Changes

==Description==

==Description==

An exudate is a type of effusion that has a high cell count and protein content.  It is often associated with [[Inflammation - Pathology|inflammation]] in the body cavities because changes to the endothelium during this process allow protein-rich fluid to escape from the vasculature and because leucocytes migrate out to the site of disease.  As with any type of inflammation, the exudate may occur in response to a bacterial infection ('''septic''') or it may be sterile ('''non-septic''').  The presence of infection and purulent material in the chest cavity is termed '''pyothorax'''. Commons causes of exudates are:

An exudate is a type of effusion that has a high cell count and protein content.  It is often associated with [[Inflammation - Pathology|inflammation]] in the body cavities because changes to the endothelium during this process allow protein-rich fluid to escape from the vasculature and because leucocytes migrate out to the site of disease.  As with any type of inflammation, the exudate may occur in response to a bacterial infection ('''septic''') or it may be sterile ('''non-septic''').  The presence of infection and purulent material in the chest cavity is termed '''pyothorax'''. Commons causes of exudates are:

*Septic

Septic exudates

**Pyothorax may be caused by:

*Pyothorax may be caused by:

***'''Penetrating wounds''' to the thorax, including bites, bullet wounds and stick injuries.

**'''Penetrating wounds''' to the thorax, including bites, bullet wounds and stick injuries.

***'''[[Rupture of the Oesophagus]]'''.  

**'''[[Rupture of the Oesophagus]]'''.  

***'''Migrating foreign bodies''', particularly grass awns in hunting dogs.

**'''Migrating foreign bodies''', particularly grass awns in hunting dogs.

***Severe forms of '''bacterial pneumonia''' that break into the pleural cavity.  

**Severe forms of '''bacterial pneumonia''' that break into the pleural cavity.  

**Septic peritonitis may be caused by:

*Septic peritonitis may be caused by:

***'''Penetrating wounds''' to the abdomen.

**'''Penetrating wounds''' to the abdomen.

***'''Rupture of the intestine''', spilling luminal contents into the peritoneal cavity.  This may be caused by trauma, strangulation, obstruction, ulceration or deeply infiltrative neoplasia.

**'''Rupture of the intestine''', spilling luminal contents into the peritoneal cavity.  This may be caused by trauma, strangulation, obstruction, ulceration or deeply infiltrative neoplasia.

***'''Rupture of an infected uterus (pyometra)''' or pyosalpinx with discharge of pus from the fimbriae of the oviducts into the abdomen.

**'''Rupture of an infected uterus (pyometra)''' or pyosalpinx with discharge of pus from the fimbriae of the oviducts into the abdomen.

***'''Rupture of an infected urinary tract'''.

**'''Rupture of an infected urinary tract'''.

**'''Septic pericarditis''', which is much more common in farm animals and leads to the production of a purulent pericardial fluid.

*'''Septic pericarditis''', which is much more common in farm animals and leads to the production of a purulent pericardial fluid.

*Non-septic

Non-septic exudates

**In the abdomen, chemical peritonitis induced by the prolonged presence of urine or bile will lead to the conversion of a [[Modified Transudate|modified transudate]] into an exudate.  Bile peritonitis is characterised by a distinctive green discolouration of the parietal peritoneum and abdominal organs.

*In the abdomen, '''chemical peritonitis''' induced by the prolonged presence of urine or bile will lead to the conversion of a [[Modified Transudate|modified transudate]] into an exudate.  Bile peritonitis is characterised by a distinctive green discolouration of the parietal peritoneum and abdominal organs.

**'''Acute necrotic pancreatitis''' is associated with necrosis of the peripancreatic fat and discharge of enzymes and other factors into the abdomen.

*'''Acute necrotic pancreatitis''' is associated with necrosis of the peripancreatic fat and discharge of enzymes and other factors into the abdomen.

**'''Neoplasia''' may produce exudates if they have large necrotic portions.

*'''Neoplasia''' may produce exudates if they have large necrotic portions.

**Infection with '''Feline Infectious Peritonitis Virus''' may cause the development of either an exudate or a modified transudate.

*Infection with '''Feline Infectious Peritonitis Virus''' may cause the development of either an exudate or a modified transudate.

==Diagnosis==

==Diagnosis==

===Clinical Signs===

===Clinical Signs===

Exudates may occur in any of the major body cavities:

Exudates may occur in any of the major body cavities.  In the '''abdomen''', there may be signs of abdominal pain (due to the underlying cause of the effusion), an abdominal fluid thrill or a palpable mass.

*In the '''abdomen''', there may be signs of abdominal pain (due to the underlying cause of the effusion), an abdominal fluid thrill or a palpable mass.

In the '''chest''', a pleural effusion (including pyothorax) may cause tachypnoea and dyspnoea if severe. Dullness will be evident on thoracic percussion if a pleural effusion has developed and the heart sounds will be muffled on auscultation.

*In the '''chest''', a pleural effusion (including pyothorax) may cause tachypnoea and dyspnoea if severe. Dullness will be evident on thoracic percussion if a pleural effusion has developed and the heart sounds will be muffled on auscultation.

'''Pericardial effusions''' may be sufficiently severe to cause '''cardiac tamponade''' and right-sided heart failure. The heart sounds will be muffled on auscultation and there may be hepatojugular reflux, a jugular pulse or signs of left-sided forward failure.  The exudate of a chronic septic pericarditis undergoes organisation and replacement with fibrous tissue which bridges the visceral and parietal pericardia.  This results in a '''restrictive pericarditis''' with clinical signs similar to cardiac tamponade.  Infections which penetrate deeply into the cardiac muscle may cause '''myocarditis''' with disruptions of the normal conduction pathways and resultant dysryhthmias.

*'''Pericardial effusions''' may be sufficiently severe to cause '''cardiac tamponade''' and right-sided heart failure. The heart sounds will be muffled on auscultation and there may be hepatojugular reflux, a jugular pulse or signs of left-sided forward failure.  The exudate of a chronic septic pericarditis undergoes organisation and replacement with fibrous tissue which bridges the visceral and parietal pericardia.  This results in a '''restrictive pericarditis''' with clinical signs similar to cardiac tamponade.  Infections which penetrate deeply into the cardiac muscle may cause '''myocarditis''' with disruptions of the normal conduction pathways and resultant dysryhthmias.

Septic processes may be accompanied by more general signs of infection, including '''pyrexia''', depression, lethargy and anorexia. Highly inflammatory exudates may cause severe pain when they damage the parietal pleura or peritoneum.  Affected animals may be reluctant to walk and will stand with a typical 'tucked-up' posture.

*Septic processes may be accompanied by more general signs of infection, including '''pyrexia''', depression, lethargy and anorexia.

*Highly inflammatory exudates may cause severe pain when they damage the parietal pleura or peritoneum.  Affected animals may be reluctant to walk and will stand with a typical 'tucked-up' posture.

===Diagnostic Imaging===

===Diagnostic Imaging===

==Treatment==

==Treatment==

Specific treatment is dependent on the cause of the effusion.  For further details, see the following sections:

Specific treatment is dependent on the cause of the effusion.  For further details, see the following sections:

*[[Peritonitis]]

[[Peritonitis]]

*[[Colic]]

[[Surgical Management of Colic|Treatment of Colic]]

*[[Feline Infectious Peritonitis Virus]]

*[[Feline Infectious Peritonitis Virus]]

*[[Pyothorax]]

*[[Pyothorax]]