deck_5071927 Flashcards
What is infective endocarditis?
microbial infection of the heart valves or mural endocardium leading to vegetations composed of thrombotic debris and organisms, often associated with destruction of underlying cardiac tissue
What else can be infected besides the heart in infective endocarditis?
-aorta-existing aneurysms-prosthetic devices
What kinds of bugs caused infective endocarditis?
mostly bacteria, some fungi
What is acute IE caused by?
infection of a previously normal heart valve by a highly virulent organism
What is the most common cause of acute IE?
Staph aureus (31% of all)
What does Staph aureus infection result in?
rapid production of necrotizing and destructive lesions
What is subacute IE caused by?
due to insidious infection of deformed valves by organisms of lower virulence
What is the most common cause of subacute IE?
viridans strep (17% of all cases) (less destructive)viridans can affect normal valves and aureus can affect abnormal valves as well
What are some species of strep viridans?
S. mitis, mutans, oralis, sanguinis, sobrinus, milleri
What are some other causes of IE?
-Enterococcus (11%)-Coag neg staph (staph epi.) (11%)-HACEK (2%)-Fungi (2%)
What are the HACEKs?
Haemophilus aphrophilus(subsequently calledAggregatibacter aphrophilusandAggregatibacter paraphrophilus);Actinobacillus actinomycetemcomitans (subsequently calledAggregatibacter actinomycetemcomitans);Cardiobacterium hominis;Eikenella corrodens; andKingella kingae.
Describe the HACEKs.
all gram negative and all commensals in the oral cavityused to be a cause of culture neg IE but can be easily isolated now
What are some causes of culture-negative endocarditis?
-bartonella (causes cat-stratch fever)-Coxiella burnetii (causes Q fever)
T or F. Gram negative bacteria adhere less readily to heart valves
T. Every cause except the HACEKs are gram+
What are some common causes of IE in IV drug users?
-S. aureus (gram+ cocci in clusters)-Pseduomonas (needle infected)- (gram - rods)-Candida albicans (no gram stain results)- huge vegetations
What are some common causes of IE in patients with prosthetic valves?
S. epi (creates a biofilm)gram + of clusters
What are some common causes of IE in patients with colon cancer?
Strep. gallolyticus (formerly S. bovis)will see blood in the stool in age over 50, gram+ cocci in pairs and chains
How does IE look grossly?
friable, bulky lesions containing fibrin, inflammatory cells, and bacteriacan be single or multiple lesions that can erode into the myocardium or develop abscesses
What is a common progression of IE lesions?
they are prone to embolize and abscesses frequently develop where they lodge, leading to sequelae such as septic infarcts
What are the most common valves affected in IE?
MITRAL and aortic
What are the most common valves affected in IE in drug users?
right side valves (especially tricuspid)
What are some risk factors for IE?
-IVDU-male sex-Age 60+-poor dentition (viridians mediated)
Heart related risk factors for IE?
-structural, valvular, congenital, or prosthetic heart disease-HIV-chronic hemodialysis (catheters, immunosuppression)-IV device (central line)
What kind of valvular heart disease puts a patient at risk for IE?
-mitral valve prolapse-degenerative calcific valvular stenosis-bicuspid aortic valve
How does acute endocarditis present?
-rapid fever development, chills, weight loss, B symptoms-dyspnea, cough, night sweats, arthalgias
How does subacute endocarditis present?
gradual onset of low-grade fever, night sweats, weight loss, fatiguecan be sick for several weeks before coming in
Other signs of IE?
-cardiac murmur (85-90%)-splenomegaly-petechiae (very common)-splinter hemorrhages
Where are petechiae common in IE?
lower legs, conjunctiva, and palate
What is splinter hemorrhages?
nonblanching linear reddish-brown lesions under the nail bed- might be a micro-abscess
Uncommon signs of IE?
-Janeway lesions-Osler nodes-Roth spots
What are Janeway lesions?
nontender erythematous violaceous modules mostly on the palms and soles- flat, not raised (cant feel them)micro-abscesses with neutrophils infiltration of capillaries
What are Osler lesions?
tender, subcutaneous violaceous nodules mostly on the pads of the fingers and toes (can appear white)raised so you can feel them
T or F. Janeway lesions are more common in acute IE
T. Although not very common at all
Note about Osler lesions and Roth spots.
sequelae of vascular-occlusion by micro-thrombi leading to localized immune-mediated vasculitis
When should IE be suspected?
In patients with fever (with /without bacteremia) and relevant cardiac risk factors or non cardiac risk factors (IVDU, recent dental procedure)
How is diagnosis of IE made?
based on clinical symptoms, blood cultures, and ECG
T or F. At least 3 sets of blood cultures should be obtained from separate sites prior to giving antibiotics
T.
What are some other hints leaning toward IE?
-elevated inflammatory markers (ESR, CRP)-anemia-positive rheumatoid factor-UA with hematuria, pyre, proteinuria
What is the Duke criteria?
guidelines for IE diagnosis
What are the pathologic Duke criteria for definite IE?
pathologic lesions: vegetation or intracardiac abscess demonstrating active endocarditis on histologymicroorganisms: culture or histology of a vegetation or intracardiac abscess
What are the clinical Duke criteria for definite IE?
-2 major criteria -1 major and 3 minor criteria-5 minor criteria
What are the major Duke criteria for diagnosis of IE?
-positive blood culture for a characteristic organisms or persistently + for an unusual organism -ECG ID of a valve-related or implant-related mass or abscess, or partial separation of artificial valve -new valvular regurg
What are the minor Duke criteria for diagnosis of IE?
-predisposing heart lesion or IVDU-fever-vascular lesions (petechiae, splinters, emboli, Janeway, etc)-Immunological phenomena (glomerulonephritis, Osler noders, Roth spots)- a single + culture for an unusual bacteria -worsening or changing of a murmur
How is IE treated?
vancomycin (assuming gram +!!). Adjust for gram negative
What are some cardiac complications of IE?
-valvular insufficiency, -heart failure, -chord rupture, -suppurative pericarditis
What are some neurologic complications of IE?
-embolic stroke, -brain abscesses, -intracerebral hemorrhage
What is a complication of right-sided IE?
septic pulmonary emboli
What are some possible metastatic infections caused by IE?
-vertebral osteomyelitis-septic arthritis-psoas abscess
What is a systemic immune reaction caused by IE?
glomuleronephritis
Prognosis of IE?
In hospital mortality: 18-23%six-month mortality rate: 22-27%
