Editing Ascites

''Abnormal accumulation of fluid in the peritoneal cavity.''

== '''Aetiology''' ==

* '''Portal hypertension'''
** Cirrhosis (>80%)
*** ''Caused by renal sodium/water retention and portal hypertension -> increased hydrostatic pressure within hepatic sinusoids and splanchnic vasculature, driving extravasation into the extracellular compartment''
** Non-cirrhotic
*** Pre-hepatic PV obstruction (chronic mesenteric venous thrombosis or multiple hepatic metastases)
*** Post-hepatic venous obstruction (Budd-Chiari syndrome)
*** ''Also caused by increased hydrostatic pressure''
* '''Cardiac'''
** Congestive heart failure
** Chronic pericardial tamponade
** Constrictive pericarditis
** ''Also caused by increased hydrostatic pressure and sodium/water retention''
* '''Malignancy'''
** Peritoneal carcinomatosis
*** Primary peritoneal mesothelioma
*** Metastatic carcinoma
**** GIT - gastric, colonic, pancreatic
**** GUT - ovarian
** Retroperitoneal obstruction of lymphatic channels
*** Lymphoma
*** Lymph node metastases (testicular cancer, melanoma)
** Obstruction of lymphatic channels at the base of the mesentery
*** GIT carcinoid tumours
** ''Malignant cells can produce intra-peritoneal fluid independently; there can be portal hypertension; and the re-absorptive capacity can be reduced by malfunctioning lymphatics.''
* '''Miscellaneous'''
** Bile ascites (iatrogenic or traumatic)
** Pancreatic ascites (acute pancreatitis or pseudocyst)
** Chylous ascites
*** Disruptions of retroperitoneal lymphatic channels
*** Malignant disease (most common cause of chylous ascites; and lymphoma is most common malignancy)
*** ''Can work up further with CT or lymphoscintigraphy if doubt''
** Primary lymphatic hypoplasia
** Infectious
*** Tuberculous peritonitis
** Myxoedema
** Nephrotic syndrome
** Serositis in connective tissue disease

== '''Pathophysiology''' ==

* An imbalance between the peritoneal fluid produced and the capacity of the lymphatic system to drain it
* Depends on mechanism - see italics above

== '''Presentation''' ==

* Full, bulging abdomen with shifting dullness (requires 1.5L of fluid to be present before it can be detected by percussion)

== '''Severity''' ==

* Refractory ascites
** Resistant ascites
*** Unresponsive to diuretics (spironolactone 400mg and furosemide 160mg daily)
*** Poor prognosis
*** Associated with advanced cirrhosis, hepatorenal syndrome
** Intractable ascites
*** Can't tolerate diuretics because of adverse effects

== '''Workup''' ==

* If this is a non-cirrhotic patient, with no known heart or kidney problems, do a CT and sample the fluid as they probably have cancer
* Diagnostic paracentesis
** Indications
*** New ascites
*** Signs or symptoms of infection
*** Therapeutic paracentesis can also be considered
** Technique
*** Don't worry about INR or platelet count - significant bleeding is almost unheard of. Major contraindication is DIC or clinically evident fibrinolysis.
*** Usual site is 3cm medial and 3cm superior to ASIS in LLQ (better than RLQ as caecum can become distended with lactulose)
*** Use either angular or Z-track technique to prevent a leak
*** Appearance
**** Normal - yellow, transparent
**** Cloudy - when leucs > 5000
**** Clear - when <1000 cells
**** Blood - can be from a traumatic tap - should send the fluid in a tube containing an anticoagulant
**** Opalescent - lipid or chylous ascites
** Routine tests
*** Cell count/differential 
**** Total leucocyte count should be <250cell/mm, otherwise suspect SBP
*** Albumin concentration (send serum albumin too)
*** Total protein concentration
** Optional tests
*** Culture/gram stain
*** Glucose concentration
*** LDH
*** Lipase/amylase
** Other tests
*** TB
*** Adenosine deaminase activity (for tuberculous peritonitis)
*** Cytology (suspected malignancy)
*** Triglyceride concentration (will be 2-8x higher than plasma in chylous ascites)
*** Bilirubin
*** Serum pro-BNP, CEA (CA125 is not helpful), ALP
* Calculate serum-ascites albumin gradient (serum albumin - ascitic albumin)
** Directly related to portal pressure
** SAAG >=1.1 g/dL = portal HTN (where there is a large difference between ascitic albumin and serum albumin, ie ascitic albumin is low)
*** Cirrhosis
*** Alcoholic hepatitis
*** Vascular obstructions (PV or Budd-Chiari)
*** CCF
*** Liver mets
*** Fatty liver disease of pregnancy
*** Myxoedema
** SAAG < 1.1g/dL (no portal HTN)
*** Peritoneal carcinomatosis
*** Nephrotic syndrome
*** Pancreatitis
*** Peritoneal TB
*** Serositis
*** Biliary ascites
*** Chylous ascites/post-operative lymphatic leak

== '''Treatment''' ==

* Ascites secondary to cirrhosis
** Results from renal retention of sodium and water
** Goal of treatment is to mobilise ascitic fluid by creating net negative balance of sodium
** Decrease sodium intake
*** Fluid restriction not necessary in cirrhotics on dietary sodium restriction and diuretics - unless they have serum sodium < 125, in which case restrict 1.5L/day
*** 1.5-2g daily sodium restriction
*** Monitor with daily weights, food diary
** Increase sodium excretion
*** Generally both spironolactone and furosemide
* Ascites secondary to malignancy
** Therapeutic paracentesis - either repeated or indwelling catheter
** Diuretics may help if portal hypertension is also present
** Peritoneovenous shunts (Denver shunt) - two silastic tubes connected by a pump; mainly travelling to IJV or SVC
* Low SAAG ascites
** Treat underlying cause
* Chylous ascites
** Maintain or improve nutrition
** Reduce rate of chyle formation
*** High protein, low fat diet
**** Reducing intake of long-chain triglycerides may help, as these are transported in splanchnic circulation as chylomicrons
*** Consider TPN
*** Consider somatostatin and diuretics
*** Most patients settle with non-operative management, but can consider exploration and use of fibrin glue to plug the hole
** Correction of underlying disease process
* Albumin
** Cameron's suggests only giving albumin replacement if >5L of ascites are taken off at a time - no morbidity or mortality benefit, but does lead to better electrolyte balances and creatinine levels afterwards
** Tom says the indications for albumin are if either the patient is low in albumin and needs the replacement, or the patient is at risk of post-paracentesis hypotension due to major fluid shifts. So generally, only need to replace albumin for transudative effusions/ascites.
** Should replace 6-8g/L of fluid removed
* TIPS
** Indications: refractory ascites requiring large volume paracentesis more frequently than monthly, refractory variceal bleeding, and as a bridge to liver transplantation
** Contraindication - worsening hepatic encephalopathy
* Peri-op management of ascites
** Increased risk of AKI, infections including SBP, wound dehiscence and herniation, recurrence of hernia
** Evaluate and stratify liver disease
** Assess urgency of operation
** Optimise patient
*** Hepatologist/HPB/LTU/anaesthetics
*** Bloods - platelets/coags/LFTs/UEC/albumin/BSLs/ammonia
*** Imaging - USS to assess liver/PV/varices
*** Nutrition
*** Medical management of ascites
*** TIPS for refractory ascites
*** Encephalopathy - lactulose
*** Coagulopathy - see cirrhosis topic
*** GOC - transplant



[[Category:Liver]]