magnet ingestion and gastrointestinal morbidity. Arch Dis Child. 2002;87(6):539-540.

2. Tay ET, Weinberg G, Levin TL. Ingested magnets: the force within. Pediatr Emerg Care. 2004;20(7):466-467.

3. Lee SK, Beck NS, Kim HH. Mischievous magnets: unexpected health hazard in children. J Pediatr Surg. 1996;31(12):1694-1695.

4. Arana A, Hauser B, Hachimi-Idrissi S, et al. Management of ingested foreign bodies in childhood and review of the literature. Eur J Pediatr. 2001;160(8):468-472.

5. Wahbeh G, Wyllie R, Kay M. Foreign body ingestion in infants and children: location, location, location. Clin Pediatr. 2002;41(9): 633-640.

6. Lai AT, Chow TL, Lee DT, et al. Risk factors predicting the development of complications after foreign body ingestion. Br J Surg. 2003;90(12):1531-1535.

7. Williams C, McHenry CR. Unrecognized foreign body ingestion: an unusual cause for abdominal pain in a healthy adult. Am Surg. 2004;70(11): 982-984.

8. Oestreich AE. Multiple magnet ingestion alert. Radiology. 2004;233(2):615.

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