MDJunction - People Helping People
 
Ask a Question
05/26/2011 04:52 PM

Informative article/Ascites

TamieJP
TamieJPPosts: 2315
Senior Member

http://www.endonurseinstitute.com/c_ascites.html

Key Points for Diagnosing Ascites

Author: Terry Markiewicz, MS, RN, CGRN

Ascites is a condition often seen by GI nurses. It is an accumulation of fluid in the abdominal cavity. The name comes from a Greek word, "askos," which means bag or sack. The exact mechanisms in the formation of ascites are unclear. It can be the result of hepatic or non-hepatic causes.

In the United States, cirrhosis is by far the most common cause of ascites, accounting for approximately 85 percent of all cases. Most liver disease in our country is related to alcohol, so most patients with ascites are alcoholics. Malignancies, heart disease, tuberculosis, dialysis and other disorders account for the remainder of cases.

Patient History

Diagnosing ascites should include a few key points. The patient's history is crucial and should incorporate questions directed at intake of alcohol. Daily consumption of approximately 80 grams of ethanol for a time period of 10 to 20 years is necessary for the development of cirrhosis. This equals eight beers, a liter of wine or eight ounces of hard liquor. As many of us have witnessed, people often understate their alcohol intake, so careful questioning is crucial.

Weight is becoming increasingly more important in the formation of liver disease. It may be possible that as the tendency toward obesity in the United States continues, nonalcoholic steatohepatitis (NASH) will overtake alcohol as the primary cause of cirrhosis. This is an inflammation of the liver as a result of an accumulation of fat. As well as weight, diabetes and hyperlipidemia contribute to NASH. NASH may be suspected in a patient with cirrhosis with no other obvious cause.

Along with alcohol use and NASH, chronic Hepatitis C is a common cause of cirrhosis. The patient should be questioned about risk factors, such as blood transfusions, substance abuse, tattoos and acupuncture, dialysis, or birth in a region known for high rates of Hepatitis C.

Cirrhosis from unknown causes is termed "cryptogenic." With a detailed patient history and specific lab testing, the incidence of cryptogenic cirrhosis is dropping.

Ascites can also be caused by malignancies. Major sources are peritoneal carcinomatosis, breast, colon, lung and pancreatic cancers. A small percentage of people with ascites have more than one cause, and this makes diagnosis that much more difficult.

Physical Findings

Certain physical findings are associated with ascites. Abdominal girth is a clue, but this is not specific to ascites; it can also be increased by bowel distention, tumors or other sources.

A test called the ‘puddle sign' can detect as little as 120 ml of ascitic fluid. The patient lies prone for several minutes, then rises to the hands and knees. A stethoscope is placed on the most dependent portion of the abdomen. As the stethoscope is moved across the abdomen away from the examiner, a finger is flicked against the abdomen. Increasing loudness at the edge of the ‘puddle' suggests the presence of ascites. This can be a difficult position for some patients to maintain.

Another test, for "shifting dullness," can also be used, but is not very sensitive in overweight patients. The patient lies in a supine position. The examiner percusses from the tympanic bowel downward to a line of dullness, and this line is marked. The patient then turns to one side, and the examiner again percusses and remarks the line of dullness. A significant shift in the line suggests toe presence of at least 500 ml of ascitic fluid.

Large amounts of fluid are necessary for a "fluid wave" to be present. One examiner presses on the patient's abdomen vertically at the midline. A second examiner taps the flank sharply with one hand while palpating the opposite side. If ascites is present, the second examiner will feel the impulse of the tapping with the other hand.

Ultrasound is also useful in detecting the presence of ascitic fluid. CT scans can also do this, but they come with the risks of X-ray exposure and reaction to dye. Additionally, ultrasounds may be more cost effective.

Paracentesis

The gold standard for diagnosing ascites is abdominal paracentesis. Generally, the patient is lying on the back with the head of the bed slightly elevated. A needle of sufficient length to penetrate through the abdominal wall is used. Areas with scar tissue should be avoided due to possible adhesions. The lower left quadrant is the site used most frequently. If there are multiple scars, ultrasound can be used to determine an appropriate site.

A "Z" technique is used to seal off any leakage of fluid after the needle has been removed. The skin is pulled downward while the needle is inserted, and released once ascitic fluid is flowing.

Lab tests performed with the initial paracentesis should include cell count, albumin, and total protein at a minimum. Other tests may be done as indicated by the patient's history. Additionally, the overall appearance of the fluid can be useful.

Uncomplicated ascites fluid is generally clear yellow. Blood may indicate trauma during the needle insertion, or it may be a sign of malignancy. Ascitic fluid that is infected will be cloudy. Milky (chylous) fluid most often indicates the presence of triglycerides. Elevated serum bilirubin levels will cause a brownish coloration. Fluid that is dark brown may mean a biliary perforation, ruptured gall bladder or perforated duodenal ulcer.

Ascitic fluid for cell count is collected in a purple-top tube with EDTA, an anticoagulant, to prevent clotting. WBC and PMN (neutrophil) counts are usually the most important data from cell counts.

Close to the time of paracentesis, a serum albumin should be obtained. Ideally, the specimens should be obtained within an hour of each other. Along with the ascitic fluid albumin level, the serum–to ascites albumin gradient (SAAG) is calculated. The ascitic fluid albumin level is subtracted from the serum level. If the difference, or gradient, is greater than 1/1g/dL, portal hypertension is present.

A smaller gradient can almost certainly exclude the possibility of portal hypertension. Causes of low SAAG ascites include peritoneal carcinomatosis, TB, dialysis, surgically-caused ascites and cardiac disease.

Ascitic Fluid Infections

Culturing of ascitic fluid is commonly done whenever infection is suspected. Keep in mind that signs of ascites fluid infections can be very subtle, so cultures may be indicated even for very mild or questionable symptoms. Cirrhotic patients are more prone to infections due to immune system defects. Blood culture bottles should be prepared and filled at the bedside for the best results. Infected ascitic fluid can fall into one of five types.

Spontaneous bacterial peritonitis (SBP) has a positive culture and an elevated PMN count. These patients should also have no identifiable source of infection that could be treated surgically. Monomicrobial nonneutrocytic bacterascites (MNCool is distinguished by a fluid culture that is positive for only one organism, and has a decreased PMN count, as well as no source of infection that could be surgically treated.

Culture-negative neutrocytic ascites (CNNA) will have negative cultures, but elevated PMN count. The PMN count must be determined before any antibiotics have been given for proper classification as CNNA. CNNA may actually be SBP, but with poor results from the ascitic fluid culture for whatever reason. These three types of ascitic fluid infections are spontaneous.

Additionally, infections can be classified as secondary bacterial peritonitis. This diagnosis is made with a culture that is positive for more than one organism, the PMN count is elevated, and there is an identifiable surgically treatable source of infection. This category may require emergency surgery. The remaining type of ascitic fluid infection is most often caused by a traumatic paracentesis, with bowel bacteria leaking into the peritoneal cavity, and is not often seen. Polymicrobial bacterascites is marked by positive cultures for more than one organism and a low PMN count.

A newer development that is being studied is the use of bedside reagent strips (dipsticks), which may reduce the time for positively diagnosing infected ascitic fluid.

In addition to infections of ascitic fluid, other complications include cellulitis, tense ascites (which should be treated immediately with therapeutic paracentesis), pleural effusion (if the effusion is large in a cirrhotic patient, this is referred to as hepatic hydrothorax; this may be the result of a diaphragmatic defect) and abdominal wall hernias.

Treatment of Ascites

Treatment of ascites depends on the cause. Of those with low SAAG ascites, the most common cause is peritoneal carcinomatosis. If the malignancy is ovarian, surgical debulking of the tumor and chemotherapy may be beneficial. If the cause is other than ovarian, life expectancy is short and treatment may be limited to therapeutic paracentesis. Diuretics for these patients may only serve to reduce circulating volume and not reduce the volume of ascitic fluid. Other low-SAAG types of ascites may be cured by dealing with the underlying cause.

Infected ascitic fluid should be treated with appropriate antibiotic therapy. If there is an identified source that is surgically treatable, emergency surgery may be indicated.

High-SAAG ascites is almost always caused by cirrhosis. If the patient is alcoholic, ascites may actually be resolved, or at least become more responsive to treatment, if alcohol intake is stopped. With many patients, however, this may not be possible. Education on a diet low in sodium, for the patient and whoever may be preparing food, will be vital. Fluid restrictions at home are not likely to be successful. Diuretics may be helpful to reduce the volume of ascitic fluid. Therapeutic paracentesis is beneficial.

Older wisdom dictated that only limited volumes of ascitic fluid be removed at any one time, for the fear of hemodynamic instability. Newer knowledge has replaced this; many liters of ascitic fluid can be safely taken off. Additionally, paracentesis can be repeated as ascites fluid reaccumulates.

TIPS (transjugular intrahepatic portosystemic shunt) is a procedure usually done under local anesthetic that can help reduce ascites that does not respond to diuretics. A stent is placed in the liver between the portal vein and a hepatic vein to enhance blood flow and reduce pressure. This procedure is performed in interventional radiology.

Prognosis of Cirrhotic Patients

The prognosis of patients with cirrhosis can be determined by using the Child-Pugh scoring system. Points are assigned based on serum bilirubin and albumin levels, INR, presence and degree of ascites, and presence and degree of encephalopathy. The points are totaled; the larger the total (as in Class C, representing the highest total), the lower the life expectancy.

Conclusion

Ascites can be the result of a variety of causes. As GI nurses, many of the patients we see will have cirrhosis as the cause. Patient history and careful specimen collection are fundamental to diagnosing and treating this population.

Reply

05/27/2011 03:19 AM
cocoa2010
Posts: 106
Member

thank you Tamie

Have copied to read later

x


05/27/2011 07:26 AM
cocoa2010
Posts: 106
Member

Tamie

Thank you so much for this, very, very useful. I have noted the site too!

take care

x

Reply

Share this discussion with your friends:


Disclaimer: The information provided in MDJunction is not a replacement for medical diagnosis, treatment, or professional medical advice.
In case of EMERGENCY call 911 or 1.800.273.TALK (8255) to the National Suicide Prevention Lifeline. Read more.
Contact Us | About Us
Copyright (c) 2006-2014 MDJunction.com All Rights Reserved