Unexpected Chylous Ascites During Umbilical Hernia Repair in a Patient with Necrotizing Pancreatitis: A Case Report

Introduction

Chylous ascites is the presence of thoracic or intestinal lymph in the abdominal cavity [1]. Various theories as to the mechanism by which this occurs have been proposed over time. One theory suggests damage can occur to the surrounding lymphatic channels, causing disruption and effusion of lymph into the abdominal cavity [1]. This is often seen after operations or trauma to the thoracic cavity or abdominal aorta [2–5]. Another theory states that portal hypertension, commonly seen in cirrhosis patients, can cause spontaneous rupture of lymph tracts due to excessive flow from portal venous shunting [4–6]. Inflammatory and infectious etiologies have been reported in cases of sarcoidosis, Mycobacterium species infection, and filariasis [1,7–9]. Various malignancies have been linked to chylous ascites, such as non-Hodgkin B-cell lymphoma, carcinoid tumors, and Kaposi’s sarcoma, and 50% of cases are caused by lymphomas [7,10]. In cases of malignancy, tumors can invade lymphatic drainage or precipitate fibrosis of the primary lymph node, where both mechanisms can lead to obstructed flow and spillage of the ascitic fluid [7,10]. Congenital anomalies can cause chylous ascites, seen in cases of primary lymphatic hypoplasia associated with Turner syndrome and Klippel-Trenaunay syndrome [7,10]. However, chylous ascites due to chronic pancreatitis is rare. This report presents the case of a 65-year-old man with a history of necrotizing pancreatitis and an incidental finding of chylous ascites during elective umbilical hernia repair, along with a review of the literature on chylous ascites in patients with chronic pancreatitis.

Case Report

A 65-year-old man presented to the operating room for scheduled hernia repair. He had no concerns at the time of the procedure. His medical history included hypertension and insulin-dependent diabetes mellitus. He had a history of cholelithiasis, acute recurrent necrotizing pancreatitis, and an umbilical hernia, but had no history of alcohol or tobacco use.

Two years prior to admission for hernia repair, the patient presented due to recurrent episodes of gallstone pancreatitis. A CT scan showed acute necrotizing pancreatitis with cholelithiasis. A pseudocyst in the tail of the pancreas was discovered. Soon thereafter, he had a cholecystectomy. Weeks later, endoscopic ultrasound showed progression of pancreatitis with the development of diffuse fluid in the abdomen. A cystogastrostomy stent was placed to drain the pancreatic pseudocyst.

At 18 months prior to admission, a CT scan of the abdomen showed increased free fluid in the upper abdomen, with 3.5 cm of fluid collection in the tail of the pancreas. The pancreas showed necrosis with a moderate amount of pericardial fluid.

An abdominal CT scan 13 months prior to admission showed diffuse ascites, enlarging of the pancreatic pseudocyst, dilated small bowel from adynamic ileus attributed to pancreatic inflammation, and a small midline abdominal hernia with possible ascitic fluid. Inflammatory changes in the mesentery were noted, and the liver exhibited mild fatty liver changes. Complete blood count showed a low hematocrit and low lymphocytes. A complete metabolic panel showed low total protein and low albumin, but normal liver enzymes, triglycerides, and cholesterol levels.

For a short time, the patient’s medical course was relatively stable. Then, 3 months prior to admission, an abdominal CT scan demonstrated a new mass in the head of the pancreas (Figures 1, 2). Portal vein compression by an enlarged head and body of the pancreas led to high-grade stenosis of the proximal splenic vein. The main pancreatic duct and common bile duct were both dilated. The middle lobe of the liver contained a new, ill-defined heterogenous area of hypoattenuation, and numerous varices were noted in the esophagus and stomach, indicating portal congestion. Multiple mesenteric lymph nodes were enlarged with inflammatory changes. Fine-needle aspiration of the pancreatic head mass was sent to pathology and was reported as benign. At the time, the patient requested surgical intervention for hernia repair.

On admission, pre-operative examination results were normal. Upon insertion of the laparoscope, ascitic fluid was encountered (Figure 3). The fluid had a viscous, milky-white color, appearing diffusely in the abdomen. The patient had 2 hernias and both hernia sacs tracked up into the pocket walled off by chylous fluid at the anterior abdominal wall. Intraoperatively, both hernia sacs began enlarging and filling with ascitic fluid (Figure 4). The surgeon worked into the hernia defects to open the chyle collection and debrided the cavity (Figures 5, 6). Of note, the liver appeared normal on gross examination. The ascitic fluid was drained intraoperatively and sent for cytology. The hernia was repaired, and the patient had no concerns. Postoperative laboratory test results showed elevated alkaline phosphatase but normal liver enzymes. Pathology diagnosed chylous ascites of unclear etiology: amylase 15 U/L, total protein 1.5 mg/dL, albumin 0.6 mg/dL, triglycerides 700 mg/dL, acid-fast bacilli negative, and a serum ascites-albumin gradient (SAAG) of 0.9 g/dL. The fluid was leukocyte-predominant with an undifferentiated cell count, and no epithelial cells or organisms were seen. A postoperative CT scan showed unchanged appearance of the pancreatic head mass with ductal dilation (Figure 7). High-grade stenosis of the portal confluence was still present. The patient was in good condition and was discharged the following day.

Discussion

We report a multifactorial case of chylous ascites due to recurrent acute necrotizing pancreatitis and portal hypertension. We theorize long-standing chronic inflammation of the pancreas, along with pancreatic compression of the portal vein, led to spillage of chyle into the peritoneum, promoting chylous ascites. The present case demonstrates how ascites can develop from multiple pathologies occurring simultaneously. It is critical to consider the possibility of more than 1 cause when dealing with a rare manifestation of a disease. A literature review was necessary to understand the pathophysiology occurring in our patient and demonstrates how rarely chylous ascites occurs in chronic pancreatitis. Additional research into the disease process is warranted.

Chylous ascites is the collection of chyle in the abdominal cavity, commonly seen in cases of abdominal trauma and liver cirrhosis. The diagnosis of chylous ascites is made via diagnostic paracentesis. Rudy et al define chylous ascites as a fluid with opaque, thick consistency, a triglyceride level of >200 mg/dL, a SAAG of <1.1 g/dL, and total protein between 2.5 to 7.0 g/dL [5]. The ascitic fluid in our patient had almost triple the triglycerides needed to meet the diagnostic criteria and a low SAAG, characteristic of chylous ascites. However, the ascitic fluid had a lower protein content than expected. Low protein content is often found in ascitic fluid from portal hypertension. We determined that the presence of recurrent episodes of necrotizing pancreatitis, along with a long history of portal hypertension, led to chylous ascites.

The pathophysiology of chylous ascites is not fully understood but can be divided into portal-based and non-portal-based [10]. Portal-based chylous ascites can occur due to elevated pressures within the portal venous system [10]. The dilation of lymph vessels occurs as a result of cirrhosis, causing increased lymph fluid production due to hepatic venous congestion [5]. Increased splanchnic flow causes an increase in hydrostatic pressure and effusion out of the lymphatic channels, leading to rupture of the serosal lymphatic channels [6]. Also, elevated pressures in the splenic vein can increase intestinal lymphatic drainage pressures, causing leakage of lymph into the abdominal cavity [2,7,8].

Non-portal-based chylous ascites can occur due to inflammation of organs in the abdomen. Pancreatitis accounts for approximately 4% of all nontraumatic chylous ascites [11]. A literature review and case report in the American Journal of Gastroenterology from 1984 by Goldfarb et al proposed the concept of pancreatitis causing compression of lymphatic channels and direct damage by pancreatic enzymes [12]. Over time, additional reports continued to propose the same theories [1,11,13,14]. Other than pancreatitis, radiation therapy is a well-reported inflammatory cause of chylous ascites. Aalami et al performed a literature review of 207 patients with gynecologic malignancies, reporting that treatment with radiation therapy led to development of chylous ascites in 3% of patients [7]. They found that radiation to the abdomen caused fibrosis of the lymphatic vessels to occur, leading to obstruction and extravasation of chylous fluid [7]. A lesser-known cause of non-portal-based chylous ascites is the nematode Wucheria bancrofti, which causes filariasis. Filariasis leads to a chronic lymphedematous state, where pressure in the extremities builds up and promotes rupture of the lymphatic tracts, similar to the mechanism in portal hypertension [7]. To date, a systematic review of chronic pancreatitis and chylous ascites has not been conducted, leaving a gap in knowledge.

After an extensive literature search, we found a small number of cases with chylous ascites in the setting of chronic pancreatitis. In 1953, a case report of a child with pancreatitis and chylous ascites secondary to a pseudocyst was reported [12]. This is believed to be the first mention of chylous ascites and chronic pancreatitis in the same report. Soon thereafter, the first 2 reported case of chylous ascites due to chronic pancreatitis occurred in 1960 [12]. A 54-year-old man with alcoholism had chronic relapsing pancreatitis, in whom chylous ascites appeared 8 weeks after a severe attack of pancreatitis [12,15]. The other case report was of a 76-year-old woman with chronic pancreatitis, chylous ascites, and chylothorax [12,16]. Both cases were mentioned in a review of pancreatitis and chylous effusions by Goldfarb et al, who determined that pancreatitis is very rare cause of chylous effusion. In 1979, chylous ascites was discovered as a complication of a distal splenorenal shunt in a patient with chronic pancreatitis [17]. Another report of chylous ascites came from a study published in 1994, where laparoscopy was studied in the diagnostic evaluation of ascites of unknown origin. Out of all of the patients in the study, only 1 patient had chylous ascites in the presence of chronic pancreatitis [18]. In the study, malignancy was the leading cause of ascites, followed by tuberculosis and cirrhosis, while pancreatitis was the least common cause [18]. These examples were among the few earlier cases where chylous ascites was seen in the presence of chronic pancreatitis. Khan et al reported the case of a patient with acute pancreatitis due to hypertriglyceridemia who presented with a normal serum amylase and lipase. Of note, our patient had a low to normal amylase level. Khan et al stated that the association of normal amylase and lipase levels with acute pancreatitis manifesting as chylous ascites is extremely rare [19]. The paper is similar to our report, as both present patients with underlying diagnoses exhibiting the presence of chylous ascites. Khan et al stated that abdominal CT can be useful in establishing the diagnosis of acute pancreatitis when hypertriglyceridemia results in unusual laboratory findings [19]. This is similar to our report, where a low SAAG, which often excludes portal hypertension, in the presence of a low protein content, present in portal hypertension, makes determining the sole cause of the chylous ascites difficult. In summary, the interpretation of laboratory values and imaging can be difficult when multiple risk factors are present.

At the turn of the new millennia, more cases would be published, helping strengthen the connection between chylous ascites and chronic pancreatitis. In 2008, a study from van der Gaag et al sampled 609 patients who underwent pancreaticoduodenectomy [20]. Of those patients sampled, 66 had chylous ascites, and of the 66 patients with chylous ascites, 11 had chronic pancreatitis. The paper determined focal chronic pancreatitis was seen significantly more often in patients with isolated chylous ascites [20]. After performing regression analysis, van der Gaag et al concluded that chronic pancreatitis was acting as an independent associated factor in chylous ascites. The paper theorized long-standing inflammation from chronic pancreatitis could cause congestion of lymphatic channels, leading to risk of damage during operations, but evidence was lacking [20]. In 2013, Andraus et al reported a patient with chronic pancreatitis and chylous ascites that mimicked liver cirrhosis [2]. They reported the case of a 37-year-old man with non-insulin-dependent diabetes mellitus with long-term tobacco and alcohol use. The patient had chylous ascites, necrosis of the pancreatic head and tail, thrombosis of the splenic vein, and esophageal varices. They stated their patient was the first case of chronic pancreatitis mimicking cirrhosis at initial presentation [2]. The report by Andraus et al is noteworthy, as our patient presented with many of the same features. Both patients had a cirrhotic liver presentation. However, rather than chronic alcoholism, our patient had an enlarged pancreatic mass compressing the portal vein, leading to portal hypertension.

In 2015, a study published by Pan et al looked at the incidence and risk factors of chylous ascites after pancreatic resection. Of 49 patients with chylous ascites, 11 had chronic pancreatitis. After performing univariable and multivariable analyses, the study determined focal chronic pancreatitis is a significant cause of chylous ascites [21]. Most recently, in 2017, 2 case reports of chylous ascites and chronic pancreatitis were published. Kumar et al presented the case of a patient with chylous ascites due to idiopathic chronic pancreatitis managed with endoscopic stenting [22]. Liver enzymes were normal, elevated triglycerides were present in the ascitic fluid, and the SAAG was <1.1 g/dL [22]. Santos et al reported a patient with chylous ascites seen in necrotizing pancreatitis and pseudocyst formation, with an SAAG >1.1 [23]. Both of these cases had presentations similar to our patient’s.

The long-term effects of chylous ascites are seen in malabsorptive states, presenting with protein loss and malnutritio45]. The leakage of chyle prevents protein from returning to systemic circulation, which can lead to hypogammaglobulinemia and risk of infection [14]. The mainstay of chylous ascites treatment is conservative management with a high-protein, low-fat, medium-chain triglyceride (MCT) diet [8,24,25]. Our patient was counseled to consume a high-protein, lowfat diet. In our patient, the presence of the pancreatic head mass means the recurrence of chylous ascites is still plausible. If conservative management fails, somatostatin has been shown to be beneficial in management of chylous ascites by lowering portal pressure [5,14,24–27]. Dababneh et al stated that somatostatin can decrease portal pressures via splanchnic vasodilatory inhibition, but also inhibits fat absorption, triglyceride concentration, and lymphatic flow, which are all major factors in the development of chylous ascites [27]. Orlistat has also been shown to be successful in management of chylous ascites via reversible inhibition of pancreatic and stomach lipase, which reduces the availability for fatty acid absorption [27]. TIPS, or transjugular hepatic portosystemic shunt, has shown success in managing cirrhotic patients with chylous ascites [10,27].

As a last option, surgical intervention can treat chylous ascites [5,26,27]. Surgical intervention can involve performing a laparotomy to close a fistula causing leakage of chylous ascites into the abdomen, resect a malignancy allowing the formation of the ascitic fluid, or introducing a peritoneal shunt [10,27]. In the presence of portal vein stenosis manifesting as portal hypertension, as seen in our patient, portal vein stenting has been reported as a viable treatment option. Poo et al reported a case of portal hypertension and chylous ascites managed by stenting of the portal vein, in which portal vein stenting was indicated due to further progression of portal vein narrowing and presence of chylous ascites. Portal vein stenting allowed the team to evaluate the effect of restoration of normal portal flow on the ascites. The post-stent venography demonstrated excellent flow, with the ascitic drain output reaching as low as 0 milliliters within 24 hours of stent placement [28]. The patient returned for follow-up 1 year later, and the serial CT scans demonstrated resolution of the chylous ascites [28]. Poo et al stated that endovascular techniques have increasingly been indicated as safe, effective alternatives in managing portal vein thrombosis, which our patient showed on CT imaging. If our patient’s chylous ascites not have resolved with conservative management, portal vein stenting would have been considered as a next step.

Conclusions

The formation of chylous ascites is rarely seen in patients with chronic pancreatitis and non-cirrhotic portal hypertension. We report the case of a 65-year-old man with a history of necrotizing pancreatitis and portal hypertension amidst an incidental finding of chylous ascites upon elective umbilical hernia repair. This case corroborates the literature while introducing unique findings in a patient with chylous ascites. Further research into the development of chylous ascites is necessary to determine if prevention is possible.