Bezoar Composition
Bezoars are conglomerates of undigested foreign materials that accumulate in the gastrointestinal tract, classified by their composition into phytobezoars (vegetable/fruit fibers), trichobezoars (hair), pharmacobezoars (medications), and other types. 1, 2
Types Based on Composition
The most commonly encountered bezoar types include:
- Phytobezoars: Composed of vegetable or fruit fibers and seeds, representing the most common type of bezoar 3, 4
- Trichobezoars: Composed of hair, typically seen in patients with psychiatric conditions or hair-pulling disorders 1, 5
- Pharmacobezoars: Composed of medication residues that fail to dissolve properly 1, 2
Risk Factors for Formation
Bezoar formation occurs due to impaired gastric grinding mechanisms or disrupted interdigestive migrating motor complex, with specific risk factors including:
- Reduced gastric motility and gastroparesis, which impair normal digestive processes 3, 1
- Loss of pyloric function, preventing normal gastric emptying 3
- Hypoacidity, which reduces the breakdown of ingested materials 3
- Prior gastric surgery (vagotomy, pyloroplasty, gastric bypass, sleeve gastrectomy), which alters normal anatomy and function 3, 6
- Poor mastication habits and high consumption of high-fiber foods, particularly in post-bariatric surgery patients 3
Clinical Context After Bariatric Surgery
Following Roux-en-Y gastric bypass (RYGB), the relatively restricting gastro-jejunostomy and small gastric pouch create additional risk factors for phytobezoar formation 3. The composition in this setting is predominantly vegetable and fruit fibers that cannot pass through the narrowed anatomical structures.
Common Pitfalls
Do not assume all bezoars are gastric in location—while most form in the stomach, they can migrate to the small intestine, colon, or even rectum, causing obstruction at unusual sites 1, 5. The composition remains the same regardless of location, but the treatment approach differs significantly based on anatomical position 3.