Aetiology

Foreign body obstruction or impaction will depend on the physical properties of the object (size, shape, and composition). It is also related to the areas of normal acute anatomical angulations or abnormal congenital/acquired narrowing at any point within the gastrointestinal (GI) tract, which may serve as barriers to the free passage of a foreign body.[21][22][23][24][25]

  • The most common foreign bodies found in children are coins; other objects include buttons, crayons, and similar items.

  • The most common foreign bodies found in adults are food (pork/chicken meat); other common foreign bodies include chicken/fish bones, partial dentures, fruit stones, and toothpicks.

  • Prisoners, people who have an intellectual disability, and patients with psychiatric pathologies may present with unusual objects, such as razor blades, pencils, toothbrushes, silverware, batteries, different kinds of wires, screws, or nails. Multiple objects can often be found in the same patient.[4]​

  • The corrosive nature of alkaline batteries may lead to erosion or perforation of the GI tract. Alkaline batteries can leak potassium hydroxide, which causes liquefaction necrosis due to dissolution of proteins and collagen, saponification of lipids, and dehydration of tissue cells.[16]

  • Magnet ingestion can cause serious and potentially life-threatening complications, particularly if more than one is ingested, as the magnets can attract each other through the intestinal wall, causing bowel wall ischaemia and perforation.[3][19]

Pathophysiology

The entire GI tract can be involved. Fortunately, the vast majority of all swallowed objects pass through the GI tract without problems. Foreign bodies have been described in the oropharynx, oesophagus, stomach, small bowel, common bile duct, colon, and rectum. Pathophysiological considerations include the following:

  • Areas of acute angulation or physiological narrowing that predispose to foreign body impaction or obstruction, including:

    • Oropharynx

    • Cricoid cartilage (due to cricopharyngeus muscle)

    • Upper oesophageal sphincter, a high-pressure area of about 1-3 cm in length at the level of the cricopharyngeus area

    • Aortic arch

    • Anterior crossing of the left main bronchus

    • Left atrium

    • Lower oesophageal sphincter, (located 2-4 cm proximal to the esophagogastric junction at the level of the diaphragm, composed of intrinsic esophageal muscles, sling fibers of proximal stomach, and crural diaphragm)

    • Stomach at the level of the pyloric sphincter

    • Duodenal loop

    • Duodeno-jejunal junction

    • Appendix

    • Ileocecal valve region.

  • Congenital or acquired narrowing at any point within the GI tract that serves as a barrier to the free passage of a foreign body and seems to be more predisposed to impaction.

  • The physical properties of the foreign body (size, shape, and composition) may also play an important role. Large spherical or cylindrical objects may or may not pass through the oesophagus. Once a foreign body has reached the stomach it has a more than 80% chance of passing through the GI tract without further complications. However, objects >6 cm long or that have a diameter >2.5 cm may become entrapped at the pylorus. When a foreign body has reached the small intestine, there are two areas in which objects may become impacted: the C-shape of the duodenum and the level of the ileocaecal valve.

  • Following the ingestion of multiple magnets, there is potential for enteric fistula formation between magnets in adjacent loops of bowel; this is associated with perforation, peritonitis, and bowel ischaemia and/or necrosis.[3][19]

Classification

Categories of patients

Foreign body ingestions are seen in 6 broad categories of patients:

  • Children

  • Those with predisposing factors or underlying GI mechanical problems

  • People with an intellectual disability or psychiatric problems (characterised by repeated ingestion of multiple, large, or unusual objects)

  • Adults with unconventional sexual behaviour

  • Prisoners (secondary gain) or people who engage in criminal activities (people who transport illicit drugs by internal concealment, such as body packers)

  • Patients undergoing instrumentation or surgery.

Objects ingested

The objects ingested differ by group.

  • The most common foreign bodies found in children are coins; other objects include clothing buttons, button batteries, magnets, crayons, and similar items.

  • The most common foreign bodies found in adults are food (pork/chicken meat). Other common foreign bodies include chicken/fish bones, partial dentures, fruit stones, or toothpicks.

  • Prisoners, people who have an intellectual disability, and patients with psychiatric pathologies may present with unusual objects, such as razor blades, pencils, toothbrushes, silverware, batteries, different kinds of wires, screws, and nails.

Site of entrapment

The site of entrapment differs with age groups.

  • Entrapment at the upper oesophageal sphincter is most commonly seen in children (75% of cases).

  • Entrapment at the lower oesophageal sphincter is most commonly seen in adults (70% of cases).

  • Rectocolonic foreign bodies are more prevalent in adults.

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