Infective Endocarditis Flashcards by amo x

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

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What are vegetations?

They are deposits of pathogen, platelets, fibrin and other serum molecules

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What is the pathophysiological consequence of infective endocarditis?

The formed vegetations have the potential to embolise and cause further complications

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Which valve is most commonly affected in infective endocarditis?

Mitral valve

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Which valve is most commonly affected in infective endocarditis - who are IVDUs?

Tricuspid valve

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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

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What three congenital heart defects are associated with infective endocarditis?

Ventricular septal defect

Patent ductus arteriosus

Atrial septal defect

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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

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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

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What are Roth’s spots?

They are defined as boat-shaped retinal haemorrahages, which are pale in the centre

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What are Osler’s nodes?

They are defined as tender subcutaneous nodules in the fingers and toes

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What are Janeaway lesions?

They are defined as painless erythematous macule on the palms and soles

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What additional feature is present in IVDUs?

Discitis

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What six investigations are used to diagnose infective endocarditis?

Blood Tests

Blood Culture

Urinalysis

ECHO Scan

ECG Scan

Chest X-Ray (CXR)

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What four blood test results indicate infective endocarditis?

Decreased Haemoglobin Levels

Increased WCC Levels

Increased CRP Levels

Increased ESR Levels

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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

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What is the first line laboratory investigation used to diagnose infective endocarditis?

Blood culture

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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

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What eight organisms commonly colonise infective endocarditis?

Staphylococcus Aureus

Staphylococcus Epidermis

Streptococcus Viridans

Streptococcus Bovis

Coxiella Burnetti

HACEK Organisms

Candida

Aspergillus

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What is the most common organism to colonise infective endocarditis?

Staphylococcus Aureus

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In which two patient groups does infective endocarditis tend to be caused by staphylococcus aureus?

Intravenous drug users

> 2 months of prosthetic valve surgery

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In which patient group does infective endocarditis tend to be caused by staphylococcus epidermis?

Initial 2 months following prosthetic valve surgery

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In which two patient groups does infective endocarditis tend to be caused by streptococcus viridian?

Poor dental hygiene

Dental procedures

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In which patient group does infective endocarditis tend to be caused by streptococcus bovis?

Colorectal cancer

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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