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Immuno mikro eng > Infective Endocarditis > Flashcards

Infective Endocarditis Flashcards

1
Q

What is the definition of infective endocarditis?

A

Infection of endocardium of heart, implying presence of microorganisms on the lesion

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2
Q

What is endarteritis?

A

The arterial form of endocarditis

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3
Q

What valves are most commonly involved in endocarditis?

A

Most commonly mitral, secondarily aortic

Tricuspid very common in IV drug users

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4
Q

What other valvular heart disease is associated with endocarditis?

A

Rheumatic heart disease -> often affects mitral valve

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5
Q

What other condition is associated with endocarditis? What type of septal defect is least relevant?

A

Congenital heart disease - most commonly congenital bicuspid aortic valve

Least relevant is atrial septal defect (low pressure, minimal turbulence)

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6
Q

What are degenerative / incidental conditions which are associated with endocarditis?

A

Post-MI thrombus

Intercardiac pacemaker wires, prostheses, or IV drug use

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7
Q

What is the primary pathogenesis mechanism which initiates endocarditis?

A

Turbulent blood flow, often caused by heart murmur, results in deposition of platelets and fibrin - Nonbacterial thrombic endocarditis (NBTE)

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8
Q

Is the lesion often found on the high or low pressure side of an insufficiency or shunt?

A

Low pressure side

i.e. Mitral prolapse would lead to left atrial endocarditis

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9
Q

How does NBTE contribute to pathology?

A

Once bacteremia occurs, usually by trauma to a heavily colonized mucosal surface, bacteria adhere to NBTE site and cover up with fibrin / platelets to avoid immune response

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10
Q

Why is the immune system an issue in endocarditis?

A

Immune complexes will begin to form and circulate, causing glomerulonephritis and a number of systemic issues

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11
Q

What are common heart complications of endocarditis?

A

Valvular changes / abscesses
Rupture of IV septum, chordae tendinae
Myocardial infarcation in about 50%

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12
Q

What are pathologic changes in the kidney due to IE?

A
  1. Abscess
  2. Infarcation
  3. Focal or diffuse glomerulonephritis
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13
Q

What is one major CNS complication of IE? One more? hehe

A

Mycotic aneurysm formation in arterial wall (abscess formation of vasovasorum)

Will be silent until rupture occurs causing subarachnoid hemorrhage

Also fibrin plates can break off and cause cerebral emboli

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14
Q

What is a common cause of PE in IV drug users? What is this called?

A

Formation of embolus due to endocarditis of the right ventricle (constant venous stimulation of infected skin / bacteremia)

Called: Septic pulmonary emboli

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15
Q

What are three commonly tested clinical manifestations of IE around the body?

A
  1. Osler’s nodes
  2. Janeway lesions
  3. Roth spots
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16
Q

What skin change is typical of the eyes in IE and why?

A

Conjunctival petechiae, due to immune complexes which always circulate

17
Q

In what patients would fever actually not be present in infective endocarditis?

A

CHF, old age, prior antibiotic therapy, renal failure

Usually remittent - fluctuating temperatures

18
Q

What are general constitutional symptoms of IE? Via the heart?

A

Nonspecific malaise

Via the heart: new or changing murmur

19
Q

What is often present in fingertips of IE patients?

A
  1. Petechiae
  2. Clubbing
  3. Splinter hemorrhages (under nails)
  4. Osler’s nodes - painful nodular lesions due to immune complex deposition
20
Q

What are Janeway lesions?

A

Hemorrhagic, macular (flat), painless plaques on palms / soles mostly due to emboli

21
Q

What are Roth spots?

A

Oval, pale, retinal lesions surrounded by hemorrhage near optic disc on retinoscopy

22
Q

What are two behavioral CNS symptoms due to IE?

A
  1. Toxic encephalopathy - confusion due to persistent bacteremia
  2. Seizures
23
Q

What lab values (CBC) are common in IE?

A

Anemia in chronic infection, leukocytosis without anemia in acute

Almost 100% elevated sedimentation rate (C-reactive protein causing inflammation)

24
Q

What does urinalysis show?

A
  1. Proteinuria in most cases
  2. Microscopic hematuria with white / red cell casts
  3. Bactinuria
25
Q

What is the most important confirmatory lab test?

A

Blood culture, looking for continuous bacteremia over 24 hours (via 3 sets).

Only if patient has received antibiotics would we expect a negative test

26
Q

What is the primary echo used to diagnose IE?

A

Transesophageal echocardiogram (does not have to be positive), false positives are rare. Better for looking at aortic valve than 2D echo

If, bacteremia + TEE are positive = IE

27
Q

What is the most common cause of endocarditis in patients with mitral valve prolapse?

A

Viridans Streptococci, especially from dental procedures. Good prognosis

28
Q

What is a common cause of IE in older men after GU procedures or women after obstetrical procedures?

A

Enterococci (gram + cocci)

29
Q

What is one Strept that is uncommon to cause disease?

A

S. pneumoniae

30
Q

What is the most common cause of prosthetic valve endocarditis?

A

Staphylococcus epidermidis, usually due to asterile valve placement

31
Q

What is one gram negative which indicates rapid early valve replacement if causing endocarditis?

A

Pseudomonas

32
Q

What is the most common cause of IE in patients with normal valves? What special population does it infect?

A

S. aureus, poor prognosis, also causes myocardial abscess and valve ring abscesses, with metastatic infection to other organs

This is the pathogen of choice for IV drug users (other than Candida) -> but less severe course due to left-sided heart involvement

33
Q

What is the HACEK group responsible for and what does it stand for?

A

Culture-negative endocarditis, microbes which require longer incubation time to detect (2-3 weeks)

H - Haemophilus spp.
A - Aggregatibacter actinomycetemcomitans
C - Cardiobacterium hominis
E - Eikenella corrodens
K - Kingella kingae
34
Q

What is special about the therapy needed for fungal IE?

A

Cure is virtually impossible without surgery

35
Q

Why is antibiotic treatment of IE difficult?

A

Deep within vegetation there is poor nutrient and blood supply -> need high doses of prolonged bactericidal antibiotics

36
Q

When is surgical intervention really needed in IE?

A

Prosthetic valves, hard to cure organisms, CHF, >1 embolic complication, organism can not be cleared in bloodstream

Immuno mikro eng (56 decks)

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