Du Quoc Minh QuanGroup 19 – Class Y12DUniversity of Medicine and Pharmacy, HCMC

Ascites

Chapter 4

Abdominal paracentesis Ascitic fluid analysis

Since it’s important to follow a global guideline of diagnosis, treatment and prognosis of a disease, I want you guys to knows a lot about evidence-based medicine before we start

Evidence-based medicine

Abdominal paracentesis

Final confirmation of ascites is based on successful abdominal paracentesis or detection of ascites on imaging

Determination of the cause of ascites is based on the results of the history, physical examination and ascitic fluid analysis.

In general, few other tests are required.

The need of paracentesis

All inpatients and outpatients with new-onset ascites (class I – level C)

All patients with ascites who are admitted to the hospital

Repeat on patients (wheather hospitalized or not) in whom symptoms, signs or laboratory abnormalities suggest development of infection.

Indications

Absolute contraindication Acute abdomen that requires surgery

Relative contraindications Coagulopathy, only when clinically evident

fibrinolysis or disseminated intravascular coagulation (DIC) is present.

Pregnancy Distended urinary bladder Abdominal wall cellulitis

Contraindications

Recent studies show that no deaths or infections were caused by paracentesis.

Abdominal wall hematomas ~ 1% Hemoperitoneum < 0,1% Bowel entry by the paracenteis needle <

0,1%

Complications

No data is supported for transfusing blood products (fresh frozen plasma and/or platelets) routinely before paracentesis in patients with cirrhosis and coagulopathy.

A study of 1100 large volume paracenteses show no hemorrhagic complication despite: No prophylactic transfusions Lowest platelet counts ~ 19000 cells/mm3

(54%<50000) Highest INR ~ 8.7 (75% >1.5 and 26,5% > 2.0)

Transfusion of blood products

Left lower quadrant is the preferred location. On the LLQ abdominal wall:

2 finger breadths (3 cm) cephalad & 2 finger breadths medial to the anterior superior

iliac spine

Has been shown to be thinner and with a larger pool of fluid than the midline. And is usually a good choice for needle

insertion for performance of a therapeutic paracentesis.

Location

Ultrasonography on the LLQ abdominal wall

A 1 or 1.5 inch 21 or 22 gauge needle can be used for diagnostic paracentesis in lean patients

A 3.5 inch 22 gauge needle can be used in obese patients.

Larger caliber (15 or 16 gauge), multi-hole needles can be used for therapeutic paracentesis.

Plastic-sheathed catheters can be shaved off into the peritoneal cavity and can lead to the need for laparoscopy or laparotomy to retrieve the piece that was shaved off.

Size of needle

Ascitic fluid analysis

Most ascitic fluid is transparent and tinged yellow

Blood-tinged fluid may result from either a traumatic tap or malignancy

Bloody fluid from a traumatic tap is heterogeneously bloody ; Nontraumatic bloody fluid is homogeneously red.

Inspection

Cloudy ascitic fluid with a purulent consistency indicates infection

Green or dark-brown ascitic fluid means bilious or deep jaudince / upper GI perforation

White ascitic fluid means chylous

Inspection

Inspection

On the basis of cost analysis, tests can be classified asroutine, optional, unusual, and unhelpful

Tests

! Have not been standardized WBC count in uncomplicated cirrhotic

ascites usually < 500 cells/mm3

Any inflammatory process can result in an elevated ascitic fluid WBC count. SBP is the most common cause (PMNs > 70%).

Raised WBC + bloody fluid can be caused by traumatic tap => correct 1 PMN for every 250 RBC

Cell count and differentials

Can ascitic fluid be classified into exudate/transudate fluid ?

Before the 1980s, the ascitic fluid total protein concentrationwas used to classify ascites as : Exudative (greaterthan 2.5 g/dL [25 g/L]) Transudative (less than 2.5 g/dL [25 g/L]).

Total protein

This classification doesn’t work well. Since 1980s they’ve stopped using these

terms. Nowsaday, total protein can be combined

with SAAG to categorize ascites

But…

The serum-ascites albumin gradient (SAAG) has been proved to categorize ascites better than the total protein concentration or other parameters

The SAAG is based on oncotic-hydrostatic balance => Why ?

Serum-ascites albumin gradient (SAAG)

SAAG = Albuminserum – Albuminascitic fluid

SAAG >=1.1 g/dL (11 g/L) the patient can be considered to have portal hypertension ( accuracy approximately 97%)

The SAAG does not explain the pathogenesis of ascites formation, nor does it explain where the albumin came from—that is, liver or bowel.

How to calculate SAAG

Source of ascites

SAAG > 1.1

Ascites protein < 2.5

Cardiac ascitesBudd-Chiary (early)

Ascites protein > 2.5

CirrhosisBudd-Chiary (late)Alcohol hepatitisAcute liver failure

SAAG < 1.1

Ascites protein > 2.5

Peritoneal pathology- Maglinancy- Tuberculosis

Pancreatic ascites

Ascites protein < 2.5

Nephrotic syndrome

New method - blood culture bottles - with ascitic fluid detects bacterial growth in approximately 80%.

Gene probes are now commercially available for the detection of bacteremia; hopefully, they will also lead to rapid (30-minute) and accurate detection of organisms in ascitic fluid.

Culture will continue to be required, however, for assessment of the susceptibility of the organism to antibiotics

Culture

Normally, LDH molecule is too large to enter the ascitic fluid readily from blood.

[LDH] in ascitic fluid is usually less than one half of the serum level (uncomplicated cirrhotic ascites)

In SBP, ascitic fluid LDH level rises because of the release of LDH from neutrophils.

In secondary peritonitis, LDHascitic fluid > LDHserum , higher than those in SBP

LDH

In uncomplicated cirrhotic ascites, amylaseascitic

fluid usually is one half that of the serum value, approximately 50 U/L.

In patients with acute pancreatitis or intestinal perforation (with release of luminal amylase into the ascitic fluid), the fluid amylase concentration is elevated markedly, usually greater than 2000 U/L approximately five-fold greater than

simultaneous serum values

Amylase

[Glucose]ascitic fluid = [Glucose]serum

Glucose in ascitic fluid in consumed by WBCs or bacteria

=> in late spontaneous bacterial peritonitis (or other infection of ascitic fluid), [Glucose]ascitic fluid drops to 0 mg/dL

Glucose

Have a sensitivity of 60% in detecting malignant ascites. Why ?

Because malignant ascites is caused by: peritoneal carcinomatosis massive liver metastases hepatocellular carcinoma superimposed on

cirrhosis Chylous ascites caused by lymphoma

Cytologic examination

Cytopathology of the cells in asitic fluid

Adenosine deaminase (ADA) levels are used for diagnosing tuberculosis in several locations.

ADA levels showed high sensitivity (100%) and specificity (97%) using cut-off values from 36 to 40 IU/L in diagnosis tuberculosis ascites.

ADA

J Clin Gastroenterol. 2006 Sep;40(8):705-10.Value of adenosine deaminase (ADA) in ascitic fluid for the diagnosis of tuberculous peritonitis: a meta-analysis.

Gram stains of body fluids demonstrate bacteria only when more than 10,000 bacteria/mL are present.

Gram stain of ascitic fluid is most helpful in the diagnosis of free perforation of the intestine into ascitic fluid.

Not useful is SBP, sensitivity rate ~ 10%

Gram-stain

Triglyceride: in opalescent or frankly milky ascitic fluid or diagnosis of chylous ascites

Smear and Culture for Tuberculosis Red blood cell count: in bloody fluid Bilirubin:

should be measured in ascitic fluid that is dark brown

An ascitic fluid bilirubin level > 6 mg/dL) and greater than the serum level of bilirubin suggests biliary or proximal small intestinal perforation into ascitic fluid

We also do

In diagnosis of ascitesJournal of Hepatology 2010 vol. 53 j 397–417

EASL Guideline

Neutrophil count and culture of ascitic fluid (by inoculation into blood culture bottles at the bedside) should be performed to exclude bacterial peritonitis (Level A1)

EASL Guideline

It is important to measure ascitic total protein concentration, since patients with an ascitic protein concentration of less than 15 g/L have an increased risk of developing spontaneous bacterial peritonitis (Level A1) and may benefit from antibiotic prophylaxis (Level A1).

EASL Guideline

Measurement of the serum–ascites albumin gradient may be useful when the diagnosis of cirrhosis is not clinically evident or in patients with cirrhosis in whom a cause of ascites different than cirrhosis is suspected (Level A2)

EASL Guideline

Thank you