CHYLOUS ASCITES
July 12th, 2005
Amy Gosalie, M.D.
Definition/History
Chylous ascites is best defined as extravisation of triglyceride-rich milky/creamy fluid from the abdominal
or thoracic lymphatics into the peritoneal cavity. Though ancient anatomist observed lymphatics, real
insight into the lymphatic system was not established until Gasare Asellio of Cremona discovered cordlike vessels that oozed white fluid in the abdominal wall of a dog on which he was performing an autopsy
in 1622. 25 years later, Jean Pecquet discovered the thoracic duct, and still another 25 years later,
Morton described the first reported case of chylous ascites in a 2-year-old boy who died of disseminated
tuberculosis. Though thought to be rare, incidence of chylous ascites is increasing with more aggressive
abdominal and cardiothoracic surgery surgery as well as increasing survival of patients with malignancy
and chronic liver disease. A 20-year review of patients admitted to Charity Hospital in New Orleans
between 1936 and 1956 revealed an incidence of 1 per 187,000 hospital admissions. More recently, an
incidence of 1 per 20,000 admissions incidence was cited at a 30-year review in a local, reputable
hospital.
Anatomy Review
Lymphatics play a pivotal role in clearing the interstitium of debris and bacteria as
well as functioning to transport absorbed water and lipids from the intestines to the
circulation. The intestinal, descending thoracic, hepatic, and lumbar lymphatic trunks
Thoracic Duct
merge anterior to the L1 and L2 vertebrae to form the cysterna chyli between the IVC
and the aorta. The cysterna then forms the thoracic duct that passes through the
aortic hiatus and enters the posterior mediastinum where it continues cephalad until
Cysterna Chyli
the level of T5 when it crosses to the left, entering the superior mediastinum and
empties between the internal jugular vein and the left subclavian vein though a
bicuspid valve. The lymph is composed of a variety of interstitial substances and
debris (proteins and bacteria) as well as chylomicrons from the intestinal conversion
of long chain triglycerides to monoglycerides and fatty acids packaged in
chylomicrons.
Pathophysiology
Three mechanisms are postulated to play a role in formation of chylous ascites. All three have the
common pathway of disruption or obstruction of lymphatics:
1. Primary lymph node fibrosis: Usually caused by malignancy that obstructs the flow of lymph from
the gut to the cisterna chili. The subserosal lymphatics get “backed up” and fluid leaks from them
into the peritoneal cavity. This can lead to increased collagen deposition in the basement
membrane of the lymphatics, further compromising gut absorption and may lead to a proteinloosing enteropathy with ensuing malnutrition, malabsorption, and immunosuppresion.
2. Direct leakage of lymph fluid through a lymphoperitoneal fistula. This is most commonly acquired
after surgery or trauma.
3. Exudation of lymph fluid through the walls of retroperitoneal megalymphatics with or without a
fistula. This most commonly occurs because of congenital abnormalities.
Another mechanism in cirrhotics and patients with increased caval pressures (right sided failure,
constrictive pericarditis, dilated cardiomyopathy) is the phenomenon of increased hepatic lymph
production at a pace that overwhelms egress of lymph into the venous circulation through the bicuspid
valve that gates lymphatic from venous circulation.
Etiology/Differential Diagnosis
The treatment of patients with chylous ascites depends on identifying the principle cause of the
accumulation of lymphatic fluid in the peritoneum. The majority of cases of chylous ascites in the adult
American population is abdominal malignancy (mainly lymphoma) and cirrhosis, accounting for 2/3 of all
reported cases. Infectious etiologies are more frequent in “developing” countries
 Neoplastic: Most common cause in adults in developed world, with lymphoma accounting for up
to 50%. Tumors disrupt lymphatic flow by disrupting lymphatics by compression or invasion.
Other tumors known to cause chyloperitoneum include ovary, colon, kidney, prostate, pancreas,
breast, testicular, KS and stomach. Carcinoid involves lymph nodes and additionally produces
seritonin that enhances fibrosis and destruction of lymphatic architecture. Another category of
neoplastic diseass that can cause chylous ascites is lymphangiomyomatosis, a condition (usually
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of young women) that is caused by hamartomatous hyperplasia of pulmonary, mediastinal, and
abdominal lymphatic smooth muscle.
Cirrhosis: Excessive lymph flow leads to rupture if serosal lymphatic channels. Patients may
present with liver failure and have chylous ascites, or alternatively, they may develop this finding
in the setting of HCC, shunt surgery, or thoracic duct damage after sclerotherapy.
Infectious: As stated above, these causes are more common outside of the US. Tuberculosis
and filariasis (usually Wuchereria bancrofti) are two often-sited organisms throughout the
developing world. MAC infection has also been noted as a cause of chylous ascites in patients
with AIDS. Whipple’s disease is another rare, infectious cause of chylous ascites ( Tropheryma
whippelii).
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Inflammatory: Radiation therapy to the abdomen is the most common inflammatory cause in
several reviews and is felt to be secondary to fibrosis that obstructs lymphatic flow. Constrictive
pericarditis causes increased capillary pressure and extravisation leading to increased lymph fluid
production while impeding drainage of the thoracic duct with increased venous pressures. Other
causes include idiopathic retroperitoneal fibrosis (Ormond’s disease), sarcoid, celiac sprue, and
pancreatitis.
 Postoperative and traumatic: Post-op chylous ascites can occur early (1 week) or late (weeks to
months) because of different processes. In the early onset variety, division of lymph vessels
leads to extravisation of lymphatic fluid. In the late onset variety, adhesions or other extrinsic
compression are felt to play a more dominant role. Trauma that results in intestinal or mesenteric
injury may cause chylous ascites. 10% of pediatric cases are secondary to “the Battered Child
Syndrome.”
 Congenital Syndromes: Mainly occur in childhood and include: yellow nail syndrome, KlippelTrenaunay syndrome, primary lymphatic hypoplasia, and primary lymphatic hyperplasia.
 Other: Right heart failure and nephrotic syndrome.
Clinical Presentation/Ascitic Analysis
Not surprisingly, chylous ascites does not present differently than non-chylous ascites. The diagnosis is
often made after the paracentesis:
Color
Milky and cloudy
The workup after discovering chylous ascites includes
Triglycerides Above 200 mg/dL
standard blood work like CBC, electrolytes, LFTs as well
Cell count
>500, lymphocyte predominance
as triglycerides, total cholesterol, total protein, albumin,
Total protein 2.5-7.0 g/dL
amylase and lipase. Imaging is recommended as well,
SAAG
<1.1 if not secondary to cirrhosis
with older texts recommending lyphangiography and
Cholesterol
Low (ascites/serum<1)
lymphoscintigraphy. Most current sources recommend
LDH
110-200 IU/L
abdominal CT scan to identify pathologic nodes, masses
Culture
+ in TB
and in the case of post-operative chylous ascites, it may
ADA
? elevated in TB (controversial)
also confirm suspicion of a thoracic duct injury.
Cytology
+ in malignancy
Identification of a cause is critical in establishing a
Amylase
Elevated in pancreatitis
definitive treatment plan for patients with chylous ascites.
Glucose
Under 100 mg/dL
Management
 Find the primary problem
 Dietary: high-protein, low fat diet with medium chain triglycerides is important initial management
of patients with chylous ascites. Avoidance of long-chain triglycerides avoids conversion to
monoglycerides and fatty acids and therefore decreases chylomicron formation.
Supplementation with medium chain triglycerides insures hepatic absorption of fat, bypassing the
intestinal lymphatics. Cirrhotics shloud be managed with a low sodium diet and diuretics
 TPN: Patients who fail diet should be fasted and started on TPN.
 Somatostatin and Octreotide: Thought to function by inhibiting lymph fluid excretion by action
medicated on receptors found in the intestinal wall of lymphatic vessels
 Surgery: May benefit patients with post-op, neoplastic, congenital causes
 Large Volume Paracentesis
 Peritovenous shunts: Refractory cases. Viscosity of chyle may lead to more frequent obstruction
References
Alami, O. et al. Chylous Ascites: A collective review. Surgery 2000; 128:761-8.
Cardenas, A. and Chopra, S. Chylous Ascites. Am Journal of Gastro. 97:8, 2002. 1896-1900.
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