In vivo diagnosis of Toxoplasma gondii myocarditis in a cat

Authors: Oleynikov D, Letunovskaya A, Battaia S, Santilli RA
Publication: Australian Veterinary Practitioner, Volume 49, Issue 2, pp 31-35, Jun 2019
Publisher: Australian Veterinary Association

Animal type: Cat
Subject Terms: Animal remedies/veterinary medicines, Cardiology, Clinical examination, Respiratory system, Toxicology
Article class: Clinical Report

---

Abstract:

CASE REPORT: A 15-year-old intact female mixed-breed cat was presented for evaluation of acute respiratory distress and a history of several near-syncopal episodes. Thoracic radiographs revealed a moderate, patchy alveolar pulmonary pattern and moderate cardiomegaly. The ECG showed junctional rhythm with a rate ranging from 120 and 140 beats/min and isorhythmic atrioventricular dissociation with synchronisation type I. The echocardiogram showed moderate left atrial dilation, decreased systolic function and a restrictive transmitral flow pattern. Mild myocardial thickening with diffuse myocardial hypoechogenicity was also noted. Cardiac troponin I was markedly increased (6.66 ng/mL). Based on the results of the diagnostic tests, acute myocarditis was suspected. Standard therapy for acute congestive heart failure was established with oxygen and furosemide and once the cat was stabilised, an endomyocardial biopsy was performed. Histopathology revealed acute lymphocytic myocarditis with severe cardiomyocyte damage. Myocardial tissue PCR was positive for Toxoplasma gondii. The cat was discharged with congestive heart failure therapy, doxycycline and trimethoprim-sulfonamide, but died suddenly 10 weeks later. Postmortem histopathology confirmed the diagnosis of acute myocarditis secondary to T. gondii infection.

CONCLUSION: An antemortem diagnosis of T. gondiiassociated myocarditis was able to be made in a cat using endomyocardial biopsy and myocardial PCR analysis, when a definitive diagnosis could not be achieved with the standard diagnostic work-up.

KEYWORDS: cats; endomyocardial biopsy; myocarditis; toxoplasmosis

---