Infective Endocarditis Flashcards
What is infective endocarditis?
It is defined as a condition in which there is inflammation of the endocardium, the inner lining of the heart covering the heart valves, secondary to infection
This inflammation results in the formation of vegetations on the affected heart valves
What are vegetations?
They are deposits of pathogen, platelets, fibrin and other serum molecules
What is the pathophysiological consequence of infective endocarditis?
The formed vegetations have the potential to embolise and cause further complications
Which valve is most commonly affected in infective endocarditis?
Mitral valve
Which valve is most commonly affected in infective endocarditis - who are IVDUs?
Tricuspid valve
What are the eleven risk factors associated with infective endocarditis?
Male Gender
Older Age
Intravenous Drug Users
Poor Oral Hygiene
Recent Piercings
Endocarditis History
Valvular Heart Disease
Prosthetic Heart Valves
Rheumatic Heart Disease
Hypertrophic Cardiomyopathy
Congenital Heart Disease
What three congenital heart defects are associated with infective endocarditis?
Ventricular septal defect
Patent ductus arteriosus
Atrial septal defect
What are the thirteen clinical features of infective endocarditis?
Fever > 38C
Dyspnoea
Fatigue
Night Sweats
Weight Loss
Tachycardia
New Heart Murmur
Splinter Haemorrhages
Bibasal Crepitations
Finger Clubbing
Splenomegaly
Roth’s Spots
Osler’s Nodes
How can we remember the clinical features of infective endocarditis?
FROM JANE
Fever
Roth’s spots
Osler’s nodes
New murmur
Janeway lesions
Anaemia
Nail changes
Emboli
What are Roth’s spots?
They are defined as boat-shaped retinal haemorrahages, which are pale in the centre
What are Osler’s nodes?
They are defined as tender subcutaneous nodules in the fingers and toes
What are Janeaway lesions?
They are defined as painless erythematous macule on the palms and soles
What additional feature is present in IVDUs?
Discitis
What six investigations are used to diagnose infective endocarditis?
Blood Tests
Blood Culture
Urinalysis
ECHO Scan
ECG Scan
Chest X-Ray (CXR)
What four blood test results indicate infective endocarditis?
Decreased Haemoglobin Levels
Increased WCC Levels
Increased CRP Levels
Increased ESR Levels
What additional blood test is used to investigate infective endocarditis? Why?
U&Es
They are conducted to identify the baseline renal function and creatinine clearance
This enables individuals to be started on nephrotoxic antibiotics, such as gentamicin
What is the first line laboratory investigation used to diagnose infective endocarditis?
Blood culture
How do we conduct blood cultures in cases of suspected infective endocarditis?
They should be obtained on three occasions, at least 30 minutes apart, from three separate peripheral sites
What eight organisms commonly colonise infective endocarditis?
Staphylococcus Aureus
Staphylococcus Epidermis
Streptococcus Viridans
Streptococcus Bovis
Coxiella Burnetti
HACEK Organisms
Candida
Aspergillus
What is the most common organism to colonise infective endocarditis?
Staphylococcus Aureus
In which two patient groups does infective endocarditis tend to be caused by staphylococcus aureus?
Intravenous drug users
> 2 months of prosthetic valve surgery
In which patient group does infective endocarditis tend to be caused by staphylococcus epidermis?
Initial 2 months following prosthetic valve surgery
In which two patient groups does infective endocarditis tend to be caused by streptococcus viridian?
Poor dental hygiene
Dental procedures
In which patient group does infective endocarditis tend to be caused by streptococcus bovis?
Colorectal cancer
What are HACEK organisms?
Haemophilus
Actinobacillus
Cardiobacterium
Eikenella
Kingella
What are the five blood culture negative organisms associated with infective organisms?
HACEK organisms
Coxiella burnetti
Chlamydia species
Bartonella species
Legionella
What is the feature of infective endocarditis on urinalysis?
Microscopic haematuria
What is the first line imaging investigation used to diagnose infective endocarditis?
ECHO scan
What are the four features of infective endocarditis on ECHO scans?
Intra-Cardiac Vegetation
Valvular Root Abscess
New Valvular Regurgitation
New Partial Dehiscence of Prosthetic Valve
Which ECHO scans are preferred to diagnose infective endocarditis - transoesophageal or transthoracic?
Transthoracic
When are transoesophageal ECHO scans recommended to diagnose infective endocarditis?
They are only recommended when infective endocarditis is clinically suspected, however initial transthoracic scan is negative
How are ECG scans used to diagnose infective endocarditis?
They are used to identify the development of first degree AV heart block, which is a complication of infective endocarditis
What is the feature of first degree AV heart block on ECG scans?
PR prolongation > 200ms
How are CXRs used to diagnose infective endocarditis?
They used to identify the development of heart failure, which is a complication of infective endocarditis
Which criteria is used to diagnose infective endocarditis?
Duke’s criteria
What does Duke’s criteria state for a definitive diagnosis of infective endocarditis to be obtained?
It states that one of the following criteria must be obtained…
Positive Blood Culture/Histology
OR
Two Major Criteria
OR
One Major Criterion & Three Minor Criteria
OR
Five Minor Criteria
What does Duke’s criteria state for a possible diagnosis of infective endocarditis to be obtained?
It states that one of the following criteria must be obtained…
One Major Criterion & One Minor Criterion
OR
Three Minor Criteria
What does Duke’s criteria state for a rejected diagnosis of infective endocarditis to be obtained?
It states that one of the following criteria must be obtained…
Firm Alternative Diagnosis
Sustained Features > 4 Days of Antibiotics
What are the two major criteria in the ‘Duke’s Criteria’’?
Microbiology Evidence
Positive ECHO Features
What is the microbiology evidence of Duke’s major Criteria?
> 2 positive results for typical microorganisms (Streptococcus Viridans, HACEK Group)
OR
Persistent bacteraemia from 2 blood cultures taken > 12 hours apart OR > 3 positive blood cultures when the pathogen is less specific (Staph. aureus, Staph. epidermis)
OR
A positive serology for for Coxiella burnetti, Bartonella species or Chlamydia psittaci
OR
Positive molecular assays for specific gene targets
What are the five minor criteria in the ‘Duke’s Criteria’’?
Risk Factors
Fever > 38C
Vascular Features
Immunological Features
Microbiological Evidence
What are the two risk factors in Duke’s criteria?
Predisposing heart condition
OR
IVDU
What are the six vascular features in Duke’s Criteria?
Septic Emboli
Splenomegaly
Finger Clubbing
Splinter Haemorrhages
Janeway lesions
Petechiae
What are the three immunological features in Duke’s Criteria?
Glomerulonephritis
Osler’s Nodes
Roths Spots
What is the microbiology evidence of Duke’s minor Criteria?
A positive blood culture that don’t meet major criteria
What is the pharmacological management option of infective endocarditis?
Antibiotics
What is the first line management option of infective endocarditis?
Antibiotics
What are antibiotics used to manage infective endocarditis?
They are the first line management option of infective endocarditis
How do we determine the antibiotic regimen in infective endocarditis?
It is dependent upon multiple factors, including previous antibiotic use, valvular type affected, microorganism involves and antibiotic sensitivity of the particular organism
Describe the antibiotic course used to manage infective endocarditis
The antibiotic course is administered from the first day a negative set of blood cultures is obtained – even though antibiotics will have been administered before this
It is advised that they are administered intravenously for a period of two weeks, before switching to oral preparations
How long is the antibiotic course of infective endocarditis, affecting prosthetic valves?
6 weeks
How long is the antibiotic course of infective endocarditis, affecting native valves?
2 - 6 weeks
What is the initial blind antibiotic therapy used to treat infective endocarditis affecting native valves?
Amoxicillin +/- Gentamicin
What is the initial blind antibiotic therapy used to treat infective endocarditis affecting native valves - in those with a penicillin allergy, MRSA or severe sepsis?
Vancomycin + Gentamicin
What is the initial blind antibiotic therapy used to treat infective endocarditis affecting prosthetic valves?
Vancomycin
What is the antibiotic therapy used to treat staphylococci infective endocarditis affecting native valves?
Flucloxacillin
What is the antibiotic therapy used to treat staphylococci infective endocarditis affecting native valves - in those with a penicillin allergy or MRSA?
Vancomycin & Rifampicin
What is the antibiotic therapy used to treat staphylococci infective endocarditis affecting prosthetic valves?
Flucloxacillin & Rifampicin & Gentamicin
What is the antibiotic therapy used to treat streptococci infective endocarditis affecting native/prosthetic valves?
Benzylpenicillin
What is the antibiotic therapy used to treat streptococci infective endocarditis affecting native/prosthetic valves - in those with a penicillin allergy or MRSA?
Vancomycin & Gentamicin
When is surgery used to manage infective endocarditis?
It is the second line management option of infective endocarditis
What are the two surgical management options of infective endocarditis?
Valvular heart repair
Valvular heart replacement
In which five circumstances is urgent surgical management of infective endocarditis recommended?
Valvular Incompetence
Aortic Abscess
Infection Resistant To Antibiotics
Congestive Heart Failure
Recurrent Emboli
How do we prophylactically manage infective endocarditis?
Antibiotics
When do we recommend prophylactic management of infective endocarditis?
The guidelines currently don’t recommend the use of prophylactic antibiotics against infective endocarditis whilst patients undergo dental procedures or procedures affecting the gastrointestinal, genitourinary or respiratory tracts
However, if individuals undergo these procedures and subsequently require antibiotics for a suspected infection, the antibiotics selected should also provide effective cover against infective endocarditis
What are the eight complications of infective endocarditis?
Valvular Destruction
Aortic Root Abscess
Heart Failure
Pericarditis
Arrythmias
Myocardial Infarction
Pulmonary/Splenic/Stroke Emboli
Septicaemia
