Acites Flashcards
What is an acite?
ascites is the non-physiologic accumulation of fluid in the peritoneum, most commonly secondary to liver disease or malignancy
Give the three underlying pathophysiological mechanisms behind ascites:
1) sodium and water retention
2) portal hypertension
3) low serum albumin
What are the 4 causes of acites?
Cirrhosis (75%)
Malignancy (10%)
Heart failure (3%)
TB (1%)
What causes sodium and water retention in liver failure? (3)
1) in liver failure, there is decreased breakdown of peripheral arterial vasodilators such as nitric oxide, ANP and prostaglandins
2) this causes peripheral arterial vasodilation which reduces the effective blood volume of the body
3) this stimulates the sympathetic nervous system and the RAAS system to promote salt and water retention
What two veins join to form the portal vein?
1) superior mesenteric
2) splanchnic
Describe how portal hypertension can cause ascites:
Normally, the liver receives blood from the spleen and gastrointestinal organs via the portal vein. When fibrosis becomes extensive, it is harder for blood to flow through the liver. As a consequence, the blood coming from the portal vein may start to back up, leading to portal hypertension, which refers to increased blood pressure in the portal vein. As a result, fluid may start to leak out of the portal vein and into the abdomen, leading to ascites.
Describe how low serum albumin can cause ascites:
it contributes to a reduced plasma oncotic pressure
Why is there a low serum albumin in liver cirrhosis?
the liver produces albumin
If there is severe abdominal pain associated with ascites, what is the likely diagnosis?
spontaneous bacterial peritonitis
What is spontaneous bacterial peritonitis?
it is a bacterial infection of the ascitic fluid. If not caught and treated promptly, bacteria can enter the bloodstream and lead to sepsis. In turn, sepsis can trigger a systemic inflammatory response and circulatory dysfunction. The end-stage result is organ damage and failure, such as kidney failure, or the worsening of liver failure.
What does acites look like?
The presentation of ascites can vary depending on its severity. Those with mild ascites may have an abdomen that appears normal, whereas those with more severe ascites may have a very large distended abdomen. As the fluid accumulates in the abdominal cavity. The belly button can also protrude from the body with severe ascites.
What does acites feel like to a patient?
Ascites can put pressure within the abdomen, causing it to feel very large and tight. As the abdomen grows larger, the increased pressure on nearby organs may cause abdominal discomfort, lack of appetite, and shortness of breath.
Give two findings on examination that support diagnosis of ascites:
1) positive shifting dullness
2) peripheral oedema
Describe how to carry out the shifting dullness test:
percuss the abdomen to identify any dullness and then roll the patient towards you and percuss in this position to see if the dullness has shifted to an area of prior tympany
Name three laboratory investigations for ascites:
an aspiration of peritoneal fluid should be obtained for:
1) cell count (neutrophil levels for bacterial peritonitis)
2) gram stain and culture
3) protein measurement (serum-ascites albumin gradient)
What are the risk factors for acites?
portal hypertension:
cirrhosis (most common)
alcoholic hepatitis
heart failure
IVC obstruction
Budd-Chiari syndrome
malignancy
hypoalbuminemia
nephrotic syndrome
enteropathy
malnutrition
infections
peritoneal tuberculosis
What are the common symptoms of acites?
abdominal pain
rapid weight gain
early satiety
What may be seen on physical examination?
distended abdomen
peripheral oedema
may see signs of liver disease
spider angiomata
palmar erythema
gynecomastia
hepatomegaly
jaundice
may see signs of heart failure
jugular venous distention
What is the protein measurement unit when analysing peritoneal fluid in ascites?
serum-ascites albumin gradient
What does a serum-ascites albumin gradient higher than 11g/L indicate in ascites?
it is caused by portal hypertension..
What does a serum-ascites albumin gradient lower than 11g/L indicate in ascites?
it is caused by a non-liver cause such as pancreatitis or cancer
Give three conditions associated with straw-coloured ascites fluid:
1) cirrhosis
2) malignancy
3) infection
Give a condition associated with chylous ascites fluid:
obstruction of the main lymphatic duct
Give three conditions associated with haemorrhagic ascites fluid:
1) ruptured ectopic pregnancy
2) pancreatitis
3) abdominal trauma
Give 4 ways in which ascites patients can reduce sodium intake and increase renal Na+ excretion (to produce a net reabsorption of fluid):
1) restrict dietary sodium
2) avoid Na+ retaining or Na+ rich drugs
3) fluid restriction
4) diuretics
What diuretic is given for ascites?
spironolactone (if no response, add furosemide)
Name two classes of drugs rich in sodium:
1) antacids
2) antibiotics
Name two Na+ retaining drugs?
1) NSAIDs
2) corticosteroids
What is the name of the process that drains fluid from the peritoneal cavity?
paracentesis
Give two instances where paracentesis is needed to treat ascites:
1) when a tense, painful ascites needs to be drained
2) diuretic therapy is insufficient
Give two risk factors associated with paracentesis:
1) hypovolaemia
2) renal dysfunction
(due to an accentuation of arteriolar vasodilation)
Name three shunts that can be used to treat ascites:
1) transjugular intrahepatic portosystemic shunt (TIPS)
2) peritoneo-bladder conduit
3) long-term abdominal drain
Describe how a transjugular intrahepatic portosystemic shunt can treat resistant ascites:
it re-routes blood from the portal vein to the hepatic vein to reduce portal hypertension
Describe how a peritoneal-bladder conduit can treat resistant ascites:
it removes ascites fluid from the peritoneal cavity into the urinary bladder through a surgical join
