Infective Endocarditis Flashcards
What is infective endocarditis?
This is a microbal infection of the heart valves, lining of the heart chamber and the blood vessels.
What is the incidence of Infective Endocarditis?
5-15 cases per 100,000 per annum
What percentage of IE patients are over 60yrs?
> 50%
What percentage of pesons with Rheumatic Fever develop IE
24%
What percentage of persons with congenital heart disease develops IE
19%
What is the fatality rate of bacterial endocarditis
20%
(increased in prosthetic valves)
(increased in anti-biotic resistant organisms)
List 7 groups of aetiological agents that can cause Infective Endocarditis
Oral Cavity Commensals Bowel or Urinary Tract Commensals Skin Commensals Post operative Q Fever Endocarditis HACEK Group Yeast and Fungi
Oral Commensals account for what percentage of IE cases (subacute IE that is)
75%
What group of oral commensal cause Subacute IE
Viridans Streptococci
Strep. Mitis
List 3 groups of bowel, urinary commensals that can cause Infective Endocarditis
Enterococcus Faecalis
E.Faecium
Strep. Bovis
In the event that a patient is found to have IE secondary to Strep. Bovis ( Strep. Gallolyticus) what investigation is important to be done?
Colonoscopy, as the patient is likely to have a large bowel malignancy
What is the most common cause (organism) of Acute Endocarditis
Staphylococcus Aureus
List 1 skin commensal that can cause IE (acute)
Staphylococcus Aureus
How does a skin commensal like Staph aureus get into the blood steam to cause IE?
Abscess
Vascular access sites
Skin infections
Apart from Staph. Aureus list 2 other causative agents of Acute Infective Endocarditis
Strep. pneumoniae
Strep. Pyogenes
What group of bacteria is usually the source of Infective endocarditis secondary to operation (post-op commensals)
Coagulase negative staphylococcus
List two examples of Coagulase Negative Staphylococcus
Staph. Epidermis
Staph. Lugdenesis
A patient that has a h/o conatct with farm animals, most likely has what type of infective endocarditis
Q Fever Endocarditis
Which bacteria causes Q Fever Endocarditis
Coxiella Bumetii
What is the treatment for Q Fever Endocarditis
Lifelong antibiotics
List the “slow growing, fastdidious, gram negative organisms, oropharyngeal commensals” that can cause Infective Endocarditis
HACEK Group H- Haemophillus Aphrophilus A- Aggregatibacter Actino. C- Cardiobacterium Hominis E- Eikenella Corrodens K- Kigella Kingae
List 2 yeast/ fungi that can cause infective endocarditis
Candida
Aspergillus
(in dwelling catheters)
List the 4 steps in the pathogenesis of infective endocarditis
1) Occurs at Site of Endothelial damage
2) Avascular Valve protects microb from WBCs
3) Vegetations may grow and cause obstruction or embolize
4) Adjacent tissue destroyed, abscess may form
Why does the infection in IE usually occur at sites of endothelial damage ?
Because they attract deposits of platelets and fibrin that are vulnerable to colonization by microbs
List 5 complications of IE
Valve Regurgitation Skin lesions Vasculitis Mycotic Aneurysm Infarct of kidney or spleen
What is the difference between acute and subacute Infective Endocarditis
Acute endocarditis can develop suddenly and become life-threatening within days while subacute endocarditis develops slowly over a period of several weeks or months
What are the 4 factors that determine the presentation of IE
- subacute/acute IE
- Causative agent
- Site of infection
- presence of valve shunt or prosthesis
Subacute Endocarditis should be suspected in a patient with Congenital Heart disease, or valvular heart disease when they experience which symptoms?
- Night Sweats
- Persistent Fever
- Weight Loss
- Unusual Tiredness
- night sweats
- new signs of valve dysfuction
Subacute Endocarditis should be suspected in a patient with Congenital Heart disease, or valvular heart disease when they experience which signs?
Splinter Haemorrhage Purpura Petechial haemorrhage Osler's nodes digital clubbing
What is the difference between osler’s nodes and janeway lesions
Osler’s nodes are painful tender swellings at the fingertips while janeway lesions are rare non-tender macules on the palms and soles
List three signs/symptoms of acute endocarditis
severe febrile illness
prominent changing heart murmurs
petechiae
What are the signs of post operative IE
unexplained fever in a patient who has had heart valve surgery
List three differentials for infective endocarditis
Lyme Disease Atrial Myoxma (non cancerous tumour) Antiphospholipid Syndrome (mistakenly attack body tissue)
List 5 investigations done for a pt with IE
Blood culture ECG Echocardiogram ESR/CRP CXR
How is misdignosis of skin commensals avoided when taking blood cultures for IE?
Blood culutres taken from 2/3 different sites at 3 hr intervals.
NB// Both aerobic and anaerobic culture required
what are three main reasons for doing an Echo in a pt with IE
- detecting and following the progress of vegetations
- detect abscess
- assess valve damage
List two types of Echo
Transesophageal (90% sensitivity)
Transthoracic (65% sensitivity)
Which is better in assessing abscess formation and in pts with prosthetic valves, Transoesophageal or transthoracic Echocardiography?
Transesophageal
True or False
Faluire to detect vegetations does not exclude diagnosis
True
In infective Endocarditis, what might an ECG reading show?
May show the development of an AV block
What is the empirical treatment for Subacute Infective Endocarditis?
amoxicillin (2g 6times daily IV)
+/- Gentamicin
What is the empirical treatment for Acute Infective Endocarditis?
Vancomycin (1g bd IV) + gentamicin (1mg/kg bd IV) +Rifampicin (300-600 mg po)
What is the empirical treatment for Infective Endocarditis caused by Enterococcus?
Amoxicillin + Gentamicin
If pen allergic: vancomycin + gentamicin —for 4wks (6wks if prosthetic valve);
review need for gentamicin after 2wks.
List 5 indications for cardiac surgery in a patient with infective endocarditis
Heart Failure due to valve damage
Failure of antibiotic therapy
Large vegetations on left sided heart valves (high risk of emboli)
Previous evidence of systemic emboli
Abscess formation
What is the criteria for diagnosis of infective endocarditis?
Duke’s Modified Criteria
- 2 major
- 5 minor
- 1 major , 3 minor
DUKE’S MODIFIED CRITERIA
List 5 major criteria.
- Typical organism (Staph, Strep) from 2 cultures
- Persistent positive blood culture >24hrs
- 3+ positive cultures taken over 1hr
- Positive echo findings of vegetations
- New valvular regurgitation
DUKE’S MODIFIED CRITERIA
List 7 minor criteria.
- Predisposing valvular and cardiac abnormality
- Pyrexia >38oC
- Blood cultures suggestive but may not meet major criteria
- Embolic Phenomenon
- Vasculitis phenomenon
- IV drug misuse
- suggestive echo findings
