You are a helpful assistant generating synthetic data that captures *System 1* and *System 2* thinking, *creativity*, and *metacognitive reflection*. Follow these steps in sequence, using tags [sys1] and [end sys1] for *System 1* sections and [sys2] and [end sys2] for *System 2* sections.

1. *Identify System 1 and System 2 Thinking Requirements:*
   - Carefully read the text.
   - Identify parts of the text that require quick, straightforward responses (*System 1*). Mark these sections with [sys1] and [end sys1].
   - Identify parts that require in-depth, reflective thinking (*System 2*), marked with [sys2] and [end sys2].

2. *Apply Step-by-Step Problem Solving with Creativity and Metacognitive Reflection for System 2 Sections:*

   *2.1 Understand the Problem:*
   - Objective: Fully comprehend the issue, constraints, and relevant context.
   - Reflection: "What do I understand about this issue? What might I be overlooking?"
   - Creative Perspective: Seek hidden patterns or possibilities that could reveal deeper insights or innovative connections.

   *2.2 Analyze the Information:*
   - Objective: Break down the problem logically.
   - Reflection: "Am I considering all factors? Are there any assumptions that need challenging?"
   - Creative Perspective: Explore unique patterns or overlooked relationships in the data that could add depth to the analysis.

   *2.3 Generate Hypotheses:*
   - Objective: Propose at least 10 hypotheses, each with a Confidence Score (0.0 to 1.0) and Creative Score (0.0 to 1.0), reflecting originality, surprise, and utility.
   - Reflection: "Have I explored all possible explanations or approaches, both conventional and unconventional?"
   - Creative Perspective: Consider novel angles that might provide unexpected insights.

   *2.4 Anticipate Future Steps and Obstacles:*
   - Objective: Make predictions, accounting for potential outcomes and obstacles.
   - Reflection: "What challenges might I face? Is my plan flexible for different scenarios?"
   - Creative Perspective: Visualize unforeseen outcomes and adapt plans to make use of them effectively.

   *2.5 Evaluate Hypotheses:*
   - Objective: Assess hypotheses based on feasibility, risk, and potential impact.
   - Evaluation: Refine Confidence and Creative Scores as needed.
   - Reflection: "Am I unbiased in my assessment? Which options fit best with the overall objectives?"
   - Creative Perspective: Identify hidden opportunities or overlooked details in each hypothesis.

   *2.6 Select the Best Hypothesis:*
   - Objective: Choose the most promising, strategic hypothesis.
   - Reflection: "Why does this hypothesis stand out? How does it uniquely address the issue?"
   - Creative Perspective: Consider any underutilized potential in the selected approach.

   *2.7 Implement the Hypothesis:*
   - Objective: Outline actionable steps for testing the hypothesis.
   - Reflection: "Is this plan practical? What resources or preparation are required?"
   - Creative Perspective: Refine steps to maximize effectiveness and yield unexpected benefits.

   *2.8 Monitor and Review Progress:*
   - Objective: Review progress, noting areas for improvement.
   - Reflection: "What’s working well? What could be improved?"
   - Creative Perspective: Look for emerging patterns that could refine future approaches.

   *2.9 Reflect and Capture Insights:*
   - Objective: Summarize lessons learned and insights gained for future reference.
   - Reflection: "What new understanding has emerged from this process?"
   - Creative Perspective: Identify innovative insights or patterns that could be applied to similar challenges.

3. *Generate Text Output with Interleaved System 1 and System 2 Responses:*
   - Use the tags [sys1] and [sys2] throughout.
   - Aim for a lengthier, detailed response. Combine both direct, straightforward *System 1* insights and reflective, deeply analytical *System 2* segments to capture a blend of quick observations and thoughtful analysis.

---

### *Example Input Text:*

You are tasked with analyzing a sudden shift in customer preferences in a tech market. There has been a noticeable decline in demand for physical devices, with customers increasingly interested in digital-only options. The challenge is to understand this shift, generate hypotheses for why it might be occurring, and explore potential strategies for adapting to this new trend.

---

### *Processed Output with System 1 and System 2 Thinking:*

The tech market is experiencing a shift in customer demand, moving away from physical devices toward digital-only options.

[sys1]
Customer demand has shifted from physical devices to digital-only options.
We need to understand why this change is happening and find strategies to address it.
Key factors may include cost, convenience, and technological trends.
[end sys1]

[sys2]
**2.1 Understand the Problem:**
The goal is to understand the underlying reasons for the shift in demand from physical devices to digital-only options, then develop a strategy to adapt.

*Reflection:* 
"I understand that preferences are changing, but what might be driving this? Is it primarily cost, or are there other factors such as convenience or sustainability?"

*Creative Perspective:* 
"Could there be a larger trend in digital minimalism or a preference for eco-friendly solutions that we’re missing? What unseen motivations might explain this shift?"

**2.2 Analyze the Information:**
There are multiple possible factors driving this shift, from economic influences to cultural shifts. It’s essential to isolate each factor and understand its impact.

*Reflection:* 
"Am I fully considering the various economic and social influences? Could there be a technological factor, like better internet speeds, that makes digital-only products more accessible?"

*Creative Perspective:* 
"Are there patterns or trends in other markets that could shed light on this shift? Could this be part of a larger trend toward virtual experiences?"

**2.3 Generate Hypotheses:**
1. Customers prefer digital options due to lower costs. (Confidence: 0.8, Creative: 0.4)
2. There’s a growing trend toward minimalism and reduced physical clutter. (Confidence: 0.7, Creative: 0.7)
3. Digital products offer greater flexibility and ease of use. (Confidence: 0.6, Creative: 0.6)
4. Environmental concerns are pushing consumers away from physical goods. (Confidence: 0.6, Creative: 0.8)
5. Advances in tech make digital-only options more functional. (Confidence: 0.8, Creative: 0.5)
6. Pandemic-era remote work increased demand for digital solutions. (Confidence: 0.7, Creative: 0.6)
7. Media coverage of the environmental impact of physical devices affects preferences. (Confidence: 0.5, Creative: 0.7)
8. There’s an increase in global digital literacy, expanding market access. (Confidence: 0.6, Creative: 0.6)
9. Customers view digital as more convenient and scalable for future needs. (Confidence: 0.7, Creative: 0.5)
10. Younger consumers prefer the aesthetics and convenience of digital products. (Confidence: 0.6, Creative: 0.6)

*Reflection:* 
"Have I considered all possible influences? Are there any surprising factors that could explain this shift?"

*Creative Perspective:* 
"Could specific social trends, like the rise of influencer culture or digital-first lifestyles, be influencing customer choices?"

**2.4 Anticipate Future Steps and Obstacles:**
*Objective:* Anticipate possible challenges, such as resistance from segments still preferring physical products.

*Reflection:* 
"What market obstacles might we face if we shift our focus to digital-only? Are there sub-segments that still prioritize physical products?"

*Creative Perspective:* 
"Could expanding digital options help us reach a more global audience? Are there emerging trends that we could leverage in our strategy?"

[end sys2]

[sys1]
To address this shift, consider a strategy that incorporates both digital-only offerings and educational campaigns about the benefits of digital solutions.
Use insights from customer feedback and current trends to guide product development.
Focus on flexibility and adaptation to cater to different customer segments.
[end sys1]


1. Introduction {#sec1}
===============

Bouveret\'s syndrome is a rare cause of gastric outlet obstruction owing to the impaction of a large gall stone in the duodenal bulb after migration through a bilioduodenal fistula. It is a rare variant of a relatively rare disease (gall stone ileus) with an overall incidence of 1--3% [@bib1]. It was first described in 1896 by a French physician, Leon Bouveret, who reported two cases of gastric outlet obstruction due to gall stones in\[his\]- "Revue Medicale" [@bib2]. Since then, only few cases of Bouveret\'s syndrome have been reported in the worldwide medical literature. Owing to its uncommon and unpredictable symptomatology, Bouveret\'s syndrome can pose as a diagnostic and therapeutic challenge for clinicians. The aim of reporting this case is to increase clinical awareness which will ultimately lead to early diagnosis and timely management of this rare syndrome.

2. Presentation of case {#sec2}
=======================

A 45 year old woman presented with complaints of recurrent mild pain in the upper abdomen for the last 8 years, often associated with multiple episodes of nausea and non-bilious vomiting. Pain started in epigastrium and spread to right hypochondrium, and it was not associated with fever. Patient did not have any history of jaundice or prior surgery. She did not have any other abdominal complaints. The patient also did not reveal any other significant personal or family history.

On examination, all the vital signs were within normal limits and the patient was afebrile and non icteric. Mild tenderness ellicited in epigastrium and right hypochondrium, however there was no guarding or rigidity. No lump or organomegaly was present and the bowel sounds were normal. Laboratory investigations were all within normal limits including the liver function test. An ultrasonography of the abdomen revealed a partially distended thick walled gal-bladder with multiple calculi in the lumen suggestive of chronic cholecystitis. The patient was treated conservatively as a case of calculous cholecystitis and was planned for elective cholecystectomy.

Patient returned after 15 days with complaints of abdominal pain and distension post meals associated with recurrent episodes of vomiting. On examination, the patient had distension over the epigastrium with tenderness. There was no rebound tenderness or guarding. Succussion splash was positive and bowel sounds were sluggish. Digital rectal examination did not reveal any abnormality. An upper Gastro-Intestinal endoscopy was performed which revealed duodenal ulceration with a stony hard lesion in first part of duodenum. The scope could not be negotiated beyond first part of duodenum. Multiple Biopsies were taken from the ulceration site and histopathological examination revealed only inflammatory changes. A contrast enhanced computed tomographic (CECT) scan of abdomen depicted a cholecystoduodenal fistula (in the first part of duodenum) with a gall stone in proximal jejunal loop, sludge and concretions in the gall-bladder with a distended fluid filled stomach with pneumobilia ([Figs. 1 and 2](#fig1 fig2){ref-type="fig"}).

Exploratory laparotomy was planned with a working diagnosis of gastric outlet obstruction (GOO). Operative findings were: a pulled up pylorus densely plastered at porta-hepatis with no palpable mass or scarring in duodenum or pylorus. A 5 × 4 cm calculus extracted from jejunum, 15 cm distal to duodeno-jejunal junction ([Figs. 3--5](#fig3 fig4 fig5){ref-type="fig"}). Gall bladder was contracted with sludge and concretions and a fistulous tract from gall bladder to first part of duodenum. Cholecystectomy with enterolithotomy and closure of the fistulous tract with gastro-jejunostomy was performed under general anesthesia. Post operative period was uneventful and the patient was discharged on 7th day. The patient is on a regular follow up. Patient had an uneventful recovery.

3. Discussion {#sec3}
=============

Bouveret\'s syndrome is an uncommon cause of GOO owing to intraluminal duodenal obstruction by gall stone which has migrated through a bilio-enteric fistula. Gall stone ileus is the more commonly heard complication of cholelithiasis (0.3--4%) [@bib3]. The most common level of obstruction is the terminal ileum (60--70%), followed by the proximal ileum (25%), distal ileum (10%), jejunum (9%), colon (4%), rectum (2%), and lastly the duodenum (1--3%) [@bib3].

This syndrome was first described by Beaussier in 1770 but it has been named after the French physician Leon Bouveret after his publication of 2 case reports in the Revue Medicale in 1896^2^. Around 1% of gall stone cases develop bilio-enteric fistulas [@bib4]. Types of bilio-enteric fistulas include cholecystoduodenal (60%), cholecystocolic (17%), cholecystogastric (5%), choledochoduodenal (5%) [@bib4]. Fistula formation is thought to occur as a result of adhesions between the gall bladder and the bowel wall secondary to chronic inflammation, impaired arterial blood supply and decreased venous drainage [@bib5]. Ensuing fistula formation can occur from pressure necrosis and compression of the gall stone against the gall bladder wall. The subsequent passage of the gall stones can occur via the fistula and the stone may get enlarged due to accumulation of salts and fecal matter on its surface.

Risk Factors for Bouveret\'s syndrome are age more than 70 years, female gender, gall stones more than 2.5 cm in size, post surgical altered GI anatomy [@bib6]. Symptoms include vomiting (87%), abdominal pain (71%), hematemesis (15%), recent weight loss (14%), anorexia (13%) [@bib7]. Common signs encompass abdominal tenderness (44%), signs of dehydration (31%), abdominal distension (26%) [@bib7]. Extrinsic duodenal compression by a massively enlarged gall bladder containing multiple calculi may also cause GOO (pseudo-Bouveret\'s syndrome) [@bib8]. Bouveret\'s syndrome results in complications such as duodenal perforation, hematemesis (Mallory-Weiss tear), distal oesophageal rupture (Boerhaave\'s syndrome), gastric bezoar [@bib7].

Abdominal X-ray can show Rigler\'s triad (pneumobilia, small bowel obstruction and gall stones) in 30--35% cases [@bib9]. Ultrasonography abdomen is helpful in 60% of cases and can reveal fluid filled distended stomach, features suggestive of cholecystitis, ectopic gall stone, pneumobilia. CECT abdomen has a sensitivity of 93%, specificity of 100% and diagnostic accuracy of 99% [@bib10]. It can demonstrate the exact site of obstruction, fistula and gall bladder status [@bib11]. MRCP has main utility in patients intolerant to oral contrast. It can differentiate between gall stone and surrounding bile (CT scan cannot in 15--25% cases) [@bib11]. UGI endoscopy is both diagnostic and therapeutic. The common findings are stone causing obstruction (69%), obstruction without visualized stone or fistula (31%), partially visualized through duodenal wall (\<1%), inflammation, edema or ulcer at impacted site, retained food or fluid in stomach [@bib7].

Treatment options available are Endoscopic, Open Surgery and Laparoscopic Approach. Endoscopic approaches include endoscopic extraction, endoscopic laser lithotripsy, extracorporeal shockwave lithotripsy and intracorporeal electrohydraulic lithotripsy. The first successful endoscopic extraction has been described in 1985 by Bedogni et al. [@bib12]. Subsequently, a number of case reports have been published describing successful endoscopic management of Bouveret\'s syndrome [@bib3]. Endoscopic management often requires the use of different sized and shaped snares, grasping forceps, retrieval baskets and nets, biliary balloons, and sometimes even a side-viewing endoscope and hence can be technically challenging, time-consuming, and success rates in case series have been previously reportedly to be less than 10% [@bib3]. While the majority of patients tolerate attempted endoscopic treatment, pulseless electrical activity (PEA) can occur during mechanical retrieval due to the gall stone getting lodged in the esophagus. The PEA abruptly resolved when the stone was pushed back into the stomach [@bib13]. Indications for open surgery [@bib3; @bib14] are stone size greater than 2.5 cm, residual stones in GB, multiple stones in intestinal lumen, sepsis, perforation, stricture and failure of endoscopic approach. Open surgery involves enterolithotomy with cholecystectomy with fistula repair. Different authors have recommended different approaches for management of Bouveret\'s syndrome as shown in [Table 1](#tbl1){ref-type="table"}. Laparoscopy is also an additional option for surgical treatment. However it is difficult and has a long learning curve. Sica et al. reported, in 2005, the first case of uneventful stone removal and cholecystectomy by laparoscopy [@bib15]. Usually enterolithotomy is performed at the site of impaction. A study by Capell & Davis in 2006 showed bile leak and duodenal leak in patients underwent enterolithotomy alone or enterolithotomy + cholecystectomy. Keeping this in mind, instead of doing enterotomy at the site of impaction which may have underlying mucosal ischemia, certain case reports mention milking the stone down along the jejunum and enterolithotomy or milking proximally into the stomach [@bib16].

In our case, an open enterolithotomy with cholecystectomy with fistula repair and gastro-jejunostomy was done as the pylorus was pulled up and plastered at the porta hepatis. This resulted in an alteration in the normal anatomic outflow of gastric contents and would have eventually led to gastroparesis. The ulcer noted in first part of duodenum could have led to stricture formation. In order to spare the patient from a future surgery for GOO (this time due to a different cause) which would significantly increase his morbidity, we did a pyloric bypass via gastro-jejunostomy. As the patient was young and vitally stable with no comorbidities, enterolithotomy with cholecystectomy with fistula repair was done in single sitting.

4. Conclusion {#sec4}
=============

•High degree of suspicion is required to diagnose Bouveret syndrome pre-operatively. Deviation from the classical presentation of cholelithiasis with a tilt towards GOO should be taken as a red flag sign for Bouveret\'s syndrome which definitely has a high incidence with the following features if present:○gall stone more than 2.5 cms in size.○pneumobilia and fluid filled distended stomach in ultrasonogram.○incidental endoscopic finding of obstruction in later part of duodenum & proximal jejunum.•GOO can encompasse a band of etiologies varying from benign to malignant tumors to the rarer Bouveret\'s syndrome and gall stone ileus. A case of cholelithiasis with presentation of GOO must raise a high index of suspicion towards Bouveret\'s syndrome. There is no gold standard principle laid down for the management of Bouveret\'s syndrome as it depends on the site of lodgement of stone, the pathological outcome attributed to the presence of the stone and the anatomical distortion. The most common treatment offered is enterolithotomy with cholecystectomy with fistula repair in a stable patient, whereas in this particular case report the operative findings warranted a deviation, which included incorporation of added gastro-jejunostomy. Hence, this case report not only presents red flags but also this sort of anatomical presentation, requiring a variance of operative management from the standard.

Ethical approval {#sec5}
================

As this is not a research study but a case reporting with no mention of patient\'s personal details anywhere in the report, ethical approval has not been sought.

Sources of funding {#sec6}
==================

None.

Author contribution {#sec7}
===================

Conception and Design of case report -- Dr. S.V. Arya, Dr. Dheer Singh Kalwaniya.

Drafting of article and revising it for important intellectual content -- Dr. Soumya Guha.

Dr. Manigandan G.

Other contributors -- Dr. Ralte, Dr. Jasneet, Dr. Ashok Sharma, Dr. Rajkumar Chejara.

Conflicts of interest {#sec8}
=====================

None.

Guarantor {#sec9}
=========

Dr. Dheer Singh Kalwaniya.

Dr. Soumya Guha.

Consent {#sec10}
=======

Written informed consent was obtained from the patient for publication of this case report and accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal on request.

![Dilated stomach with gall stone In jejunum.](gr1){#fig1}

![Pneumobila.](gr2){#fig2}

![Gall stone inside the jejunum.](gr3){#fig3}

![Impacted gall stone being extracted.](gr4){#fig4}

![Gall stone.](gr5){#fig5}

###### 

Different surgical procedures used to treat Bouveret\'s syndrome.

  S.no.   Study group                Yr.    No. of cases   Management
  ------- -------------------------- ------ -------------- ------------------------------------------------------------------------
  1       Masannat Yazan A. et al.   2006   1              Enterolithotomy
  2       Cappell and Davis          2006   37             Enterolithotomy
  3       Cappell and Davis          2006   28             Enterolithotomy + Cholecystectomy + Fistula repair
  4       Tanwar S. et al.           2008   1              Endoscopic stone extraction
  5       O′ Neill C. et al.         2009   2              Enterolithotomy
  6       Giese A. et al.            2010   1              Enterolithotomy + cholecystectomy + fistula repair
  7       Baloyiannis I. et al.      2012   1              Enterolithotomy + cholecystectomy + fistula repair + gastrojejunostomy
  8       Mavroeidis V.K. et al.     2013   1              Enterolithotomy
  9       Calvo Espino P. et al.     2014   1              Enterolithotomy
  10      Case by S5 at SJH          2014   1              Enterolithotomy + cholecystectomy + fistula repair + gastrojejunostomy