Photo Quiz - November 2018

A 50/M with diabetes, hypertension, hypothyroidism, coronary artery disease and left ventricular (LV) dysfunction underwent dual chamber pacemaker implantation in 2008. He underwent pacemaker re- implantation elsewhere in 2011. In August 2012, he developed gradual onset of fever not responding to antibiotics. During the workup for pyrexia of unknown origin, transthoracic echocardiography (TTE) revealed vegetations around the leads. Positive blood culture is shown in Figure 1.

Figure 1: LPCB mount of the positive blood culture of the patient with infective endocarditis

What is your diagnosis? View Answer

Answer

The patient underwent emergency surgery with removal of pacemaker and the leads. Microbiological cultures of the vegetation grew Scedosporium prolificans.

He was treated with L-AmB and voriconazole by the CTVS team and discharged in stable condition. Two months later, in November 2012, he presented with complaints of syncope. Investigation revealed a vegetation on the tricuspid leaflet. He underwent excision of the vegetation and tricuspid valve replacement (TVR). Blood cultures and valve cultures grew S.prolificans. Post surgery, he was continued on voriconazole and terbinafine. In May 2013, he underwent a repeat PPI and in October 2013 (one year post first TVR), again presented with complaints of syncope while still on voriconazole and terbinafine. TTE revealed TV IE. A redo TVR with removal of 2 out of 3 leads of the pacemaker was done. Blood cultures grew S. prolificans and DST revealed an AmB resistant and voriconazole sensitive isolate. He was initiated on caspofungin, voriconazole and terbinafine. In March 2014, he presented with a 4th episode of S. prolificans IE of TV and underwent 3rd TVR along with voriconazole, caspofungin and terbinafine. However, a month later, there was recurrence of the vegetation on the TV along with pulmonary embolic episode. Surgical intervention was not possible this time and despite aggressive antifungal therapy, the patient eventually succumbed to the fungal sepsis.

  • The most common presentations of Scedosporium infections are pulmonary and bone and soft tissue infections in immunocompetent hosts.
  • Disseminated infections are more common and often more complicated in immunocompromised patients with hematological malignancies or those on immunosuppressive treatment regimens.
  • S. prolificans endocarditis is rare with high mortality. Risk factors for endocarditis including IV drug use, pacemaker implantation and porcine bio- prosthetic valves.
  • Diagnosis is established by microbiological cultures ( Blood cultures and vegetation/valve cultures).
  • No standard therapy for S. prolificans based on clinical evidence has been established.
  • Combination of surgery with medical management appears to have best chances of cure.
  • Combination antifungal drug therapy has been successful in several cases. In vitro, the combinations of itraconazole + terbinafine, voriconazole + terbinafine, ravuconazole + caspofungin and voriconazole + miltefosine have synergic effects.
  • Effective infection control measures during interventional cardiac procedures is most imperative for prevention of such life threatening infections.

Final diagnosis: Scedosporium prolificans pacemaker infection with tricuspid valve endocarditis

Case provided by: Dr Prerna Khurana (ID Fellow), Dr Smita Sarma, Dr Prasad Rao Voleti, Dr Anil Bhan, Dr Usha Baveja, Dr Neha Gupta