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This information is provided by Provet for educational purposes only.

You should seek the advice of your veterinarian if your pet is ill as only he or she can correctly advise on the diagnosis and recommend the treatment that is most appropriate for your pet.

Pericardial effusions are not common in dogs, and they are rare in cats, and differentiating the underlying cause is important so that appropriate therapy can be given.

Basically a pericardial effusion is an abnormal accumulation of fluid within the pericardial sac, and it can consist of :

  • A transudate
    • Right-sided heart failure
    • Hypoproteinaemia
    • Diaphragmatic-pericardial hernia with liver lobe trapped in pericardial sac
  • Inflammatory fluid (exudate)
    • Bacterial infection - foreign bodies, bite wounds, haematogenous spread
    • Feline infectious peritonitis
    • Toxoplasmosis (cats)
    • Coccidiomycosis -  in endemic parts of the world (not in UK)
  • Blood/serosanguinous
    • Neoplasia - the commonest cause of pericardial effusion in dogs.-  aortic body tumours (most often seen in old brachycephalic dogs) , chemodectomas, haemangiosarcoma (especially in German Shepherd Dogs and Golden Retrievers), mesothelioma,  intrathoracic thyroid carcinoma
    • Idiopathic pericardial effusion - second most common cause of pericardial effusion in dogs. Does not occur in cats.
    • Coagulopathies - eg warfarin poisoning
    • Trauma

The history and clinical signs associated with pericardial effusions and the cardiac tamponade that results are the same whatever the fluid consists of :

History :

  • General weakness
  • Poor exercise tolerance
  • Collapse
  • Ascites/pleural effusion may be present as well
  • Weight loss
  • Dyspnoea/tachypnoea - not common

Key clinical findings include :

  • A weak, rapid pulse
  • Heart sounds are difficult to hear (muffled)
  • Distension of the major veins - jugular pulse 

In addition there may be signs associated with an underlying cause, for example :

  • Elevated body temperature if there is infection present
  • Other signs of trauma eg fractured ribs. 
  • Epistaxis
  • Cough - if the animal is in heart failure 
  • Diarrhoea if the re is a protein-losing enetropathy
  • Polydispsia/polyuria if there is a protein-losing nephropathy

The diagnosis is confirmed by radiography with/without ultrasound examination

Management of pericardial effusions involves :

  • Identification and treatment of any primary cause
  • Pericardiocentesis - successful for about 50% of idiopathic pericardial effusions
  • Pericardiectomy - can cure idiopathic pericardial effusions which otherwise require repeated pericardiocentesis. 
  • Rescetion of neoplasm - justifiable for chemodectomas which are slow growing
  • Anti-tumour therapy for neoplasia - eg cisplatin may cause remission in mesotheliomas
  • Haemangiosarcoma - prognosis poor - even after paricardiectomy (mean survival time 4 months)


Updated October 2013