Infective Endocarditis Flashcards
What is the venturi effect
non-bacterial thrombotic endocarditis and NVE develop on the sides of low pressure sink just beyond the valve or intraventricular defect or stenosis
Cardiac valves lack what?
blood supply so it limits access of antibiotics to valve by diffusion only
What are the cardiac location involved with infective endocarditis
Native or prosthetic Valves
Low pressure side of a VSD
MUral endocardium damaged by jets of blood or foreign bodies lets bacteria stick to it
Intracardiac devices
What is infective endarteritis?
analogous process in arteriovenous shunts, arterioarterial shunts (PDA), or aortic coarctation, abnormal vessel
What procedures increase the risk of Induced bacteremia
Endoscopy 0-20% Colonoscopy 0-20% Barium Enema 0-20% Dental Extraction 40-100% Transesophageal Echocardiography 0-20%
Prosthetic valve endocarditis
hospital acquired < 2months after valve surgery
PVE>12months after surgery infective organisms similar to community acquired NVE
What is the etiology of Current Infective Endocarditis
Congenital heart Dz Illicit IV drug use Degenerative valve disease (living too long) Intracardiac devices Increased incidence in elderly
Health care associated NVE
55% nosocomial & 45% community onset
Health care exposure within 90 days
What is the pathogenesis of Endocarditis
Adehsin molecule
Fibronectin binding proteins -required for S. aureus to attach to endothelium
Clumping factor
Glucans or FimA
Platelet fibrin vegetations form dense microcolonies of microbes
What is the problem with microcolonies in vegetations?
they are metabolicallu inactive and resistant to antimicrobial agents
What is the pathophysiologic conaequences and clinical manifestations
Constitutional symptoms
Damage to intracardiac structures
Embolization of vegetation fragments leading to infarction
Tissue injury
How does endocarditis present
previously normal valve murmurs absent initially then develop in 85%
CHF in 30-40% with a valvular dysfunction (leaky valve)
Fever
Petechiae
Subungual (slpinter hemorrhages
Osler nodes-tender subcutaneous nodules on distal pads of digits
Janeway lesion-nontender maculae on palms and soles
Roth spots- retinal hemorrhages
Signs of acute infective endocarditis
Splenomegaly Stiff neck Delirium Paralysis Pallor Gallops Rales Cardiac arrhythmia
What is a cardiac echo used for with endocarditis
Anatomic confirmation of infective endocarditis, sizing of vegetations, detection of intracardiac complications, and assessment of cardiac function
Transthroacic echocardiography (TTE)
Noninvasive and exceptionally specific
Cannot image vegetations <2 mm in diameter
20% of patients inadequate due to emphysema or body habitus
Sensitivity ~65% of patients with definite clinical endocarditis
Not adequate for prosthetic valves or detecting intracardiac complications
