Swallowing a small piece of plastic is common and often causes immediate anxiety. However, most incidents, especially those involving small, smooth fragments, resolve without medical intervention. The human digestive system is resilient and designed to handle various non-food materials. In most cases, the plastic simply transits the gastrointestinal tract harmlessly, similar to other indigestible matter.
The Immediate Journey Through the Upper GI Tract
The initial phase involves the plastic moving past the throat and into the esophagus, the muscular tube connecting the throat to the stomach. If the piece is small enough to pass the throat without choking, it typically moves quickly down the esophagus via peristalsis. Discomfort in the chest or throat usually indicates the object is briefly lodged, requiring immediate attention if swallowing becomes impossible.
Once in the stomach, the plastic encounters a highly acidic environment (pH 1.5 to 3.5). This hydrochloric acid breaks down organic material but does not dissolve common synthetic plastic polymers. The plastic fragment remains chemically intact while the mechanical churning of the stomach prepares the contents for the next stage.
Passage and Elimination
After the stomach, the plastic moves into the small intestine, the longest section of the digestive tract. Movement through the small and large intestines is driven by peristalsis, muscular contractions that push contents forward. A small, blunt object is generally swept along with the rest of the intestinal contents.
The majority of ingested foreign bodies, estimated at 80% to 90%, pass through the entire gastrointestinal tract without complications. Elimination typically occurs between 24 and 72 hours, though it can occasionally take up to a week. Monitoring the stool for the plastic’s passage is the primary approach, and consuming sufficient fiber helps bulk the stool and facilitate movement.
Characteristics That Cause Complications
While most small, smooth plastic pieces pass safely, complications arise from problematic characteristics like size and shape. Size is a factor because large objects may be unable to pass through narrow points, such as the pylorus (the opening from the stomach to the small intestine). For adults, objects larger than 2.5 centimeters in diameter are less likely to pass the pylorus.
The shape of the plastic also determines risk. Sharp-edged or pointed fragments, such as pieces of a broken toy, pose a threat to the intestinal wall. These sharp objects can cause perforation, a puncture allowing contents to leak into the abdominal cavity. A long or rigid shape, even if not sharp, increases the risk of impaction or obstruction, where the object gets stuck and blocks passage.
When to Seek Emergency Medical Care
A swallowed foreign body becomes a medical emergency when severe symptoms appear. Immediate evaluation is required for:
- Persistent vomiting, especially if the patient cannot keep down liquids, signaling a potential obstruction.
- Severe, worsening abdominal pain or tenderness, indicating irritation or perforation.
- High fever, suggesting a potential infection.
- Gastrointestinal bleeding, such as blood in the stool or vomit.
- Inability to pass gas or stool for a prolonged period, suggesting a dangerous blockage.
Objects containing batteries (particularly button or disc batteries) or multiple magnets are immediate emergencies regardless of symptoms, due to the high risk of severe corrosive injury or tissue necrosis.