Fluid in the abdominal cavity (ascites)

Ascites (hydroperitoneum) is the pathologic accumulation of fluid in the abdomen.

Overview

Certain disorders may lead to the accumulation of fluid in the abdominal cavity – the condition referred to as the ascites. The term “ascites” is derived from the Greek word “askos” which means “bag, sac”. In healthy males, there is typically no fluid in the peritoneal cavity, whereas in females there may be up to 20 ml of fluid in the peritoneum depending on the phase of the menstrual cycle.

Ascites, as the result of trauma or any acute condition (appendicitis, diverticulitis, perforated ulcer), usually develop very fast, whereas in case of chronic diseases such as chronic liver diseases or heart failure this process may develop for several months or even years.

Doctor holding in hand word AscitesCauses

In about 80-84% of individuals, ascites is caused by portal hypertension related to chronic liver disease, another 10% are thought to be related to cancer.

Possible causes of fluid build up in the abdomen include:

  • Portal hypertension due to cirrhosis, alcoholic hepatitis, fatty liver, fulminant hepatic failure, Budd-Chiari syndrome, heart failure, constrictive pericarditis, tricuspid insufficiency, portal vein thrombosis;

  • Hypoalbuminemia (low albumin levels in the blood) due to kidney diseases, protein-losing enteropathy or severe malnutrition;

  • Myxedema (severe hypothyroidism);

  • Chylous, pancreatic, bile or urine ascites due to ductal disruption;

  • Ovarian diseases, Meigs’ syndrome;

  • Peritonitis due to bacterial or fungal infections;

  • Peritoneal carcinomatosis or massive metastases, hepatocellular carcinoma, primary mesothelioma;

  • Systemic lupus erythematosus;

  • Vasculitis;

  • Familial Mediterranean fever;

Classification

  • Stage 1: mild ascites, fluid visible only on ultrasound or CT;

  • Stage 2: ascites detectable, although the fluid volume is relatively small;

  • Stage 3: visible without any additional exams;

  • Stage 4: tense ascites;

Symptoms

Small amounts of fluids cause no symptoms and may even not be noticed by a person, although when the amount of fluid in the abdomen increases a person will experience:

  • Abdominal distension;

  • Shortness of breath;

  • Weight gain;

  • Abdominal discomfort, sometimes pain;

Fever is suggestive of infected fluid in the abdomen, namely bacterial peritonitis. 

Other symptoms vary widely depending on the underlying cause. In the case of liver diseases jaundice, easy bruising, enlarged liver and spleen, gastrointestinal bleeding with bloody vomiting, enlarged breasts in men, etc. may be present. Pain behind the sternum, shortness of breath which worsen during any physical activities are present in individuals who suffer from heart failure. Cancer is known to cause unintended weight loss and chronic fatigue.

Complications

As time passes ascites may become inflamed and spontaneous bacterial peritonitis occurs characterized by the fever, abdominal tenderness, and pain.

Chronic liver diseases may cause the combined failure of the liver and kidneys, portal vein thrombosis and splenic vein thrombosis.

Diagnosis

Complete blood count, liver enzymes and coagulation tests should be performed to evaluate the liver function.

  • Ultrasound examination may be used to estimate the amount of fluid in the abdomen and condition of the internal organs, as small as 5-10 ml of fluid in the abdomen can be detected by ultrasonography;

  • CT scan is performed to detect the fluid accumulation in the abdomen and is indicated when the underlying cause of ascites is unknown;

  • Diagnostic abdominal paracentesis is a procedure during which the fluid from the abdomen is obtained by a puncture with the following measurement of the serum-ascitic gradient (SAAG) ;

Management

Treatment of ascites implies the detection and treatment of the underlying cause and depends on it.  The abdominal fluid volume shouldn’t be decreased very quickly as it may lead to collapse, therefore, the goal is to remove not more than 1 l of fluid a day.   

  • Low salt diet

    Restriction of sodium intake to 2 g/day is usually enough, water intake should be restricted to 1-1.5 l/day only if blood sodium levels are low.

  • Diuretics

    Spironolactone is usually prescribed to boost fluid excretion. However, if it is not enough furosemide should be added.

  • Fluid drainage

    In case of severe or refractory to diuretics, large-volume ascites paracentesis should be performed to drain the fluid.

  • Transjugular intrahepatic portosystemic shunt (TIPS)

    TIPS may be used to decompress the liver ducts and reduce the fluid accumulation, although this method is not curative.

 

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