A 55-year-old woman has undergone an orthotopic heart transplant for cardiomyopathy. She recovers well from surgery and during the first post-transplant month has weekly endomyocardial biopsies that show mild acute rejection. This is treated with an increase in immunosuppressive therapy, and the rejection subsides. In week 5, she develops a fever and chest pain.

A chest xray shows mild pulmonary edema. A chest CT shows no pulmonary infiltrates or masses. The heart shows some minimal heterogeneity in attenuation that involves the left ventricular wall and septum. An echo shows no valvular lesions, but there is slightly decreased wall motion and reduced cardiac output. Another endomyocardial biopsy is performed.

Question 4.1 - What type of heart disease do you think is present?

The findings suggest a myocardial disease. The diffuse nature is against an acute ischemic event. A myocarditis is more likely.

Question 4.2 - What are possible infectious agents?

In an immunocompromised patients, opportunistic infections can occur, in addition to the more standard bacterial infections. Fungal and protozoal infections should be considered.

Questions 4.3 - What is the diagnosis?

The microscopic appearance, with a pseudocyst filled with bradyzoites, is typical for T. gondii. No cats allowed in the patient's house, please.

Question 4.4 - What antibiotic regimen is indicated?

Azithromycin, or pyrimethamine plus sulfadiazine.