Pericardial effusion (PE) is in the list of differential diagnoses when a patient presents with weakness or collapse, weak
pulses and muffled heart sounds.
DVM, Dipl. ACVIM
The clinician may elect to perform radiographs, which reveal a globoid cardiac silhouette, followed by an ultrasound examination
defining the fluid within the pericardial cavity.
At this point, some of the common diagnoses, including hemangiosarcoma with hemorrhage, idiopathic and infectious pericarditis,
quickly come to mind. However, recently investigators from Tufts and the University of Wisconsin-Madison reported on a series
of cases in dogs where the cause of the PE was lymphosarcoma (MacGregor et al in the Proceedings of the 21st ACVIM Forum,
2003, pg 952). Of course, the definitive long-term treatment of lymphosarcoma is markedly different than the more commonly
considered causes of PE.
These nine cases all presented with signs relating to their pericardial disease. They had collapse episodes, and most had
ascites. Blood tests were not helpful in reaching the diagnosis. Following the imaging by radiographs and ultrasound, pericardiocentesis
and cytological analysis revealed the presence of neoplastic lymphocytes. Three of the patients were treated with combination
chemotherapies which included doxorubicin, resulting in survivals of 157, >328, and >659 days, respectively. Survival times
are comparable with multicentric lymphosarcoma if cardiac issues can be successfully managed.
Thus, the clinician should be aware that pericardial effusion may be the only presenting sign of cardiac or pericardial lymphosarcoma.
In humans it is noted that sometimes biopsy of the heart or pericardium may be necessary when cytology does not provide a
conclusive diagnosis (Gowda et al in Angiology 599-604 Sept.-Oct. 2003). One should consider this option in refractory PE
of uncertain etiology in our veterinary patients.
A pericardial window may be opened by thoracotomy if necessary to improve cardiovascular hemodynamics (Stepian et al J Small
Animal Practice 2000, pgs 342-347). Alternatively, the biopsy may be obtained and window opened via a videothoracoscopic procedure
(Kovak et al, JAVMA 2002, Volume 221, No. 7).