- Clinical science
Ascites is the abnormal accumulation of fluid in the peritoneal cavity and a common complication of diseases presenting with portal hypertension (e.g., liver cirrhosis, acute liver failure) and/or hypoalbuminemia (e.g., nephrotic syndrome).Other conditions resulting in ascites are chronic heart failure, visceral inflammation (e.g., pancreatitis), and malignant tumors. Clinical features include progressive abdominal distension, shifting dullness, and a positive fluid wave test. Ascites may be associated with abdominal pain in rare cases. An adequate clinical assessment should be followed by imaging (e.g., ultrasound), which helps to identify even very small quantities of ascitic fluid in the peritoneal cavity. If the onset of ascites is spontaneous or the origin is unclear, an abdominal paracentesis and ascitic fluid assessment may be performed (i.e., to determine the appearance, composition). Management involves treating the underlying condition in addition to sodium restriction and diuretic therapy. Severe or refractory ascites may require therapeutic abdominal paracentesis. A severe complication is spontaneous bacterial peritonitis.
- The etiology can be determined using the serum-ascites albumin gradient (SAAG) based on Starling's law.
- Calculation: SAAG = (albumin levels in serum) - (albumin levels in ascitic fluid)
≥ 1.1 g/dL (obsolete term: transudate)
< 1.1 g/dL (obsolete term: exudate)
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- Progressive abdominal distension
- Fluid wave test; : a wave produced by tapping one side of the abdomen; in a patient in supine position; this wave will be transmitted to the other side via ascitic fluid.
- Shifting dullness: change of resonance from dull to tympanic when patient changes from supine to lateral decubitus position.
- Abdominal pain may be present
- Abdominal wall hernias (e.g., umbilical, inguinal, or incisional hernias)
- Peripheral or generalized edema
- Symptoms associated with increased abdominal distension
- Signs of underlying disease
- Chylous ascites
- Bloody ascites
- Dilutional hyponatremia as a result of overhydration despite normal or increased sodium concentration (see )
Ultrasound (best initial test): Reliable detection even of smaller quantities of ascitic fluid: lower limit of detection approx. 30 mL
- Anechoic free fluid can often be located in the perihepatic, perisplenic, and/or in the recto-uterine pouch.
- CT scan
- Ultrasound (best initial test): Reliable detection even of smaller quantities of ascitic fluid: lower limit of detection approx. 30 mL
Ultrasound-guided diagnostic paracentesis
- Indications: first diagnosed ascites, worsening ascites or suspected complication.
- Ascitic fluid analysis
|Criteria for analyzing ascitic fluid|
Portal hypertensive ascites (high albumin gradient)
Non-portal hypertensive ascites (low albumin gradient)
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|Cell count and differentiation|| || |
|Protein concentration|| || |
Eggs (protein) → “EGGsudate”
- Treatment of the underlying disease (e.g., using anticoagulation in case of a thrombosis or tuberculostatics in case of a tubercular peritonitis)
- Sodium restriction
- Regular weight control
- Water restriction or avoiding overhydration
- Portal hypertensive ascites: usually responsive; may be treated in the same way as ascites caused by liver cirrhosis (see ).
- Non-portal hypertensive ascites (exudate): usually not effective; therefore it is essential to focus on treating the underlying disease!
- Regular control of potassium and creatinine during diuretic therapy
Treatment of refractory ascites
- Indication: inadequate response to diuretics, frequent recurrence, or when diuretic therapy is contraindicated
Therapeutic large-volume paracentesis
- The patient should lie on their back or slightly to one side.
- The right or left lateral lower abdomen is a preferred spot for paracentesis (e.g., Monro's point on the Monro-Richter line)
- Ultrasound helps identify the location of larger quantities of ascitic fluid and mark the puncture site.
- Saline infusion after procedure to supplement removed fluids
- Substitution of albumin
- In the case of a large-volume paracentesis (> 5 L), intravenous infusion of 6–8 g albumin per liter ascites is recommended in order to avoid intravascular volume depletion.
- Iatrogenic infection
- Blood pressure drops (monitoring!)
- Impairment of renal function (risk of hepatorenal syndrome)
- Local bleeding
- Therapeutic large-volume paracentesis
- Definition: bacterial infection of ascitic fluid in the absence of other intra-abdominal causes (which would otherwise lead to secondary bacterial peritonitis )
- Etiology and risk factors
- Clinical features
- First-line: 3rd generation cephalosporin IV broad spectrum therapy– e.g., ceftriaxone 2 g IV 1-0-0
- Follow-up after 48 h via repeated paracentesis
- Prognosis: high recurrence (up to 70%) and mortality rate (20–30%)
We list the most important complications. The selection is not exhaustive.