Definition:
Ascites is the abnormal accumulation of fluid within the abdominal cavity which if severe can cause significant abdominal distension and respiratory compromise.
Signs:
General: cachexia, pallor
Abdominal distension with umbilical eversion and shifting dullness or fluid thrill on palpation
Signs of chronic liver disease
Lymphadenopathy if underlying malignancy
Raised JVP (Right heart failure/CCF)
Large abdominal scars – may indicate previous tumour resection
Smaller scars/dressings indicating recent paracentesis or ascitic tap
Peripheral oedema
Symptoms:
Abdominal distension and discomfort
Weight gain
Breathlessness if significant ascites
Nausea
Symptoms related to underlying cause e.g. change in bowel habit, PR bleeding if colorectal malignancy, or peripheral oedema in congestive cardiac failure or nephrotic syndrome
Causes:
Most common:
Cirrhosis with portal hypertension (usually secondary to alcoholic liver disease or viral hepatitis)
Malignancy – most commonly gastric, ovarian, liver metastases or lymphoma
Congestive Cardiac failure
Nephrotic syndrome
Less common:
Budd-Chiari syndrome
Portal vein thrombosis
Constrictive pericarditis
Malabsorption
Abdominal TB
Hypothyroidism
Ovarian disease
Investigations:
Full liver screen (see chronic liver disease document)
Abdominal USS
Colour flow Doppler if Budd Chiari syndrome suspected
Echo
Urine dip – ?protein (nephrotic syndrome)
If new ascites or if the diagnosis is uncertain an ascitic tap should be performed with specimens sent for:
- Microscopy, gram stain and culture
- Cytology
- Cell counts including differential white cell count
- Albumin, LDH, glucose and amylase
- The macroscopic appearance of the ascitic fluid should be noted (e.g. is it blood stained or turbid)
- Ensure a recent serum sample has been sent for albumin level so that SAAG can be calculated
Calculate serum ascites:albumin gradient (SAAG):
Serum albumin-ascites albumin
If >1.1 then likely transudative ascites caused by portal hypertension (heart failure, cirrhosis, nephrotic syndrome)
If <1.1 then likely exudative ascites (TB, pancreatitis, malignancy)
Management:
Investigate and treat underlying cause if possible
Salt restriction and optimise patient’s nutrition
Diuretics – start with spironolactone and then add in loop diuretics if further diuresis still required – aim to achieve 1kg weight loss/day with close monitoring of electrolytes and renal function
Daily weights
Therapeutic paracentesis may be necessary – particularly if there is very large or tense ascites causing discomfort or breathlessness – however only temporary option as fluid reaccumulates quickly
Consider a TIPS procedure if portal hypertension and requiring frequent paracentesis
Exudative ascites less likely to respond to diuretics
Therefore try to treat the cause and consider therapeutic paracentesis for symptom relief
Complications of ascites:
Spontaneous bacterial peritonitis (SBP) is one of the most common complications of ascites and this can be life-threatening. It is due to intra-abdominal bacterial infection causing peritonitis. SBP should be suspected if a patient with ascites develops fever and worsening abdominal pain. It can sometimes present atypically e.g. with drowsiness. Ascitic fluid tends to be turbid with high WCC. SBP requires urgent admission to hospital for assessment and intravenous antibiotics and paracentesis. A full septic screen should be sent off including blood cultures as it is important to try to identify the organism before antibiotics are started. This may not be possible if the patient is grossly septic, in which case empirical treatment should be started.
Top tip:
Ascites without signs of chronic liver disease is usually secondary to malignancy – look carefully for signs of an underlying primary tumour
Ensure you examine the JVP in a patient with ascites and to complete your examination state that you would want to perform a full cardiovascular examination
Only mention conditions which you would be comfortable to explain in further detail – don’t mention Budd-Chiari syndrome in your differential if you don’t know what this is!
In the interests of time, when examining for ascites only perform either shifting dullness or a fluid thrill tests in the exam, don’t do both.
Written by Jo Corrado
Resources used to write this document are listed in the references section of this webpage