29-09-22 - Valvular Heart Disease, Endocarditis Flashcards
Learning outcomes
- Define the terms stenosis and incompetence
- Describe the common causes of cardiac valve stenosis and incompetence
- Define the term infective endocarditis
- Name the risk factors for infective endocarditis
- Describe the composition of a vegetation
- Describe the local and systemic complications of infective endocarditis
- Describe the principles of diagnosis, treatment and prevention of infective endocarditis
- Know the names of some organisms that cause infective endocarditis
What are the 4 components of the valve?
- Components of valves:
1) Valve ring – fibrous ring that allows for the attachment of cusps of valves. The 4 fibrous rings are known as annulus fibrosus
2) Cusps
3) Chordae (chordae tendinea) – Chordae are the thick, strong, tendinous connections between the mitral valve and tricuspid valve cusps and the papillary muscles
4) Papillary muscles – only for mitral and tricuspid valve. Provide tensile strength to the cusps to prevent prolapse/inversion
What is the meaning of stenosis? What is the meaning of incompetence?
What are 2 other names for it?
What are the 4 most common functional failures in valves?
What are their associated murmurs?
Why are right side heart valve conditions not listed?
- Stenosis is narrowing of the valve outlet caused by thickening of valve cusps, or increased rigidity or scarring.
- Incompetence (Or insufficiency or regurgitation) is caused by an incomplete seal when valves close, allowing blood to flow backwards
- 4 most common functional failures in valves and their associated heart murmurs:
1) Mitral stenosis – high pitched early diastolic heart sound
2) Mitral incompetence – mid systolic, high-pitched sound
3) Aortic stenosis - high-pitched, “diamond shaped” crescendo-decrescendo, mid-systolic ejection murmur
4) Aortic incompetence - the typical murmur of aortic regurgitation is a soft, high-pitched, early diastolic decrescendo murmur - The same conditions occur in right side heart valves, but they are less common, and involved in less severe disease
Valvular lesions, pathological cause, clinical features
Valvular lesions, pathological cause, clinical features
What are 3 different types of common causes of cardiac valve stenosis and incompetence?
- Common types of causes of cardiac valve stenosis and incompetence:
1) Congenital heart disease (birth defects)
* Valve atresia – improper formation of the valves
* E.g aortic atresia
2) Cardiomyopathy
* Cardiomyopathy is a general term for diseases of the heart muscle, where the walls of the heart chambers have become stretched, thickened or stiff.
* This affects the heart’s ability to pump blood around the body.
* Hypertrophic cardiomyopathy - the heart muscle cells enlarge and the walls of the heart chambers thicken
* Dilated cardiomyopathy - type of heart muscle disease that causes the heart chambers (ventricles) to thin and stretch, growing larger.
3) Acquired
* Rheumatic fever
* Myocardial infarction
* Age related – idiopathic aortic calcific stenosis
* Endocarditis
What is rheumatic fever?
Why can it develop?
What causes these infections?
What age group is it most common in?
How often might it occur?
What is it mediated by?
What effect does rheumatic fever have on the heart?
How can this cause disease later in life?
- Rheumatic fever is an acute multisystem disease that can affect the heart, joints, and connective tissue
- Rheumatic fever may develop if strep throat or scarlet fever infections are not treated properly or after strep skin infections (impetigo).
- Bacteria called group A Streptococcus (group A strep) cause these infections.
- Rheumatic fever is most common children aged 4-16 years old
- It may occur in recurrent episodes
- Rheumatic fever is more immune mediated than direct infection
- In some people, repeated strep infections cause the immune system to react against the tissues of the body including inflaming and scarring the heart valves.
- This is what is referred to as rheumatic fever.
- Rheumatic heart disease can then result from the inflammation and scarring of heart valves caused by rheumatic fever
- This can cause chronic valve disease of all 4 heart valves decades later
What is infective endocarditis (IE)?
What determines the damage and severity of clinical illness from IE?
How is IE classified?
Why must be careful with subacute/chronic IE?
What are 2 clinical signs of infective endocarditis?
- Infective endocarditis (IE), also called bacterial endocarditis, is an infection caused by bacteria that enter the bloodstream and settle in the heart lining, a heart valve or a blood vessel and lead to the formation of vegetations (abnormal growths)
- The virulence (harmfulness) of organisms is what determines damage and severity of clinical illness
- IE can be classified as acute and subacute (chronic condition)
- Acute IE is caused by more virulent organisms and can lead to more severe problems quicker
- Sub-acute IE is a chronic condition caused by a less virulent organism, won’t cause a lot of problems, and can be easy to miss
- We must be careful with sub-acute/chronic IE, as patients present with fever, joint pain, splinter haemorrhages, clubbing, and it can be easy to not even consider IED
- Clinical signs of IE:
1) Splinter haemorrhages
* Clots can migrate from the affected heart valve and find their way into various parts of the body.
* If this happens in the finger, it can cause damage to the capillaries resulting in a splinter haemorrhage.
2) Clubbing
* IE causes Increases blood flow to the distal fingers, which causes tissue hypertrophy in the fingers, leading to the appearance of clubbing
What are the 3 risk factors for Infective endocarditis?
- Risk factors of infective endocarditis:
1) Valve damage
* Especially after rheumatic fever
2) Bacteraemia – presence of viable bacteria in the blood
* Can be from:
* Dental – why we are asked if we have had rheumatic fever at the dentist – procedures can be covered with antibiotics
* Catheterisation
* 10% unknown
* IV drug abuse
3) Immunosuppression
* Suppression of the body’s immune system and its ability to fight infections and other diseases
What are vegetations?
When can vegetations of the heart valve form?
How do they form?
What condition is this known as?
Are they dangerous on their own?
How can they become infected?
Why is it difficult for the immune system to deal with infected thrombotic vegetations?
- A vegetation is an abnormal growth
- Vegetations of the heart valves can form when there has been damage to the heart valves (e.g from rheumatic fever)
- Platelets and fibrin can come to try and heal this damage, leading to the formation of thrombotic vegetations (known as non-bacterial thrombotic endocarditis - NBTE)
- By itself, NBTE does not pose any particular health risk, but fragments of vegetation may break off and move towards the brain or heart, causing an embolism.
- In addition, the vegetation can provide a point of accumulation for bacteria (e.g staphylococci and streptococci) and lead to the infective form of the condition, infective endocarditis.
- When bacteria get into these thrombotic vegetations, they can grow
- It is difficult for the immune system to deal with this, as it is a point of high blood flow, making it heard for immune cells such as phagocytes to access this site
- Pieces of the vegetation can break off and cause emboli if blood blots break off and block vessels
What are 3 different types of valve endocarditis?
How do valves appear?
What organisms are they caused by?
How can IV drug abuse cause valve disease?
- 3 different types of valve endocarditis and IV drug abuse valve conditions:
1) Acute native valve endocarditis
* Native = not prosthetic valves
* Valves may be normal
* Aggressive disease
* Caused by highly virulent organisms, such as Staph. aureus and group B streptococci
2) Subacute native valve endocarditis
* Chronic condition
* Abnormal valves
* Cause little to no pain, but may deteriorate
* Caused by low virulent organisms, such as alpha-haemolytic streptococci, enterococci
* We must be careful with sub-acute/chronic IE, as patients present with fever, joint pain, splinter haemorrhages, clubbing, and it can be easy to not even consider IED
3) Prosthetic valve endocarditis
* 10-20% of cases
* 5% of mechanical and bio-prosthetic valves become infected
* Mitral are more susceptible than aortic
* Early onset: Staph. aureus, gram-negative bacilli, Candida species
* Late onset: staphylococci, alpha-haemolytic streptococci, enterococci
4) IV drug abuse
* 75% have no underlying valvular abnormalities
* 50% involve the tricuspid valve
* Staph. aureus most common cause
Principles of diagnosis, treatment and prevention of infective endocarditis. What can be done in terms of:
* Prevention
* Diagnostics
* Treatment
- Principles of diagnosis, treatment and prevention of infective endocarditis (IE)
1) Prevention
* Before diagnosis, we want to prevent
* Knowing if someone has a had rheumatic fever is a big help, as this is a big risk factor
* We need to treat Strep infections that can lead to rheumatic fever with anti-biotics
* We need to have prophylactic (disease prevention) cover for invasive procedures e.g dental procedures
2) Diagnosis
* We must be careful with sub-acute/chronic IE, as patients present with fever, joint pain, splinter haemorrhages, clubbing, and it can be easy to not even consider IED
* We diagnose IE with a high degree of clinical suspicion
* We use imaging, such as echocardiography to try and diagnose
* We can use blood cultures, but we may have to repeat many times, as sub-acute IE is episodic
3) Treatment
* We used High dose intravenous antibiotics to treat IE, as it is difficult for immune cells to reach the infected site to get at the thrombotic vegetation
What 3 things are people with aortic stenosis (aortic valve narrowing) at risk of?
What are the 3 causes of aortic stenosis?
What are 3 consequences of aortic stenosis?
What are 3 clinical symptoms of aortic stenosis?
- 3 things people with aortic stenosis (aortic valve narrowing) are at risk of
1) Left ventricular hypertrophy
2) Syncope (fainting)
3) Sudden cardiac death - Cause of aortic stenosis:
1) Calcification of congenital bicuspid aortic valve
2) Senile calcification – prevents the full opening of the valve during systole
3) Rheumatic fever - Consequences of aortic stenosis:
1) Increases the work of the heart
2) Ventricular hypertrophy – can cause ischemia due to increased oxygen demand
3) Causes cardiac failure late in the clinical course - Clinical symptoms of aortic stenosis:
1) Dyspnoea (breathlessness)
2) Angina (chest pain)
3) Syncope (fainting)
What are 5 causes of aortic incompetence (aka regurgitation/insufficiency)?
What are 4 consequences of aortic incompetence?
- Causes of aortic incompetence (aka regurgitation/insufficiency)
1) MI
* Aortic incompetence can develop post MI due to rupture of papillary muscle
* This leads to the patient getting better post MI, and then worse
2) Infective endocarditis
3) Rheumatic fever (closely related to IE)
4) Can occur in the presence of aortic stenosis
5) Marfan’s syndrome
* Marfan’s syndrome is a genetic disorder that changes the proteins that help make healthy connective tissue.
* This leads to problems with the development of connective tissue, which supports the bones, muscles, organs, and tissues in your body.
* Leads to valves being floppy
- Consequences of aortic incompetence:
1) Increases volume of blood to be pumped significantly
2) Increases the work of the heart
3) Cardiac hypertrophy
4) Cardiac failure
How can mitral stenosis develop?
What are 4 consequences of mitral stenosis?
- Mitral stenosis can be congenital (birth defect) or occur as a result of rheumatic fever, both of which are rare
- 4 consequences of mitral stenosis:
1) Restricts blood flow to the left ventricle
2) Atrial fibrillation – irregularly irregular
3) Back pressure results in pulmonary hypertension
4) Finally causes right heart failure
What are 4 causes of mitral incompetence?
What are 2 consequences of mitral incompetence?
- Cause of mitral incompetence is cusp damage from:
1) Rheumatic heart disease – scarring
2) Floppy valve – stretch
3) Marfan’s syndrome – affects connective tissue formation
4) Infective endocarditis – perforation (hole made) - Consequences of mitral incompetence:
1) Pulmonary hypertension- blood going back into pulmonary circulation, which increases pressure
2) Right ventricular hypertrophy – heart has to pump more blood to keep up with back flow
Valvular lesions, pathological cause, clinical features
Valvular lesions, pathological cause, clinical features
