Infective Endocarditis Flashcards
What is endocarditis?
Inflammation of the cardiac endocardium affecting valves, mural endocardium, or implanted devices
It can be secondary to infection or a noninfectious process.
How many new cases of infective endocarditis are diagnosed each year in the United States?
10,000–15,000 new cases
Incidence varies from 0.6 to 11.6 cases per 100,000 person-years.
What is the male to female ratio for infective endocarditis cases?
> 2:1
The incidence is higher in men than women.
What is the median age at diagnosis for infective endocarditis?
Increasing over the years, primarily affecting patients above the age of 60
Majority of cases occur in older adults.
What are common risk factors for developing infective endocarditis?
- 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.
What percentage of infective endocarditis cases are healthcare-associated?
Approximately 23–27%
Includes cases related to intravascular catheters and devices.
What is the mortality range for patients diagnosed with infective endocarditis?
18 to 23% in-hospital mortality
6-month mortality is reported to be 22–27%.
What factors contribute to poor outcomes in infective endocarditis?
- Female gender
- Diabetes mellitus
- Low serum albumin
- Poor surgical candidacy
Prognosis varies with specific conditions of IE.
True or False: The incidence of infective endocarditis has changed significantly in recent decades.
False
Despite improvements in diagnosis and treatment, the incidence has remained relatively stable.
What are the traditional classifications of endocarditis?
- Acute
- Subacute
- Chronic
Classification also includes native vs. prosthetic valve endocarditis and endocarditis associated with intravenous drug use.
Which organism is now the most prevalent cause of infective endocarditis?
Staphylococcus aureus
This shift is due to a decline in rheumatic heart disease and an increase in nosocomial infections.
What type of endocarditis is commonly associated with intravenous drug use (IVDU)?
Right-sided endocarditis
This type often occurs in individuals with no prior structural heart disease.
What is the typical mortality rate for infective endocarditis caused by Staphylococcus aureus?
~40%
Particularly high in cases involving prosthetic valves.
What is the role of damaged valve endothelium in the pathogenesis of endocarditis?
Increases susceptibility to bacterial adherence and infection
Damage can be due to turbulent blood flow, trauma, and chronic inflammation.
Fill in the blank: The majority of vegetations in infective endocarditis form on the _______ aspect of valves.
low pressure
Typically occurs on the atrial surface of the mitral valve and ventricular surface of the aortic valve.
What are some common microbiological causes of infective endocarditis?
- Staphylococcus aureus
- Coagulase-negative staphylococci
- Viridans group streptococci
- Enterococcus species
- HACEK group
Table 3.1 provides detailed microbiologic etiology.
Which organism is associated with gastrointestinal disorders in infective endocarditis cases?
Streptococcus gallolyticus
Up to 60% of patients with this organism may have bowel adenoma or carcinoma.
What complications are frequent in infective endocarditis caused by coagulase-negative staphylococci?
Heart failure (>40%) and substantial mortality (approximately 25%)
This organism is often associated with indwelling devices.
What is the common presentation of infective endocarditis due to viridans streptococci?
Subacute syndrome with symptoms lasting weeks to months
Valvular complications are less common compared to S. aureus cases.
True or False: Endocarditis due to Streptococcus pneumoniae is common.
False
It accounts for only 1.4% of cases and is often missed in diagnosis.
What is the significance of Enterococcus faecalis in infective endocarditis?
Accounts for 90% of enterococcal cases, often in elderly or debilitated patients
Frequently associated with underlying cardiac disorders or prosthetic valves.
What is the common cause of failure in infective endocarditis?
Aortic or mitral valvular involvement.
Which enterococcal species is the most common cause of infective endocarditis?
Enterococcus faecalis.
What percentage of enterococcal endocarditis cases does Enterococcus faecalis account for?
90%.
What demographic is primarily affected by enterococcal endocarditis?
The elderly and debilitated individuals.
What proportion of enterococcal endocarditis cases are healthcare-associated?
25%.
What is the mortality rate range for enterococcal endocarditis?
11 to 18%.
What does HACEK stand for?
A group of fastidious, gram-negative bacteria.