Cardiac pathology Part 2 Endocarditis & cardiomyopathies Flashcards
How does Streptococci viridians cause endocarditis? (aka describe the pathogenesis)
It has low virulence so it can only infect valves that have been damaged previously. It grows vegetations (fibrin & platelets) on valves which then trap more bacteria (because the state of bacteremia) causing further inflammation.
How would you treat bacterial endocarditis in a patient with +ve blood cultures & a history of Chronic rheumatic heart disease?
Patient will have damaged valves from the CRHD,
Causal agent: S. viridians
Rx: prophylactic antibiotics
What is the most common cause of bacterial endocarditis (excluding IV drug abusers)
S. viridians
What is the most common cause of bacterial endocarditis in patients who abuse IV drugs?
S. aureus
How does S. aureus cause endocarditis? (aka describe the pathogenesis)
It is very virulent so it is able to infect healthy valves (especially the tricuspid valve) it causes large vegetations which destroy the valves (acute endocarditis)
How does S. epidermidis cause endocarditis?
It infects prostatic valves
Endocarditis of prostatic valves is due to which organism?
S. epidermidis
What causes endocarditis in patients with colorectal cancer?
S. bovis
How does S. bovis cause endocarditis?
It infects the heart valves of patients with colorectal cancer
What are the HACEK organisms that cause endocarditis with -ve blood cultures?
Hemophilus
Actinobacillus
Cardio bacterium
Eikenella
Kingella
Hemophilus
Actinobacillus
Cardio bacterium
Eikenella
Kingella
Cause endocarditis with which unique feature?
Endocarditis with -ve blood cultures
What are the signs of endocarditis (common to all)
- Fever
- Janeway lesions (painless palmar/soles)
- Osler’s nodes (painful fingers)
- Splinter hemorrhages.
- Roth spots (embolization)
- Anemia of chronic disease
A 54-year-old male presents to the emergency department complaining of fever, fatigue, and shortness of breath that have progressively worsened over the past two weeks. He has a history of intravenous drug use, specifically heroin, but hasn’t used intravenously for the past six months. On physical examination, the patient appears ill and febrile with a temperature of 39.2°C (102.6°F), heart rate of 110 beats per minute, and blood pressure of 120/80 mmHg. Auscultation reveals a new-onset systolic murmur.
Bacterial endocarditis due to an infection with S. aureus
A 62-year-old male with a history of mitral valve prolapse and prior dental procedures presents to the clinic with a complaint of fatigue, low-grade fever, and weight loss over the past few weeks. He reports experiencing episodes of chills and night sweats. On examination, there are multiple small petechiae over the conjunctiva and nail beds. Auscultation reveals a new-onset diastolic murmur.
Bacterial endocarditis due to S. viridians
A 45-year-old male with a history of intravenous drug use presents to the emergency department with a chief complaint of fever, fatigue, and a new-onset heart murmur. He also reports night sweats and weight loss over the past month. On examination, multiple painful, erythematous nodules are found on his fingers. Laboratory tests reveal elevated inflammatory markers and blood cultures are ordered.
Bacterial endocarditis due to S. aureus
What are the lab values to look out for when dealing with bacterial endocarditis?
- +ve blood cultures (except HACEK)
- Anemia of chronic disease (low Hb, TIBC, serum Fe, O2 saturation & high ferritin)
Describe the pathogenesis of Non-Bacterial Thrombotic Endocarditis
It causes sterile vegetations that appear during states of hypercoagulability or adenocarcinomas
Where do the vegetations arise in Non-Bacterial Thrombotic Endocarditis? What is a complication as a result of this?
Usually the mitral valve along the lines of closure which inhibit valve closure resulting in mitral regurgitation