Congenital chylous ascites treated successfully with MCT-Based formula and octreotide.

Medium chain triglyceride (MCT)-based diet, total parenteral nutrition (TPN) and repeated paracentesis are considered as supportive management for congenital chylous ascites (CCA). TPN is considered where therapy with oral MCT is poorly tolerated by the patient especially young infant with unstable hemodynamic. Surgery is recommended when medical therapy fails. Herein, we report a 2½-month-old infant with CCA, treated successfully with octreotide intravenous infusion after the initial failure to response to conventional conservative therapy with MCT-enriched formula and paracentesis.

INTRODUCTION

Congenital chylous ascites (CCA) is a rare disease that results from maldevelopment of the intra-abdominal lymphatic system. It is defined as the accumulation of triglyceride-rich milky fluid (chyle) into the peritoneal cavity in infants younger than three months.[1] Medium chain triglyceride (MCT)-based diet or total parenteral nutrition (TPN) with or without abdominal paracentesis is the time-honored conservative management. Surgery is recommended when conservative therapy fails.[2] Here we describe a 2½-month-old infant with CCA who improved dramatically with intravenous infusion of octreotide, a synthetic somatostatin analog, after the initial failure to repose to traditional supportive therapy with MCT-based formula and paracentesis.

CASE REPORT

A 2½-month-old female infant born to parents of nonconsanguineous marriage was referred with complaint of gradual distension of abdomen since the age of 1 month. Her weight (4.2 kg) and length (52 cms) were both below 3rd percentile of WHO growth standards. On examination, she had tense ascites, resulting severe respiratory distress but characteristically had no edema [Figure 1a]. Ultrasonography of abdomen depicted normal abdominal findings other than presence of massive ascites [Figure 2a].

Figure 1

Pre-treatment photograph of the baby showing massive abdominal swelling without pedal edema (Inset — thick milky white turbid ascitic fluid collected after abdominal paracentesis) (a) and posttreatment photograph showing regression of abdominal swelling (b)

Figure 2

Showing pre-treatment thick ascites on abdominal ultrasound (a) and post-treatment resolution of ascites (b)

About 200 ml of thick milky white turbid ascitic fluid was removed by abdominal paracentesis. Child's initial respiratory distress was relieved temporarily. Biochemical examination showed triglyceride: 5896 mg/dL, total protein: 4.8 g/dL, lactate dehydrogenase: 341 U/L and total white cell count: 200 cells/mm3 with 80% lymphocyte. Culture of ascitic fluid was normal. Serum electrolytes, liver and renal functions were normal.

A diagnosis of congenital chylous ascites was made and breast feeding was stopped. Child's nutrition was maintained with oral MCTbased diet (SIMYL-MCT powder, FDC Limited). A feeding regimen was made in such a way that it can fulfill the amount of required calorie intake which depends upon the existing body weight. But unfortunately it failed to improve the condition and needed repeat paracentesis on day 7. Baby was then started with continuous intravenous infusion of octreotide initially at a rate of 1μg/kg/hr and gradually increased to 2μg/kg/hr over 48 hours, with a subsequent plan for TPN if the ascites would not respond. Weight and abdominal girth were measured daily. The abdominal girth reduced markedly from 42 cms to 32 cms over 3 days [Figure 1b]. Octreotide was continued in tapering dosage from day 7 and stopped on day 10. No ascites was seen on follow-up ultrasonogram [Figure 2b]. Throughout the entire treatment course, no side effects of octreotide, such as diarrhea, hypoglycemia or hypotension, were found. Child was discharged shortly thereafter with advice to continue the MCT-based diet. The feeding regime in a given patient will depend upon the amount of prescribed calorie intake, which depends upon his/her body weight. The total calorie intake should be above the average requirement so as to promote positive anabolic response. During follow-up at 1 month and 6 month, the child was doing well and there was no recurrence of ascites. Weaning was started at 6 month of age with carbohydrates based diet and frequency of formula feeding with SIMYL-MCT powder gradually reduced. At last follow-up she has completed her first birthday, taking normal diet and did not show any recurrence of ascites.

DISCUSSION

Etiology of chylous ascites vary in different age group, which include developmental defect of the lymphatic system, nonspecific bacterial, parasitic and tuberculous peritoneal infection, liver cirrhosis, malignant neoplasm, blunt abdominal trauma and surgical injury. In neonatal period, the most common being the malformation of the lymphatic vessels, as in atresia or stenosis of the major lacteals, mesenteric cysts and lymphangiomatosis. Obstruction of the lymphatics from external compression, as in malrotation, incarcerated hernia, intussusception, inflammatory enlargement of lymph nodes and malignancy may also give rise to this rare condition.[13] However, in majority of cases, no specific abnormalities is identified even after laparotomy, and the CCA is thought to be due to a condition called “leaky lymphatics”, probably because of a delayed maturation of the lacteals.[4]

Ultrasonography of the abdomen is the initial step that confirms the presence of ascites. Analysis of the fluid obtained by abdominal paracentesis is the most useful diagnostic method. The ascitic fluid known as chyle, is usually color free or milky white. The appearance of the ascitic fluid depends on its composition, cellular substance and diet. The protein and triglyceride content is usually high with predominance of lymphocytes on differential count.[5] But the true challenge is to determine the underlying cause of the chylous ascites. The initial diagnostic investigation includes ultrasonography and computed tomography or magnetic resonance imaging of the abdomen to exclude conditions that necessitate immediate surgical intervention. Diagnosis of malformation of the lymphatics is suspected when everything comes out negative. Further diagnostic tests like lymphangiography and lymphoscintigraphy are imperative if surgery is decided, with the purpose of identifying the site of the leakage of chyle preoperatively.

Chylous ascites should be managed properly as it is a potentially fatal condition. The available conservative treatment is MCT-based diet or TPN with or without drainage of ascitic fluid. But the success rate of dietetic therapy varies with increased recurrence potential and needs prolonged therapy. Although surgical ligation of the chylous fistula is recommended when conservative treatment fails, but surgery is invasive and requires expertise and is associated with increased mortality.[2] Given the limitations of the existing treatment modalities, the use of octreotide, a synthetic analog of somatostatin, has been considered. Octreotide decrease the absorption of fats and lowers the triglyceride concentration in thoracic duct. It also reduces gastric, intestinal and pancreatic secretions. Lymph production is decreased due to its effect on splanchnic circulation.[6] Since its first successful use to treat the chylous effusion by Caty et al., marked variation were found regarding its dosing regimen, modes of drug administration and duration of treatment in the existing literature.[26789] We started continuous intravenous of octreotide initially at a rate of 1μg/kg/hr, gradually step-up to 2μg/kg/hr, continued in tapering doses from day 5 and finally stopped on day 10. A dramatic response was observed within 72 hrs of infusion, with complete resolution of ascites by 10th day after treatment. In addition, our child did not develop significant adverse effect related to its long term use.

Due to a very rare incidence of this disorder, the existing literature includes mainly case reports where octreotide was continued along with TPN and with or without MCT-based formula. After recovery, the treatment was continued with MCT-based diet and child was kept under follow-up for a variable period.[678910] Our experience is almost similar as observed by Mishra R et al,[6] and highlights MCT-based diet and octreotide should be the initial treatment for CCA in neonatal period. TPN and surgical intervention, which need expertise, should be reserved for octreotide-resistant cases. Moreover, octreotide therapy reduces the length of treatment and hospitalization; lessen the financial burden as well as allay the parenteral anxiety. To clarify many unresolved issues regarding standard step-by-step treatment protocol, route and duration of octreotide therapy as well its uses in recurrence, authors also propose here a well-designed prospective randomized study with long term follow-up.