Infections and inflammation of the heart

Question 1

What is infective endocarditis and what does it require?

Answer 1

Inflammation of the endocardial surface of the heart, usually due to an infection. Requires the formation of vegetations.

Question 2

What are the sx of acute endocarditis and what type of individuals are affected?

Answer 2

1) Acute onset of high grade fevers and chills
2) Rapid onset of CHF (Due to rapid valve failure)

Usually affect those who had prior procedures (e.g. prosthetic valve placement) or IV drug use.

Question 3

What condition is associated with heart murmurs, petchiae or skin and palate, and nail bed hemorrhages (splinter hemorrhages)?

Answer 3

Infective endocarditis.

Question 4

What is the pathogenesis of endocarditis?

Answer 4

1) Endothelial surface injury- turbulent flow/ high pressure blood flow disrupts endothelium, causing platelets to stick to the damaged endothelium.
2) Formation of sterile fibrin-platelet vegetation
3) Episode of bacteria occurs- presence of vegetations allow bacteria to adhere to these sites (healthy individuals without vegetations can clear bacteria quickly)
4) “Burying” of bactera by additional platelets/vegetations growing over them, allowing escape of immune surveillance
5) Proliferation and growth of bacteria → growth of vegetation → valve incompetence
6) Dissemination: bits of vegetation can break off and travel to other parts of the body

Question 5

Despite varying presentations of myocarditis depending on the organism involved, what are some common sx?

Answer 5

Chest pain and palpitations that can lead to ventricular arrhythmias and cardiogenic shock associated with EKG changes.

Question 6

What are Aschoff bodies?

Answer 6

They are granulomas formed by cell mediated inflammatory response. Consist of lymphocytes, plasma cells, and giant cells, Anitschkow bodies or “caterpillar cells”.

Question 7

What is the endocardium?

Answer 7

inner most surface of heart including endothelium and underlying basement membrane structures. Also covers the heart valves.

Question 8

What are the components of vegetations?

Answer 8

Necrotic debris, thrombus, organisms, platelets, fibrins

Question 9

What are the sx of acute rheumatic fever?

Answer 9

J: Migratory polyarthritis

O: pancarditis

N: Subcutaneous nodules

E: Erythema marginatum

S: Sydenham chorea

+ Minor sx (fever, athralgia, myalgia, etc.)

Question 10

What aged individuals does myocarditis affect the most?

Answer 10

Middle aged adults (30-50); can happen in adolescents

Question 11

what are some rare findings of infective endocarditis?

Answer 11

1) Roth spots (retinal hemorrhage)
2) Janeway lesions
3) Osler nodes

Question 12

What are the two main different clinical presentation of IE?

Answer 12

Acute vs. Subacute

Question 13

acute rheumatic fever sx present after what type of symtpmos and when?

Answer 13

2-4 weeks after streptococcal infection (URI sx)

Question 14

What are Janeway lesions and what condition is it associated with?

Answer 14

Painless palm or sole lesions

Associated with infective endocarditis

Question 15

What are HACEK bacteria and what are they involved in? What is unique about them?

Answer 15

HACEK: Haemophilus, Actinobacillus, Cardiobacterium, Eikenella, Kingella- associated with prosthetic valve endocarditis.

Unique: Negative blood cultures bc they’re hard to grow

Question 16

What are teh sx of pericarditis due to acute rheumatic fever?

Answer 16

Pericardial friction rub on exam + cp

Question 17

What are the most common bacteria that infects valves of IV drug abusers and which valve is commonly affected?

Answer 17

S. aureus; most commly affects tricuspid valve.

Question 18

Answer 18

Anitschkow cells (caterpillar cells)

Question 19

What is the characteristic finding in the myocardium (or other layers of heart) in histology due to acute rheumatic fever?

Answer 19

Aschoff bodies which consisst of lympocytes, plasama cells, activated macrophages known as Anitschkow cells)

Question 20

Palpitations, syncope, chest pain, dyspnea, muscle aches, fever, fatigue, and erythema migrans are associated with what condition?

Answer 20

Lyme carditis

Question 21

What are roth spots and what are they associated with?

Answer 21

Retinal hemorrhage due to immune-mediated vasculitis. Associated with infective endocarditis

Question 22

Central or peripheral indwelling catheters, pacemaker wires, implantable defibrillators, and chemotherapy lines are risk factors for what?

Answer 22

Infective endocarditis

Question 23

What type of people does myocarditis manifest in (healthy vs. underlying heart disease) and what is the prognosis and why?

Answer 23

Affects healthy people and can result in rapidly progressive (and often fatal) HF and arrhythmia due to systolic dysfunction.

Question 24

What are common sx of infective endocarditis due to infection of valve in IV drug user?

Answer 24

S. aureus infects tricuspid valve. TV murmur may be absent but commonly manifest as pulmonary sx.

Question 25

What are the sx of subacute endocarditis?

Answer 25

Flu-like sx:

1) Low grade fever/chills
2) nonspecific fatigue
3) Weight loss

Question 26

What are the risk factors in regards to age and sex?

Answer 26

Age >60 + male sex

Question 27

What are teh sx of syndenham chorea and what condition is it associated with?

Answer 27

Associated with rheumatic fever.

Sx: Emotional lability, personality change, muscular weakness, uncoordinated, involuntary, purposeless movements.

Question 28

Which bacteria are associated with health-care associated endocarditis (e.g. intravascular devices)

Answer 28

Staph aureus

Question 29

What is jaccoud arthropathy?

Answer 29

Seen in acute rheunmatic fever; fingers and joints are out of alignment due to laxity of ligament and tendons. However, this is a reversible process unlike rheumatoid arthritis, as the fingers can be placed back to look normal again.

Question 30

In order to diagnose viral myocarditis, waht needs to be excluded?

Answer 30

CAD or other non inflammatory causes (e.g. toxin exposure, alcohol use)

Question 31

Characteristics of viral myocarditis in biopsy

Answer 31

Myofiber necrosis/ diruption with significant mononuclear cell infiltrates (e.g. lymphocytes, macrophages, monocytes)

Question 32

What are the sx of pancarditis due to acute rheunmatic fever?

Answer 32

SOB, dyspnea on exertion, paroxysmal noctural dyspnea, CP, and/or orthopnea

Question 33

What are the risk factors for IE besides age and sex?

Answer 33

1) Poor dentition/ dental infections
2) Structural heart disease (valvular or congenital)
3) IV drug use
4) Prosthetic valves/ intravascular devices
5) Rheumatic heart disease

Question 34

What causes lyme disease and what are the common sx?

Answer 34

Borrelia; common signs include erythema migrans rash, rheumatologic sx (pain in large joints, effusions), neurological manifestations (e.g. facial nerve palsy)

Question 35

What two combination of sx is consistent with endocarditis until proven otherwise?

Answer 35

New regurgitatnt murmur + recurrent/ unremitting fever = endocarditis

Question 36

What leads to lyme carditis? What is the most common reocnized clinical feature of lyme carditis?

Answer 36

Borrelia directly invades tissues of the heart leading to pancarditis.

Most common clinical feature is AV block

Question 37

What are lung nodules associated with and how do they occur?

Answer 37

Infectiev endocarditis; Septic emboli- vegetation containing bacteria can break off from valve and infect the lungs, leaiding to nodules.

Question 38

What are osler nodes and what condition are they associated with?

Answer 38

Painful fingertip nodules; associated with infective endocarditis

Question 39

What are the changes to the valves due to rheumatic fever and what is the manifestation?

Answer 39

usually affecst mitral valve (sometimes + aortic valve). Results in thickening of leaflet and chordae tendinae. ALso results in fusion of commissures. Leads to stenosis with “fish mouth appearance” that causes regurgitations

Question 40

Which 3 bacterial strains are associated with endocarditis in prosthetic valves?

Answer 40

Coag neg. staph (S. epidermidis) + Staph aureus are primary causes

Also HACEK bacteria (Haemophilus, Actinobacillus, Cardiobacterium, Eikenella, Kingella)

Question 41

What is the most severe complication of endocarditis?

How do they occur and how do they present?

Answer 41

Cerebral/neurologic complications.

Mechanism: Vegetations break off of valve (containing bacteria) and get flicked into arterial circulation and then travel to the brain.

Sx:

• Ischemic/ hemorrhagic stroke, TIA (can precede dx of IE)
• Silent cerebral embolism- emboli goes to brain but no neurologic sx but end up with brain abscess

Question 42

What is the pathogenesis of viral myocarditis? What type of individuals are involved?

Answer 42

Usually indivdiuals with predisposing immunogenic background. This is because healthy individuals with strong immune systems can clear the virus from the heart when infected. Individuals who are predisposed to infections have easy breakdown of T cell tolerance (becomes reactive to self), resulting in chronic autoimmune mediated damage to the myocardium. This results in dilated CM.

Question 43

How do valvular changes occur in response to acute rheumatic fever?

Answer 43

As a consequence of acute rheumatic fever, the inflammatory changes in the heart continues via molecular mimicry. This can affect the valves of the heart (usually MV and sometimes aortic), and sx of valvular damage occur 10-30 years after episode of ARF.

Question 44

Why is myocarditis due to T. cruzi hard to detect?

Answer 44

Once it infects the heart, it can go into an “indeterminant phase” in which individuals test positive for exposure but there is no evidence of disease present (e.g. clinical signs or evidence in blood stream). Due to this quiescent phase in the heart, individuals are asymyptomatic but they cause chronic immune mediated damage to the heart, which can progress to cardiac insufficiency in 10-20 years.

Question 45

What is the cause of acute rheumatic fever?

Answer 45

Complications of pharyngitis due to group A beta-hemolytic streptococci leads to molecular mimicry, in which bacterial M protein resembles myocardial proteins and other types of cells in the body. As a result, due to molecular mimicry, there is autoimmune attack on the body, including cardiac cells (anti-cardiac antibdies demonstrated).

Question 46

What is the most common etiology of myocarditis? What are the organisms involved?

Answer 46

1) Viral: most common; involves Parvovirus B19, HHV-6, Coxsackie A + B
2) Bacterial: Borrelia species
3) Fungal: Trypanosoma cruzi

Question 47

What is a unique feature in acute rheumatic fever in how it affects the heart?

Answer 47

It is not a direct infection of the heart; it is an autoimmune disease that develops from group A beta hemolytic streptococcal infection, most typically a complication of pharyngitis.

Question 48

What is the only manifestation of acute rheumatic fever that can cause long-term disability or death?

Answer 48

Pancarditis

Question 49

What organisms are involved in acute presentations of IE and why?

Answer 49

They are the virulent organisms: S. auereus, Strep pyogenes. These are virulent organisms that infect normal valves. They cause systemic toxicity and are rapidly fatal if untreated.

Question 50

What is the population affected by acute rheumatic fever?

Answer 50

Children, primarily age 5-15.

Question 51

Answer 51

Aschoff bodies

Question 52

What type of individuals are septic emoblization of vegetation in IE commonly affect?

Answer 52

IV drug abusers

Question 53

What are examples of complications of infective endocarditis that patients can present with?

Answer 53

1) Cardiac complications (e.g. valvular insufficiency, CHF)
2) Neurologic complications
3) Septic embolization sx (e.g. lung nodules, emboli in kidneys leading to hematuria or infarction)
4) Systemic inmmune rxn- if person is sick for long enough, can get systemic immune response to bacteria

Question 54

How does infective endocarditis affect the lumen of a valve?

Answer 54

Doesn’t cause stenosis; instead, the valve simply gets destroyed, leading to regurgitation.

Question 55

What organisms cause subacute presentation of IE and why?

Answer 55

Common organisms such as strep viridans (mouth) or enterococci infect. They usually infect valves in individuals with underlying structural or congenital heart disease. The presentation is more indolent in nature and individuals can live untreated up to one year.

Question 56

What occurs in the endocardium due to acute rheumatic fever?

Answer 56

Small vegetations or fibrin deposition and fibrinoid necrosris along lines of closure that lead to regurgitation (most commonly affects MV)

Question 57

What organism causes Chagas disease and what heart condition can it lead to?

Answer 57

Trypanosoma cruzi; myocardial involvement occurs in most infected individuals

Question 58

Why are gram positive bacteria more likely to be the culprit of endocarditis?

Answer 58

The factors of ability of bacteria to cause infective endocarditis are:

1) Access to circulation
2) Survival in the blood stream
3) Adherance to the endothelium.

Gram positive bacteria are better at circulating in the blood stream and have adhesion factors that allow them to stick to the endotheloum/vegetations.