Recurrent Pleural Effusion After Acute Pancreatitis: Contemplate the Possibility of Pancreaticopleural Fistula

Abstract

Pancreaticopleural fistula (PPF) is a relatively rare but dreaded complication evolving due to pancreatic pathophysiology, frequently associated with chronic pancreatitis. Its manifestation subsequent to acute pancreatitis is rare and represents an intriguing diagnostic challenge owing to its predisposition to imitate a primary respiratory disease. Here we narrate the case of a 40-year-old male whose condition evolved to a moderate right-sided pleural effusion with mild pleural effusion on the left side in a span of 4 weeks subsequent to an episode of acute-on-chronic pancreatitis with multiple collections and an adjoining fistulous tract. The diagnosis of PPF was confirmed by pleural fluid analysis revealing an amylase level of 1,717 U/L, and contrast-enhanced computed tomography of the abdomen demonstrated an atrophic pancreas with a multi-loculated pancreatic tail and a fistulous tract communicating between collections of the pancreatic body and tail to the right pleural cavity as well as to the left pleural cavity, causing mild to moderate pleural effusion on the right side and minimal effusion on the left side. Following conventional management with intercostal drainage on the right side along with octreotide therapy, culminated in progressive diminishing effusion and consequent fistula closure by the end of 3 months during follow-up visits. This report focuses on the unusual presentation of PPF and highlights the importance of a high index of suspicion in patients with a history of pancreatitis with pleural effusion and promotes an early management approach that yields better outcomes.

Introduction

Pancreaticopleural fistula (PPF) is an infrequent but widely recognised complication of pancreatic disorder, which develops when the pancreatic ductal system and the pleural cavity connect with each other abnormally. This phenomenon occurs as a result of a breach caused by autodigestive lytic pancreatic enzymes, which liquefy their way through the retroperitoneum and go across the diaphragm via the inferior vena cava (IVC) hiatus to access the right pleural space; or the aortic or oesophageal hiatus to invade the left pleural space. ¹ As a result, the pleural fluid becomes exudative, along with strikingly elevated amylase levels, and tends to be recurrent in nature. ² Although PPF is most frequently encountered in the instance of chronic pancreatitis, having an estimated prevalence of 0.4%-4.5% in this group of patients, it is noteworthy when it is identified as an acute complication of chronic pancreatitis manifestation. ³ While digestive tract symptoms may be mild or insignificant, patients typically present with significant respiratory symptoms, such as cough, dyspnoea and pleuritic chest pain. ⁴ Patients may sometimes undergo extensive work-ups for primary pulmonary, infectious or malignant aetiologies until an actual pancreatic culprit can be identified, owing to this misleading presentation, which frequently results in diagnostic delays. ⁵ Therefore, a high level of inquiry is extremely important, particularly for patients who present with a prolonged, recurrent or severe pleural effusion and who possess a recent or previous history of pancreatitis. Pleural fluid analysis that reveals an amylase level exceeding 1,000 U/L—on average, higher than 10,000 U/L is what is needed when making the diagnosis. ⁶ Confirming the diagnosis, as well as delineating the pancreatic ductal architecture, and describing the fistulous tract have all been made achievable by cross-sectional imaging, such as contrast-enhanced computed tomography (CECT), along with cholangiopancreatography using magnetic resonance imaging (MRCP). ⁷ Management strategies have evolved from primarily surgical approaches to a step-up paradigm encompassing conservative measures, endoscopic therapy and surgery for refractory cases. ⁸ In an effort to emphasise the challenges involved in diagnosing pancreatitis-related complications, we present this case of a 40-year-old man who acquired a pancreaticopleural fistula as an aftermath of acute inflammation over chronic pancreatitis and successful management with a conservative strategy with an intercostal drainage (ICD) tube and octreotide.

Case Presentation

A 40-year-old man had a significant medical history of heavy alcohol use dating back 10 years. He first arrived at an outside hospital complaining of nausea, vomiting and acute-onset epigastric abdominal discomfort. CECT of the abdomen showed acute-on-chronic pancreatitis with an atrophied head and body, surrounding peripancreatic fluid, and numerous cystic accumulations in the tail region. Serum lipase was high at 1,717 U/L (normal <60 U/L). The patient received intensive intravenous liquids, bowel rest and analgesics as part of a conservative treatment plan with gradual symptomatic improvement over 7 days and was discharged home.

The patient arrived at our facility 4 weeks after being discharged with right-sided pleuritic chest pain, a non-productive cough and increasing dyspnoea on exertion. The patient denied experiencing chills, fever or stomach pain again. Upon a standard physical exam, the patient had a respiratory rate of 22 breaths per minute, an oxygen saturation of 91% on room air and was afebrile. Reduced breath sounds and dullness with respect to percussion across the right lower hemithorax were detected on auscultation.

The abdomen was distension-free, supple and non-tender. A significant, right-sided pleural effusion that occupied about two-thirds of the hemithorax and was accompanied by a mediastinal shift was seen on a chest radiograph (Figure 1).

Figure 1.

Chest Radiograph Posteroanterior (PA) View Showing Right Side Mild to Moderate Effusion With Left Side Blunting of Costophrenic Angle Indicating Mild Pleural Effusion.

A therapeutic thoracentesis produced 600 mL of a straw-coloured liquid. Analysis of the pleural fluid showed an exudative discharge, with a standard lactate dehydrogenase (LDH) level of 482 U/L, a glucose level of 96 mg/dL and an amylase concentration level of 1,717 U/L. Both bacterial cultures yielded negative results, and cytology showed no signs of cancerous cells. Given the history of pancreatic-related disease and the markedly elevated pleural fluid amylase, the likelihood of a PPF was taken into consideration. A CECT scan of the chest and abdomen revealed pleural effusion on both sides, which was mild to moderate on the right side and mild on the left, along with multiple loculated collections at the pancreatic tail end that connected to the main pancreatic duct and small amounts of peripancreatic fluid surrounding the head and body of the organ. A visible breach and fistulous tract were noted along the posterior aspect of the right crus of the diaphragm as well as along the oesophageal side of the left crus (Figures 2–4).

Figure 2.

Axial View, High-resolution Computed Tomography (HRCT) Thorax Scan Image Showing Abnormal Connection Extending into the Right Pleural Cavity. The Long Green Arrow Indicates the Abnormal Communication Across the Right Crus of the Diaphragm with the Right Pleural Cavity. The Short Green Arrow Shows an Abnormal Breach Across the Right Subdiaphragmatic Space With an Adjacent Sectional Image of the Liver.

Figure 3.

Coronal View, High-resolution Computed Tomography (HRCT) Thorax Scan Image Showing Abnormal Fistulous Connection Extension from Abdominal Cavity into the Right Pleural Cavity With Associated Effusion Across the Right Crus of the Diaphragm. The Green Arrow Shows the Exact Location of the Pancreaticopleural Fistula.

Figure 4.

Right Parasagittal View, Combined Contrast-enhanced Computed Tomography (CECT) of Thorax and Abdominal region. The Green Arrow Shows the Posterior Location of the Fistulous Tract and Moderate Pleural Effusion During Supine Position. Abnormal Fluid Accumulation is Visible in the Right Subdiaphragmatic Location As Well As Moderate Pleural Effusion on the Right Side.

Total parenteral nutrition (TPN), bowel rest and the insertion of an ICD chest tube comprised the initial therapy. Additionally, the patient began receiving 100 µg of octreotide subcutaneously three times a day. Over the course of the following 7 days, pleural fluid amylase remained elevated, and chest tube output remained consistently high, averaging 100-150 mL daily. The magnitude of the effusion in the pleura did not decrease, according to serial imaging. On Day 4, the chest insertion tube was removed. A week later, follow-up chest radiography showed that the pleural effusion had totally cleared, and the patient’s respiratory problems had fully subsided. With a low-fat diet and a schedule for follow-up outpatient appointments, the patient was discharged. The patient did not exhibit any symptoms or another instance of pleural effusion at the 3-month follow-up.

Discussion

The formation of an aberrant link that connects the pancreatic duct with the pleural space leads to PPF, an unusual but medically significant complication associated with pancreatic illness. The alteration of the pancreatic ductal structure, which facilitates the fragmentation of the adjacent structures by the enzyme-rich pancreatic fluid across retroperitoneal planes, is the core pathological process.^1-3

Generally pursuing the direction of minimum resistance, the resulting fluid flows higher up through the diaphragm’s gastro-oesophageal as well as aortic space, eventually extending into the pleural cavity.^{4, 5} Severe necrotising inflammatory activity often triggers this phenomenon in the context of acute pancreatitis, leading to ductal disruption and a form of fistulisation. ⁶

The usual clinical manifestation in most of the cases and divergence from routine presentation is seen in this case, wherein respiratory manifestations are predominant, whereas gastrointestinal symptoms are either minimal or insignificant, which could be explained through this process. ⁴

PPF represents a diagnostic challenge, which has been fairly well documented in the published literature. In individuals suffering from a previous history of pancreatitis who demonstrate a persistent or recurring pleural effusion, a substantial degree of caution is required. Pleural fluid analysis is considered an essential component of diagnosis. A pleural fluid amylase value exceeding 1,000 U/L is essentially diagnostic for PPF, including levels often approaching 10,000 U/L in active fistulas, as put forth in an extensive study performed by Wypych et al. ⁵

In the same way, Ali et al. demonstrated that the pleural fluid amylase concentrations were greater than 5,000 U/L in each individual with diagnosed PPF in their case series. The important insight that shifted the diagnostic evaluation for our subject from a fundamental pulmonary process to a pancreatic origin was the identification of 1,717 U/L of amylase generated from pleural fluid. ⁶

Establishing the diagnosis, detailing the architecture of the pancreatic tract and regulating management are all made feasible utilising cross-sectional imaging. CECT has insufficient sensitivity for directly imaging the fistulous tract, although it is excellent for evaluating the severity of pancreatic necrosis, peripancreatic inflammatory reaction and the possibility of detection of fluid in the pleural space. With declared sensitivity rates ranging from as high as 86% for the detection of the fistulous tract, Galluzzo et al. found that MRCP is the most efficient and non-invasive approach for diagnosing a PPF owing to its better soft tissue contrast properties and ability to visualise fluid-filled structures without utilising ionising radiation. ⁷

In our situation, CECT was helpful in verifying the diagnosis and properly determining the exact position of the pancreatic tail ductal disruption, which significantly influenced the subsequent observation and conservative management that followed. The advancement of PPF management techniques is indicative of a larger trend towards step-up and minimally invasive methods. In the past, surgery was the cornerstone of care. ⁵

Earlier to the widespread adoption of therapeutic endoscopic retrograde cholangiopancreatography (ERCP), surgical fistulectomy and distal pancreatectomy had been associated with favourable outcomes but involved substantial morbidity, particularly a significant rate of complications of post-surgical procedures, as reported by Cazzo et al. in a comprehensive narrative review along with interpretation of case series. Nonetheless, an innovative approach is presently chosen by modern management. Conventional medical management is usually the first approach. ⁸

Efficacy rates of 30%-50% ³ have already been observed for this strategy, which includes gastrointestinal rest, TPN to minimise pancreatic stimulation and administration of somatostatin or its analogue octreotide to suppress pancreatic secretions. Octreotide’s efficacy in facilitating fistula resolution by reducing splanchnic blood circulation and the exocrine pancreatic secretion offers support to its usefulness in this circumstance. The moderate-volume output sustained in our patient for a brief period of a 7-day trial of this regimen, with concomitant chest tube drainage, demonstrating that conservative therapy was effective. When conservative treatments do not succeed, the primary interventional treatment is currently acknowledged to be the use of an endoscopic procedure (ERCP) combined with pancreatic duct stenting. By bridging the ductal disruption location with a stent, ERCP attempts to channelise pancreatic fluid flow away from the fistulous tract and encourage the process of healing. In certain individuals, this method proved to be linked to success rates of 70%-90%.^6-9

With an average period to resolution of 14 days, Koshitani et al. recognised that the most useful indicator of fistula closure was the proper setup of a stent across the leak. The prompt clearance of the pleural effusion after proper conservative management, enabling better drainage and suppressed secretion, helped in our patient’s gradual clinical improvement with these documented results. ¹⁰ Moreover, patients with severe complications such as disconnected pancreatic duct syndrome, in which endoscopic bridging is anatomically impossible due to complete ductal disruption, or those who do not respond to endoscopic therapy, are qualified for surgical treatment, which typically entails fistula tract excision, pancreaticojejunostomy or distal pancreatectomy. ¹¹ A recent systematic review study recommended scheduling an early surgical consultation in these cases, pointing out that delayed surgical intervention longer than 6 weeks of unsuccessful medical treatment and endoscopic intervention could result in higher morbidity associated with ongoing nutritional depletion and sepsis. ¹² Our case complements the limited body of evidence establishing the effectiveness of the conservative medical treatment strategy for PPF that develops in the context of acute necrotising pancreatitis. It emphasises the usefulness of a high index of suspicion and the significance of detecting this condition in individuals with respiratory manifestations and a prior history of pancreatitis, as well as the diagnostic value of pleural fluid containing amylase and MRCP and the effectiveness of a conservative therapeutic approach.

Conclusions

A PPF is a relatively uncommon but potentially devastating complication of acute pancreatitis that should be considered in any patient with a history of pancreatitis and a chronic or recurring pleural effusion. The diagnosis necessitates a high index of suspicion and is verified by cross-sectional imaging, ideally MRCP, and significantly higher pleural fluid amylase levels. Management ought to use a step-by-step approach, starting with conservative medical management, but prompt transfer to ERCP stenting provides a minimally invasive option. For patients with detached duct syndrome or refractory conditions, surgery remains a viable treatment option. This case clearly illustrates the deceptive nature of PPF and the importance of a comprehensive strategy and prompt approach for successful outcomes.