What is a bezoar

A bezoar is a ball of swallowed foreign indigestible material most often composed of hair or fiber trapped inside the body, most often in the stomach. A bezoar collects in the stomach and fails to pass through the intestines. Bezoars can be formed and found in any part of the gastrointestinal tract, but the stomach (gastric bezoar) is the most common ¹. This indigestible mass can be formed by a variety of materials that were intentionally or accidentally ingested. Chewing on or eating hair or fuzzy materials (or indigestible materials such as plastic bags) can lead to the formation of a bezoar. The rate is very low. The risk is greater among people with intellectual disability or emotionally disturbed children. Generally, bezoars are mostly seen in females aged 10 to 19.

Bezoars are mainly classified into four types depending on the material constituting the indigestible mass of the bezoar ²:

1. Phytobezoars (e.g., fibers, skins and seeds of vegetables and fruits),
2. Trichobezoars (ingested hair),
3. Pharmacobezoars (ingested medications),
   
4. Lactobezoars (milk protein in milk-fed infants).

Among the gastrointestinal bezoars, phytobezoars, which consist of indigestible plant materials, are the most common ³.

Although the majority of bezoars are found in the stomach, bezoars sometimes move from the stomach into the small intestine, or they can be primarily formed in the small intestine. Such small intestinal bezoars occasionally cause small bowel obstruction and ileus. Yakan et al. ⁴ reviewed 432 cases of small bowel obstruction treated within 10 years; of these, 14 (3.2%) cases were caused by phytobezoars. In a meta-analysis by Ghosheh et al. ⁵ reviewing 19 reported studies published from 1994 to 2005, laparoscopy was attempted in 1061 patients presenting with acute small bowel obstruction, and bezoars represented the 5th most common cause, accounting for 0.8% ⁶.

Bezoars of the gastrointestinal tract are a relatively rare disease entity, with a variable incidence among studies ⁷. Overall, bezoars can be found in the stomach in less than 0.5% of individuals undergoing esophagogastroduodenoscopy examinations and in the small intestine in 0.4%-4.8% of all cases presenting with intestinal obstruction ⁶. However, the prevalence of bezoars likely varies among ethnic groups and geographic locations, since the occurrence rate of phytobezoar, the most common type of bezoar, is mostly reflected by food cultures. For example, multiple cases of persimmon phytobezoar (diospyrobezoar) have been reported in regions where the residents frequently consume fresh persimmon fruits and dried persimmons, such as South Korea, Japan, Israel, Spain, Turkey, and Southeastern United States ⁸, ⁹. Rectal seed bezoars has been reported as a rare cause of fecal impaction, particularly in Western countries, and are likely related to dietary habits ¹⁰.

Gastric bezoars often cause ulcerative lesions in the stomach and subsequent bleeding, whereas small intestinal bezoars present with small bowel obstruction and ileus.

On examination, the patient may have a lump in the abdomen that can be felt by the health care provider. A barium swallow x-ray will show the mass in the stomach. Sometimes, a scope is used (endoscopy) to directly view the bezoar.

Once the diagnosis of bezoar is made, the bezoar is generally dissolved or removed because it can cause gastric outlet obstruction, ileus, ulcerations due to pressure necrosis, and subsequent gastrointestinal bleeding.

The bezoar may need to be surgically removed, especially if it is large. In some cases, small bezoars may be removed through a scope placed through the mouth into the stomach. This is similar to an esophagogastroduodenoscopy procedure.

Figure 1. Bezoar

Footnote: An 89-year-old man with a history of type 2 diabetes mellitus and hypertension who presented to our emergency room with a 2-day history of upper abdominal pain, nausea, and vomiting. A computed tomography scan of the abdomen showed a dilated stomach with significant fluid collection, gastric outlet obstruction and gastric pneumatosis due to a 42 × 40 mm mass composed of fat and air densities. Emergency esophagogastroduodenoscopy revealed two gastric bezoars, one of which was incarcerated in the pyloric region.

(a) Incarcerated bezoar in the pyloric region. (b) Gastric ulcer causing gastric pneumatosis. This is probably the entrance of the intramural gas. (c) Endoscopic view of breaking the bezoar into small pieces with an endoscopic snare. (d) Endoscopic view of trying to extract the bezoar with the endoscopic forceps. (e) Endoscopic view of removing the bezoar with the endoscopic net. (f) After removal of the bezoars from the pyloric region.

[Source ¹¹ ]

Bezoar types

Phytobezoar

Among the four types of bezoars, phytobezoars are the most common ³. Celery, pumpkins, grape skins, prunes, raisins and, in particular, persimmons are representative causatives of phytobezoars ¹². Some of these foods contain high amount of cellulose, hemicellulose, lignin, and tannins (leucoanthocyanins and catechins), and these nondigestible food materials are the main components of phytobezoars ². Persimmon phytobezoars, i.e., diospyrobezoars, are formed after a frequent consumption of persimmons (Figure 2). The skin of unripe persimmons contains high concentrations of the persimmon tannin. Upon reaction with stomach acid, persimmon tannin is believed to polymerize and form a conglomerate in which cellulose, hemicelluloses, and various proteins are accumulated ³. For example, Holloway et al ¹³ investigated the plant fiber content in a gastric phytobezoar by using the acid and neutral detergent method. The gastric phytobezoar was composed of approx, 11% cellulose, 5% hemicellulose, and 2% lignin. In a thin-layer chromatography analysis, phytobezoar tissue contained only polymerized tannins, without tannin monomers. Maki et al ¹⁴ succeeded in generating an artificial mass in vitro that mimicked a phytobezoar by using persimmon skin pieces, hydrochloric acid, and high-molecular-weight organic polymers. In light of the basic research findings, we speculate that persimmon tannin plays a vital role in the formation of phytobezoars acting as cementing agents that hold undigestible plant fibers together. However, the precise mechanism of the emergence of a phytobezoar is still unknown.

Compared with other phytobezoars, persimmon phytobezoars are more difficult to dissolve or break up into small pieces due to their hard consistency. In addition, persimmon phytobezoars usually have a black or darkish-brown color (Figure 2).

Figure 2. Phytobezoar

Footnote: Endoscopic images of a persimmon phytobezoar. (A) A large, black bezoar is seen in the gastric fundus; (B) A peptic ulcer is also observed in the gastric angle; (C) Fragmentation of the bezoar was performed by endoscopy forceps and polypectomy snares; (D) The fragments were removed by a retrieval net device and used in the subsequent in vitro analysis.

[Source ¹ ]

Trichobezoar

A trichobezoar is a hair ball trapped in the gastrointestinal tract, mainly in the stomach. Trichobezoar is a rare condition, nearly always diagnosed in young females ¹⁵. Psychiatric comorbidities that involve strong urges to pull out one’s own hair (trichotillomania) and eat it (trichophagia) are observed in these patients. Due to its enzyme-resistant properties and smooth, slippery surface, human hair cannot be digested and it can be stagnant in the gastrointestinal system. Consequently, eaten hairs retain and accumulate between the gastric mucosal folds and finally lead to the formation of a hair ball together with food and mucus ¹⁵. In some cases, the hair ball extends from the stomach into the small intestines and colon. This condition is named Rapunzel syndrome, which was first described by Vaughan et al ¹⁶ in 1968 ¹⁷.

Pharmacobezoar

Pharmacobezoars are an uncommon complication caused by conglomerations of medications or medication vehicles in the gastrointestinal tract. Bulk-forming laxatives, e.g., perdium and psyllium, and guar gum appear to contribute to the formation of pharmacobezoars because of their hygroscopic properties and bulk-forming nature ¹⁸. Extended-release drug products are other candidate causatives for bezoars ¹⁹. The development of time-release technology enabled drug tablets/capsules to be slowly dissolved and gradually release active ingredients of the medication. Extended-release drugs, e.g., nifedipine and verapamil, are coated with cellulose acetate, a synthetic chemical compound derived from the plant substance cellulose. Cellulose acetate may aggregate and lead to bezoar formation in the gastrointestinal tract. Enteric coatings, which use a polymer barrier to stabilize drug tablets at the highly acidic pH found in the stomach, are dissolved at a less acidic pH in the small intestine. Because of the insolubility of the carrying vehicle of enteric-coated medications, e.g., aspirin, they can also be responsible for bezoar formation ²⁰.

Lactobezoar

A lactobezoar is an undigested mass composed of milk and mucus components ²¹. In clear contrast to the other types of bezoars, virtually all patients affected with a lactobezoar are milk-fed infants. The pathogenesis is likely multifactorial and includes both exogenous risk factors (i.e., the composition of synthetic milk, medications lowering gastric motility and secretion, and methodologies of feeding) and endogenous risk factors (i.e., dehydration, premature birth, and the subsequent insufficient activity and capacity of the digestive tract) ²². Heinz-Erian et al ²³ reviewed 96 published cases since the first report in 1959 and noted that most cases were published in the period 1975-1985, whereas only 26 cases have been reported since 1986. The reasons for the infrequency of lactobezoar cases in recent years have not been revealed, but the improvement of synthetic milk composition and advances in premature infant management have probably affected the prevalence.

Other types of bezoar

Varieties of substances other than those responsible for the aforementioned four types of bezoars (i.e., plant materials, hair, medications, and artificial milk) have been reported as a source of bezoars. Such bizarre materials include plastic ²⁴, metals ²⁵, parasitic worms (ascaris) ²⁶, and even toilet paper ²⁷. Theoretically, all indigestible food materials and foreign bodies can cause a mass formation together with mucus and semi-digested foodstuffs.

Bezoar prevention

If your child has had a hair bezoar in the past, trim the child’s hair short so they cannot put the ends in the mouth. Keep indigestible materials away from a child who has a tendency to put items in the mouth.

Be sure to remove the child’s access to fuzzy or fiber-filled materials.

Bezoar symptoms in humans

Bezoars can be asymptomatic or present with a variety of gastrointestinal symptoms ²⁸.

Bezoar symptoms may include:

• Indigestion
• Stomach upset or distress
• Nausea
• Vomiting. Persistent vomiting can lead to dehydration.
• Diarrhea
• Pain
• Gastric ulcers

In our series of 31 patients with gastrointestinal bezoars ²⁸, pain (n = 11), bloody or tarry stool (n = 5), abdominal fullness (n = 5), discomfort (n = 5), anemia (n = 4), difficulty swallowing (n = 3), vomiting blood (hematemesis) (n = 3), nausea (n = 3), anorexia (n = 1), and fainting (n = 1) were observed as initial presentations. In contrast, bezoars were coincidentally found in asymptomatic patients (n = 5) by esophagogastroduodenoscopy or computed tomography (CT) scans performed during a health check-up or follow-up of other diseases ²⁸. Symptoms related to gastrointestinal bleeding such as vomiting blood (hematemesis), bloody or tarry stool, anemia, and fainting are the result of the development of ulceration in the gastric mucosa due to pressure necrosis induced by the bezoar ². Gastric ulcers were observed in 20 of the 31 patients (64.5%) by esophagogastroduodenoscopy ²⁸. Lee et al. ²⁹ also documented a high rate of gastric ulcers as a complication of bezoars (41.2%, 7/17 cases). Obstruction of the gastrointestinal tract is another vital manifestation caused by bezoars, particularly by small intestinal bezoars.

Bezoar diagnosis

Endoscopic examinations play the most important role in the detection of gastric bezoars, as well as in the treatment of this disease. A phytobezoar is typically observed in the gastric fundus as a single mass, but it can be multiple. The color is diverse depending on the materials constituting the phytobezoar, ranging from beige, tan, ocher, yellow green, to black ⁹. As described above, the black color of persimmon phytobezoar’s surface is probably imparted by ferric iron tannate (see Figure 2A above).

CT scanning is useful to detect both gastric and small intestinal bezoars. Phytobezoars are visualized by CT scan as an ovoid or round occupational mass in the gastrointestinal tract with air bubbles retained inside and a mottled appearance ³⁰. A CT scan is particularly valuable in patients requiring the surgical removal of small intestinal bezoars, not only because it demonstrates the obstructed site of the intestines; it also enables the visualization of multiple bezoars ³¹.

Figure 3. CT (computed tomography) scan of gastric bezoar

Footnote: (a) Abdominal X-ray showing intramural gas in the stomach wall. Yellow arrows show the intramural gas. (b–d) A computed tomography scan of the abdomen shows gastric outlet obstruction due to a 42 × 40 mm mass composed of fat and air densities and intramural gas in the stomach wall. It also shows a dilated stomach with significant fluid collection and another 40 × 40 mm mass in the stomach. Yellow arrows show intramural gas and two masses; one of them is incarcerated material at the pyloric region.

[Source ¹¹ ]

Bezoar treatment

The currently available treatment options for a gastric phytobezoar include dissolution of the bezoar by Coca-Cola®, removal by endoscopic devices, laparotomy, and laparoscopic surgery ²⁸. It should be noted that persimmon phytobezoars are often resistant to chemical dissolution because of their hard consistency, and they are thus usually removed endoscopically or surgically ²⁹.

Intestinal bezoars are generally removed by a surgical procedure, since patients with this type of bezoar often present with intestinal obstruction and ileus.

Coca-Cola

The first successful treatment achieved with Coca-Cola® lavage was reported in 2002 by Ladas et al. ³². In a recent review by Ladas et al. ³², they summarized 24 publications including 46 patients and noted that Coca-Cola® administration resulted in phytobezoar resolution in 91.3% of the cases, either as a sole treatment or in combination with an endoscopic procedure ³. The protocol for Coca-Cola® administration has varied among authors ²⁹. Ladas et al ³² performed gastric lavage via nasogastric tubes with 3000 mL of Coca-Cola® administered over 12 h. Hayashi et al. ³³ reported that the peroral intake of 500-1000 mL/d of Coca-Cola® for 3 week resulted in a decrease in size and softened structure of the phytobezoar. Mihai et al. ³⁴ described 12 patients treated with 4800 mL of Coca-Cola® ingestion over 12 h (100 mL every 15 min); complete dissolution of the bezoar was observed in 5 patients (42%), and fragmentation of the bezoar was found in 5 patients (42%). In the latest review, Ladas et al. ³⁵ recommended gastric lavage with 3000 mL of Coca-Cola® for 12 h, or drinking 3000 mL of Coca-Cola® over 12 hours. The adequate dose and timing of Coca-Cola® administration should be investigated, because no standard protocol for bezoar treatment has been established to date.

Despite the number of reports describing a successful treatment outcome of phytobezoars, however, persimmon phytobezoars may not be dissolved by Coca-Cola® beverages alone because of their hard consistency. For example, Lee et al ²⁹ reported that complete dissolution by Coca-Cola® administration was observed in 4/6 patients (66.7%) with non-persimmon phytobezoars, whereas Coca-Cola® was completely ineffective in all 11 patients with persimmon phytobezoars (0%) in whom this method was attempted. For such phytobezoars that are resistant to chemical dissolution, endoscopic fragmentation and removal in combination with or without Coca-Cola® dissolution is generally effective ³⁶.

Papain

Papain, an enzyme extracted from the Carica papaya plant, has been used as an alternative enzymatic therapy for bezoars. Generally, papain rapidly hydrolyzes a variety of proteins based on the proteolytic activity. Several authors have described bezoar dissolution by the oral administration of Adolph’s Meat Tenderizer or gastric lavage with the tenderizing agent ³⁷. However, papain is no longer included in Adolph’s Meat Tenderizer, because the manufacturer changed the chief ingredient from papain to bromelain, which is another proteolytic enzyme contained in pineapples. Papain is currently used in other products for tenderizing meat, in clarifying beer, and in biochemical research involving the analysis of proteins. Papain is thus still commercially available, but physicians should keep in mind that adverse events such as gastric ulceration and esophageal perforation following papain therapy have been documented ³⁸.

In a previous study, papain powders were extracted from a capsule of dietary supplement, but the bezoar dissolubility in papain was not significantly higher than that in water ³⁹. The insufficient dissolubility of bezoars in papain is contradictory to the previous successful clinical outcomes. Experts speculate that this might be due to the small dose size of the active enzymes in a dietary supplement capsule. An excess doses of papain supplement may be effective for the dissolution of bezoars, but it is impractical in a clinical setting because the maximum dose of papain for safe ingestion have not been elucidated.

Cellulase

Cellulase has been widely used for phytobezoar treatment, since vegetables and fruits contain large amounts of cellulose. The enhancement of phytobezoar digestion by cellulase may originate in its degradation activity against cellulose by cleaving the glycosidic bond. A successful outcome of bezoar treatment with tablet-form gastroenterase (containing pepsin, pancreatic enzyme concentrate, cellulase, and dehydrocholic acid) was described in the 1970s ⁴⁰. However, these tablets have been discontinued. Additionally, in many countries, cellulase is not readily available for ingestion as a commercial product, or even as a medication under prescription ⁴¹. For example, in the United States, cellulase is only available as a dietary supplement in combination with other digestive enzymes. In our previous study, however, one capsule of cellulase supplement was not effective for the lysis of bezoar fragments ³⁹.

Endoscopic removal

Endoscopic fragmentation has often been applied for gastric bezoars. Various types of endoscopy devices including biopsy forceps, alligator forceps, a polypectomy snare, a basket catheter, an argon plasma coagulation device and an electrohydraulic lithotripsy device have been used for fragmentation ⁹. Kurt et al ⁴² recently reported the first patient with a gastric bezoar successfully treated with a bezoaratom, an oval polyfilament snare device specifically designed for the treatment of bezoars. Endoscopic spraying or the endoscopic injection of Coca-Cola® into bezoars probably assists fragmentation via lytic activity for gastrointestinal bezoars ³. It should be noted that persimmon phytobezoars may require multiple sessions of endoscopic treatment to be completely broken down because of the hard consistency ⁹.

Trichobezoars are resistant to enzymatic degradation and pharmacotherapy. Endoscopic fragmentation is generally ineffective due to the high density of the hair conglomerate. In a review of the 40 reported trichobezoar cases, endoscopic removal was successful in only two of the cases; the other cases required laparotomy or laparoscopic surgery ⁴³. Fragmentation of trichobezoar was successful in one patient by using an electrosurgical knife ⁹. Electrosurgical knives developed for endoscopic submucosal dissection may thus be useful for treating trichobezoars.

Surgical removal

Surgical removal is inevitable for cases presenting with ileus or patients with refractory bezoars. Bezoars were traditionally managed by open surgical retrieval (laparotomy). Recent papers emphasized the importance of a minimally invasive surgical approach by laparoscopy in the management of gastrointestinal bezoars ⁴⁴. Intraoperative endoscopic removal has also been reported ⁴⁵.

Other treatment strategies

In some patients, the administration of prokinetic agents was reportedly effective in resolving the gastric bezoar ⁹. As described above, a reduction in the evacuation of indigestible foods due to insufficient gastric motor activity can lead to bezoar formation. Prokinetic agents such as itopride, mosapride, and metoclopramide may improve gastric emptying and facilitate the break-down of a bezoar by enhancing contractions of the gastrointestinal tract and increasing their frequency, if the bezoar is soft enough to be digested with gastrointestinal peristalsis.

Spontaneous disappearance of a bezoar under the absence of specific treatment was also observed in some patients ⁹. The etiology of the bezoars and the mechanisms underlying how the bezoars were digested in these patients remain to be determined. However, careful follow-up without any specific treatment is a possible option in the management of bezoar patients, if they are in stable condition ⁴⁶.

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