Ascites Flashcards
Define
Accumulation of free fluid within the peritoneal cavity
% survival within 5 years of onset
10-20%
poor prognosis
Ascites is common from what
Post-operation
Complication of cirrhosis
*Main causes
Local inflammation Low protein (inability to pull fluid back into intravascular space by osmosis) Low flow (fluid can't move forwards through system e.g. due to a clot)
When would local inflammation cause ascites
Peritonitis
Intra-abdominal surgery (post)
Abdominal cancers (ovarian)
Infection (TB)
When would you see low protein
Hypoalbumineamia
Nephrotic syndrome
Malnutrition
When would you see low flow (and ascites resulting)?
Cirrhosis (portal hypertension)
Budd-chiari syndrome (occlusion of hepatic veins that drain liver)
Cardiac failure
Constrictive pericarditis
Risk factors
High sodium diet
Hepatocellular carcinoma
Splanchnic vein thrombosis, resulting in portal hypertension
Clinical presentation
- Abdominal swelling (develop over days or wks)
- Distended abdomen
- Fullness in the flanks and SHIFTING DULLNESS
- Mild abdominal pain and discomfort
- Respiratory distress and difficulty eating
- Scratch marks on abdomen (caused by itching due to jaundice i.e. liver failure)
- Peripheral oedema
Why is shifting dullness important in presentation
confirms the presence of fluid
Diagnosis
- Shifting dullness
- Diagnostic aspiration of 10-20ml of fluid using Ascitic Tap
- Protein measurement of ascitic fluid from ascitic tap (transudate or exudate)
What would be done with (diagnostic) aspiration of fluid using ascitic tap
Check for Raised white cell count (bacterial peritonitis)
Gram stain and culture
Cytology and malignancy
Amylase to exclude pancreatic ascites
Protein measurement of ascitic fluid from ascitic tap: what is meant by transudate
Low protein (<30g/L)
Protein measurement of ascitic fluid from ascitic tap: causes of transudate
- Portal hypertension e.g. cirrhosis
- Constrictive pericarditis
- Cardiac failure
- Budd-Chiari syndrome
Protein measurement of ascitic fluid from ascitic tap: what is meant by exudate
High protein (>30g/L)
Protein measurement of ascitic fluid from ascitic tap: causes of exudate
- Malignancy
- Peritonitis
- Pancreatitis
- Peritoneal tuberculosis
- Nephrotic syndrome
Treatment
- Treat underlying cause
- Increase renal sodium excretion (or reduce sodium)
- Drain fluid (paracentesis) - can drain 5 litres at a time, used to relieve symptomatic tense ascites
- Transjugular Intraheptic Portosytemic Shunt (for resistant ascites, risky)
Treatment - what diuretic should be given
Aldosterone antagonist e.g. oral spirolactone
since it spares K+
Describe how ascites results from cirrhosis
In cirrhosis -> peripheral arterial vasodilation (controlled by NO, other vasodilators) -> reduction in effective blood volume
Activation of sympathetic nervous system and RAAS, promoting salt and fluid retention
Oedema formation is encouraged by hypoalbuminaemia and mainly localised to peritoneal cavity due to portal hypertension.
What increased hydrostatic pressure in ascites
Portal hypertension
RAAS activation
What causes oedema in ascites
Oncotic pressure decreases in liver cirrhosis due to hypoalbuminaemia
Hydrostatic pressure > oncotic pressure
Ascites signs
Distended abdomen
Shifting dullness
Investigations
Ascitic tap = culture, gram stain, cytology, protein
Management
Restrict fluid and sodium
Spironolactone
Treat underlying cause
Appearance of transudate vs Exudate
Transudate = clear Exudate = Cloudy
Albumin level in Transudate vs Exudate
Transudate: 11g/L or more below serum albumin
Exudate: <11g/L below the serum albumin
