Infective Endocarditis Flashcards

1
Q

What is endocarditis?

A

Inflammation of the cardiac endocardium affecting valves, mural endocardium, or implanted devices

It can be secondary to infection or a noninfectious process.

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2
Q

How many new cases of infective endocarditis are diagnosed each year in the United States?

A

10,000–15,000 new cases

Incidence varies from 0.6 to 11.6 cases per 100,000 person-years.

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3
Q

What is the male to female ratio for infective endocarditis cases?

A

> 2:1

The incidence is higher in men than women.

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4
Q

What is the median age at diagnosis for infective endocarditis?

A

Increasing over the years, primarily affecting patients above the age of 60

Majority of cases occur in older adults.

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5
Q

What are common risk factors for developing infective endocarditis?

A
  • Prior structural heart disease
  • Intravenous drug use (IVDU)
  • Poor dentition/dental infection
  • Intravascular catheter/device presence
  • Immunocompromised state (e.g., HIV)
  • Invasive procedures

About ¾ of patients with IE have prior structural heart disease.

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6
Q

What percentage of infective endocarditis cases are healthcare-associated?

A

Approximately 23–27%

Includes cases related to intravascular catheters and devices.

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7
Q

What is the mortality range for patients diagnosed with infective endocarditis?

A

18 to 23% in-hospital mortality

6-month mortality is reported to be 22–27%.

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8
Q

What factors contribute to poor outcomes in infective endocarditis?

A
  • Female gender
  • Diabetes mellitus
  • Low serum albumin
  • Poor surgical candidacy

Prognosis varies with specific conditions of IE.

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9
Q

True or False: The incidence of infective endocarditis has changed significantly in recent decades.

A

False

Despite improvements in diagnosis and treatment, the incidence has remained relatively stable.

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10
Q

What are the traditional classifications of endocarditis?

A
  • Acute
  • Subacute
  • Chronic

Classification also includes native vs. prosthetic valve endocarditis and endocarditis associated with intravenous drug use.

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11
Q

Which organism is now the most prevalent cause of infective endocarditis?

A

Staphylococcus aureus

This shift is due to a decline in rheumatic heart disease and an increase in nosocomial infections.

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12
Q

What type of endocarditis is commonly associated with intravenous drug use (IVDU)?

A

Right-sided endocarditis

This type often occurs in individuals with no prior structural heart disease.

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13
Q

What is the typical mortality rate for infective endocarditis caused by Staphylococcus aureus?

A

~40%

Particularly high in cases involving prosthetic valves.

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14
Q

What is the role of damaged valve endothelium in the pathogenesis of endocarditis?

A

Increases susceptibility to bacterial adherence and infection

Damage can be due to turbulent blood flow, trauma, and chronic inflammation.

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15
Q

Fill in the blank: The majority of vegetations in infective endocarditis form on the _______ aspect of valves.

A

low pressure

Typically occurs on the atrial surface of the mitral valve and ventricular surface of the aortic valve.

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16
Q

What are some common microbiological causes of infective endocarditis?

A
  • Staphylococcus aureus
  • Coagulase-negative staphylococci
  • Viridans group streptococci
  • Enterococcus species
  • HACEK group

Table 3.1 provides detailed microbiologic etiology.

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17
Q

Which organism is associated with gastrointestinal disorders in infective endocarditis cases?

A

Streptococcus gallolyticus

Up to 60% of patients with this organism may have bowel adenoma or carcinoma.

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18
Q

What complications are frequent in infective endocarditis caused by coagulase-negative staphylococci?

A

Heart failure (>40%) and substantial mortality (approximately 25%)

This organism is often associated with indwelling devices.

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19
Q

What is the common presentation of infective endocarditis due to viridans streptococci?

A

Subacute syndrome with symptoms lasting weeks to months

Valvular complications are less common compared to S. aureus cases.

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20
Q

True or False: Endocarditis due to Streptococcus pneumoniae is common.

A

False

It accounts for only 1.4% of cases and is often missed in diagnosis.

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21
Q

What is the significance of Enterococcus faecalis in infective endocarditis?

A

Accounts for 90% of enterococcal cases, often in elderly or debilitated patients

Frequently associated with underlying cardiac disorders or prosthetic valves.

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22
Q

What is the common cause of failure in infective endocarditis?

A

Aortic or mitral valvular involvement.

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23
Q

Which enterococcal species is the most common cause of infective endocarditis?

A

Enterococcus faecalis.

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24
Q

What percentage of enterococcal endocarditis cases does Enterococcus faecalis account for?

A

90%.

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25
Q

What demographic is primarily affected by enterococcal endocarditis?

A

The elderly and debilitated individuals.

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26
Q

What proportion of enterococcal endocarditis cases are healthcare-associated?

A

25%.

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27
Q

What is the mortality rate range for enterococcal endocarditis?

A

11 to 18%.

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28
Q

What does HACEK stand for?

A

A group of fastidious, gram-negative bacteria.

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29
Q

What is the prevalence of HACEK organisms in infective endocarditis cases?

A

About 1.4%.

30
Q

Which organisms are included in the HACEK group?

A
  • Haemophilus parainfluenzae
  • Aggregatibacter actinomycetemcomitans
  • A. aphrophilus
  • A. paraphrophilus
  • A. snegnis
  • Cardiobacterium hominis
  • C. valvarum
  • Eikenella corrodens
  • Kingella kingii
  • K. denitrificans.
31
Q

What is the typical demographic for HACEK infections?

A

Younger individuals.

32
Q

What is the mortality rate for endocarditis caused by HACEK organisms?

A

4%.

33
Q

What are common causes of non-HACEK gram-negative bacilli infective endocarditis?

A

Members of Enterobacteriaceae and Pseudomonas spp.

34
Q

What percentage of infective endocarditis cases occur on native versus prosthetic valves?

A

40% on native valves and 60% on prosthetic valves.

35
Q

What is the range of cases of fungal endocarditis among all cases?

A

2–4%.

36
Q

What are some host risk factors for fungal endocarditis?

A
  • Parenteral drug abuse
  • Indwelling vascular catheters
  • Prosthetic devices
  • Compromised immune system.
37
Q

What is the most frequently implicated fungus in endocarditis?

A

Candida spp.

38
Q

What are the two types of Candida spp. commonly involved in endocarditis?

A
  • C. albicans
  • Non-albicans Candida.
39
Q

What is a common challenge in diagnosing Aspergillus infective endocarditis?

A

Infrequency of positive blood cultures.

40
Q

What percentage of endocarditis cases remain unidentified despite advanced diagnostic techniques?

A

5–10%.

41
Q

What factors can lead to culture-negative cases of endocarditis?

A
  • Previous antibiotic therapy
  • Fastidious organisms
  • Organisms that cannot be grown using conventional techniques.
42
Q

What are the four cardinal Oslerian manifestations of infective endocarditis?

A
  • Persistent bacteremia or fungemia
  • Active valvulitis
  • Large-vessel embolic events
  • Immunologic vascular phenomena.
43
Q

What is the most common symptom present in patients with infective endocarditis?

A

Fever.

44
Q

What percentage of patients with infective endocarditis experience fever?

A

80–90%.

45
Q

Which patients are less likely to present with fever in infective endocarditis?

A

Elderly and immunocompromised patients.

46
Q

What are common nonspecific symptoms of infective endocarditis?

A
  • Fatigue
  • Weight loss
  • Malaise
  • Chills
  • Night sweats
  • Arthralgias
  • Myalgias.
47
Q

What physical exam findings are indicative of infective endocarditis?

A
  • New or changing murmurs
  • Signs of congestive heart failure.
48
Q

What are Osler’s nodes?

A

Small, tender, violaceous subcutaneous nodules.

49
Q

What are Janeway lesions?

A

Non-tender, erythematous skin lesions resulting from septic emboli.

50
Q

What is the diagnostic criteria used for infective endocarditis?

A

The Duke criteria.

51
Q

What is needed for a definitive diagnosis of infective endocarditis according to the Duke criteria?

A

Pathological evidence or clinical evidence including two major criteria or one major criterion and three minor criteria.

52
Q

What is the recommended number of blood cultures to obtain for suspected infective endocarditis?

A

Three separate sets.

53
Q

What are common laboratory findings in patients with infective endocarditis?

A
  • Anemia
  • Elevated ESR
  • Elevated CRP.
54
Q

What imaging technique is central to the diagnosis and management of infective endocarditis?

A

Echocardiography.

55
Q

What is the first echocardiographic method performed in suspected infective endocarditis?

A

Transthoracic echocardiography (TTE).

56
Q

What echocardiographic method is indicated for better image quality in suspected infective endocarditis?

A

Transesophageal echocardiography (TEE).

57
Q

What is the hallmark lesion of infective endocarditis (IE)?

A

Vegetation

Typically presents as an oscillating mass attached to a valvular structure.

58
Q

Under what circumstances may transthoracic echocardiography (TTE) be considered sufficient?

A

Good-quality negative TTE with low clinical suspicion

Negative echocardiography should prompt repeat studies if suspicion for IE is high.

59
Q

What are the three most frequent and severe complications of infective endocarditis?

A
  • Heart failure
  • Perivalvular extension of infection
  • Embolic events
60
Q

Which echocardiographic technique is preferred for assessing perivalvular extension and its complications?

A

Transesophageal echocardiography (TEE)

TEE is more effective in diagnosing perivalvular extensions.

61
Q

What are common sites for vegetations in infective endocarditis?

A
  • Atrial side of the mitral valve
  • Atrial side of the tricuspid valve
  • Ventricular aspects of the aortic valve
  • Ventricular aspects of the pulmonic valve
62
Q

What is the role of echocardiography in the context of embolic events?

A

Predicts embolic risk by assessing size, mobility, and location of vegetations

Vegetations greater than 10 mm are at higher risk of embolism.

63
Q

What complications can result from valve destruction in native valve infective endocarditis?

A

Acute regurgitation leading to heart failure

The mechanism may involve valve perforation, torn leaflet, or flail leaflet.

64
Q

What is the importance of multi-slice computer tomography (MSCT) in the diagnosis of infective endocarditis?

A

Provides high-resolution anatomic information and detects valvular and perivalvular damage

MSCT can identify cardiac lesions and extracardiac complications.

65
Q

True or False: Echocardiography is operator-dependent.

A

True

66
Q

Fill in the blank: Significant regurgitation can be caused by _______.

A

Chordal rupture and flail leaflet

67
Q

What is the role of MRI in evaluating infective endocarditis?

A

Evaluation of complications such as paravalvular and myocardial abscesses

MRI is less accurate than TTE and TEE for identifying vegetations.

68
Q

What imaging modality is used to measure metabolic activity in diagnosing infective endocarditis?

A

18-fluorodeoxyglucose (FDG)-PET

Helpful in cases where TTE and TEE fail to recognize vegetations due to acoustic shadowing.

69
Q

List at least three structural complications of infective endocarditis.

A
  • Leaflet perforation
  • Abscess
  • Valve dehiscence
70
Q

What echocardiographic findings suggest the diagnosis of infective endocarditis?

A

Vegetation on cardiac valves

Vegetations typically occur on the low-pressure side of high-velocity jets.

71
Q

What is the significance of valve dehiscence in prosthetic valve infection?

A

Leads to partial detachment of the valve ring from surrounding tissue

This can cause rocking motion of the prosthetic valve.

72
Q

What echocardiographic information is superiorly acquired by TTE compared to TEE?

A
  • Left ventricular function
  • Severity of regurgitant lesions
  • Filling pressures
  • Pulmonary artery pressures