Infective Endocarditis Flashcards
(36 cards)
What is the definition of infective endocarditis?
Infection of endocardium of heart, implying presence of microorganisms on the lesion
What is endarteritis?
The arterial form of endocarditis
What valves are most commonly involved in endocarditis?
Most commonly mitral, secondarily aortic
Tricuspid very common in IV drug users
What other valvular heart disease is associated with endocarditis?
Rheumatic heart disease -> often affects mitral valve
What other condition is associated with endocarditis? What type of septal defect is least relevant?
Congenital heart disease - most commonly congenital bicuspid aortic valve
Least relevant is atrial septal defect (low pressure, minimal turbulence)
What are degenerative / incidental conditions which are associated with endocarditis?
Post-MI thrombus
Intercardiac pacemaker wires, prostheses, or IV drug use
What is the primary pathogenesis mechanism which initiates endocarditis?
Turbulent blood flow, often caused by heart murmur, results in deposition of platelets and fibrin - Nonbacterial thrombic endocarditis (NBTE)
Is the lesion often found on the high or low pressure side of an insufficiency or shunt?
Low pressure side
i.e. Mitral prolapse would lead to left atrial endocarditis
How does NBTE contribute to pathology?
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
Why is the immune system an issue in endocarditis?
Immune complexes will begin to form and circulate, causing glomerulonephritis and a number of systemic issues
What are common heart complications of endocarditis?
Valvular changes / abscesses
Rupture of IV septum, chordae tendinae
Myocardial infarcation in about 50%
What are pathologic changes in the kidney due to IE?
- Abscess
- Infarcation
- Focal or diffuse glomerulonephritis
What is one major CNS complication of IE? One more? hehe
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
What is a common cause of PE in IV drug users? What is this called?
Formation of embolus due to endocarditis of the right ventricle (constant venous stimulation of infected skin / bacteremia)
Called: Septic pulmonary emboli
What are three commonly tested clinical manifestations of IE around the body?
- Osler’s nodes
- Janeway lesions
- Roth spots
What skin change is typical of the eyes in IE and why?
Conjunctival petechiae, due to immune complexes which always circulate
In what patients would fever actually not be present in infective endocarditis?
CHF, old age, prior antibiotic therapy, renal failure
Usually remittent - fluctuating temperatures
What are general constitutional symptoms of IE? Via the heart?
Nonspecific malaise
Via the heart: new or changing murmur
What is often present in fingertips of IE patients?
- Petechiae
- Clubbing
- Splinter hemorrhages (under nails)
- Osler’s nodes - painful nodular lesions due to immune complex deposition
What are Janeway lesions?
Hemorrhagic, macular (flat), painless plaques on palms / soles mostly due to emboli
What are Roth spots?
Oval, pale, retinal lesions surrounded by hemorrhage near optic disc on retinoscopy
What are two behavioral CNS symptoms due to IE?
- Toxic encephalopathy - confusion due to persistent bacteremia
- Seizures
What lab values (CBC) are common in IE?
Anemia in chronic infection, leukocytosis without anemia in acute
Almost 100% elevated sedimentation rate (C-reactive protein causing inflammation)
What does urinalysis show?
- Proteinuria in most cases
- Microscopic hematuria with white / red cell casts
- Bactinuria
