S Venkatesan, G Gnanavelu, G Karthikeyan, V Jaganathan, R Alagesan, M Annamalai, S Shanmugasundaram, S Geetha, A Balaguru, G Anuradha
Madras Medical College, Chennai
The definitive diagnosis of infective endocartitis (IE) remains a contentious clinical issue. Many diagnostic criteria have been advanced. However, none has withstood the test of time. Currently Duke’s criteria is considered as de facto standard. Documentation of vegetation within the cardiac chambers and positivity of blood culture is the sine qua non of IE and evidently they constitute the major criteria. Ironically, according to Duke’s criteria, IE could still be diagnosed in the absence of vegetation, provided it fulfils other major criteria of culture positivity. In this context, we report our analysis of patients with IE without vegetation. Out of 24 patients admitted between 2004-2005 in our hospital with the diagnosis of IE, 4 patients failed to show vegetations. All had rheumatic heart disease (RHD) and presented with prolonged fever. All had severe eccentric mitral regurigitation (MR). One had severe aortic regurgitation (AR) also. One had flail posterior mitral leaflet (PML). All had blood culture positive - 3 for staphylococcus auerus 1 for pseudomonas. None had vegetations on the first echocardiographic examination. Transesophageal echcardiography (TEE) also failed to detect a vegetation or abscess. The diagnosis of IE was made on the basis of Duke’s criteria (1 major and 3 minor features). Treatment was started based on culture positivity and sensitivity. All patients underwent serial echocardiography every week for 6 weeks. New mobile vegetation was detected in 1 patient in anterior mitral leaflet (AML) measuring 12 mm after 2 weeks. Three patients never showed any evidence of vegetation. One patient developed cerebral vasculitis and another renal insufficiency during the course of treatment. Two patients stabilized with medical management. One expired and other had refractory cardiac failure and was referred for emergency surgery. The mechanism of absence of vegetation in IE could be varied. Simple temporal dissociation between appearance of vegetation and the clinical syndrome should be the first possibility. Further, vigorous antimicrobial treatment might have prevented the formation of vegetation. But, as we have seen in few patients, it never appeared. This was possibly due to layered vegetation like that of a thrombus on the surface of the valve or adjacent myocardium. The process of vegetation formation need not be endoluminal, it can burrough into the tissue plane intramurally without projecting into the cavity. Spontaneous rupture of chordae secondary to inflammation without any vegetation is another possibility.
We conclude , even though vegetations are consideredsine quo non of IE in many clinical situations, IE occurs without vegetation. The mechanisms could be varied.