Chylous ascites (CA) is defined as a milky appearing, triglyceride-rich peritoneal fluid in the abdominal cavity. It is an uncommon clinical condition that was first reported in 1912. It is characterized by the accumulation of true chyle from thoracic or intestinal lymph. Various etiologies have been described, and it usually occurs due to trauma, rupture of the lymphatics secondary to obstruction, or an increase in the peritoneal lymphatic pressure. CA is rich in nutrients and immunoglobulins that become biologically unavailable after accumulating in the peritoneal cavity. This can lead to dehydration, electrolyte imbalance, malnutrition, and suppression of the immune system. It can be associated with a high mortality rate that can reach up to 40% to 70%, depending on the underlying etiology. Therefore, prompt diagnosis and treatment are warranted.
Etiology of chylous ascites can be classified as follows:
In western countries, abdominal malignancy, and cirrhosis are considered the main causes of CA. In developing and eastern countries, the majority are secondary to infections, such as tuberculosis and filariasis. However, a review of 190 patients with CA identified a total of 41 different etiologies. The most common cause was lymphatic anomalies (32%), which is more prevalent in the pediatric population. Malignant diseases were the second common etiology (7%). Cirrhosis and mycobacterial infections were identified as the cause of CA in 11% and 10% of the cases, respectively.
In 1992, a large university-based hospital estimated the incidence of chylous ascites to be approximately 1 in 20,000 admissions over 20 years. However, the incidence of CA has likely increased because of improved care and treatment of patients with cancer and their increased survival rates. CA is a morbid condition, and it is associated with high mortality rates depending on the underlying etiology (40% to 70%).
The pathophysiology of chylous ascites varies depending on the etiology. This can be divided into three mechanisms:
1) Acquired lymphatic disruption
Acquired lymphatic disruption can be traumatic or secondary to surgical procedures. This causes dilation of the retroperitoneal lymphatics with drainage of lymph into the abdomen through a fistula between the lymphatic system and retroperitoneum. The dilation can also be a result of the increased production of lymph and the elevated pressure in the hepatic veins that are seen in cases of portal hypertension (HTN) secondary to cirrhosis and constrictive pericarditis.
2) Fibrosis of the lymphatic system
This is mostly seen in malignancies obstructing the lymphatic flow from the gut into the cisterna chyli, with leakage from the subserosal dilated lymphatics into the peritoneal cavity and lymph node fibrosis.
3) Congenital causes
Congenital anomalies such as congenital lymphangiectasia cause exudation of lymph into the peritoneal cavity causing CA.
The underlying cause of chylous ascites is the disruption of lymphatic flow. Lymph mainly originates in the intestine and the liver, as well as other organs in the abdomen. Long-chain triglycerides (TG) in the diet are absorbed as chylomicrons into the lymphatic system following conversion into monoglycerides and FA in the small intestine. This attributes to the milky appearance of lymph due to the high content of TGs.
In cases of CA, due to portal hypertension, endothelial compromise occurs due to high lymphatic pressure, leading to the dilation of lymphatic channels, which results in their rupture and CA formation. In non–portal etiology, lymph material is filtered as an exudate into the peritoneum by a fistula that is formed retroperitoneally due to congenital or acquired megalymphatics. Over time, the deposition of collagen in the basement membrane (BM) of the lymphatic channels occurs due to increased lymphatic pressure leading to a decline in the capacity of absorption of the intestinal mucosa. This can lead to protein-losing enteropathy manifested by inadequate absorption, malnutrition, and steatorrhea.
The evaluation of a patient with ascites should start with a thorough history and physical examination. A detailed history should describe the presenting symptoms, and include the past medical history (for example, malignancy, liver or renal diseases and inquiry about any recent trauma), family history, surgical history, history of travel, and social history.
Patients with chylous ascites usually complain of painless, progressive abdominal distention that could extend over weeks to months. This is the most common symptom in up to 81% of the patients. Less common symptoms among patients with chylous ascites include pain or peritonitis in 11%, diarrhea, dysphagia (as reported in atraumatic causes due to goiter or para-esophageal hernia compressing the thoracic duct and leading to the formation of chylothorax and CA), peripheral edema, weight gain and shortness of breath, resulting from the increased abdominal pressure. Other less specific symptoms include loss of appetite, fatigue, nausea, lymph nodes enlargement, fullness, fever, and night sweats.
Physical examination reveals a distended abdomen that could be tense on palpation. Classic signs to detect ascites can also be seen, such as shifting dullness and a transmission thrill (fluid wave). Surgical scars seen by inspection could suggest a traumatic etiology. Enlarged lymph nodes can be seen. Other general exam findings seen in the setting of malignancy, renal, or liver disease should be evaluated. For example, patients with cirrhosis may have characteristic physical exam findings, like cachexia, jaundice, temporal wasting, palmar erythema, spider angiomas on the chest and abdomen, gynecomastia, decreased breath sounds and dullness on chest percussion in the setting of pleural effusion, tense abdomen in the setting of ascites, caput medusae, confusion and disorientation (hepatic encephalopathy) in decompensated disease.
Other physical exam findings can be related to specific syndromes like yellow-nail syndrome or Klippel-Trenaunay syndrome.
It is essential to obtain both blood and ascitic fluid analysis to diagnose and evaluate chylous ascites. Standard blood tests are required and include a complete blood count, basic metabolic panel, lipid profile, liver function tests, total protein, albumin, lactate dehydrogenase (LDH), amylase, and lipase.
The following tests are considered on a case-by-case basis and depending on the clinical presentation:
Abdominal paracentesis is essential in the diagnosis of CA. CA is suspected when ascites appear milky. A triglyceride level in the ascitic fluid should be obtained, and a concentration greater than 200 mg/dL supports the diagnosis. Fat globules and leucocytes with a predominance of lymphocytes are shown after staining with Sudan III and undergoing microscopic examination. If tuberculosis is suspected, acid-fast bacilli smear, culture, and polymerase chain reaction (PCR) should be performed. Adenosine deaminase is considered both a sensitive (93%) and a specific (94%) diagnostic test for peritoneal tuberculosis, but in some cases, a peritoneal biopsy may be needed.
Lipoprotein electrophoresis is considered a gold standard in the diagnosis of CA by identifying chylomicrons. Elevated ascitic fluid triglyceride levels are the best parameter for diagnosing CA. With a sensitivity and specificity of up to 95%, a recent study has suggested a triglyceride cutoff point of 187 mg/dL (2.13 mmol/L) or a range of 148 to 246 mg/dL (1.69 to 2.80 mmol/L) to establish CA.
Computed tomography (CT) of the abdomen is useful to diagnose abdominal masses and lymph nodes in some cases of CA. Fat fluid level is the pathognomonic feature of chylous ascites on a CT scan, which can be demonstrated by positioning the patient in a supine position for some time before imaging is done. Because the specific gravity of lipids is less than that of water, it leads to the formation of a fat fluid level, which may also be seen by ultrasonography.
Lymphangiography is considered a gold standard in the diagnosis of CA in cases of lymphatic obstruction. Lymphangiography and lymphoscintigraphy are effective in the selection of patients for surgery, assessment of the effects of treatment outcomes, detection of abnormalities in the retroperitoneal nodes, in addition to detection of any leakage, fistulization, and permeation of the thoracic duct.
Other tests: CA-125 could be particularly elevated in patients with cirrhosis and chylous ascites.
There are limited therapeutic options for chylous ascites. Therefore managing the underlying cause and applying conservative measures to improve patient comfort, reducing recurrence, and optimizing outcomes are the cornerstones in managing chylous ascites.
A special diet is recommended that is low in fat, containing mainly medium-chain TGs and high in protein. Medium-chain triglycerides spare the lymphatic system through absorption by enterocytes and being transported directly into the liver as FFA and glycerol. When these dietary changes are insufficient, bowel rest and TPN should be considered. This approach helps reduce lymphatic flow and bypasses the intestine. Nutritional consultation should be considered to help manage the TPN and select the ideal lipid formulation.
Medical therapy includes different medications that may help decrease the accumulation of CA:
Surgical interventions may be beneficial if all the conservative measures fail in treating CA. This should be considered if CA was due to congenital causes or as a result of surgery or malignancy. Laparotomy is usually performed to insert a shunt, close a fistula, or resect a malignancy.
Chylous ascites is rare. Differential diagnosis may include:
The prognosis among patients with chylous ascites depends on the underlying etiology. CA can be associated with a high mortality rate that can reach up to 40% to 70%. It can be highly morbid. The prognosis of CA cases that are non-surgical is worse than the surgical cases. Although malignancies are considered a significant cause for CA, it has been reported that it is associated with improved survival when treated, especially in patients with lymphomas due to the recent introduction of better chemotherapy regimens, and monoclonal antibodies. Prior to the advent of these new protocols in chemotherapy, CA that occurred concurrently with lymphomas, usually led to poor prognosis, with a 3-month death rate of 90%.
Chylous ascites contain nutrients and immunoglobulins, which get depleted due to its accumulation in the peritoneal cavity, leading to loss of fluids, impaired nutrition, electrolyte abnormalities, and suppression of immunity. Therefore, adequate diagnosis and treatment are mandatory. Over time, the deposition of collagen in the basement membrane of the lymphatic channels occurs due to increased lymphatic pressure leading to a decline in the capacity of absorption of the gut mucosa. This can lead to protein-losing enteropathy.
Patient education is considered one of the main cornerstones in managing cases of chylous ascites and its underlying etiologies. Patients must be aware of the importance of dietary modification as the main and initial step in managing CA. For symptomatic treatment of chylous ascites, a diet that is high in protein and low in fat with medium-chain triglycerides (MCT) is recommended. MCTs are found in palm and coconut oil, full-fat milk, cheese, and butter, which contain capric and lauric acid. Other oils and fats, including nuts, red meat, fish, olive oil, and avocado should be avoided because they contain (LCT). MCTs are sometimes considered to be unpalatable and may cause abdominal distension, which can result in poor dietary compliance related to nausea and vomiting. Therefore patients should be warned about the above-mentioned side effects. Also, patients with CA due to cirrhosis should be educated about following a diet that is low in sodium in addition to diuretic use.
Normally, total protein ranges are between (2.5 to 7.0 g/dL) and may vary depending on the underlying cause. For example, liver cirrhosis has a total protein level below 2.5 g/dL. To diagnose portal hypertension in the setting of hepatic disease (SAAG) can be used, which stands for the serum to ascites albumin gradient. Having a SAAG that is less than 1.1 g/dL excludes portal hypertension and suggests other causes. On the other hand, patients with CA due to cirrhosis will have a SAAG that is above 1.1 g/dL. Interestingly, CA-125 is elevated in patients with CA due to cirrhosis.
Improving outcomes in chylous ascites depend on the underlying cause. For example, the introduction of better and new chemotherapy protocols, including but not limited to rituximab, and monoclonal antibodies, resulted in improvement in the rates of survival and symptom resolution, especially in lymphomas. Also, ensuring a strong patient-doctor relationship will certainly result in better compliance with the dietary measures required to treat chylous ascites.
|||Cárdenas A,Chopra S, Chylous ascites. The American journal of gastroenterology. 2002 Aug; [PubMed PMID: 12190151]|
|||Al-Busafi SA,Ghali P,Deschênes M,Wong P, Chylous Ascites: Evaluation and Management. ISRN hepatology. 2014; [PubMed PMID: 27335837]|
|||Browse NL,Wilson NM,Russo F,al-Hassan H,Allen DR, Aetiology and treatment of chylous ascites. The British journal of surgery. 1992 Nov; [PubMed PMID: 1467885]|
|||Khoury T,Schneider R, Chylous Ascites: A Rare Adverse Effect of Methimazole Treatment for Grave's Disease-A Case Report and Review of the Literature. Case reports in endocrinology. 2015; [PubMed PMID: 26366308]|
|||Capristo E,Spuntarelli V,Treglia G,Arena V,Giordano A,Mingrone G, A case report of chylous ascites after gastric bypass for morbid obesity. International journal of surgery case reports. 2016; [PubMed PMID: 27846453]|
|||Steinemann DC,Dindo D,Clavien PA,Nocito A, Atraumatic chylous ascites: systematic review on symptoms and causes. Journal of the American College of Surgeons. 2011 May; [PubMed PMID: 21398159]|
|||Aalami OO,Allen DB,Organ CH Jr, Chylous ascites: a collective review. Surgery. 2000 Nov; [PubMed PMID: 11056439]|
|||Lizaola B,Bonder A,Trivedi HD,Tapper EB,Cardenas A, Review article: the diagnostic approach and current management of chylous ascites. Alimentary pharmacology [PubMed PMID: 28892178]|
|||Lopez-Gutierrez JC,Tovar JA, Chylothorax and chylous ascites: management and pitfalls. Seminars in pediatric surgery. 2014 Oct; [PubMed PMID: 25459015]|
|||Chen J,Lin RK,Hassanein T, Use of orlistat (xenical) to treat chylous ascites. Journal of clinical gastroenterology. 2005 Oct; [PubMed PMID: 16145348]|
|||Berzigotti A,Magalotti D,Cocci C,Angeloni L,Pironi L,Zoli M, Octreotide in the outpatient therapy of cirrhotic chylous ascites: a case report. Digestive and liver disease : official journal of the Italian Society of Gastroenterology and the Italian Association for the Study of the Liver. 2006 Feb; [PubMed PMID: 16389001]|
|||Nguyen V,Vassaur H,Buckley FP 3rd, Spontaneous chylous ascites, chylomediastinum and bilateral chylothoraces encountered during laparoscopic incarcerated paraesophageal hernia repair. Journal of surgical case reports. 2015 Oct 27; [PubMed PMID: 26506835]|
|||Thaler MA,Bietenbeck A,Schulz C,Luppa PB, Establishment of triglyceride cut-off values to detect chylous ascites and pleural effusions. Clinical biochemistry. 2017 Feb; [PubMed PMID: 27750038]|
|||Runyon BA,Montano AA,Akriviadis EA,Antillon MR,Irving MA,McHutchison JG, The serum-ascites albumin gradient is superior to the exudate-transudate concept in the differential diagnosis of ascites. Annals of internal medicine. 1992 Aug 1; [PubMed PMID: 1616215]|
|||Almakdisi T,Massoud S,Makdisi G, Lymphomas and chylous ascites: review of the literature. The oncologist. 2005 Sep; [PubMed PMID: 16177287]|
|||Prasad S,Patankar T, Computed tomography demonstration of a fat-fluid level in tuberculous chylous ascites. Australasian radiology. 1999 Nov; [PubMed PMID: 10901978]|
|||Shah SS,Ahmed K,Smith R,Mallina R,Akhbari P,Khan MS, Chylous ascites following radical nephrectomy: a case report. Journal of medical case reports. 2008 Jan 11; [PubMed PMID: 18190695]|
|||Evans J,Clark MF,Mincher L,Varney VA, Chylous effusions complicating lymphoma: a serious event with octreotide as a treatment option. Hematological oncology. 2003 Jun; [PubMed PMID: 12802812]|
|||Alam SE,Kar SM,Kar PM, Successful management of chylous ascites: A report of two cases. Saudi journal of kidney diseases and transplantation : an official publication of the Saudi Center for Organ Transplantation, Saudi Arabia. 2016 Mar; [PubMed PMID: 26997396]|
|||Guillem P,Billeret V,Houcke ML,Triboulet JP, Successful management of post-esophagectomy chylothorax/chyloperitoneum by etilefrine. Diseases of the esophagus : official journal of the International Society for Diseases of the Esophagus. 1999; [PubMed PMID: 10466051]|
|||Kawasaki R,Sugimoto K,Fujii M,Miyamoto N,Okada T,Yamaguchi M,Sugimura K, Therapeutic effectiveness of diagnostic lymphangiography for refractory postoperative chylothorax and chylous ascites: correlation with radiologic findings and preceding medical treatment. AJR. American journal of roentgenology. 2013 Sep; [PubMed PMID: 23971461]|
|||Bhardwaj R,Vaziri H,Gautam A,Ballesteros E,Karimeddini D,Wu GY, Chylous Ascites: A Review of Pathogenesis, Diagnosis and Treatment. Journal of clinical and translational hepatology. 2018 Mar 28; [PubMed PMID: 29577037]|
|||Makino Y,Shimanuki Y,Fujiwara N,Morio Y,Sato K,Yoshimoto J,Gunji Y,Suzuki T,Sasaki S,Iwase A,Kawasaki S,Takahashi K,Seyama K, Peritoneovenous shunting for intractable chylous ascites complicated with lymphangioleiomyomatosis. Internal medicine (Tokyo, Japan). 2008; [PubMed PMID: 18277030]|
|||Sriperumbuduri S,Zimmerman D, Cloudy Dialysate as the Initial Presentation for Lymphoma. Case reports in nephrology. 2018; [PubMed PMID: 30402307]|
|||Jagosky M,Taylor B,Taylor SP, A Case of Chyloperitoneum Secondary to Follicular Lymphoma and a Review of Prognostic Implications. Case reports in hematology. 2016; [PubMed PMID: 27429812]|
|||Weinstein LD,Scanlon GT,Hersh T, Chylous ascites. Management with medium-chain triglycerides and exacerbation by lymphangiography. The American journal of digestive diseases. 1969 Jul; [PubMed PMID: 4306924]|
|||Gracey M,Burke V,Anderson CM, Medium chain triglycerides in paediatric practice. Archives of disease in childhood. 1970 Aug; [PubMed PMID: 4918706]|
|||Khandwalla HE,Fasakin Y,El-Serag HB, The utility of evaluating low serum albumin gradient ascites in patients with cirrhosis. The American journal of gastroenterology. 2009 Jun; [PubMed PMID: 19491852]|
|||Uriz J,Cárdenas A,Arroyo V, Pathophysiology, diagnosis and treatment of ascites in cirrhosis. Bailliere's best practice [PubMed PMID: 11139347]|
|||Kumar KS,Lee WM, Chylous ascites with marked elevation of CA-125 in cirrhosis. The American journal of gastroenterology. 2000 Nov; [PubMed PMID: 11095368]|