Chronic pancreatitis complicated by pancreatic pleural fistula leading to black pleural effusion: a case report

Chronic pancreatitis complicated by pancreatic pleural fistula leading to black pleural effusion: a case report | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Case Report Chronic pancreatitis complicated by pancreatic pleural fistula leading to black pleural effusion: a case report Wenwen Yu, Jincong Wang, Xie Zhang, Yunlei Li, Legui Zheng This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7649714/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 01 Apr, 2026 Read the published version in BMC Pulmonary Medicine → Version 1 posted 14 You are reading this latest preprint version Abstract Background Pancreaticopleural fistula, a rare but serious complication of chronic pancreatitis, typically presents with recurrent massive hemorrhagic pleural effusion. Respiratory symptoms dominate the clinical picture, while abdominal signs are often subtle. Case presentation A 43-year-old male was admitted with a 5-day history of chest tightness. Chest CT revealed massive left pleural effusion, and closed thoracic drainage yielded large amounts of black pleural fluid. Routine biochemical, cytological, and microbiological tests of the effusion failed to identify the cause. Given the patient’s history of alcohol abuse and chronic abdominal distension, an abdominal CT was performed, showing atrophy and multiple calcifications in the body and tail of the pancreas. Serum and pleural fluid amylase levels were measured at 354 U/L and >6000 U/L, respectively. Contrast-enhanced upper abdominal CT and MRCP further demonstrated a fistula extending from the pancreas to the left pleural cavity. The patient was diagnosed with chronic pancreatitis, pancreaticopleural fistula, and pancreatic-related pleural effusion. Following multidisciplinary consultation between gastroenterology and gastrointestinal surgery, treatment included continued closed thoracic drainage, parenteral nutrition, intravenous somatostatin, and omeprazole for enzyme and acid suppression. The patient’s condition improved significantly. Conclusions Patients with chronic pancreatitis complicated by pancreaticopleural fistula may present predominantly with respiratory symptoms and lack significant abdominal manifestations, which can lead to missed or delayed diagnosis. A markedly elevated amylase level in pleural fluid serves as a crucial diagnostic clue. Confirmation of pancreaticopleural fistula can be achieved through upper abdominal imaging evaluation. Pancreaticopleural Fistula Pleural Effusion Chronic Pancreatitis Figures Figure 1 Figure 2 Figure 3 Background Pancreaticopleural fistula (PPF) is a rare but serious complication of chronic pancreatitis. It may present with recurrent, massive hemorrhagic pleural effusion, predominantly featuring respiratory symptoms with minimal abdominal manifestations, often leading to missed or misdiagnosis. This article reports a case of chronic pancreatitis complicated by PPF, which initially manifested as chest tightness and resulted in massive black pleural effusion. By reviewing relevant literature, we summarize the etiology, clinical features, diagnosis, and treatment of PPF, aiming to enhance clinicians’ awareness of uncommon causes in the differential diagnosis of pleural effusion and to emphasize the critical role of measuring pleural fluid amylase levels in diagnosing pancreaticopleural fistula. Case presentation A 43-year-old male was admitted due to chest tightness for 5 days, accompanied by dyspnea exacerbated by activity and abdominal distension. He denied abdominal pain, nausea, vomiting, cough, sputum, chest pain, hemoptysis, fever, or night sweats. Chest CT at our hospital revealed massive left pleural effusion, and subsequent closed thoracic drainage yielded dark black bloody fluid.Physical examination on admission: Temperature 36.4°C, respiratory rate 20 bpm, pulse 104 bpm, blood pressure 135/77 mmHg, SpO₂ 99%. The patient was alert and in fair general condition. No jaundice or superficial lymphadenopathy was noted. The right lung had coarse breath sounds without rales; breath sounds were absent on the left side with dullness to percussion. Heart sounds were regular without murmurs. The abdomen was soft and non-tender, with no hepatosplenomegaly, rebound tenderness, or Murphy’s sign. Shift dullness was negative. No lower limb edema.Laboratory findings: Pleural fluid: Black and turbid (Fig. 1 A), Rivalta test positive, specific gravity 1.028, nucleated cells 585×10⁶/L (neutrophils 35%, lymphocytes 23%, macrophages 42%). Biochemistry: Total protein 38.3 g/L, ADA 20.4 U/L, LDH 759 U/L. CEA: 0.58 ng/mL. Bacterial cultures, TB X-pert, and repeated cytopathology were all negative. Blood tests: WBC 4.52×10⁹/L, neutrophils 65.2%, Hb 116 g/L, PLT 297×10⁹/L; CRP 11.2 g/L. PCT, liver/renal function, electrolytes, cardiac enzymes, coagulation, tumor markers, infectious serology, IgG4, BNP, and TB-IGRA were largely normal. Imaging: Chest CT showed massive left pleural effusion with obscured left lung and mediastinal shift to the right (Fig. 1 B). Past history: Alcohol-related liver disease with > 10 years of daily alcohol intake (~ 250 mL liquor), unresolved abdominal distension without prior treatment. Initially diagnosed with pleural effusion of unknown origin, the patient received piperacillin-tazobactam and closed thoracic drainage.Common causes including trauma, parapneumonic effusion, empyema, TB, and malignancy were ruled out. Given his alcohol abuse, an abdominal CT showed atrophy and calcifications in the pancreatic body and tail. Serum and pleural amylase were elevated at 354 U/L and > 6000 U/L, respectively. Contrast-enhanced upper abdominal CT and MRCP confirmed pancreatic atrophy with calcifications (Fig. 2 A, 3 A) and a fistulous tract extending from the pancreatic body through the esophageal hiatus into the left pleural cavity (Fig. 2 B, 3 B). The final diagnosis was chronic pancreatitis with pancreaticopleural fistula and pancreatic pleural effusion, confirmed by gastroenterology and gastrointestinal surgery consultations. As no acute abdomen was present, conservative management was prioritized. The patient was transferred to gastroenterology for parenteral nutrition, somatostatin infusion, omeprazole, and continued drainage. His condition improved with resolution of effusion and decreased amylase.Within one year post-discharge, he was readmitted twice for alcohol-induced acute pancreatitis, managed conservatively. He subsequently abstained from alcohol. Discussion Pancreatic fistula was first defined by Cameron et al. in 1976 as an internal fistula wherein pancreatic exocrine secretions drain into body cavities instead of the duodenum [ 1 ]. Pancreaticopleural fistula (PPF) arises from inflammation or trauma leading to rupture of the main pancreatic duct or its branches into the retroperitoneal space. Pancreatic secretions then track superiorly, often through the aortic or esophageal hiatus, forming a fistula into the pleural cavity, penetrating the mediastinal pleura, and resulting in unilateral or bilateral pleural effusions [ 2 , 3 ]. Fistulae occur in 3–7% of patients with chronic pancreatitis, manifesting as pancreatic pleural or ascitic effusions [ 4 ]. In contrast, pleural effusions associated with acute pancreatitis are typically reactive, self-limiting, occurring in only 3–17% of cases [ 5 ]. In adults, PPF most commonly complicates chronic alcoholic pancreatitis, whereas in children, it is frequently associated with idiopathic pancreatitis or structural anomalies [ 6 ]. Given its rarity, current evidence is largely limited to case reports. Pancreatic pleural effusions are often recurrent, massive, and hemorrhagic. Several reports, including the present case, describe black pleural fluid [ 7 , 8 ]. Koide et al. [ 9 ] and Huang et al. [10] suggest that hemolysis may contribute to the black discoloration. A markedly elevated pleural fluid amylase level is a simple and reliable diagnostic indicator, typically exceeding 1000 U/L. A level greater than 5000 U/L is considered highly specific and may be diagnostic for PPF [ 11 ]. Notably, elevated pleural amylase can also occur in malignancy or esophageal rupture; these were ruled out in this case through clinical history, CT imaging, and cytopathological analysis. While the sensitivity of CT for detecting pancreato-mediastinal fistulas is approximately 50%, MRCP offers a higher sensitivity of up to 80%, making it the preferred non-invasive modality for identifying PPF [ 12 , 13 ]. Patients with suspected PPF should undergo thorough imaging—including abdominal ultrasound, CT, MRCP, and/or ERCP—to identify pancreatic pathology. In our case, both contrast-enhanced upper abdominal CT and MRCP revealed a thick-walled cystic lesion above the pancreas communicating with the left pleural space, confirming the diagnosis of PPF. Initial management is conservative, involving closed thoracic drainage, parenteral nutrition, and intravenous somatostatin analogs to suppress pancreatic secretion. Approximately half of patients respond to this approach [ 14 ]. For refractory cases, endoscopic retrograde cholangiopancreatography (ERCP) with therapeutic interventions—such as sphincterotomy, stone extraction, pancreatic stenting, nasopancreatic drainage, or stricture dilation—is recommended [ 14 ]. Surgery, including cyst resection or pancreaticojejunostomy, is reserved for failures of endoscopic therapy [ 15 ]. Our patient presented initially with chest tightness and massive black bloody pleural effusion, leading to admission under respiratory medicine. Despite a significant alcohol history, he had no typical abdominal symptoms, underscoring the insidious nature of chronic pancreatitis. Unexplained black hemorrhagic effusion prompted measurement of pleural amylase, which was significantly elevated. Subsequent abdominal CT revealed pancreatic atrophy with calcifications, and MRCP demonstrated a fistulous tract extending into the chest, consistent with PPF. The patient responded favorably to conservative medical management. Discussion In the differential diagnosis of hemorrhagic pleural effusion, extra-thoracic causes should be considered alongside pulmonary diseases and trauma. PPF should be suspected in patients with a history of chronic alcohol use or pancreatitis. Pleural fluid amylase measurement is a useful initial test. Abdominal contrast-enhanced CT or MRCP can subsequently confirm the presence of a fistula. First-line treatment is conservative medical management. Refractory cases may require endoscopic or surgical intervention. Declarations Ethics approval and consent to participate Not applicable. Consent for publication Written informed consent for publication of their clinical details and/or clinical images was obtained from the patient. A copy of the consent form is available for review by the Editor of this journal. Competing interests The authors declare no competing interests. Funding This study has not been funded. Author Contribution W.Y contributed to manuscript preparation. The corresponding author, L.Z, conceptualized the presented idea and is responsible for this manuscript. W.Y, J.W, X.Z, Y.L and L.Z were the physicians involved in data collection. W.Y and L.Z supervised the manuscript. All authors read and approved the final version of the manuscript. Acknowledgement W.Y contributed to manuscript preparation. The corresponding author, L.Z, conceptualized the presented idea and is responsible for this manuscript. W.Y, J.W, X.Z, Y.L and L.Z were the physicians involved in data collection. W.Y and L.Z supervised the manuscript. All authors read and approved the final version of the manuscript. Data Availability Data is provided within the manuscript. References Cameron JL, Kieffer RS, Anderson WJ, et al. Internal pancreatic fistulas: pancreatic ascites and pleural effusion. Annals of Surgery, 1976, 184: 587-593. DOI:10.1097/00000658-197611000-00009. Bernal, Martinez, Ortiz, et al. Recurrent Pleural Effusion Secondary to a Pancreatic-Pleural Fistula Treated Endoscopically. The American journal of case reports, 2017, 18:750-753. DOI:10.12659/ajcr.903925. Jamil SB, Abbas SH, Kazim M, et al. A 58-year-old woman with gallstones, chronic pancreatitis, and pancreatic pseudocyst presenting with pleural effusion due to a pancreaticopleural fistula. Am J Case Rep, 2022,23:e934247. DOI: 10.12659/AJCR.934247 . Chebli J, Gaburri P, Aécio Flávio Meirelles de Souza, et al. Internal Pancreatic Fistulas: Proposal of a Management Algorithm Based on a Case Series Analysis.Journal of Clinical Gastroenterology, 2004, 38:795-800. DOI:10.1097/01.mcg.0000139051.74801.43. Sut M, Gray R, Ramachandran M, et al. Pancreaticopleural fistula: a rare complication of ERCP-induced pancreatitis. Ulster Medical Journal, 2009, 78(3):185-186. Ito H, Matsubara N, Sakai T, et al. Two cases of thoracopancreatic fistula in alcoholic pancreatitis: clinical and CT findings. Radiat Med, 2002, 20(4):207-211. DOI:doi:http://dx.doi.org/. Saraya T, Light RW, Takizawa H, et al. Black pleural effusion. Am J Med, 2013,126(7):641.e1-6. DOI:10.1016/j.amjmed.2012.11.017. Miyadera K, Hisakane K, Kato Y, et al. Black pleural effusion caused by a pancreaticopleural fistula associated with autoimmune pancreatitis: A case report. Medicine, 2022, 101(36):4. DOI:10.1097/MD.0000000000030322. Koide T, Saraya T, Nakajima A, et al. A 54-year-old man with an uncommon cause of left pleural effusion. Chest, 2012, 141(2):560-563. DOI:10.1378/chest.11-1493. [10]Huang T Y, Tsai M J. Education and imaging. Gastrointestinal: black pleural effusion induced by pancreaticopleural fistula. J Gastroenterol Hepatol, 2013, 28:1798-1798. DOI:10.1111/jgh.12409. Ali T, Srinivasan N, Le V, et al. Pancreaticopleural fistula. Pancreas, 2009, 38(1):26-31.DOI:10.1097/MPA.0b013e3181870ad5. Roland Materne, Patrick Vranckx, Carl Pauls, et al. Pancreaticopleural fistula: diagnosis with magnetic resonance pancreatography. Chest, 2000, 117(3):912-914. DOI:10.1378/chest.117.3.912. Tirkes T. Advances in MRI of Chronic Pancreatitis. Adv Clin Radiol, 2024,6(1):31-39. DOI: 10.1016/j.yacr.2024.04.002 . Safadi BY, Marks JM. Pancreatic-pleural fistula: the role of ERCP in diagnosis and treatment. Gastrointest Endosc, 2000,51(2):213-215. DOI: 10.1016/s0016-5107(0)70422-6. Pan G, Wan M H, Xie K L, et al. Classification and Management of Pancreatic Pseudocysts. Medicine, 2015, 94(24):e960. DOI:10.1097/MD.0000000000000960. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 01 Apr, 2026 Read the published version in BMC Pulmonary Medicine → Version 1 posted Editorial decision: Revision requested 06 Oct, 2025 Reviews received at journal 05 Oct, 2025 Reviewers agreed at journal 04 Oct, 2025 Reviews received at journal 02 Oct, 2025 Reviewers agreed at journal 02 Oct, 2025 Reviews received at journal 02 Oct, 2025 Reviewers agreed at journal 30 Sep, 2025 Reviewers agreed at journal 30 Sep, 2025 Reviewers agreed at journal 29 Sep, 2025 Reviewers invited by journal 28 Sep, 2025 Editor invited by journal 26 Sep, 2025 Editor assigned by journal 22 Sep, 2025 Submission checks completed at journal 22 Sep, 2025 First submitted to journal 18 Sep, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7649714","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Case Report","associatedPublications":[],"authors":[{"id":525215982,"identity":"30f90a14-3dcd-4bcd-bb97-dfe960845792","order_by":0,"name":"Wenwen Yu","email":"","orcid":"","institution":"Affiliated Yueqing Hospital of Wenzhou Medical University","correspondingAuthor":false,"prefix":"","firstName":"Wenwen","middleName":"","lastName":"Yu","suffix":""},{"id":525215996,"identity":"2cde1eda-8385-4bc3-b25e-d3041235a320","order_by":1,"name":"Jincong Wang","email":"","orcid":"","institution":"Affiliated Yueqing Hospital of Wenzhou Medical University","correspondingAuthor":false,"prefix":"","firstName":"Jincong","middleName":"","lastName":"Wang","suffix":""},{"id":525216000,"identity":"df974c34-6338-4dc2-99c6-dfc8f4ccb80f","order_by":2,"name":"Xie Zhang","email":"","orcid":"","institution":"Affiliated Yueqing Hospital of Wenzhou Medical University","correspondingAuthor":false,"prefix":"","firstName":"Xie","middleName":"","lastName":"Zhang","suffix":""},{"id":525216001,"identity":"c681cef3-3993-4df0-9c8e-27096d205962","order_by":3,"name":"Yunlei Li","email":"","orcid":"","institution":"Affiliated Yueqing Hospital of Wenzhou Medical University","correspondingAuthor":false,"prefix":"","firstName":"Yunlei","middleName":"","lastName":"Li","suffix":""},{"id":525216003,"identity":"a0a27444-675b-4340-baca-3bbab16194f9","order_by":4,"name":"Legui Zheng","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA2UlEQVRIie3OPwrCMBTH8QeFN5VmfS7qEQqCONmrNBScCh7Af50yeQDBKziLY6Rgl7pXcCkFN6EiCG6mdTd1E8wXEjL8PhAAk+lX89VxwJL1ozlBQP8LAjWx3WZLNwv2Wb6becg29zLfDYGtIx0ZBQOeJhbSdUs8DYDOUkfCPnFxQKTjFriwwCVfR8aPithIaVFysWhCQlRkSsiWoB6xnrTSS2/AhXSRsPphYlOmIU4S5KenmHuMxcXtKSZtttKQrgQggFjd76X9ea/qRDWZAzCpHZtMJtOf9gJhEEOyw6CgSAAAAABJRU5ErkJggg==","orcid":"","institution":"Affiliated Yueqing Hospital of Wenzhou Medical University","correspondingAuthor":true,"prefix":"","firstName":"Legui","middleName":"","lastName":"Zheng","suffix":""}],"badges":[],"createdAt":"2025-09-18 12:38:21","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7649714/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7649714/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1186/s12890-026-04123-3","type":"published","date":"2026-04-01T16:00:00+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":93330054,"identity":"5cd66db9-e508-440e-8b84-1ff1b1f517fa","added_by":"auto","created_at":"2025-10-12 11:28:32","extension":"docx","order_by":0,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":204000,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript9.21.docx","url":"https://assets-eu.researchsquare.com/files/rs-7649714/v1/4fb77a5c5fa5306f827dba08.docx"},{"id":93329527,"identity":"024b010e-0cad-4ac3-9a1e-549c5a3b25b2","added_by":"auto","created_at":"2025-10-12 11:12:32","extension":"json","order_by":1,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":7185,"visible":true,"origin":"","legend":"","description":"","filename":"9904eef6d09c4494b777cb173a293e9e.json","url":"https://assets-eu.researchsquare.com/files/rs-7649714/v1/c8715d6554efd7a35b14dc6b.json"},{"id":93329627,"identity":"2cba7da3-3949-40d4-84ad-70c68cd8e222","added_by":"auto","created_at":"2025-10-12 11:20:32","extension":"xml","order_by":2,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":38018,"visible":true,"origin":"","legend":"","description":"","filename":"9904eef6d09c4494b777cb173a293e9e1enriched.xml","url":"https://assets-eu.researchsquare.com/files/rs-7649714/v1/e1fc97fade5729a844a74299.xml"},{"id":93329626,"identity":"e67341ff-4ab9-4fd2-be2a-b9ba4725eb63","added_by":"auto","created_at":"2025-10-12 11:20:32","extension":"jpeg","order_by":3,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":129722,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7649714/v1/cd023d317d09757aa939dfe0.jpeg"},{"id":93329629,"identity":"477638be-e697-4c69-8838-a8c3819ae0e6","added_by":"auto","created_at":"2025-10-12 11:20:32","extension":"jpeg","order_by":4,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":252368,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage2.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7649714/v1/e2e573c7ee42327a55b63f3f.jpeg"},{"id":93330420,"identity":"d3769987-68a6-4c86-9c39-2693200c44b6","added_by":"auto","created_at":"2025-10-12 11:44:32","extension":"jpeg","order_by":5,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":136602,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage3.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7649714/v1/48ede89a39e09ae8fc42f7ef.jpeg"},{"id":93329529,"identity":"29d24476-eac7-4bd4-bb84-b5534a8cfbf0","added_by":"auto","created_at":"2025-10-12 11:12:32","extension":"png","order_by":6,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":53897,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-7649714/v1/1562eb868da859209f72b6ab.png"},{"id":93330055,"identity":"171153fd-e669-4ec6-9c82-2ecfd738566c","added_by":"auto","created_at":"2025-10-12 11:28:32","extension":"png","order_by":7,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":111030,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-7649714/v1/ddaa16c21f4b47a1b8bbd3c7.png"},{"id":93330072,"identity":"c58f457a-dab0-4ca3-8037-05e65c12de8b","added_by":"auto","created_at":"2025-10-12 11:36:32","extension":"png","order_by":8,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":38728,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-7649714/v1/bea65ee2f6ccf7232a736ea1.png"},{"id":93329535,"identity":"b27045c1-eda3-410d-860e-b6d0b9f6bcf4","added_by":"auto","created_at":"2025-10-12 11:12:32","extension":"xml","order_by":9,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":36394,"visible":true,"origin":"","legend":"","description":"","filename":"9904eef6d09c4494b777cb173a293e9e1structuring.xml","url":"https://assets-eu.researchsquare.com/files/rs-7649714/v1/ab169a8a967ed7db7fb919f5.xml"},{"id":93329534,"identity":"cd3f1235-3ab2-472b-8fc4-7ec42c6e5c52","added_by":"auto","created_at":"2025-10-12 11:12:32","extension":"html","order_by":10,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":42683,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-7649714/v1/96dd18b81f0011e1f74b1e7f.html"},{"id":93329522,"identity":"cb074fcb-2552-4fc6-94c0-152c31bef756","added_by":"auto","created_at":"2025-10-12 11:12:32","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":127856,"visible":true,"origin":"","legend":"\u003cp\u003e(A) Black pleural fluid obtained via thoracic drainage from the left pleural cavity. (B) Axial chest CT image demonstrating massive left-sided pleural effusion with obscuration of the left lung and mediastinal shift to the right.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-7649714/v1/dfcfbfddc46eb9172f79b86f.png"},{"id":93329625,"identity":"187ac7c9-7b97-4ce7-85d2-15572e8d3f63","added_by":"auto","created_at":"2025-10-12 11:20:32","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":247193,"visible":true,"origin":"","legend":"\u003cp\u003e(A) Contrast-enhanced axial CT of the upper abdomen showing pancreatic atrophy with multiple clustered dense calcifications in the body and tail. (B) Coronal CT reconstruction demonstrating a tubular fluid-density tract (red arrow) extending upward from the pancreatic body through the esophageal hiatus toward the left pleural cavity.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-7649714/v1/ff75578cda97614ebc688c2d.png"},{"id":93329524,"identity":"2c16815b-388e-400a-87ae-963d92fcb95d","added_by":"auto","created_at":"2025-10-12 11:12:32","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":126851,"visible":true,"origin":"","legend":"\u003cp\u003e(A) Contrast-enhanced MRI with MRCP reveals an irregularly shaped cystic fluid signal in the pancreatic body, accompanied by volume loss and heterogeneous signal intensity in the body and tail. (B) Coronal MRI demonstrates a tubular fluid-signal tract (white arrow) extending superiorly from the pancreatic body through the esophageal hiatus into the left pleural cavity.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-7649714/v1/20f1668b0e81d7ee8ef2c3d5.png"},{"id":106343947,"identity":"d8a7c991-d4d5-4039-a092-2b02bacbdd25","added_by":"auto","created_at":"2026-04-07 16:11:07","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":933825,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7649714/v1/e92c273e-78f6-4202-b877-98b051b97632.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Chronic pancreatitis complicated by pancreatic pleural fistula leading to black pleural effusion: a case report","fulltext":[{"header":"Background","content":"\u003cp\u003ePancreaticopleural fistula (PPF) is a rare but serious complication of chronic pancreatitis. It may present with recurrent, massive hemorrhagic pleural effusion, predominantly featuring respiratory symptoms with minimal abdominal manifestations, often leading to missed or misdiagnosis. This article reports a case of chronic pancreatitis complicated by PPF, which initially manifested as chest tightness and resulted in massive black pleural effusion. By reviewing relevant literature, we summarize the etiology, clinical features, diagnosis, and treatment of PPF, aiming to enhance clinicians\u0026rsquo; awareness of uncommon causes in the differential diagnosis of pleural effusion and to emphasize the critical role of measuring pleural fluid amylase levels in diagnosing pancreaticopleural fistula.\u003c/p\u003e"},{"header":"Case presentation","content":"\u003cp\u003eA 43-year-old male was admitted due to chest tightness for 5 days, accompanied by dyspnea exacerbated by activity and abdominal distension. He denied abdominal pain, nausea, vomiting, cough, sputum, chest pain, hemoptysis, fever, or night sweats. Chest CT at our hospital revealed massive left pleural effusion, and subsequent closed thoracic drainage yielded dark black bloody fluid.Physical examination on admission: Temperature 36.4\u0026deg;C, respiratory rate 20 bpm, pulse 104 bpm, blood pressure 135/77 mmHg, SpO₂ 99%. The patient was alert and in fair general condition. No jaundice or superficial lymphadenopathy was noted. The right lung had coarse breath sounds without rales; breath sounds were absent on the left side with dullness to percussion. Heart sounds were regular without murmurs. The abdomen was soft and non-tender, with no hepatosplenomegaly, rebound tenderness, or Murphy\u0026rsquo;s sign. Shift dullness was negative. No lower limb edema.Laboratory findings: Pleural fluid: Black and turbid (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eA), Rivalta test positive, specific gravity 1.028, nucleated cells 585\u0026times;10⁶/L (neutrophils 35%, lymphocytes 23%, macrophages 42%). Biochemistry: Total protein 38.3 g/L, ADA 20.4 U/L, LDH 759 U/L. CEA: 0.58 ng/mL. Bacterial cultures, TB X-pert, and repeated cytopathology were all negative. Blood tests: WBC 4.52\u0026times;10⁹/L, neutrophils 65.2%, Hb 116 g/L, PLT 297\u0026times;10⁹/L; CRP 11.2 g/L. PCT, liver/renal function, electrolytes, cardiac enzymes, coagulation, tumor markers, infectious serology, IgG4, BNP, and TB-IGRA were largely normal. Imaging: Chest CT showed massive left pleural effusion with obscured left lung and mediastinal shift to the right (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eB). Past history: Alcohol-related liver disease with \u0026gt;\u0026thinsp;10 years of daily alcohol intake (~\u0026thinsp;250 mL liquor), unresolved abdominal distension without prior treatment.\u003c/p\u003e\u003cp\u003eInitially diagnosed with pleural effusion of unknown origin, the patient received piperacillin-tazobactam and closed thoracic drainage.Common causes including trauma, parapneumonic effusion, empyema, TB, and malignancy were ruled out. Given his alcohol abuse, an abdominal CT showed atrophy and calcifications in the pancreatic body and tail. Serum and pleural amylase were elevated at 354 U/L and \u0026gt;\u0026thinsp;6000 U/L, respectively. Contrast-enhanced upper abdominal CT and MRCP confirmed pancreatic atrophy with calcifications (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eA,\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eA) and a fistulous tract extending from the pancreatic body through the esophageal hiatus into the left pleural cavity (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eB, \u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eB).\u003c/p\u003e\u003cp\u003eThe final diagnosis was chronic pancreatitis with pancreaticopleural fistula and pancreatic pleural effusion, confirmed by gastroenterology and gastrointestinal surgery consultations. As no acute abdomen was present, conservative management was prioritized. The patient was transferred to gastroenterology for parenteral nutrition, somatostatin infusion, omeprazole, and continued drainage. His condition improved with resolution of effusion and decreased amylase.Within one year post-discharge, he was readmitted twice for alcohol-induced acute pancreatitis, managed conservatively. He subsequently abstained from alcohol.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003ePancreatic fistula was first defined by Cameron et al. in 1976 as an internal fistula wherein pancreatic exocrine secretions drain into body cavities instead of the duodenum [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Pancreaticopleural fistula (PPF) arises from inflammation or trauma leading to rupture of the main pancreatic duct or its branches into the retroperitoneal space. Pancreatic secretions then track superiorly, often through the aortic or esophageal hiatus, forming a fistula into the pleural cavity, penetrating the mediastinal pleura, and resulting in unilateral or bilateral pleural effusions [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. Fistulae occur in 3\u0026ndash;7% of patients with chronic pancreatitis, manifesting as pancreatic pleural or ascitic effusions [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. In contrast, pleural effusions associated with acute pancreatitis are typically reactive, self-limiting, occurring in only 3\u0026ndash;17% of cases [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. In adults, PPF most commonly complicates chronic alcoholic pancreatitis, whereas in children, it is frequently associated with idiopathic pancreatitis or structural anomalies [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Given its rarity, current evidence is largely limited to case reports.\u003c/p\u003e\u003cp\u003ePancreatic pleural effusions are often recurrent, massive, and hemorrhagic. Several reports, including the present case, describe black pleural fluid [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Koide et al. [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e] and Huang et al. [10] suggest that hemolysis may contribute to the black discoloration. A markedly elevated pleural fluid amylase level is a simple and reliable diagnostic indicator, typically exceeding 1000 U/L. A level greater than 5000 U/L is considered highly specific and may be diagnostic for PPF [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Notably, elevated pleural amylase can also occur in malignancy or esophageal rupture; these were ruled out in this case through clinical history, CT imaging, and cytopathological analysis. While the sensitivity of CT for detecting pancreato-mediastinal fistulas is approximately 50%, MRCP offers a higher sensitivity of up to 80%, making it the preferred non-invasive modality for identifying PPF [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. Patients with suspected PPF should undergo thorough imaging\u0026mdash;including abdominal ultrasound, CT, MRCP, and/or ERCP\u0026mdash;to identify pancreatic pathology. In our case, both contrast-enhanced upper abdominal CT and MRCP revealed a thick-walled cystic lesion above the pancreas communicating with the left pleural space, confirming the diagnosis of PPF.\u003c/p\u003e\u003cp\u003eInitial management is conservative, involving closed thoracic drainage, parenteral nutrition, and intravenous somatostatin analogs to suppress pancreatic secretion. Approximately half of patients respond to this approach [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. For refractory cases, endoscopic retrograde cholangiopancreatography (ERCP) with therapeutic interventions\u0026mdash;such as sphincterotomy, stone extraction, pancreatic stenting, nasopancreatic drainage, or stricture dilation\u0026mdash;is recommended [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. Surgery, including cyst resection or pancreaticojejunostomy, is reserved for failures of endoscopic therapy [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. Our patient presented initially with chest tightness and massive black bloody pleural effusion, leading to admission under respiratory medicine. Despite a significant alcohol history, he had no typical abdominal symptoms, underscoring the insidious nature of chronic pancreatitis. Unexplained black hemorrhagic effusion prompted measurement of pleural amylase, which was significantly elevated. Subsequent abdominal CT revealed pancreatic atrophy with calcifications, and MRCP demonstrated a fistulous tract extending into the chest, consistent with PPF. The patient responded favorably to conservative medical management.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eIn the differential diagnosis of hemorrhagic pleural effusion, extra-thoracic causes should be considered alongside pulmonary diseases and trauma. PPF should be suspected in patients with a history of chronic alcohol use or pancreatitis. Pleural fluid amylase measurement is a useful initial test. Abdominal contrast-enhanced CT or MRCP can subsequently confirm the presence of a fistula. First-line treatment is conservative medical management. Refractory cases may require endoscopic or surgical intervention.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003cp\u003eNot applicable.\u003c/p\u003e\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003cp\u003e Written informed consent for publication of their clinical details and/or clinical images was obtained from the patient. A copy of the consent form is available for review by the Editor of this journal.\u003c/p\u003e\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003cp\u003eThe authors declare no competing interests.\u003c/p\u003e\u003c/p\u003e\u003ch2\u003eFunding\u003c/h2\u003e\u003cp\u003eThis study has not been funded.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eW.Y contributed to manuscript preparation. The corresponding author, L.Z, conceptualized the presented idea and is responsible for this manuscript. W.Y, J.W, X.Z, Y.L and L.Z were the physicians involved in data collection. W.Y and L.Z supervised the manuscript. All authors read and approved the final version of the manuscript.\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e\u003cp\u003eW.Y contributed to manuscript preparation. The corresponding author, L.Z, conceptualized the presented idea and is responsible for this manuscript. W.Y, J.W, X.Z, Y.L and L.Z were the physicians involved in data collection. W.Y and L.Z supervised the manuscript. All authors read and approved the final version of the manuscript.\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003e Data is provided within the manuscript.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eCameron JL, Kieffer RS, Anderson WJ, et al. Internal pancreatic fistulas: pancreatic ascites and pleural effusion. Annals of Surgery, 1976, 184: 587-593. DOI:10.1097/00000658-197611000-00009.\u003c/li\u003e\n\u003cli\u003eBernal, Martinez, Ortiz, et al. Recurrent Pleural Effusion Secondary to a Pancreatic-Pleural Fistula Treated Endoscopically. The American journal of case reports, 2017, 18:750-753. DOI:10.12659/ajcr.903925.\u003c/li\u003e\n\u003cli\u003eJamil SB, Abbas SH, Kazim M, et al. A 58-year-old woman with gallstones, chronic pancreatitis, and pancreatic pseudocyst presenting with pleural effusion due to a pancreaticopleural fistula. Am J Case Rep, 2022,23:e934247. DOI: 10.12659/AJCR.934247 .\u003c/li\u003e\n\u003cli\u003eChebli J, Gaburri P, A\u0026eacute;cio Fl\u0026aacute;vio Meirelles de Souza, et al. Internal Pancreatic Fistulas: Proposal of a Management Algorithm Based on a Case Series Analysis.Journal of Clinical Gastroenterology, 2004, 38:795-800. DOI:10.1097/01.mcg.0000139051.74801.43.\u003c/li\u003e\n\u003cli\u003eSut M, Gray R, Ramachandran M, et al. Pancreaticopleural fistula: a rare complication of ERCP-induced pancreatitis. Ulster Medical Journal, 2009, 78(3):185-186.\u003c/li\u003e\n\u003cli\u003eIto H, Matsubara N, Sakai T, et al. Two cases of thoracopancreatic fistula in alcoholic pancreatitis: clinical and CT findings. Radiat Med, 2002, 20(4):207-211. DOI:doi:http://dx.doi.org/.\u003c/li\u003e\n\u003cli\u003eSaraya T, Light RW, Takizawa H, et al. Black pleural effusion. Am J Med, 2013,126(7):641.e1-6. DOI:10.1016/j.amjmed.2012.11.017.\u003c/li\u003e\n\u003cli\u003eMiyadera K, Hisakane K, Kato Y, et al. Black pleural effusion caused by a pancreaticopleural fistula associated with autoimmune pancreatitis: A case report. Medicine, 2022, 101(36):4. DOI:10.1097/MD.0000000000030322. \u003c/li\u003e\n\u003cli\u003eKoide T, Saraya T, Nakajima A, et al. A 54-year-old man with an uncommon cause of left pleural effusion. Chest, 2012, 141(2):560-563. DOI:10.1378/chest.11-1493. [10]Huang T Y, Tsai M J. Education and imaging. Gastrointestinal: black pleural effusion induced by pancreaticopleural fistula. J Gastroenterol Hepatol, 2013, 28:1798-1798. DOI:10.1111/jgh.12409.\u003c/li\u003e\n\u003cli\u003eAli T, Srinivasan N, Le V, et al. Pancreaticopleural fistula. Pancreas, 2009, 38(1):26-31.DOI:10.1097/MPA.0b013e3181870ad5.\u003c/li\u003e\n\u003cli\u003eRoland Materne, Patrick Vranckx, Carl Pauls, et al. Pancreaticopleural fistula: diagnosis with magnetic resonance pancreatography. Chest, 2000, 117(3):912-914. DOI:10.1378/chest.117.3.912.\u003c/li\u003e\n\u003cli\u003eTirkes T. Advances in MRI of Chronic Pancreatitis. Adv Clin Radiol, 2024,6(1):31-39. DOI: 10.1016/j.yacr.2024.04.002 .\u003c/li\u003e\n\u003cli\u003eSafadi BY, Marks JM. Pancreatic-pleural fistula: the role of ERCP in diagnosis and treatment. Gastrointest Endosc, 2000,51(2):213-215. DOI: 10.1016/s0016-5107(0)70422-6.\u003c/li\u003e\n\u003cli\u003ePan G, Wan M H, Xie K L, et al. Classification and Management of Pancreatic Pseudocysts. Medicine, 2015, 94(24):e960. DOI:10.1097/MD.0000000000000960.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-pulmonary-medicine","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"pulm","sideBox":"Learn more about [BMC Pulmonary Medicine](http://bmcpulmmed.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/pulm/default.aspx","title":"BMC Pulmonary Medicine","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Pancreaticopleural Fistula, Pleural Effusion, Chronic Pancreatitis","lastPublishedDoi":"10.21203/rs.3.rs-7649714/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7649714/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003ePancreaticopleural fistula, a rare but serious complication of chronic pancreatitis, typically presents with recurrent massive hemorrhagic pleural effusion. Respiratory symptoms dominate the clinical picture, while abdominal signs are often subtle.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCase presentation\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA 43-year-old male was admitted with a 5-day history of chest tightness. Chest CT revealed massive left pleural effusion, and closed thoracic drainage yielded large amounts of black pleural fluid. Routine biochemical, cytological, and microbiological tests of the effusion failed to identify the cause. Given the patient’s history of alcohol abuse and chronic abdominal distension, an abdominal CT was performed, showing atrophy and multiple calcifications in the body and tail of the pancreas. Serum and pleural fluid amylase levels were measured at 354 U/L and \u0026gt;6000 U/L, respectively. Contrast-enhanced upper abdominal CT and MRCP further demonstrated a fistula extending from the pancreas to the left pleural cavity. The patient was diagnosed with chronic pancreatitis, pancreaticopleural fistula, and pancreatic-related pleural effusion. Following multidisciplinary consultation between gastroenterology and gastrointestinal surgery, treatment included continued closed thoracic drainage, parenteral nutrition, intravenous somatostatin, and omeprazole for enzyme and acid suppression. The patient’s condition improved significantly.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003ePatients with chronic pancreatitis complicated by pancreaticopleural fistula may present predominantly with respiratory symptoms and lack significant abdominal manifestations, which can lead to missed or delayed diagnosis. A markedly elevated amylase level in pleural fluid serves as a crucial diagnostic clue. Confirmation of pancreaticopleural fistula can be achieved through upper abdominal imaging evaluation.\u003c/p\u003e","manuscriptTitle":"Chronic pancreatitis complicated by pancreatic pleural fistula leading to black pleural effusion: a case report","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-10-12 11:12:27","doi":"10.21203/rs.3.rs-7649714/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-10-06T08:06:05+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-10-05T15:18:48+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"218937180344858078077872158458120196956","date":"2025-10-04T18:02:15+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-10-02T14:41:55+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"292461588227314147577129292680349641248","date":"2025-10-02T11:11:39+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-10-02T07:28:07+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"307256789578572543249162105069063062951","date":"2025-09-30T18:41:48+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"24591153115307638924325204505540398968","date":"2025-09-30T04:08:55+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"111390041289948959032783199560513133387","date":"2025-09-29T11:49:11+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-09-28T18:36:56+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-09-26T08:42:21+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-09-23T03:36:56+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-09-23T03:36:49+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Pulmonary Medicine","date":"2025-09-18T12:29:22+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-pulmonary-medicine","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"pulm","sideBox":"Learn more about [BMC Pulmonary Medicine](http://bmcpulmmed.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/pulm/default.aspx","title":"BMC Pulmonary Medicine","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"0ac1a822-c8a8-46f7-bf05-160f98df3ad0","owner":[],"postedDate":"October 12th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2026-04-07T16:07:05+00:00","versionOfRecord":{"articleIdentity":"rs-7649714","link":"https://doi.org/10.1186/s12890-026-04123-3","journal":{"identity":"bmc-pulmonary-medicine","isVorOnly":false,"title":"BMC Pulmonary Medicine"},"publishedOn":"2026-04-01 16:00:00","publishedOnDateReadable":"April 1st, 2026"},"versionCreatedAt":"2025-10-12 11:12:27","video":"","vorDoi":"10.1186/s12890-026-04123-3","vorDoiUrl":"https://doi.org/10.1186/s12890-026-04123-3","workflowStages":[]},"version":"v1","identity":"rs-7649714","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7649714","identity":"rs-7649714","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}