Short Quiz on INFECTIVE ENDOCARDITIS
Instruction
2. There is 1 Mark for each correct Answer
Diagnostic criterion for infective endocarditis includes all EXCEPT:
ESR REF: Harrison’s 17th ed Chapter 118
The duke’s criteria for Infective endocarditis
Major Criteria
1. Positive blood culture
- Typical microorganism for infective endocarditis from two separate blood cultures
- Viridans streptococci, Streptococcus bovis, HACEK group, Staphylococcus aureus, or
- Community-acquired enterococci in the absence of a primary focus, or
- Persistently positive blood culture, defined as recovery of a microorganism consistent with infective endocarditis from: Blood cultures drawn >12 h apart; or
- All of three or a majority of four or more separate blood cultures, with first and last drawn
at least 1 h apart
- Single positive blood culture for Coxiella burnetii or phase 1 IgG antibody titer of >1:800 2. Evidence of endocardial involvement
- Positive echocardiogram
- Oscillating intracardiac mass on valve or supporting structures or in the path of regurgitant
jets or in implanted material, in the absence of an alternative anatomic explanation, or - Abscess, or
- New partial dehiscence of prosthetic valve, or
- New valvular regurgitation (increase or change in preexisting murmur not sufficient)
Minor Criteria
- Predisposition: predisposing heart condition or injection drug use
- Fever 38.0°C (100.4°F)
- 3. Vascular phenomena: major arterial emboli, septic pulmonary infarcts, mycotic aneurysm, intracranial hemorrhage, conjunctival hemorrhages, Janeway lesions
- Immunologic phenomena: glomerulonephritis, Osler’s nodes, Roth’s spots, rheumatoid L factor
- Microbiologic evidence: positive blood culture but not meeting major criterion as noted previously or serologic evidence of active infection with organism consistent with infective endocarditis
Infective endocarditis due to pseudomonas is mostcommonly seen with
intravenous drug abuse of pentazocin [Ref Harrison 1661/e p 891]
- Psudomonas aeruginosa infects the native heart valves of intravenous drug users as well as prosthetic heart valves.
- Foreign materials mixed with heroin or any other opioid may cause injury to valve leaflets or mural endocardium with resulting fibrosis and an increased risk for valve infection.
Note : Pentazocine is an opioid.
Infective endocarditis leads to formation of bulky and friable vegetations on the valvular leaflets.
The vegetations are composed of fibrin, neutrophils, and colonies of bacteria that cause erosion of underlying cardiac structures.
Fragments of infected vegetations may detach and cause pulmonary or systemic septic embolism.
Splinter hemorrhages in the nail bed and petechiae in skin and mucosae are also due to microscopic septic emboli.
In this case, myocardial infarction was probably due to a septic embolus in the coronary circulation.
If infective endocarditis is due to a virulent organism such as Staphylococcus aureus (a common cause of endocarditis in intravenous drug abusers), a tumultuous clinical course ensues, associated with high mortality.
With less virulent organisms, such as Streptococci viridans, Subacute infective endocarditis is the resultant clinical picture.
Subacute endocarditis arises in patients with previously malformed or damaged valves and is associated with a slower course and a better prognosis.
| Fever | 80–90 |
| Chills and sweats | 40–75 |
| Anorexia, weight loss, malaise | 25–50 |
| Myalgias, arthralgias | 15–30 |
| Back pain | 7–15 |
| Heart murmur | 80–85 |
| New/worsened regurgitant murmur | 20–50 |
| Arterial emboli | 20–50 |
| Splenomegaly | 15–50 |
| Clubbing | 10–20 |
| Neurologic manifestations | 20–40 |
|
Peripheral manifestations (Osler’s nodes, subungual hemorrhages, Janeway lesions,
Roth’s spots)
|
2–15 |
| Petechiae | 10–40 |
| Anemia | 70–90 |
| Leukocytosis | 20–30 |
| Microscopic hematuria | 30–50 |
| Elevated erythrocyte sedimentation rate | 60–90 |
| Elevated C Reactive protein level | >90 |
| Rheumatoid factor | 50 |
| Circulating immune complexes | 65–100 |
Ref: Karchmer A.W. (2012). Chapter 124. Infective Endocarditis. In D.L. Longo, A.S. Fauci, D.L. Kasper, S.L. Hauser, J.L. Jameson, J. Loscalzo (Eds), Harrison’s Principles of Internal Medicine, 18e.
Which among the following is the most common cause of acute infective endocarditis?
In a hospital cardiac care unit, there are three patients with different cardiac conditions: a 52 year old man with dilated cardiomyopathy, an 18 year old girl with mitral valve prolapse, and a 30 year old man with infective endocarditis of the mitral valve. Which of the following features do all these patients most likely share?
Which of the heart valve is most likely to be involved by infective endocarditis following a septic abortion?
Which of the following is least likely to cause infective endocarditis?
Among the options provided salmonella typhi is the organism least likely to cause infective endocarditis. Endocarditis is a very rare complication of salmonella typhi infection.
Ref: Harrisons Principles of Internal Medicine, 16th Edition, Page 732.
Which among the following is the least common cause of infective endocarditis?
Among the following, ASD is the least common cause of infective endocarditis. Here the low turbulence is responsible for decreased incidence of IE.
An IV drug user is diagnosed to have infective endocarditis involving the tricuspid valve. Which of the following is the most likely causative agent?
Blood culture is positive in which infection of staph. aureus-
Ans. is ‘c’ i.e., Infective endocarditis
. Blood culture is positive when bacteria present in blood, i.e. when there is bacteremia.
. Infective endocarditis is a complication of staphylococcal aureus bacteremia (SAB). Thus blood culture may be positive.
. Staphylococcal scalded skin syndrome (SSSS) and impetigo do not have bacteremia.
. In toxic shock syndrome (TSS) due to staphylococcus aureus, bacteremia is uncommon (in contrast, bacteremia is common in streptococcal TSS).
Ans. is ‘a’ i.e., Streptococcus viridans
. Viridans streptococci are normally resident in the mouth and upper respiratory tract. They cause transient bacteremia following tooth extraction or other dental procedures; and get implanted on damaged or prosthetic valves or in a congenitally diseased heart, and grow to form vegetations.
Ans. is ‘c’ i.e., Corynebacterium
The HACEK group includes the Haemophilus species, Actinobacillus, Cardiobacterium hominis, Eikenella corrodens and Kingella kingae.
Ans. is ‘a’ i.e., MR; ‘c’ i.e., AR
. Infective Endocarditis is common in AR, AS, MR, V SD and complex congenital heart disease.
Ans. is ‘d’ i.e., Large ASD
Pathogenesis of infective endocarditis (IE)
Infective endocarditis may develop on previously normal valve, but a variety of cardiac and vascular abnormalities predispose to infective endocarditis.
o Two most common cardiac abnormalities that predispose to infective endocarditis are –
1.Rheumatic carditis
o Rheumatic carditis causes damage to heart valve.
o Damaged part of heart may be covered with platelets and fibrin, upon which bacteria can take hold. 2. Congenital heart diseases (CHDs)
o IE occurs in CHDs where blood flow occurs due to high pressure gradient, e.g. VSD or AS. o The high pressure of jet of blood hits the endocardium and damages it.
o Infection generally starts at this lesion.
High Risk Moderate Risk Low Risk
Prosthetic heart valve MVP + M. R. Mitral valve prolapse without mitral Regurgitation.
Tetralogy of fallot T.S. ASD
PDA
AR P.S.
AS M.S. Coarctation of Aorta
VSD
MR
Ans. is ‘b’ i.e., Infective endocarditis
o As the name suggests, non-sterile means presense of organism in the vegetation that is the characteristic feature of infective endocarditis.
o Vegetation of infective endocarditis has following characteristics
Large, bulky, friable and irregular
Multiple
Present on upper surface of the cusps.
o Vegetation is a mass of platelets, fibrin, microcolonies of microorganisms (non-sterile) and scant inflammatory cells.
o Aortic and mitral valves are the most common sites of infection.
o In intravenous drug users, valves of right side are involved.
o Vegetations sometimes erode into the underlying myocardium to produce an abscess cavity —> Ring abscess. Why heart valve is the most common site of infective endocarditis ? Lets see
o As the valves of heart do not actually receive any supply of their own, defensive immune mechanism (such as WBCs) cannot approach the valves.
o So, if an organisms (such as bacteria) establishes a hold on the valve forming a vegetation, the body cannot get rid of them.
Ans. is ‘b’ i.e., Pulmonary valve is commonly involved
Infective endocarditis in I.V. drug abusers usually involves the right side of the heart.
Tricuspid valve is most commonly involved.
Pulmonary valve is involved in fewer cases only.
Most common organism causing endocarditis in I.V. drug abusers is =>staphylococcus aureus.
Other common organisms are —> Candida, Enterococcus fecalis, Pseudomonas, Serratia marcescens
Ans. is none or ‘b’ i.e., Suppurative Pericarditis
Complications of Endocarditis
o Valvular insufficiency or stenosis with cardiac failure
- Myocardial ring abscess with possible perforation of aorta, interventricular septum or free wall.
- Suppurative pericarditis with endocarditis on artificial valves, partial dehiscense with paravalvular leak. o Embolic complications
- With left sided lesions
(a) Brain (cerebral infarct or abscess, meningitis)
(b) Heart (Myocardial infarction)
(c) Spleen (abscesses)
(d) Kidney (abscesses), other sites.
o With Right sided lesions
(a) Lung (infarcts, abscess, pneumonia)
o Renal complications
Embolic phenomenon
Focal and diffuse glomerulonephritis due to trapping of antigen – antibody complexes which may lead to hematuria, albuminuria or renal failure.
Multiple abscesses : especially with acute staphylococcal endocarditis.
- So according to Robbins all of the given options can be seen. Even Braunwald’s Heart disease mentions all the four options as complications of infective endocarditis.
o If we have to go for one we will prefer suppurative pericarditis as the answer because in infective endocarditis mostly autouimmune pericarditis occurs.
In which of the following vegetation are friable and easily detachable from the cardiac valves –
Ans. is ‘d’ i.e., Infective endocarditis
o The hallmark of infective endocarditis is the presence of large, friable, bulky, potentially destructive vegetation containing fibrin, inflammatory cell, and bacteria.
o Emboli may be shed from vegetation at any time because of detachment.
Also know
o Vegetations of NBTE may also be friable and detachable to produce emboli. But they are small and non-destructive.
Ans. is ‘a’ i.e., Acute infective endocarditis
Note : Amongst the given options infective endocarditis is most destructive.
In infective endocarditis which of the following is not immune mediated –
Ans. is ‘None’
Infective endocarditis is least likely to occur in:
Answer is A (ASD)
Endocarditis is unusual in sites with a small pressure gradient as in – ASD – Harrison
Infective endocarditis is least common in‑
Answer is D (ASD)
Endocarditis is unusual in sites with a small pressure gradient as in ASD
ASD is low risk lesion for the development of infective endocarditis and the single best answer amongst the options provided.
Infective endocarditis is most commonly seen in:
Answer is B (VSD)
VSD is the most common congenital lesion to be complicated by infective endocarditis
Roth’s spots are seen in:
Answer is A (Infective Endocarditis)
Roth’s spots (lesions) are oval retinal haemorrhages with a clear pale center that are typically seen in patients with subacute bacterial endocarditis. They are believed to be caused by immune complex deposition and are included as a minor criterion amongst Duke’s criteria for clinical diagnosis of Infective Endocarditis.
Not a feature of infective endocarditis is :
Answer is C (Thrombus in left atria)
Infective endocarditis does not lead to formation of thrombi within the left atrial. It may however lead to formation of friable vegetations that may embolize to the systemic circulation as infective emboli.
Infective endocarditis is characterized by colonization or invasion of the heart valves or mural endocardium by a microbiological agent, leading to the formation of bulky, friable vegetations laden with organisms.
Which of the following is least likely to cause infective endocarditis :
Answer is C (Salmonella Typhi)
Endocarditis is common with staphylococcus albus,.streptococcus fecalis and pseadontonas aeruginosa. Endocarditis has only been mentioned as rare complication of salmonella typhi infection. —
The least likely organism to infective endocarditis amongst the options provided is salmonella typhi. Other options
|
Staphylococcus albus (Staph. epidermis) (Coagulase Negative staph.) |
treptococcus fecalis (Enterococci) |
Pseudomonas Aeroginosa Gram negative bacilli |
|
• S. epidermis (albus) is the most |
• Streptococci fecalis is the most |
• Common agent in endocarditis among |
|
Common coagulase negative |
common cause of enterococcal |
infection drug users |
|
staphylococii |
infective endocarditis |
• P. aerug inosa infects the native heart |
|
• Coagulase negative staph (S. |
• These organism account for 10 – 20% |
valves of intravenous drug users as |
|
epidermidis/alba) are the most common cause of ‘Prosthetic valve endocarditis’ |
of cases of bacterial endocarditis |
well as prosthetic heart valves |
Answer is B (Staphylococcus)
Acute Infective Endocarditis with abscess formation is most commonly associated with staphylococcus.
`The most common organism causing acute infective endocarditis overall is staphylococcus aureus. Staphylococcus aureus endocarditis is particularly virulent and associated with annular and myocardial abscess formation and a higher mortality’
Which of the following is recommended for culture sampling in Infective Endocarditis:
Answer is C (3 culture sets separated by at-least 1 hour over 24 hours)
Three culture sets separated from one another by at-least I hour should he obtained over 24 hours.
in the absence of prior antibiotic therapy three (2-bottled) culture sets separated from one another by at-least 1 hour should be obtained from different venepuncture sites over 24 hours. If the cultures remain negative 48 to 72 hours, two or three additional blood culture sets should be obtained’
Antiboiotic Prophylaxis for infective endocarditis is indicated in:
Answer is D (Coarctation of Aorta)
Coarctation of Aorta is a high risk cardiac lesion fior the development of infective endocarditis and an indication fir antibiotic prophyloxis.
Answer is A (Infective endocarditis)
Most friable vegetations with the highest risk of embolization are seen in infective endocarditis.
Friability of Vegetation and risk of embolization
Infective Endocarditis > NBTE (Marantic) > Rheumatic endocarditis and Libman Sack’s endocarditis
|
Rheumatic Fever |
Non bacterial Thrombotic |
Libman Sack’s Endocarditis |
Infective Endocarditis |
|
|
(Marantic Endocarditis) |
(SLE) |
|
|
• Small |
• Small (but larger than those |
• Medium sized(small) |
• Large, Bulky |
|
• Warty, verrucous |
of rheumatic) |
• Flat, Verrucous,lrregular |
• Irregular |
|
• Usually Firm |
• Friable |
• Usually Firm; occasionally friable |
• Friable (most friable)Q |
|
May be friable (but less than those of NBTE) (embolization rare) |
(embolization common) |
(embolization rare) |
(embolization common) . |
|
• Along lines of closure |
• Along lines of closure |
• On surface of cusps Both surfaces may be involved most common being the undersurface, less often on mural endocardium • In pockets of valves |
• Irregular vegetations on valve cusps that can extend onto the chordae. • Less often on mural endocardium |
|
• Sterile (no organisms) |
• Sterile |
• Sterile |
• Non-sterile (bacteria) |
|
• Non destructive |
• Non destructive |
• Destructive |
• Destructive |
|
Valve perforation : no |
Valve perforation : no |
Valve perforation : no |
Ulcerates or perforates |
|
Mural involvement: rare |
Mural involvement: rare |
Mural involvement: common |
underlying valve (or myocardium) |
|
• Seen in Rheumatic fever |
• Seen in hyper coagulable states e.g. cancer, promyelocytic leukemia increased estrogenic state |
• Seen in SLE |
• Seen in Infective endocarditis |
Most common site:
- Most common site for vegetations in Libman Sack’s endocarditis are the A-V values, mitral and tricuspid.
- Most common site for vegetations in NBTE is mitral and less often aortic and Tricuspid.
- Most common site for vegetations of RF is mitral followed by combined mitral and aortic.
Ans. is ‘a’ i.e., Streptococcus viridans
-
Viridans streptococci are normally resident in the mouth and upper respiratory tract. They cause transient bacteremia following tooth extraction or other dental procedures; and get implanted on damaged or prosthetic valves or in a congenitally diseased heart, and grow to form vegetations.
-
They are ordinarily non-pathogenic but can on occasion cause disease. In persons with preexisting cardiac lesions, they may cause bacterial endocarditis, Str. sanguis being most often responsible.
-
Str. Mutans are important in the causation of dental caries.
-
The transient viridans streptococcal bacteremia induced by eating, tooth-brushing, flossing and another source of minor trauma, together with adherence to biological surfaces, is thought to account for the predilection of these organisms to cause endocarditis.
-
Viridans streptococci are also isolated, often as a part of mixed flora, from sites of sinusitis, brain abscess and liver abscess.
-
Viridans streptococcal bacteremia occurs relatively frequently in neutropenic patients, particularly after bone marrow transplantation or high dose chemotherapy for cancer.
Treatment of viridans streptococcal infections include:-
-
Bacteremia in neutropenic patients → Vancomycin.
-
Other infection → Penicillin.
Ans:B.)Infective Endocarditis
Image shows:
- A:Rheumatic Heart Disease
- B:Infective Endocarditis
- C:Non Bacterial Thrombotic Endocarditis
- D:Libman Sack Endocarditis
DISTINGUISHING FEATURES OF VEGETATIONS IN MAJOR FORMS OF ENDOCARDITIS
