From the Guidelines
Free fluid in the abdomen, also known as ascites, is most commonly caused by liver cirrhosis, which leads to portal hypertension and decreased albumin production, resulting in fluid accumulation, as supported by the most recent and highest quality study 1.
Causes of Ascites
The causes of ascites can be diverse and include:
- Liver cirrhosis, leading to portal hypertension and decreased albumin production
- Heart failure, resulting in poor cardiac output and increased venous pressure
- Kidney disease, particularly nephrotic syndrome
- Cancer, especially ovarian, pancreatic, or liver malignancies that can obstruct lymphatic drainage or produce fluid
- Infections such as tuberculosis or spontaneous bacterial peritonitis
- Pancreatitis, causing fluid accumulation due to inflammation and enzyme leakage
- Trauma, resulting in hemoperitoneum or chylous ascites if lymphatic vessels are damaged
Diagnosis and Treatment
Diagnosis typically involves physical examination, imaging studies like ultrasound or CT scan, and sometimes paracentesis to analyze the fluid, as recommended by 1 and 1. Treatment focuses on addressing the underlying cause while managing symptoms through measures such as:
- Sodium restriction, with a daily limit of 5g of salt, as suggested by 1
- Diuretics, such as spironolactone or amiloride, as recommended by 1
- Therapeutic paracentesis for severe cases, as supported by 1 and 1 It is essential to note that the management of ascites should prioritize the patient's quality of life, morbidity, and mortality, as emphasized by the need for careful consideration of treatment options and potential complications, as discussed in 1 and 1.
From the Research
Causes of Free Fluid in Abdomen
- Free fluid in the abdomen can be caused by various factors, including solid organ injury, mesenteric and hollow viscus injury, and other conditions such as stercoral perforation of the colon 2
- The presence of free fluid in the abdomen without evidence of solid organ injury can be challenging to diagnose and manage, and may require immediate surgical intervention in hemodynamically unstable patients 3
- Blunt abdominal trauma can also cause free fluid in the abdomen, and the finding of isolated free fluid on computed tomography (CT) is 98% sensitive and 96% specific for true isolated free fluid 4
- Other causes of free fluid in the abdomen include bowel perforation, ascites, and fecal impaction, which can be diagnosed using imaging modalities such as CT and ultrasound 2, 5
Diagnostic Approaches
- Abdominal ultrasound can be used to diagnose free intra-abdominal fluid, and has been shown to augment the ability of medical students to identify free intra-abdominal fluid 6
- CT scanning is also commonly used to diagnose free fluid in the abdomen, and can help identify the underlying cause of the free fluid 3, 4
- Plain film and multidetector computed tomography can also be used to evaluate the site of perforation in cases of small bowel perforation 5
Management
- The management of free fluid in the abdomen depends on the underlying cause and the patient's hemodynamic status, and may require surgical intervention in some cases 3, 4
- Non-operative management may be appropriate for patients with isolated free fluid on CT and no signs of peritonitis or hemodynamic instability 4
- Patients with stercoral perforation of the colon may require emergency laparotomy and close monitoring for complications such as abscesses and sepsis 2