valvular heart disease Flashcards

Question

what is rheumatic fever?

Answer 1

- acute multi system disease (heart, joints, connective tissue) - 3 weeks post streptococcal infection - immune demoted rather than direct infection - occurs in children 4-16 - may occur in recurrent episodes - chronic valve disease years later

Answer 2

- valves may be normal - aggressive disease - virulent organism (eg staph aureus)

Answer 3

- abnormal valves - indolent but may deteriorate - alpha haemolytic streptococci, enterococci

Answer 4

10-20% of valve cases 5% of mechanical and bio prosthetic valves become infected - mitral re more susceptible than aortic - early onset = staph aureus, gram neg bacilli, candida species - later onset = staphylococci, alpha haemolytic streptococci, enterococci

Answer 5

- treat strep infection with antibiotics - prophylactic cover for invasive procedure - replace damaged valves - look for clinical suspicions and signs - imaging (echocardiograph) - BLOOD CULTURE - INTRAVENOUS ANTIBIOTICS ( increased bioavailability to get the the hard places that the bacteria form)

Answer 6

* 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

Answer 7

* 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

Answer 8

* 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

Answer 9

* 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

Answer 10

* 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

Answer 11

* 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

Answer 12

* 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

Answer 13

* 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 heart disease Flashcards

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