Accumulation of fluid in the peritoneal cavity: possible causes and symptoms of ascites
Ascites can result from liver disease, heart disease or tumours in the abdominal organs. Examining the fluid is essential to make the right diagnosis
Ascites is an accumulation of fluid in the peritoneal cavity, the space between the membranes lining the entire abdomen.
It is a condition that can be a sign of many diseases, especially liver-related, but not only.
The peritoneal cavity
Our abdomen is covered by a thin membrane called the peritoneum.
It is composed of 2 layers
- the visceral peritoneum, which lines the organs;
- the parietal peritoneum, which acts as a wall.
In the thin cavity between these layers, there is a small amount of fluid to prevent friction between the various internal organs.
When the amount of fluid in the peritoneal cavity increases, the two thin layers separate and ascites forms.
A condition that can be mild, medium or severe, depending on the amount of fluid present.
The causes of ascites
Ascites is a pathological condition that in most cases is associated with liver disease, although it is not the only organ potentially involved. In this case, the diseases that can lead to ascites are mainly:
- cirrhosis of the liver, whether viral or alcoholic;
- Budd-Chiari syndrome (a thrombosis of the supra-hepatic veins), which causes a closure of certain blood vessels. This phenomenon is created by an increase in pressures within the blood vessels of the liver, particularly within the portal vein, and, in the cirrhotic patient, also by a reduction in oncotic pressure, i.e. that which retains fluids within the blood vessels. Both of these conditions, which occur in the advanced stages of cirrhosis, can lead to the formation of fluid in the peritoneal cavity.
The heart and cancer
The heart can also be an indirect cause of ascites formation, particularly right heart failure.
As our Institute specialises in cardiovascular pathologies, in particular birth defects of the heart, we frequently treat ascites in adult congenital heart patients.
Pulmonary hypertension and right-sided decompensation can affect the liver and, consequently, increase pressures and the formation of ascites.
Last but not least, neoplasms of internal organs, such as the ovary, pancreas or intestine, may also be the cause of ascites.
These give rise to peritoneal carcinomatosis (the spread of neoplastic cells within the peritoneal cavity), which manifests itself in the formation of ascitic fluid.
Ascites, the symptoms
Patients with ascites usually come to an outpatient clinic or emergency department showing an increase in abdominal circumference, sometimes very evident to the extent of creating a herniation of the umbilicus, and complaining of:
- abdominal pain;
- difficulty eating.
Diagnosis of ascites
A simple ultrasound examination reveals the presence of fluid where it should not be: around internal organs (such as the liver or spleen) or free between the intestinal loops.
It is essential to take this fluid in order to carry out an in-depth analysis that can give us answers about the nature of this fluid.
We do a cell count and investigate the presence of proteins, albumin, LDH (lactate dehydrogenase) enzyme, assess whether the fluid is infected and look for the presence of malignant tumour cells.
This investigation is essential and allows us to make a correct diagnosis, because the causes of ascites can be varied.
Ascitic fluid can be of 2 types:
- exudate: a non-inflammatory fluid;
- exudatious: inflammatory, characterised by high levels of proteins, albumin, LDH, with possible increase in red and white blood cell counts, presence of tumour cells and isolation of germs.
Paracentesis: the examination that draws ascitic fluid
The examination in which the ascitic fluid is taken is called paracentesis:
- exploratory paracentesis, which is limited to the analysis of the fluid;
- evacuation paracentesis, which removes the fluid.
If it is necessary to remove the fluid, the manoeuvre is performed in an outpatient setting by specialised personnel.
Once a point on the left flank has been identified, after local anaesthesia, a needle is inserted to evacuate the fluid within a few hours.
In the case of severe ascites, the amount can be up to 10 litres.
For some patients, such as congenital heart patients, paracentesis may be a procedure to be performed periodically, especially in advanced stages of the disease.
For some diseases, on the other hand, diuretic therapy, which promotes renal elimination of fluid, may be sufficient.