Chapter 362 Ascites
Ascites is an accumulation of serous fluid within the peritoneal cavity. Multiple causes of ascites have been described (see Table 362-1 on the Nelson Textbook of Pediatric website at www.expertconsult.com). In children, hepatic, renal, and cardiac disease are the most common causes.
HEPATIC
RENAL
CARDIAC
INFECTIOUS
GASTROINTESTINAL
NEOPLASTIC
GYNECOLOGIC
PANCREATIC
MISCELLANEOUS
The clinical hallmark of ascites is abdominal distention, but this can also be caused by other conditions, including gaseous distention, fecal retention, tumor masses, peritoneal hemorrhage, extreme bladder distention, pregnancy, and obesity. Early satiety and dyspnea can occur with a moderate amount of ascites. Considerable intraperitoneal fluid can accumulate before ascites is detectable by the five classic physical signs: bulging flanks, flank dullness, shifting dullness, fluid wave, and the “puddle sign” (decreased auscultation of high-frequency vibrations in the central abdomen when flicking the side of the abdomen, with the patient on hands and knees). Umbilical herniation can be associated with tense ascites. Ultrasound examination is useful for detecting small amounts of ascites.
The course, prognosis, and treatment of ascites depend entirely on the cause. Abdominal paracentesis can provide symptomatic relief and may be diagnostic of the cause of the ascites. Patients with any type of ascites are at increased risk for spontaneous bacterial peritonitis.
362.1 Chylous Ascites
Chylous ascites can result from an anomaly, injury, or obstruction of the intra-abdominal portion of the thoracic duct. Although uncommon, it can occur at any age. Causes include congenital malformations, peritoneal bands, generalized lymphangiomatosis, chronic inflammatory processes of the bowel, tumors, enlarged lymph nodes, previous abdominal surgery, and trauma. Congenital anomalies of the lymphatic system are associated with Turner, Noonan, yellow nail, and Klippel-Trenaunay-Weber syndromes.
In neonates, rapidly progressing abdominal distention is noted, along with poor weight gain and loose stools. Peripheral edema is common. Massive chylous ascites can result in scrotal edema, inguinal and umbilical herniation, and respiratory embarrassment.
Diagnosis of chylous ascites depends on the demonstration of milky ascitic fluid obtained via paracentesis after a fat-containing feeding. Fluid analysis reveals a high protein content, elevated triglycerides, and lymphocytosis. If the patient has had nothing by mouth, the fluid appears serous. Hypoalbuminemia, hypogammaglobulinemia, and lymphopenia are common in these patients.
Treatment includes a high-protein, low-fat diet supplemented with medium-chain triglycerides that are absorbed directly into the portal circulation. Parenteral alimentation may be necessary if nutrition remains impaired on oral feedings and also in order to decrease lymph flow to facilitate sealing at the point of lymph leakage. Octreotide, a somatostatin analog, has been used. Paracentesis should be repeated only if abdominal distention causes respiratory distress. Laparotomy may be indicated to search for the site of the leak if a trial of dietary management has been unsuccessful.
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