Ascites in Chickens

When chickens appear dull with weight loss and swollen abdomens are presented our immediate conclusion is that the bird has peritonitis.

However, in a small number of cases there can be other causes of abdominal enlargement.

Before treating or euthanising a chicken for peritonitis, always check for pyrexia (temperature of over 42°C) and carry out abdomenocentesis to check for an exudate rather than a modified transudate.

Carrying out abdomenocentesis

• Prepare the skin on the most ventral portion of the abdomen. This may necessitate removing the feathers. Next using chlorhexidine and surgical spirit.
• Insert a 21gauge needle into the abdomen. Always insert the needle caudo-dorsally just to the right of midline taking care to avoid the liver and air sacs (Powers 2010).

Bacterial culture and sensitivity can be used to confirm sterility of the sample or peritonitis. If the sample is sterile, then there are a number of other potential causes for ascites.

NB: If peritonitis has been ruled out, do not drain the fluid unless the patient is showing signs of respiratory distress (Hochleithner 2013).

Liver dysfunction (Hochleithner 2013)

Liver function can be assessed by measuring bile acid levels in the blood - use a lithium heparin tube. Liver enzymes levels are non-specific. Radiography can be used to assess liver size; in chickens, the liver tends to fit just inside the rib cage. Ultrasonography can also be used to detect changes in the liver architecture. If liver disease is suspected then a biopsy may be carried out.

Generally speaking, liver damage can be associated with other non-specific signs such as weight loss, inappetance and green-coloured diarrhoea. Because birds produce predominantly biliverdin, jaundice is not a common sign of liver dysfunction.

Hepatic lipidosis can occur due to an inappropriate diet such as where birds are fed excessive amounts of treats including mixed corn. Serum levels of lipids can be used to assist in the diagnosis. Lactulose and milk thistle can be used to help these patients together with correcting the diet. In the short term a carbohydrate based nutritional aid can be used.

Amyloidosis

Amyloid can accumulate in the liver due to chronic inflammation. In most cases it is fatal. Attempts to identify and resolve the underlying cause may be carried out along with supportive therapy such as the use of milk thistle.

Infection

Protozoa such as blackhead can cause hepatic dysfunction however such cases ten to either recover or die rapidly thus ascites does not usually have the chance to develop.

Bacterial infections such as TB and Chlamydophila can cause disease. In both of these cases prolonged antimicrobial therapy may help but usually are unsuccessful.

Neoplasia

Neoplasia in chickens is all too common and can be due to viruses such as Marek’s disease or lymphoid leucosis. Unfortunately, in such cases euthanasia is the only option.

Cardiac Dysfunction

The heart can be examined through ultrasound or radiographically. See http://avianmedicine.net/content/uploads/2013/03/12_cardiology.pdf for more information on assessing cardiac function. This is usually something to be carried out at a referral practice.

Potential caused of cardiac failure are: endocarditis, chronic respiratory disease or more commonly neoplasia.

Where endocarditis is the cause the prognosis is guarded. A prolonged course of Marbofloxacin may be attempted together with symptomatic therapy.