Ascites

First some anatomy,
The diaphragm can be thought of as a flat horizontal muscular sheet which divides the human torso into two main areas. Above is the chest cavity which contains the heart and lungs. Below the diaphragm, lies the abdominal cavity which contains the digestive organs such as the intestines and liver, the urinary system, and reproductive organs. The front wall of the abdominal cavity is made up of skin and muscle tissue, and is covered by an inner lining called the peritoneal membrane. Normally, the abdominal contents are moist, but contain no fluid collections.

Ascites is a medical condition in which excess fluid begins to puddle within the abdominal cavity. This fluid is outside of the intestines and collects between the abdominal wall and the organs within. In extreme cases, the abdomen expands outward and the intestines actually begin to float within this "lake" of fluid. Ascites is not contagious and poses no risk to others.

Causes of ascites
Advanced liver failure accounts for the majority of cases, but about 20% of patients with ascites have a cause other than liver disease. These may be secondary to heart failure, kidney disease, or cancer. Rarely, ascites is due to pancreatic disease, a severely underactive thyroid, malnutrition, or tuberculosis.

Still liver disease is the most common cause. There are many types of liver disease, but most are due to excessive alcohol consumption or chronic hepatitis infection. When people have liver disease for a long period of time, healthy liver cells die and gradually replaced by scar tissue. The word "cirrhosis" means "scar tissue" so this condition is often called cirrhosis of the liver. This scar tissue changes the smooth liver surface into lumps and nodules distorting the normal anatomy and disrupting the blood flow out of the liver. The heart continues to pump blood into the liver with each heartbeat. If the blood cannot flow freely outward, there is an imbalance and excessive pressure builds up in the liver tissue. This is called portal hypertension. In simplistic terms, this pressure imbalance causes the surface of the liver to "weep" fluid into the abdominal cavity which accumulates causing ascites.

Symptoms
In mild cases, there are usually no symptoms. As more fluid accumulates, the abdomen begins to swell. There may be complaints of loss of appetite, frequent heartburn, fullness after eating, or abdominal pain. Eventually, there is marked distention of the abdomen - resembling the later stages of pregnancy. This may cause low back pain, changes in bowel function, and fatigue. During the day, gravity may carry some of the fluid down into the scrotum or legs causing swelling, or edema. Initially, the swelling may subside overnight. As the condition worsens, however, the swelling may extend up the leg and be present day and night. As more fluid accumulates, it may spread up into the chest cavity (pleural effusion) and cause difficulty breathing.

How your doctor knows

When a doctor exams a patient and suspects that ascites might be present, he will usually order further tests to confirm the diagnosis and help determine the cause. These tests usually include an abdominal CT scan and/or ultrasound exam of the abdomen. An ultrasound of the abdomen is often first chosen since it is a simple, non-invasive test, and readily available. Ultrasound is a very sensitive technique and can detect as little as 100 cc (about 3 ounces) of ascites.

If these special tests confirm the presence of ascites, a diagnostic abdominal paracentesis is usually performed. This is a simple procedure in which a needle is passed through the abdominal wall directly into the fluid collection. In this way, a sample of ascitic fluid can be obtained for laboratory analysis. Performed with a local anesthetic to numb the skin, abdominal paracentesis is usually a painless procedure. The risk of complications is quite low - less than 1/1000. These are most often minor, such as a bruise at the site of puncture, but may include internal bleeding, and inadvertent puncture of the intestines. Once the fluid has been obtained, it is sent to the laboratory for analysis which may include: Albumin level
Measurement of this protein in the ascitic fluid and comparison to the albumin level in the blood can help determine if the ascites is a transudate (due to liver/heart failure) or exudate (due to infection/cancer). The level of albumin in the ascitic fluid is simply subtracted from the blood albumin level - the serum-ascites albumin gradient. If the difference is over 1.1, this strongly suggests liver or heart failure as the cause.

Total Protein
When the albumin gradient is over 1.1, the measurement of the ascitic total protein level can help narrow down the diagnosis even further. Patients with cirrhosis or alcoholic hepatitis generally have a low total protein level (less than 1 g/dL). Patients with heart disease usually have an ascitic total protein level over 2 g/dL.

Cell count
To do a cell count, the technician uses a microscope to search for the presence of white blood cells (WBC) that might signify a bacterial infection within the fluid. A WBC count over 250 cell/cc suggests an infection.

Culture and Sensitivity (C&S)
If infection is suspected, the ascitic fluid is placed in bottles of sterile broth. If infection is present, bacteria may grow in the broth and can then be identified to determine which antibiotic is best for treatment. This test takes 2 to 3 days.

Cytology
The cytology technician uses a microscope and special stains to search for free floating cancer cells within the ascitic fluid. Cancer cells are often seen when ascites is due to cancer of the ovaries or when other types of malignancies (breast, colon, stomach, pancreas) have spread within the abdomen cavity. A normal cytology, however, does not rule out cancer since only a minority of cancers that spread within the abdomen shed cancer cells into the ascitic fluid. Only an abnormal (positive) cytology provides useful information. A normal cytology test does not rule out cancer.

AFB smear
If tuberculosis (TB) is suspected because of immigration from endemic areas or the presence of AIDS, this smear for "acid fast" bacteria may be requested.

Amylase level
Hgh levels of this pancreatic enzyme can are sometimes seen in disease of the pancreas - an uncommon cause of ascites.

Sugar and LDH levels
If a secondary infection is suspected, sugar and LDH enzyme levels can be checked in the specimen of ascitic fluid obtained at paracentesis. Ascitic fluid in secondary infection typically has a glucose level less than 50 and an LDH level over the normal blood level.

Treatment
Ascites is not actually a disease, but a symptom. The proper treatment depends upon the underlying cause. If infection, cancer, or heart failure is the cause, the treatment is directed appropriately to the underlying problem. However, in the majority of patients, ascites is a sign of advanced liver failure, or cirrhosis of the liver, for which there is no medical cure. Treatment of ascites does not improve survival rates. Rather, the goal of treatment is to improve symptoms by reducing the amount of fluid in the abdomen. The mainstay of treatment includes:

Avoid further liver damage
Patients who drink alcohol must stop all alcohol consumption. The use of drugs that damage the liver must be avoided - such as high doses of Tylenol.

Education regarding dietary sodium restriction
Patients must learn that it is not too much water intake that perpetuates the accumulation of ascitic fluid in the abdomen, but rather an abnormal retention of sodium (salt) within the body. Thus, sodium restriction, not fluid restriction, is the mainstay of treatment. Dietary sodium intake is usually restricted to less than 2000 mg per day. Stricter sodium restriction can accelerate fluid and weight loss. In most patients, this restriction of sodium results in a drop of sodium levels in the blood (hyponatremia). This does not usually cause any symptoms, but when hyponatremia is severe (blood sodium less than 120), the patient must also be instructed to also limit intake of water and other fluids.

Diuretic therapy ("Water Pills")
Sodium restriction may be the mainstay of treatment, but in most cases of ascites, this alone is not effective. Most patients must also take a daily dose of medications called diuretics, or "water pills." These medications cause increased urine production and help the body excrete extra sodium and water through the kidneys. Common medications include spironolactone (Aldactone), triamterene (Dyrenium), furosemide (Lasix). One regimen begins with 100 mg of spironolactone and 40 mg of furosemide every AM. If there is no weight loss in the first week, the dose is gradually increased up to a maxiumum of 400 mg of spironolactone and 160 mg of furosemide daily. About 90% of patients will respond to this combination of strict sodium restriction and diuretic therapy. Response to treatment varies and determination of the best treatment plan takes time as the dose of medications is adjusted over a period of weeks or months.

Therapeutic paracentesis
The same technique used to obtain a sample of ascitic fluid for testing can also be used to withdraw larger amounts of fluid. This is called a therapeutic or "large volume" paracentesis and is usually restricted to patients with ascites who do not respond to other forms of treatment or in patients with massive ascites. It is not uncommon for these individuals to have as much as 3 gallons of excess fluid in their abdominal cavity. Large volume paracentesis can help by removing about a gallon of fluid per session. Removal of too much fluid at one time can result in a drop in blood pressure. This rapidly relieves tense ascites, but does nothing to correct the underlying cause. The fluid eventually returns. Strict sodium restriction and diuretic therapy must be still be used to slow down the reaccumulation of fluid.

Monitor Progress
During treatment, it is important that patients undergo careful monitoring by their doctor with periodic measurements of body weight and blood tests.. This is especially true in patients taking diuretics which may cause reduced kidney function and changes in the blood levels of sodium and potassium. The rate of fluid loss varies. When the lower legs are swollen, treatment can be more aggressive, but once the edema is gone, the goal slows to about 1 pound of weight loss a day. In the absence of edema, ore rapid fluid loss can result in dehydration and kidney failure.

Refractory Ascites
About 10% of patients with cirrhosis and ascites will not respond to conventional therapy. These cases are considered to be intractable, or refractory to treatment. Refractory ascites is defined as fluid overload that does not respond to a sodium-restricted diet and high-dose diuretic therapy (e.g. 400 mg of spironolactone and 160 mg of furosemide daily). These patients may require repeated large volume paracenteses at intervals of 2 - 4 weeks. Refractory ascites is ominous prognostic sign.

Spontaneous bacterial peritonitis
When analysis of ascitic fluid reveals a white blood cell count of more than 250 cells/cc, a bacterial infection of the fluid is strongly suspected. When this happens without an obvious source of infection such as an abdominal injury or ruptured appendix, it is called spontaneous bacterial peritonitis, or SBP. Risk factors for SBP include advanced liver failure, urinary tract infection, previous SBP, low protein levels, and invasive medical procedures. There are no specific symptoms, so this diagnosis can only be made after a fluid analysis. When the cell count is over 250 cells/cc, empiric antibiotic therapy is usually begun even before the more definitive bacterial culture results are available a few days later. Most often a broad-spectrum antibiotic is utilized such as a third generation cephalosporin such as Claforan (cefotaxime) 2 gms IV every 8 hours for 5 days which covers 95% of infections. Many other broad spectrum antibiotics are available. When culture results become available, a more specific antibiotic may be chosen that more directly targets the organism responsible.

Prevention of SBP is still being studied, but some scientists suggest short-term antibiotic treatment for hospital inpatients with ascites who have very low blood protein levels, esophageal bleeding, especially if they have a prior history of SBP. The drug of choice is norfloxin (Noroxin) 400 mg daily for 7 days. After hospital discharge, about 70% of patients with SBP have a recurrence of infection within one year. That is why some physicians advocate long-term antibiotic use in outpatients who have survived an episode of SBP, but there is no scientific evidence that this is effective.

Surgery
In the 1970's, a popular technique to treat refractory ascites was the LeVeen peritoneovenous shunt. This plastic tube was surgically implanted between the abdominal cavity and a large vein allowing the excess fluid to drain directly into the circulatory system and out through the kidneys. However, the shunt often became clogged with debris and some patients had complications from the ascitic fluid entering directly into their bloodstream. Scar tissue often developed making future liver transplants difficult. The LeVeen shunt is probably best used in refractory patients who do not respond to serial therapeutic paracentesis and are not candidates for liver transplant.

Another procedure is available which lessens the formation of ascitic fluid by diverting excessive pressure in the liver veins into the main veins of the body. This technnique is called the transjugular intrahepatic portasystemic shunt, or TIPS procedure. TIPS is performed under local anesthesia by a radiologist and does not require abdominal surgery. Unfortunately, about 30% of patients develop increased mental confusion after TIPS and most cases have to be redone periodically as scar tissue blocks the shunt. Rarely, progessive jaundice and liver failure develops after a TIPS procedure. These complications limit the usefulness of this treatment.

Liver transplant
Development of ascites as a complication of cirrhosis of the liver is poor prognostic sign. About 50% of patients die of their liver disease within 2 years. Once patients become refractory to routine medical treatment, the prognosis worsens - about 75% are gone within 1 year. Liver transplant is the treatment of choice in appropriate candidates, but unfortunately, not all patients are candidates for this procedure. When appropriate, liver transplant should be considered early as the waiting list is over 12 months. Surgery should be undertaken before the terminal stage of the disease when the person is too ill to withstand major surgery and will not survive until a suitable donor is available.

Hepatorenal syndrome
This name refers to kidney failure that sometimes develops in patients with end-stage liver disease. This may happen suddenly or as a slowly progressive process. Treatment usually involves stopping diuretic therapy, an intravenous fluid challenge, and a search for a reversible cause such as dehydration or infection. Rapid kidney failure in cirrhotic patients with ascites is associated with a mortality rate of over 90% if liver transplant is not performed.

Summary
Ascites is not a disease, but most often, a grave complication of progressive liver failure. Symptoms can be very distressing and affect the quality of life. Patients with ascites are at risk of infection and kidney failure. The mainstay of treatment is dietary salt restriction and diuretic therapy. Each case is different and it may take some time to choose the proper treatment plan. In cases of tense ascites, a paracentesis may help reduce symptoms. Failure to respond to maximal medical treatment may be a sign of patient non-compliance such as not avoiding salt. True refractory ascites is a bad prognostic sign with a high mortality. It requires more aggressive treatment which may include liver transplant.