Ascites

ascites

Causes of Ascites

• Causes of ascites 17
  • Cirrhosis - 81%
  • Cancer - 10%
  • Heart failure - 3%
  • Tuberculosis - 2%
  • Dialysis - 1%
  • Pancreatic disease - 1%
  • Other - 2%

Cirr_PH

Causes Of Cirrhosis And Portal Hypertension Seen On Ultrasonography

• Aetiology of hepatic cirrhosis 18
  • Alcohol (60-70 percent)
  • Chronic hepatitis B or C (5-10 percent)
  • Biliary obstruction (5-10 percent)
  • Haemochromatosis (5-10 percent)
  • NASH (10 percent)
  • Other
    • Auto-immune
    • Drugs and toxins
    • Genetic metabolic disease

ct

Computed Tomography (CT)

• Uses and features include:
  • Often has a complementary role with ultrasound in the evaluation of patients with ascites
  • Is a sensitive tool for the detection of ascites 4
  • Provides a more complete evaluation of the abdomen and pelvis which is particularly useful in patients with an unknown source of ascites 3
  • Unlike ultrasound is not impeded by a large amount of bowel gas
• Disadvantages
  • Involves exposure to radiation
  • Risk of contrast allergy and nephropathy if intravenous contrast is used

diagpara

Diagnostic Paracentesis

• Is useful for 5
  • Confirming the presence of ascites
  • Determining the cause of ascites
  • Determining whether the fluid is infected
  • Determining whether portal hypertension is present
    • A serum - ascitic albumin gradient (SAAG) >11g/l indicates ascites due to portal hypertension
    • A serum - ascitic albumin gradient (SAAG) <11g/l indicates ascites due to other causes
• Best done under ultrasound guidance if
  • There is only a small amount of fluid
  • The fluid is loculated
  • The patient has a gross coagulopathy or multiple scars
  • After a failed paracentesis done without ultrasound guidance

doppler

Ultrasound

• Uses and features include
  • Can confirm the presence of ascites as physical examination is only moderately accurate for diagnosis 1
  • Can detect as little as a few millilitres of fluid located anterior to the liver or immediately below the diaphragm 2,3
  • Can help determine the cause of ascites such as portal hypertension, cirrhosis, portal and hepatic vein thrombosis 4,6
  • Can guide paracentesis and is particularly useful where there is only a small amount of fluid or the fluid is compartmentalised 4,5
  • Has a sensitivity and specificity of at least 85% for the diagnosis of Budd-Chiari syndrome 8
• Ultrasound features of portal hypertension include 14
  • Collateral vessels - commonly gastroesophageal, paraumbilical, splenorenal and gastrorenal veins 10,11
  • Enlarged splanchnic veins 12
  • Portal and splenic veins greater than 10mm in diameter (sensitivity and specificity of 82%) 13
  • A patent paraumbilical vein (specificity of 100% and sensitivity of 82%) 15
• Ultrasound features of liver cirrhosis include 14
  • A coarsened, heterogeneous echo pattern
  • Increased parenchymal echogenicity
  • Nodularity of liver surface
• Limitations of ultrasound include 7
  • Poor beam penetration in obese patients and those with multiple air-filled bowel loops
  • Low specificity for characterising liver lesions
  • Operator dependent

liver-biop

Liver Biopsy

• Referral for liver biopsy should be considered after a thorough non-invasive clinical, serological and radiological evaluation has failed to establish a cause of liver cirrhosis. Due consideration must given to the risk/benefit profile prior to considering biopsy, as well as how biopsy results would change management 18
• In a large prospective study which performed 354 liver biopsies for sustained abnormal liver function tests, 18% of patients had their management directly altered by the outcome of the biopsy 19
• There is a significant false negative rate (10-50%) with percutaneous liver biopsy in the diagnosis of cirrhosis. Newer procedures that incorporate mini-laproscopic techniques with direct visualisation of the liver has reduced this rate (15%) 20

no_PH_Cirr

Causes Of Portal Hypertension With No Evidence Of Cirrhosis

• Causes of portal hypertension with no evidence of cirrhosis
  • Alcoholic hepatitis
  • Congestive cardiac failure
  • Massive hepatic metastasis
  • Constrictive pericarditis
  • Budd-Chiari syndrome
    • The Budd-Chiari Syndrome (BCS) refers to obstruction of hepatic venous outflow by a group of heterogeneous disorders 8,12
    • Causes include 16
      • Hypercoagulable states
      • Tumour invasion
      • Idiopathic
    • Doppler ultrasound has a sensitivity and specificity of at least 85% for the diagnosis and is the initial imaging modality of choice if the Budd-Chiari syndrome is suspected 17
    • CT can assist in the diagnosis and compared to ultrasound, provides a more complete assessment of the abdomen
    • Hepatic venography is recommended if there is a strong clinical suspicion of Budd-Chiari syndrome, in the setting of a negative or inconclusive ultrasound result. The classical "spiderweb" pattern is often diagnostic 16

portal

Ultrasound Features Of Portal Hypertension

• Ultrasound features of portal hypertension include 14
  • Collateral vessels - commonly gastroesophageal, paraumbilical, splenorenal and gastrorenal veins 10,11
  • Enlarged splanchnic veins 12
  • Portal and splenic veins greater than 10mm in diameter (sensitivity and specificity of 82%) 13
  • A patent paraumbilical vein (specificity of 100% and sensitivity of 82%) 15

super_asc

Causes Of Ascites In A Patient Known To Have Cirrhotic Liver Disease

• Causes of ascites in a patient known to have cirrhotic liver disease 9
  • Progression of the underlying liver disease
  • Superimposed liver injury (such as alcoholic or viral hepatitis)
  • Development of hepatocellular carcinoma
  • Vascular thrombosis
  • Spontaneous bacterial peritonitis
  • Change to medications/diet

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