IR808@MnO nano-near infrared fluorescent dye's diagnostic value for malignant pleural effusion.

BACKGROUND: Malignant pleural effusion is mostly a complication of advanced malignant tumors. However, the cancer markers such as carbohydrate antigen 125 (CA 125), carbohydrate antigen 15-3 (CA 15-3), carbohydrate antigen 19-9 (CA 19-9), and cytokeratin fragment 21-1 (CYFRA 21-1) have low sensitivity and organ specificity for detecting malignant pleural effusion. RESEARCH QUESTION: Is IR808@MnO nano-near infrared fluorescent dye worthy for the diagnosis in differentiating benign and malignant pleural effusions. STUDY DESIGN AND METHODS: This experiment was carried out to design and characterize the materials for in vitro validation of the new dye in malignant tumor cells in the A549 cell line and in patients with adenocarcinoma pleural effusion. The dye was verified to possess tumor- specific targeting capabilities. Subsequently, a prospective hospital-based observational study was conducted, enrolling 106 patients and excluding 28 patients with unknown diagnoses. All patients underwent histopathological analysis of thoracoscopic biopsies, exfoliative cytological analysis of pleural fluid, and analysis involving the new dye. Statistical analyses were performed using Microsoft Excel, GraphPad Prism, and the R language. RESULTS: The size of IR808@MnO was 136.8 ± 2.9 nm, with peak emission at 808 nm, and it has near-infrared fluorescence properties. Notably, there was a significant difference in fluorescence values between benign and malignant cell lines (p < 0.0001). The malignant cell lines tested comprised CL1-5, A549, MDA-MB-468, U-87MG, MKN-7, and Hela, while benign cell lines were BEAS-2B, HUVEC, HSF, and VE. The most effective duration of action was identified as 30 min at a concentration of 5 µl. This optimal duration of action and concentration were consistent in patients with lung adenocarcinoma accompanied by pleural effusion and 5 µl. Of the 106 patients examined, 28 remained undiagnosed, 39 were diagnosed with malignant pleural effusions, and the remaining 39 with benign pleural effusions. Employing the new IR808@MnO staining method, the sensitivity stood at 74.4%, specificity at 79.5%, a positive predictive value of 69.2%, and a negative predictive value of 82.1%. The area under the ROC curve was recorded as 0.762 (95% CI: 0.652-0.872). The confusion matrix revealed a positive predictive value of 75.7%, a negative predictive value of 75.6%, a false positive rate of 22.5%, and a false negative rate of 26.3%. INTERPRETATION: The IR808@MnO fluorescent probe represents an efficient, sensitive, and user-friendly diagnostic tool for detecting malignant pleural fluid, underscoring its significant potential for clinical adoption.

Lung ultrasound for the sick child: less harm and more information than a radiograph.

In the realm of emergency medicine, the swift adoption of lung ultrasound (LU) has extended from the adult population to encompass pediatric and neonatal intensivists. LU stands out as a bedside, replicable, and cost-effective modality, distinct in its avoidance of ionizing radiations, a departure from conventional chest radiography. Recent years have witnessed a seamless adaptation of experiences gained in the adult setting to the neonatal and pediatric contexts, underscoring the versatility of bedside Point of care ultrasound (POCUS). This adaptability has proven reliable in diagnosing common pathologies and executing therapeutic interventions, including chest drainage, and central and peripheral vascular cannulation. The surge in POCUS utilization among neonatologists and pediatric intensivists is notable, spanning economically advanced Western nations with sophisticated, high-cost intensive care facilities and extending to low-income countries. Within the neonatal and pediatric population, POCUS has become integral for diagnosing and monitoring respiratory infections and chronic and acute lung pathologies. This, in turn, contributes to a reduction in radiation exposure during critical periods of growth, thereby mitigating oncological risks. Collaboration among various national and international societies has led to the formulation of guidelines addressing both the clinical application and regulatory aspects of operator training. Nevertheless, unified guidelines specific to the pediatric and neonatal population remain lacking, in contrast to the well-established protocols for adults. The initial application of POCUS in neonatal and pediatric settings centered on goal-directed echocardiography. Pivotal developments include expert statements in 2011, the UK consensus statement on echocardiography by neonatologists, and European training recommendations. The Australian Clinician Performed Ultrasound (CPU) program has played a crucial role, providing a robust academic curriculum tailored for training neonatologists in cerebral and cardiac assessment. Notably, the European Society for Paediatric and Neonatal Intensive Care (ESPNIC) recently disseminated evidence-based guidelines through an international panel, delineating the use and applications of POCUS in the pediatric setting. These guidelines are pertinent to any professional tending to critically ill children in routine or emergency scenarios. In light of the burgeoning literature, this paper will succinctly elucidate the methodology of performing an LU scan and underscore its primary indications in the neonatal and pediatric patient cohort. The focal points of this review comprise as follows: (1) methodology for conducting a lung ultrasound scan, (2) key ultrasonographic features characterizing a healthy lung, and (3) the functional approach: Lung Ultrasound Score in the child and the neonate.  Conclusion: the aim of this review is to discuss the following key points: 1. How to perform a lung ultrasound scan 2. Main ultrasonographic features of the healthy lung 3. The functional approach: Lung Ultrasound Score in the child and the neonate What is Known: • Lung Ultrasound (LUS) is applied in pediatric and neonatal age for the diagnosis of pneumothorax, consolidation, and pleural effusion. • Recently, LUS has been introduced into clinical practice as a bedside diagnostic method for monitoring surfactant use in NARDS and lung recruitment in PARDS. What is New: • Lung Ultrasound (LUS) has proven to be useful in confirming diagnoses of pneumothorax, consolidation, and pleural effusion. • Furthermore, it has demonstrated effectiveness in monitoring the response to surfactant therapy in neonates, in staging the severity of bronchiolitis, and in PARDS.

An Integrated Clinical and Computerized Tomography-Based Radiomic Feature Model to Separate Benign from Malignant Pleural Effusion.

INTRODUCTION: Distinguishing between malignant pleural effusion (MPE) and benign pleural effusion (BPE) poses a challenge in clinical practice. We aimed to construct and validate a combined model integrating radiomic features and clinical factors using computerized tomography (CT) images to differentiate between MPE and BPE. METHODS: A retrospective inclusion of 315 patients with pleural effusion (PE) was conducted in this study (training cohort: n = 220; test cohort: n = 95). Radiomic features were extracted from CT images, and the dimensionality reduction and selection processes were carried out to obtain the optimal radiomic features. Logistic regression (LR), support vector machine (SVM), and random forest were employed to construct radiomic models. LR analyses were utilized to identify independent clinical risk factors to develop a clinical model. The combined model was created by integrating the optimal radiomic features with the independent clinical predictive factors. The discriminative ability of each model was assessed by receiver operating characteristic curves, calibration curves, and decision curve analysis (DCA). RESULTS: Out of the total 1,834 radiomic features extracted, 15 optimal radiomic features explicitly related to MPE were picked to develop the radiomic model. Among the radiomic models, the SVM model demonstrated the highest predictive performance [area under the curve (AUC), training cohort: 0.876, test cohort: 0.774]. Six clinically independent predictive factors, including age, effusion laterality, procalcitonin, carcinoembryonic antigen, carbohydrate antigen 125 (CA125), and neuron-specific enolase (NSE), were selected for constructing the clinical model. The combined model (AUC: 0.932, 0.870) exhibited superior discriminative performance in the training and test cohorts compared to the clinical model (AUC: 0.850, 0.820) and the radiomic model (AUC: 0.876, 0.774). The calibration curves and DCA further confirmed the practicality of the combined model. CONCLUSION: This study presented the development and validation of a combined model for distinguishing MPE and BPE. The combined model was a powerful tool for assisting in the clinical diagnosis of PE patients.

Deep learning model for pleural effusion detection via active learning and pseudo-labeling: a multisite study.

BACKGROUND: The study aimed to develop and validate a deep learning-based Computer Aided Triage (CADt) algorithm for detecting pleural effusion in chest radiographs using an active learning (AL) framework. This is aimed at addressing the critical need for a clinical grade algorithm that can timely diagnose pleural effusion, which affects approximately 1.5 million people annually in the United States. METHODS: In this multisite study, 10,599 chest radiographs from 2006 to 2018 were retrospectively collected from an institution in Taiwan to train the deep learning algorithm. The AL framework utilized significantly reduced the need for expert annotations. For external validation, the algorithm was tested on a multisite dataset of 600 chest radiographs from 22 clinical sites in the United States and Taiwan, which were annotated by three U.S. board-certified radiologists. RESULTS: The CADt algorithm demonstrated high effectiveness in identifying pleural effusion, achieving a sensitivity of 0.95 (95% CI: [0.92, 0.97]) and a specificity of 0.97 (95% CI: [0.95, 0.99]). The area under the receiver operating characteristic curve (AUC) was 0.97 (95% DeLong's CI: [0.95, 0.99]). Subgroup analyses showed that the algorithm maintained robust performance across various demographics and clinical settings. CONCLUSION: This study presents a novel approach in developing clinical grade CADt solutions for the diagnosis of pleural effusion. The AL-based CADt algorithm not only achieved high accuracy in detecting pleural effusion but also significantly reduced the workload required for clinical experts in annotating medical data. This method enhances the feasibility of employing advanced technological solutions for prompt and accurate diagnosis in medical settings.

Acute kidney injury in hospitalized patients with nonmalignant pleural effusions: a retrospective cohort study.

BACKGROUND: Nonmalignant pleural effusion (NMPE) is common and remains a definite health care problem. Pleural effusion was supposed to be a risk factor for acute kidney injury (AKI). Incidence of AKI in NMPE patients and whether there is correlation between the size of effusions and AKI is unknown. OBJECTIVE: To assess the incidence of AKI in NMPE inpatients and its association with effusion size. STUDY DESIGN AND METHOD: We conducted a retrospective cohort study of inpatients admitted to the Chinese PLA General Hospital with pleural effusion from 2018-2021. All patients with pleural effusions confirmed by chest radiography (CT or X-ray) were included, excluding patients with diagnosis of malignancy, chronic dialysis, end-stage renal disease (ESRD), community-acquired AKI, hospital-acquired AKI before chest radiography, and fewer than two serum creatinine tests during hospitalization. Multivariate logistic regression and LASSO logistic regression models were used to identify risk factors associated with AKI. Subgroup analyses and interaction tests for effusion volume were performed adjusted for the variables selected by LASSO. Causal mediation analysis was used to estimate the mediating effect of heart failure, pneumonia, and eGFR < 60 ml/min/1.73m2 on AKI through effusion volume. RESULTS: NMPE was present in 7.8% of internal medicine inpatients. Of the 3047 patients included, 360 (11.8%) developed AKI during hospitalization. After adjustment by covariates selected by LASSO, moderate and large effusions increased the risk of AKI compared with small effusions (moderate: OR 1.47, 95%CI 1.11-1.94 p = 0.006; large: OR 1.86, 95%CI 1.05-3.20 p = 0.028). No significant modification effect was observed among age, gender, diabetes, bilateral effusions, and eGFR. Volume of effusions mediated 6.8% (p = 0.005), 4.0% (p = 0.046) and 4.6% (p < 0.001) of the effect of heart failure, pneumonia and low eGFR on the development of AKI respectively. CONCLUSION: The incidence of AKI is high among NMPE patients. Moderate and large effusion volume is independently associated with AKI compared to small size. The effusion size acts as a mediator in heart failure, pneumonia, and eGFR.

Dirofilariasis presenting as pleural effusion: a rare case report with unusual manifestations and treatment modalities.

BACKGROUND: We present an extremely rare manifestation of dirofilariasis in the pleural cavity. This is the first human pulmonary dirofilariasis reported in Lithuania; according to our knowledge, only two other patients were documented with this pathology in the world. CASE PRESENTATION: A 72-year-old woman was admitted to the hospital complaining of dyspnea, left-side chest pain, and a dry cough. She was a retiree living alone in the countryside without domestic pets (sometimes stray dogs appear) or a travel history. A complete blood count was within normal limits, with a CRP level of 16.8 mg/l and D-dimer concentration of 900 µg/l, which raised suspicion of pulmonary embolism. In chest computed tomography angiography, pulmonary embolism was excluded, and only left pleural effusion without abnormal lesions was confirmed. Left thoracocentesis was performed, and the pleural fluid was evaluated as an exudate with a predominance of eosinophils (59%), along with the presence of parasites. These parasites exhibited the morphology of Dirofilaria repens. Oral doxycycline (100 mg, twice daily) and albendazole (400 mg, twice daily) were prescribed for a 14-day course. A month later, there were no pathological findings on the chest X-ray, and the patient no longer had respiratory symptoms. However, the patient presented with an emerged, painful palpable right breastmass, where the rash was previously observed. Ultrasound imaging revealed a 1.5 × 2 cm nodule, which was surgically removed. Parasites consistent with Dirofilaria repens were suspected but not definitively identified. Pharmacological treatment for dirofilariasis was not further prescribed. CONCLUSIONS: This case encourages doctors to be more vigilant because the patient, who neither travelled nor kept any pets, contracted dirofilariasis. Diagnostic and treatment guidelines are lacking, necessitating further research. Treatment with doxycycline and albendazole yielded positive outcomes, suggesting potential efficacy for dirofilarial pleuritis.

Ultrasound quantification of pleural effusion volume in supine position: comparison of three model formulae.

BACKGROUND: To investigate the accuracy of three model formulae for ultrasound quantification of pleural effusion (PE) volume in patients in supine position. METHODS: A prospective study including 100 patients with thoracentesis and drainage of PE was conducted. Three model formulae (single section model, two section model and multi-section model) were used to calculate the PE volume. The correlation and consistency analyses between calculated volumes derived from three models and actual PE volume were performed. RESULTS: PE volumes calculated by three models all showed significant linear correlations with actual PE volume in supine position (all p < 0.001). The reliability of multi-section model in predicting PE volume was significantly higher than that of single section model and slightly higher than that of two section model. When compared with actual drainage volume, the intra-class correlation coefficients (ICCs) of single section model, two section model and multi-section model were 0.72, 0.97 and 0.99, respectively. Significant consistency between calculated PE volumes by using two section model and multi-section model existed for full PE volume range (ICC 0.98). CONCLUSION: Based on the convenience and accuracy of ultrasound quantification of PE volume, two section model is recommended for pleural effusion assessment in routine clinic, though different model formulae can be selected according to clinical needs.

PICC tip dislodgement causing massive pleural effusion and atelectasis with acute respiratory failure: a case report.

Peripheral intravenous central catheter (PICC) is a common tool for intravenous infusion for children who need central venous access. Although it is safe for physicians and nurses to place, complications like infection, occlusion, phlebitis, and bleeding can occur. We report a 5-month-old infant who suffered respiratory failure caused by catheter malposition resulting in massive fluid infusion into the thoracic cavity. Point-of-care ultrasound (POCUS) was utilized to identify a massive pleural effusion that prompted urgent drainage. Complications related to PICC in pediatric patients are not common but difficult to immediately identify sometimes. Therefore, careful attention should be paid by physicians to identify and reduce the risk of complications associated with PICC. Thus, visual tools are strongly advised to enhance the safety of invasive procedures.

Bupivacaine pleural effusion mimicking a hemothorax after a thoracoscopic microdiscectomy with epidural anesthesia.

PURPOSE: Post-operative pain after video-assisted thoracoscopic surgery is often treated using thoracic epidural analgesics or thoracic paravertebral analgesics. This article describes a case where a thoracic disc herniation is treated with a thoracoscopic microdiscectomy with post-operative thoracic epidural analgesics. The patient developed a bupivacaine pleural effusion which mimicked a hemothorax on computed tomography (CT). METHODS: The presence of bupivacaine in the pleural effusion was confirmed using a high performance liquid chromatography method. RESULTS: The patient underwent a re-exploration to relieve the pleural effusion. The patient showed a long-term recovery similar to what can be expected from an uncomplicated thoracoscopic microdiscectomy. CONCLUSION: A pleural effusion may occur when thoracic epidural analgesics are used in patents with a corridor between the pleural cavity and epidural space.

Sonography of the pleura. / Sonografie der Pleura.

The CME review presented here is intended to explain the significance of pleural sonography to the interested reader and to provide information on its application. At the beginning of sonography in the 80 s of the 20th centuries, with the possible resolution of the devices at that time, the pleura could only be perceived as a white line. Due to the high impedance differences, the pleura can be delineated particularly well. With the increasing high-resolution devices of more than 10 MHz, even a normal pleura with a thickness of 0.2 mm can be assessed. This article explains the special features of the examination technique with knowledge of the pre-test probability and describes the indications for pleural sonography. Pleural sonography has a high value in emergency and intensive care medicine, preclinical, outpatient and inpatient, in the general practitioner as well as in the specialist practice of pneumologists. The special features in childhood (pediatrics) as well as in geriatrics are presented. The recognition of a pneumothorax even in difficult situations as well as the assessment of pleural effusion are explained. With the high-resolution technology, both the pleura itself and small subpleural consolidations can be assessed and used diagnostically. Both the direct and indirect sonographic signs and accompanying symptoms are described, and the concrete clinical significance of sonography is presented. The significance and criteria of conventional brightness-encoded B-scan, colour Doppler sonography (CDS) with or without spectral analysis of the Doppler signal (SDS) and contrast medium ultrasound (CEUS) are outlined. Elastography and ultrasound-guided interventions are also mentioned. A related further paper deals with the diseases of the lung parenchyma and another paper with the diseases of the thoracic wall, diaphragm and mediastinum.

Breast ultrasound: An opportunity to detect unsuspected pleural and pulmonary abnormalities.

PURPOSE: While scanning women for breast US, is possible to observe changes in the appearance of the pleural line or in the most superficial portion of the lung. The objective of this single-center, prospective study was to determine the prevalence of a variety of pleural and pulmonary US findings during routine breast US. METHODS: In this study, there were 200 women undergoing standard breast US examination. The presence of pleural and pulmonary abnormalities in these cases was recorded. Two off-site reviewers confirmed the presence of pleura and lung changes. RESULTS: There was no abnormal finding in 168 out of 200 cases (84%) while there were one or more abnormal findings in 32 cases (16%). Pleural effusion was observed in 0.5% of cases, thickening of the pleural line 5% of cases, irregularity of the pleural line in 6% of cases, increased number of vertical artifacts in 9% of cases, subpleural nodulations in 2% of cases, and lung consolidation in 0.5%. CONCLUSION: Pleural and lung changes are not uncommon during breast US. Operators performing breast US examinations should be aware of the possibility to identify unsuspected pleuro-pulmonary abnormalities.

A patient with widespread skin lesions presenting with massive pleural effusion.

Mycosis fungoides is the most commonly seen type of cutaneous T-cell lymphoproliferative disease. While mycosis fungoides is linked to an increased risk of developing secondary malignancies, the occurrence of B-cell-originated disease in association with it is exceedingly rare. A 66-year-old male with persistent papillomatous skin eruption was admitted due to dyspnea. Chest X-ray, positron emission tomography, and chest computed tomography revealed axillary and mediastinal lymph node enlargement and right lower pulmonary lobe infiltration along with right-sided massive pleural effusion. Histological and immunohistochemical findings of pleural biopsy and axillary lymph nodes suggested a diagnosis of pulmonary extranodal marginal zone lymphoma. Skin biopsies from the abdomen, chest, and legs revealed CD4/CD8 double-positive patch stage of mycosis fungoides. After completing six cycles of chemotherapy, complete remission of lymphoma was achieved, with the skin eruptions remaining unchanged. Herein, the authors present a unique case of concomitant diagnoses of mycosis fungoides and marginal zone B-cell lymphoma of the respiratory system to emphasize the importance of careful evaluation of each finding.

ACR Appropriateness Criteria® Workup of Pleural Effusion or Pleural Disease.

Pleural effusions are categorized as transudative or exudative, with transudative effusions usually reflecting the sequala of a systemic etiology and exudative effusions usually resulting from a process localized to the pleura. Common causes of transudative pleural effusions include congestive heart failure, cirrhosis, and renal failure, whereas exudative effusions are typically due to infection, malignancy, or autoimmune disorders. This document summarizes appropriateness guidelines for imaging in four common clinical scenarios in patients with known or suspected pleural effusion or pleural disease. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

An 88-Year-Old Woman With Pneumothorax and Black Pleural Effusion.

CASE PRESENTATION: An 88-year-old woman was admitted to our hospital with the sudden onset of dyspnea after eating. The patient had undergone nephrectomy for a left renal tumor 24 years previously. The patient had been prescribed ferrous citrate for iron-deficiency anemia. She complained of appetite loss a few days before admission but had no abdominal pain. CT scan showed no abnormalities in the lungs but a mass in the liver.

Recurrent leishmaniasis infection isolated in the pleural fluid.

We present a rare case of recurrent leishmaniasis infection in a female in her 80s who re-presented with a pleural effusion. The patient was initially investigated as an outpatient for cytopenia and underwent a bone marrow biopsy which subsequently diagnosed visceral leishmaniasis. Following full treatment, and apparent recovery, she re-presented with pleural effusion, hypoalbuminaemia and cytopenia. Leishmania was eventually isolated in a pleural fluid sample obtained on therapeutic drainage, and she was treated for a recurrence at a tertiary infectious disease unit. This interesting and challenging case demonstrates the importance of suspecting leishmaniasis recurrence in previously treated cases and the diagnostic benefit of pleural fluid analysis in the context of suspected leishmaniasis.

A retrospective analysis of transudative pleural effusion due to fibrosing mediastinitis.

BACKGROUND: Pleural effusion caused by fibrosing mediastinitis is rarely reported. This study aimed to summarize the clinical manifestations, diagnosis and treatment of transudative pleural effusion due to fibrosing mediastinitis. METHODS: Medical records and follow-up data of 7 patients with transudative pleural effusion due to fibrosing mediastinitis in Beijing Chaoyang Hospital between May 2014 and Feb 2018 were retrospectively analyzed. RESULTS: These patients included 4 males and 3 females, with an average age of (64 ± 9) years. There were 3 left-sided effusions, 2 right-sided effusions and 2 bilateral effusions. Previous or latent tuberculosis was found in 6 patients. Pulmonary hypertension was indicated by echocardiography in all the 7 patients. Computed tomography pulmonary angiography (CTPA) of all the 7 cases showed increased soft tissue images visible in the mediastinum and bilateral hilus, different degrees of stenosis or occlusion in the pulmonary artery and pulmonary vein. In addition, 4 cases were found of right middle lobe atelectasis with a mediastinal window setting. There was interstitial pulmonary edema on the side of pleural effusion with a lung window setting. All the 7 patients were treated with intermittent drainage of pleural effusion combined with diuretic therapy. Five patients were treated with antituberculosis therapy. Up to now, two patients died of right heart failure and respiratory failure after 2 and 16 months respectively; The remaining 5 patients were still in follow up. CONCLUSION: Fibrosing mediastinitis can lead to pulmonary vein stenosis or occlusion, and thus cause transudative pleural effusion, which can be detected by CTPA. Pulmonary hypertension, long time of cough, and a history of tuberculosis are common in these patients. The common therapy is intermittent drainage of pleural effusion combined with diuretic therapy.

Thoracic endometrial syndrome with unilateral exudative pleural effusion.

A woman in her 40s presented with exertional dyspnoea with an absence of haemoptysis, cough, fever and weight loss. The patient had a medical history of extensive endometriosis. Investigations revealed a large right-sided pleural effusion. The effusion was aspirated and was exudative in nature.A contrast-enhanced CT thorax was performed to help exclude dual pathology. The only positive finding was bilateral breast nodules, subsequently found to be benign fibroadenomas on histological analysis of biopsy samples.After malignancy was ruled out as a cause, the patient was referred for medical thoracoscopy for a biopsy and other investigations. Histology demonstrated the presence of endometrial tissue in the pleura and thereby confirmed the diagnosis of thoracic endometrial syndrome.Video-assisted thoracoscopic surgery repair of diaphragm and talc pleurodesis was carried out in an uncomplicated procedure and the patient was discharged with good recovery.

Acute pancreatitis associated with pleural effusion: MDCT manifestations and anatomical basis.

BACKGROUND: Acute pancreatitis (AP) is a severe condition with complications that can impact multiple organ systems throughout the body. Specifically, the diffusion of peripancreatic effusion to the pleural cavity is a significant phenomenon in AP. However, its pathways and implications for disease severity are not fully understood. OBJECTIVE: This study aims to investigate the anatomical routes of peripancreatic effusion diffusion into the pleural cavity in patients with AP and to analyze the correlation between the severity of pleural effusion (PE) and the computed tomography severity index (CTSI) and acute physiology and chronic health evaluation II (APACHE II) scoring system. METHODS: 119 patients with AP admitted to our institution were enrolled in this study (mean age 50 years, 74 male and 45 female). Abdominal CT was performed, and the CTSI and APACHE II index were used to evaluate the severity of the AP, Meanwhile, the prevalence and semiquantitative of PE were also mentioned. The anatomical pathways of peripancreatic effusion draining to pleural were analyzed. Finally, the correlation relationship between the severity of AP and the PE was analyzed. RESULTS: In 119 patients with AP, 74.8% of patients had PE on CT. The anatomic pathways of peripancreatic effusion draining to pleural included esophageal hiatus in 33.7% of patients, aortic hiatus in 6.7% of patients and inferior vena cava hiatus in 3.37% of patients. The rating of PE on CT was correlated with CTSI scores (r= 0.449, P= 0.000) and was slightly correlated with the APACHE II scores (r= 0.197, P= 0.016). CONCLUSION: PE is a common complication of AP, which can be caused by anatomic pathways such as diaphragmatic hiatus. Due to its correlation with the CTSI score, the PE may be a supplementary indicator in determining the severity of AP.