Page 291 - Concise Pathology for Exam Preparation ( PDFDrive )

276 SECTION II Diseases of Organ Systems

(b) Fever
(c) Embolic phenomenon
(d) Vasculitic phenomenon
(e) Microbiologic evidence (organism grown but does not meet major criteria)
(f) Suggestive echocardiographic findings
Definite endocarditis: Two major or one major and three minor or five minor criteria
Possible endocarditis: One major and one minor or three minor criteria

Q. Enumerate the differences between acute and subacute
endocarditis.

Ans. The differentiating features of acute and subacute endocarditis are enlisted in
Table 11.5.

TABLE 11.5. Differentiating features of acute and subacute endocarditis

Features Acute bacterial endocarditis Subacute bacterial endocarditis
Duration ,6 weeks .6 weeks
Causative organisms Staphylococcus aureus, b-streptococci Streptococcus viridans
Virulence of organisms High Low
Preexisting pathology None Previously damaged valves
Lesion characteristics Large invasive and destructive Less invasive and destructive
Clinical presentation Rapid deterioration, usually fatal Gradual downhill course or recovery

Note: Classification of infective endocarditis into acute and subacute forms is largely discarded due to availability of antibiotics,
which alter the course of the same.

Q. Compare the morphological features of different types of
endocarditis.

Ans. The distinguishing features of vegetations in major forms of endocarditis are sum-
marized in Table 11.6.

TABLE 11.6. Distinguishing features of vegetations in major forms of endocarditis (Fig. 11.7)
Features Rheumatic Libman sacks Bacterial NBTE
Valves com- Mitral alone or mitral and Mitral and tricuspid Mitral, aortic, or Mainly mitral; less
monly af- aortic combined combined mitral commonly aortic
fected and aortic and tricuspid
Distribution Occur along lines of closure; Occur on cusps/leaf- On valve cusps, Occur along lines
of vegeta- atrial surface of A–V lets either on one may extend into of closure (on
tions valves and ventricular or both surfaces the chordate one side)
surface of semilunar
valves
Gross appear- Small (1–5 mm), multiple, Small to medium Large irregular, de- Small but larger
ance warty, firmly attached, pro- sized, multiple veg- structive, friable than RHD;
duce thickening, and short- etations; generally masses, damage loosely at-
ening of leaflets as well as do not produce the underlying tached; usually
fusion of valve commis- much deformity myocardium do not damage
sures leading to permanent
valvular deformity the valve
Constituents Fibrin and platelets, no bac- Granular, fibrinoid, Fibrin and plate- Fibrin–platelet
teria; adjacent endocar- eosinophilic mate- lets with bacte- thrombi, no
dium may show presence rial; sterile vegeta- rial colonies and bacteria
of Aschoff bodies tions; may contain acute inflamma-
haematoxylin tory cells
bodies equiva ent
l
to LE cells
Embolization Less common Less common Friable vegetations; Very common
very common

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