Intragastric Gallstone-Induced Bezoar: An Unusual Cause of Acute Gastric Outlet Obstruction.

ABSTRACT: Bezoars are an uncommon cause of acute gastric outlet obstruction. To our knowledge, this is the first report of a bezoar formed around a gallstone that migrated to the stomach via a cholecystogastric fistula. Our patient was a 42-year-old African American woman with long-standing type 2 diabetes. We suspect that diabetic diathesis was the major factor responsible for producing the pathologic derangement of the gallbladder and stomach, which led to development of the bezoar and serious complications.

Intragastric foreign bodies are an unusual cause of gastric outlet obstruction. Most cases are due to bezoar formation, defined as the accumulation of either organic or nonorganic material into masses or concretions that are not cleared from the stomach. While clinical manifestations of bezoars vary, they are predominantly represented by gastrointestinal symptoms, and most commonly include nausea, vomiting, and abdominal pain. Although uncommon, fatalities have been reported. (1)

We believe ours is the first report of acute gastric outlet obstruction caused by a large gallstone-induced bezoar that migrated to the stomach via a cholecystogastric fistula (CGF).

CASE REPORT

A 42-year-old African American woman, with a history of hypertension and type 2 diabetes complicated by mild peripheral neuropathy, gastroparesis, and postural hypotension, was in her usual state of stable health until, 1 day preceding admission, she had severe nausea, vomiting, and abdominal pain with an abrupt onset. She reported a total of 12 episodes of vomiting that consisted initially of food contents and subsequently of bilious material. The abdominal pain was described as cramp-like, constant, severe, and located in the epigastrium and left upper quadrant. The pain was variably aggravated by movement and cough and unrelieved by ibuprofen and metoclopramide. The patient reported feeling feverish but did not record the temperature. She denied the presence of rigors, chills, diarrhea, dysuria, back pain, cough, or shortness of breath. She offered a history of chronic early satiety, abdominal bloating, and frequent postprandial flatus and eructation. She also complained of a 1-year history of intermittent , self-limited episodes of mild nausea, vomiting, and abdominal pain. The patient had had gastric motility studies several years earlier, which confirmed a diagnosis of gastroparesis.

Acute cholecystitis had been diagnosed 1 year previously At that time, abdominal ultrasonography revealed a thickened gallbladder wall and multiple stones. However, computed tomography (CT) of the abdomen appeared normal. The patient reported complete recuperation after treatment with intravenous antibiotics and fluids. Her regular medications were glimepiride (2 mg/day), metformin (500 mg twice daily), and lisinopril (20 mg/day). The patient admitted to a record of good diabetic control over the previous 2 years.

In the emergency department, the physical examination revealed an obese woman in significant distress due to abdominal pain. Oral temperature was 98[degrees]F, respiratory rate was 18/min, blood pressure was 110/65 mm Hg in the supine position and of 80/45 mm Hg erect, and heart rate was 90/mm in the supine position and 110/min erect. Remarkable findings included moderate abdominal distention, hypoactive bowel sounds, succussion splash, and marked tenderness to deep palpation in the epigastric region and left upper quadrant without guarding or rebound tenderness. Murphy's sign was absent, and a stool sample was negative for occult blood.

On hospital admission, the patient was given intravenous fluid, prochlorperazine, and levofloxacin in addition to her usual medications. A radiographic series revealed focal ileus at the splenic flexure. Abdominal ultrasonography showed a thickened gallbladder wall filled with sludge and non-shadowing calculi. Laboratory data were remarkable for the following values: white blood count 18,000/[mm.sup.3] (normal, 4,800 to 10,800/[mm.sup.3]), with 91% neutrophils (normal, 42% to 75%), 5.7% lymphocytes (normal, 20% to 51%), and 2.8% monocytes (normal, 0% to 10%); alkaline phosphatase 137 U/L (normal, 40 to 120 U/L); amylase 123 U/L (normal, 25 to 115 U/L); and lipase 15 U/dL (normal, 5 to 25 U/dL). By the third day of hospitalization, the patient's nausea and vomiting did not improve, and the abdominal pain changed from cramp-like to a dull ache and became localized to the left upper quadrant. Moderate metabolic alkalosis with hypokalemia was also seen. Abdominal CT with contrast medium revealed a contracted gallbladder containing multiple gallstones, along with a 3-cm intragastric mass (Fig 1).

An esophagogastroduodenoscopy revealed a dark green free-floating bezoar measuring 5 cm in diameter in the gastric antrum and a normal duodenum (Fig 2). Since attempts to break and remove the bezoar were unsuccessful, the patient had a laparotomy, which revealed a chronically scarred gallbladder with massive adhesions over its anterior surface. On the posterior surface of the gallbladder, there was evidence of a CGF that was extirpated along with the gallbladder. The bezoar was removed from the stomach via a gastrotomy and was followed by gastrorrhaphy.

The pathologic examination revealed a chronically inflamed gallbladder. The gastric mass was consistent with a 5.5 x 3.5 cm bezoar. The periphery of the bezoar consisted of hardened, dark-green material with embedded fibers. The center was greenish-yellow in color, similar in appearance and consistency to a cholesterol gallstone (Fig 3). The patient's postoperative course was uneventful and was followed by a full recovery.

DISCUSSION

A review of the English-language literature yielded less than 10 articles on CGF. We were unable to find any reports of bezoar formation with a migrated gallstone as its nidus. The incidence of internal biliary fistulas is 0.5% to 4% in cholecystectomy patients. (2) Chronic cholelithiasis accounts for 95% of internal biliary fistulas and is rarely caused by peptic ulcers or malignant tumors. (2-4) In a Japanese study (5) of 1,135 spontaneous internal biliary fistulas, the incidence of the various types was 46.3% choledochoduodenal, 34.4% cholecystoduodenal, 9.3% cholecystocholedochal, 8.3% cholecystocolonic, and 2.5% CGE In approximately one fourth of internal biliary fistulas, stone migration is preceded by an attack of acute cholecystitis. In the remaining cases, chronic inflammation, gallbladder hypomotility, and bile duct oufflow obstruction are factors that lead to mucosal ulceration. The gallstone then migrates completely through the gallbladder wall, with the subsequent fistula formation. (2)

The incidence of intragastric gallstones is believed to be rare. In most cases, the gallstone enters the duodenum via a cholecystoduodenal fistula followed by retrograde migration to the stomach. (6) Small stones are generally eliminated via the stools asymptomatically or with minimal symptoms. Stones measuring more than 2.5 cm usually produce symptoms. (7,8) The most common manifestation is acute obstruction, either at the bulb of the duodenum, causing an acute pyloric outlet obstruction (Bouveret's syndrome), (2) or at the ileum, causing gallstone ileus. (8) Occasionally, as in our case, the stone is located in the gastric antrum, where intermittent obstruction of the gastric outlet leads to recurrent nausea, vomiting, and abdominal distention. (2)

A putative predisposing factor for our patient's CGF and bezoar formation is diabetes. It is well-reported that diabetics, especially those with type 2, (9) have an increased incidence of gallstones. (10-12) Additional factors, such as impaired gallbladder emptying, (12) cholesterol supersaturation, (13) crystal nucleation-promoting factors, and an enlarged gallbladder fasting volume, (10-13) have been implicated as contributing to pathologic processes in the gallbladder. It is postulated that the direct effect of hyperglycemia on the gallbladder and the wide array of hormonal, metabolic, and neural changes that occur in diabetics may also be responsible for the aforementioned pathologic gallbladder findings. (11) Whether these pathologic changes are produced by autonomic neuropathy is controversial. (10,11,14,15) In a well-known study, Stone et al (16) found that cholecystokinin (CCK)-induced gallbladder contraction was not impaired in diabetic patients without neuropathy, whereas in diabetic patients with a utonomic neuropathy, gallbladder contraction was significantly reduced. Although other studies supported this finding, (13) Fiorucci et al (17) and Shaw et al (12) reported no significant difference in gallbladder volume and CCK-induced contraction between diabetics, including those with autonomic neuropathy, and controls. Neither increased gallbladder volume nor decreased motility was correlated with increased duration of diabetes or level of hemoglobin [A.sub.1c]. (9,18)

The pathologic effect of diabetes on the stomach has been adequately described. The incidence of gastric motor disorders in diabetics ranges from 30% to 58%, with most patients having mild symptoms. (19,20) The effect of hyperglycemia on the stomach starts with impairment of the receptive relaxation phase, leading to early satiety after meals. This is followed by delayed gastric emptying of solid food (found in 27% of diabetics (19) due to loss of phase III of the interdigestive migratory motor complex, which is responsible for sweeping the stomach and the upper small intestine of indigestible solids. This defect leads to increased incidence of bezoar formation. (21,22) In advanced diabetic gastropathy, pylorospasm and antral hypomotility have been seen. (19,23) In contrast to gallbladder disease, diabetic gastroparesis definitely correlates with the presence of autonomic and peripheral neuropathy. Moreover, the effect of uncontrolled hyperglycemia has been associated with a higher incidence of symptoms. (19, 20,22,23)

It is reasonable to suggest that diabetes and neuropathy in our patient made her susceptible to the formation of cholesterol gallstones. We hypothesize that the intrinsic gallbladder hypomotility, coupled with cholesterol gallstones' ability to reduce contractility, (13) produced pressure necrosis on the wall of the unhealthy gallbladder, which led to the formation of the CGF with migration of the stone after the acute episode of cholecystitis. The large dimension of the bezoar argues against its having originated in the gallbladder. Rather, we speculate that a small gallstone migrated via the CGF to the gastric lumen and grew to its final dimension over a protracted period of time. Mitigating against the normal elimination of the stone was the diabetes-induced deficiency of phase III of the interdigestive migratory motor complex responsible for expelling solid indigestible particles. Additionally, we suspect food particles and indigestible fibers accumulated and were compacted around the gallstone by the sam e mechanism of bezoar formation. (20,23) Changes in body position and coughing resulted in the bezoar's movement, which correlated with the patient's symptoms. When the bezoar blocked the gastric outlet, it gave rise to the symptoms of acute obstruction (abdominal cramps, nausea, and intractable vomiting), which resolved when the stone moved away from the pylorus. The patient's long-standing early satiety, bloating, and abdominal distention could be attributed to chronic diabetic gastropathy. (19-23)

CONCLUSION

Cholecystogastric fistula with associated intragastric gallstones and bezoar formation has not been reported, making its diagnosis a challenge to the clinician. Diabetic patients have an increased incidence of gallbladder and stomach disorders that may be aggravated by worsening glycemic control. In these patients, the diagnosis of a bezoar should be considered in cases of intractable nausea and vomiting. Definitive diagnosis can be readily made by esophagogastro-duodenoscopy. Treatment consists of endoscopic or surgical removal. Currently, no studies correlate the incidence of internal biliary fistulas to any specific demographic characteristics or disease entity. Also, the effect of diabetes on the gallbladder and the stomach needs further elucidation.

From the Departments of Medicine and Surgery, Mercy catholic Medical center, Philadelphia, Pa.

Reprint requests to George M. Tadros, MD, Geisinger Medical center, Department of Medicine, 100 N Academy Ave, Danville, PA 17822-1401.

References

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RELATED ARTICLE: KEY POINTS

* Bezoars should be included in the differential diagnosis of intractable unexplained vomiting.

* Long-standing diabetes causes gastroparesis and intestinal motility disorders that may predispose to bezoar formation.

* Definitive diagnosis of a gastric bezoar can readily be made by endoscopy.

* Treatment of a gastric bezoar consists of endoscopic or surgical removal.