Ascites

Question 1

… refers to the presence of pathological fluid within the abdominal cavity.

Answer 1

Ascites refers to the presence of pathological fluid within the abdominal cavity.

Question 2

Ascites - In men, no fluid should be present. In women, up to … mls may be considered normal depending on the timing of their menstrual cycle.

Answer 2

In men, no fluid should be present. In women, up to 20 mls may be considered normal depending on the timing of their menstrual cycle.

Question 3

Ascites is most commonly associated with liver disease. In this context, ascites develops due to … ….

Answer 3

Ascites is most commonly associated with liver disease. In this context, ascites develops due to portal hypertension. This refers to increased pressure within the portal venous system that drains blood from the gastrointestinal tract to the liver. Other causes of ascites are broadly due to local infiltration (e.g. tumour) of the peritoneal lining, inflammation or infection.

Question 4

What is portal hypertension?

Answer 4

This refers to increased pressure within the portal venous system that drains blood from the gastrointestinal tract to the liver. Other causes of ascites are broadly due to local infiltration (e.g. tumour) of the peritoneal lining, inflammation or infection.

Question 5

Ascites can be broadly be divided into raised portal pressure (…) or normal portal pressure (…).

Answer 5

Ascites can be broadly be divided into raised portal pressure (transudates) or normal portal pressure (exudate).

Question 6

Ascites, like pleural fluid, can be broadly divided into … or …:

Answer 6

Transudate: due to the ultrafiltration of plasma (i.e. removal of fluid). It does not contain large proteins and only few cells.
Exudate: due to leakage of whole contents of plasma (i.e. fluid, cells and proteins). Largely due to an inflammatory process.

Question 7

…: due to the ultrafiltration of plasma (i.e. removal of fluid). It does not contain large proteins and only few cells.
…: due to leakage of whole contents of plasma (i.e. fluid, cells and proteins). Largely due to an inflammatory process.

Question 8

In …, rather than using the terms transudate and exudate, we refer to raised portal pressure or normal portal pressure.

Answer 8

In ascites, rather than using the terms transudate and exudate, we refer to raised portal pressure or normal portal pressure.

Question 9

Raised portal pressure (transudate) - ascites

Answer 9

Cirrhosis
Acute liver failure
Cardiac failure
Constrictive pericarditis
Budd-Chiari syndrome (hepatic venous thrombosis)
Portal vein thrombosis
Liver metastasis

Question 10

Normal portal pressure (exudate) - ascites

Answer 10

Pancreatitis
Malignancy (peritoneal carcinomatosis - widespread tumour deposition)
Infection (bacterial, fungal, tuberculosis)
Nephrotic syndrome (typically low SAAG with low protein content)
Protein-losing enteropathy
Bowel obstruction
Serositis (e.g. in connective tissue disease)

Question 11

What is the routine medical procedure completed to obtain an ascitic fluid sample?

Answer 11

An ascitic tap describes the routine medical procedure completed to obtain an ascitic fluid sample.

Question 12

An ascitic TAP (abdominal …) is a routine medical procedure that can be completed with ultrasound guidance. It should be an aseptic non-touch procedure that can be completed at the bedside. It involves inserting a small green needle into the abdomen and taking a sample of ascitic fluid.

Answer 12

An ascitic TAP (abdominal paracentesis) is a routine medical procedure that can be completed with ultrasound guidance. It should be an aseptic non-touch procedure that can be completed at the bedside. It involves inserting a small green needle into the abdomen and taking a sample of ascitic fluid.

Question 13

Describe an ascitic TAP

Answer 13

An ascitic TAP (abdominal paracentesis) is a routine medical procedure that can be completed with ultrasound guidance. It should be an aseptic non-touch procedure that can be completed at the bedside. It involves inserting a small green needle into the abdomen and taking a sample of ascitic fluid.

Question 14

Ascitic fluid samples can be sent to the lab for analysis. The two main indications include:

Answer 14

Exclusion of infection: known as spontaneous bacterial peritonitis (SBP)
Determine aetiology of ascites: provisionally based on the serum ascites albumin gradient (SAAG)

Question 15

Investigations for ascites (ascitic fluid sample)

Answer 15

Albumin: to determine the SAAG and risk of SBP
White cell count (WCC): used to assess for SBP
Microscopy, culture & sensitivity: additional samples can be sent in blood culture bottles
Amylase: if pancreatitis suspected
Triglycerides: can be raised in chylous ascites due to disruption of abdominal lymphatics
Cytology: assess for malignant cells
Lactate dehydrogenase (LDH): may be used to differentiate transudates (low <225 U/L) and exudates (high >225 U/L). SAAG preferred.A

Question 16

The serum …-… gradient (SAAG) is used to determine the cause of ascites

Answer 16

The serum ascites-albumin gradient (SAAG) is used to determine the cause of ascites.

Question 17

The … is used to determine whether the aetiology of ascites is from raised portal pressure (transudate) or normal portal pressure (exudate).

Answer 17

The SAAG is used to determine whether the aetiology of ascites is from raised portal pressure (transudate) or normal portal pressure (exudate).

Question 18

…. SAAG (>1.1 g/dL or >11 g/L): transudate

Answer 18

High SAAG (>1.1 g/dL or >11 g/L): transudate

Question 19

… SAAG (<1.1 g/dL or < 11g/L): exudate

Answer 19

Low SAAG (<1.1 g/dL or < 11g/L): exudate

Question 20

A patient presents with new abdominal swelling and reduced mobility. The serum albumin level is 32 g/L. An ascitic TAP is performed using an aseptic non-touch technique. Samples are sent for albumin, white cell count, MC&S and cytology. The ascitic fluid albumin comes back as 9 g/L.

This gives a SAAG of 23 g/L (32 - 9 = 23).
What is the aetiology of the ascites?

Answer 20

Therefore, the aetiology of the ascites is due to raised portal pressure resulting in a transudate. This is most likely to be chronic liver disease or heart failure. Further investigations are utilised to determine the cause.

Question 21

… … … (SBP) refers to bacterial infection in the ascitic fluid.

Answer 21

Spontaneous bacterial peritonitis (SBP) refers to bacterial infection in the ascitic fluid.

Question 22

… is one of the more common complications associated with chronic liver disease. Patients with ascites are at risk of developing bacterial infections. When a bacterial infection occurs within ascites it is called ….

Answer 22

SBP is one of the more common complications associated with chronic liver disease. Patients with ascites are at risk of developing bacterial infections. When a bacterial infection occurs within ascites it is called SBP.

Question 23

SBP is theorised to occur by two mechanisms:

… spread: bacterial translocation across the bowel wall
… spread: bacteria enter ascites via the bloodstream in the context of an immunosuppressed state

Answer 23

Direct spread: bacterial translocation across the bowel wall

Haematogenous spread: bacteria enter ascites via the bloodstream in the context of an immunosuppressed state

Question 24

… may present in a number of ways including peritonitis (i.e. abdominal pain), hepatic encephalopathy, upper gastrointestinal bleeding, acute kidney injury or overt sepsis. It complicates ~10% of inpatient admissions with decompensated chronic liver disease and requires early recognition and treatment

Answer 24

SBP may present in a number of ways including peritonitis (i.e. abdominal pain), hepatic encephalopathy, upper gastrointestinal bleeding, acute kidney injury or overt sepsis. It complicates ~10% of inpatient admissions with decompensated chronic liver disease and requires early recognition and treatment

Question 25

The one-year survival following an episode of SBP is ….-….%

Answer 25

The one-year survival following an episode of SBP is 30-50%.

Question 26

SBP is defined as an ascitic fluid white cell count > 250/mm3 that is predominantly … (i.e. the majority of white cells seen are …). Usually defined as >90%

Answer 26

SBP is defined as an ascitic fluid white cell count > 250/mm3 that is predominantly neutrophilic (i.e. the majority of white cells seen are neutrophils). Usually defined as >90%.

Question 27

Key definitions of SBP

Answer 27

SBP: >250/mm3 of WCC, predominantly neutrophils, cultures positive
Culture negative SBP: >250/mm3 of WCC, predominantly neutrophils, cultures negative
Bacterascites: <250/mm3 of WCC, culture-positive (suggests early-stage SBP or colonisation)
Secondary bacterial peritonitis: multiple organisms on culture, seen in 5%. Suggestive of intra-abdominal pathology (e.g. perforation).

Question 28

SBP is defined as an ascitic fluid white cell count > 250/mm3 that is predominantly neutrophilic (i.e. the majority of white cells seen are neutrophils). Usually defined as >90%.

This is typically associated with a … ascitic fluid culture. However, 60% of patients are culture-…

Answer 28

This is typically associated with a positive ascitic fluid culture. However, 60% of patients are culture-negative

Question 29

Treatment for SBP:

Answer 29

Treatment is with broad-spectrum antibiotics (e.g. third-generation cephalosporin) unless sensitivities for a particular microorganism are available. They can be given on suspicion (i.e. before the ascitic TAP result) to prevent any delay in treatment. Following an episode of SBP, patients require prophylactic oral antibiotics to reduce the risk of further episodes. The typical choice is Rifaximin.