Ascitic fluid analysis
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The document discusses ascites, its diagnosis, causes, and classification, with emphasis on the role of imaging tests and paracentesis in identifying fluid presence and its etiology. It outlines the grading system for ascites and the significance of laboratory tests performed on ascitic fluid, such as cell count, albumin gradient, and cultures. Additionally, the document highlights the differentiation between infections and other conditions causing ascites, including specific tests for tuberculosis peritonitis.
Ascitic fluid analysis
- 1. Ascitic Fluid What do you do Muhammad Asim Rana MBBS, MRCP, MRCPS, FCCP, EDIC, SF-CCM Critical Care Medicine King Saud Medical City
- 2. Ascites • Diagnosis: • established with a combination of a physical examination & an imaging test (USG). • Approx 1500 mL of fluid had to be present for flank dullness to be detected • lesser degrees of ascites can be missed. • Ultrasonography can be helpful when the physical examination is not definitive
- 3. Causes of Ascites • Ascites can be classified based on the underlying pathophysiology: • Portal hypertension – Cirrhosis – Alcoholic hepatitis – Acute liver – Hepatic veno-occlusive disease (eg, Budd-Chiari syndrome) – Heart failure – Constrictive pericarditis – Hemodialysis-associated ascites (nephrogenic ascites)
- 4. Causes of Ascites • Hypoalbuminemia – Nephrotic syndrome – Protein-losing enteropathy – Severe malnutrition • Peritoneal disease – Malignant ascites (eg, ovarian cancer, mesothelioma) – Infectious peritonitis (eg, tuberculosis or fungal infection) – Eosinophilic gastroenteritis – Starch granulomatous peritonitis – Peritoneal dialysis
- 5. Causes of Ascites • Other etiologies – Chylous ascites – Pancreatic ascites (disrupted pancreatic duct) – Myxedema – Hemoperitoneum
- 7. International Ascites Club Grading system • Grade 1 – Mild ascites detectable only by ultrasound examination • Grade 2 – Moderate ascites manifested by moderate symmetrical distension of the abdomen • Grade 3 – Large or gross ascites with marked abdominal distension
- 8. Older system grades • However, the validity of the grading system has not yet been established. In particular, the natural history of "grade 1" ascites is unclear. Grades ascites from 1+ to 4+ is also used. – 1+ is minimal and barely detectable, – 2+ is moderate – 3+ is massive but not tense – 4+ is massive and tense
- 9. Abdominal Paracentesis • Most efficient way to confirm the presence of ascites, diagnose its cause, and determine if the fluid is infected. • Safe procedure, with an extremely low incidence of serious complications despite the coagulopathy that is usually present in patients with cirrhosis. • Coagulation parameters beyond which paracentesis should be avoided. • There are no data-supported however, patients with clinically evident fibrinolysis or disseminated intravascular coagulation should not undergo paracentesis.
- 10. Tests performed on ascitic fluid • Routine tests • Cell count and differential • Albumin concentration • Total protein concentration • Culture in blood culture bottles • Optional tests • Glucose concentration • LDH concentration • Gram stain • Amylase concentration •Other tests •Tuberculosis smear and culture •Cytology •Triglyceride concentration •Bilirubin concentration
- 11. Asitic Fluid Appearance Appearance interpretation Clear Uncomplicated ascites in the setting of cirrhosis is usually translucent yellow Turbid or cloudy Spontaneously infected Milky "chylous ascites" Milky fluid usually has a triglyceride concentration greater than serum and greater than 200 mg/dL (2.26 mmol/L) and often greater than 1000 mg/dL (11.3 mmol/L). Cirrhosis ,abdominal malignancy & lymphatic abnormalities. Pink or bloody (RBC of >10,000/mm3) "traumatic tap“, or malignancy Brown Deeply jaundiced patients have brown ascitic fluid with a bilirubin concentration approximately 40 percent of the serum value. If the ascitic fluid is as brown as molasses and the bilirubin concentration is greater than the serum value, the patient probably has a ruptured gallbladder or perforated duodenal ulcer
- 12. Cell count and differential • The cell count with differential is the single most helpful test performed on ascitic fluid to evaluate for infection. • Polymorphonuclear count ≥ 250/mm3 – spontaneous bacterial peritonitis. • In bloody ascites: – one neutrophil should be subtracted from the absolute neutrophil count for every 250 red cells to yield the "corrected neutrophil count“.
- 13. Serum-to-Ascites Albumin gradient • The serum-to-ascites albumin gradient (SAAG) accurately identifies the presence of portal hypertension and is more useful than the protein- based exudate/transudate concept. • SAAG – serum albumin value - ascitic fluid albumin – (obtained on the same day). • SAAG ≥ 1.1 g/dL (11 g/L) – Indicates portal hypertension – (Budd-Chiari syndrome, heart failure, or liver cirrhosis) • SAAG <1.1 g/dL (<11 g/L) – Indicates that the patient does not have portal hypertension.
- 14. Sending Cultures • Bacterial cultures of ascitic fluid should be sent from patients with – new onset ascites • admitted with ascites • Who deteriorate with – Fever, – Abdominal pain – Azotemia, – Acidosis – confusion
- 15. Protein, Glucose, LDH • Protein — Ascitic fluid had been classified as an exudate if the total protein concentration is ≥2.5 or 3 g/dL and a transudate if it is below this cut-off. However, the exudate/transudate system of ascitic fluid classification has been replaced by the SAAG. • Measurement of total protein, glucose, and lactate dehydrogenase (LDH) in ascites may also be of value in distinguishing SBP from gut perforation into ascites • Patients with ascitic fluid that has a neutrophil count ≥250 cells/mm3 and meets two out of the following three criteria are unlikely to have SBP and warrant immediate evaluation to determine if gut perforation into ascites has occurred. – Total protein >1 g/dL – Glucose <50 mg/dL (2.8 mmol/L) – LDH greater than the upper limit of normal for serum. – Bilirubin concentration should be measured in patients with brown ascites
- 16. Glucose, LDH, Amylase Condition Glucose Uncomplicated cirrhotic ascites Similar to serum glucose peritoneal carcinomatosis Low gut perforation May be undetectable Condition LDH ascitic fluid/serum (AF/S) ratio uncomplicated cirrhotic ascites 0.4 SBP ratio approaches 1.0 infection or tumor. more than 1.0 Condition ascitic Amylase AF/S ratio of amylase uncomplicated cirrhotic ascites 40 IU/L 0.4 pancreatitis or gut perforation ↑ ↑ Pancreatic ascites ↑↑↑ (2000 IU/L) ↑↑↑ ( 6.0)
- 17. Tests for tuberculous peritonitis • Direct smear • 0 to 2% sensitivity in detecting Mycobacteria. • Culture • When one liter of fluid is cultured, sensitivity for Mycobacteria 62 to 83% . • Fluid for PCR for tuberculosis . • Cell count • Tuberculous peritonitis can mimic the culture-negative variant of SBP, but lymphocyte cells usually predominate in tuberculosis. • Adenosine deaminase • Adenosine deaminase activity of ascitic fluid has been proposed as a useful non-culture method of detecting tuberculous peritonitis; however, patients with cirrhosis and tuberculous peritonitis usually have falsely low values .