Cardiology Flashcards
Name some of the most common underlying congenital heart disease conditions in which IE occurs.
ventricular septal defects, patent ductus arteriosus, aortic valve abnormalities including bicuspid aortic valve and tetralogy of fallot
What is the triad of infective endocarditis?
endothelial damage, platelet adhesion and microbial adherence
Name some of the most common causative organisms of infective endocarditis.
Staphylococcus Aureus, Streptococcus Viridans,
Describe how a patient with IE would present.
Persistent low-grade fever, especially without another clear focus, is a concerning feature and should promote IE as a consideration. This is especially if there is a history of congenital heart disease, previous cardiac surgery or indwelling prosthetic material.
A heart murmur is almost always present formed either by turbulent flow around the vegetation or due to underlying heart disease.
Name some cutaneous manifestation of IE.
Petechiae – on skin and can be present on mucous membranes or conjunctival
Osler’s nodes – painful erythematous raised lesions on ends of fingers or toes
Janeway lesions – small, painless, erythematous, haemorrhagic raised lesions on palms or soles
Splinter haemorrhages – linear haemorrhagic streaks in the nail bed
Name two investigations required in suspected IE.
blood cultures and Echocardiography (ECHO)
What criteria is used for diagnosing IE?
Modified dukes criteria
In order to confirm a diagnosis of IE, how many of the modified dukes criteria need to be present?
In order to confirm the diagnosis there should be two major criteria, one major and three minor criteria or five minor criteria. The diagnosis is suspected if 1 major and 1 minor criteria or 3 minor criteria present.
What do organisms causing infective endocarditis have specific surface receptors for?
Fibronectin that allow the microbe to adhere to the thrombus at the outset.
What is acute rheumatic fever?
A systemic illness that occurs 2-4 weeks after pharyngitis due to cross-reactivity to streptococcus pyogenes
What is the gram stain of streptococcus pyogenes?
Gram-positive cocci
Name the two cytolytic toxins produced by streptococcus pyogenes.
Streptolysin S and O
Name some risk factors for developing IE.
Children and young people Poverty Overcrowded and poor hygiene places Family history of rheumatic fever D8/17 B cell antigen positivity
What is the diagnostic criteria for IE called?
Revised jones criteria.
in severe acute rheumatic failure, a heart murmur might be heard on examination, what valve is commonly affected?
Mitral
Name some investigations you’d like to do in suspected IE.
Bloods: ESR, CRP, FBC (WBC),
Blood cultures to exclude sepsis
Rapid Antigen Detection Test
Throat culture: may be negative by the time rheumatic fever symptoms occur
Anti-streptococcal serology: ASO and anti-DNASE B titres
ECG: prolonged PR interval
CXR if carditis is suspected: congestive heart failure may be seen in ARF due to valvular damage
Echocardiography
Which virulence factor causes B cells to produce a substance that cross reacts with tissues in the heart, brain, joints and skin?
M proetiens in the cell wall are immunogenic and stimulate B cells to make anti-M protein antibodies which cross reacts with other tissues e.g.. heart, brain, joints and skin.
Is ASD acyanotic or cyanotic?
Acyonotic
Name some risk factors for developing ASD.
Maternal smoking in 1st trimester
Maternal diabetes
Maternal rubella
Maternal drug use e.g. cocaine & alcohol
Name some symptoms of large ASD in paediatric patients.
Tachypnoea
Poor weight gain
Recurrent chest infections
What might be seen on an ECG of a child with an ASD?
Tall P wave (right atrial enlargement)
Right bundle branch block (incomplete)
Right axis deviation
What test is gold standard in diagnosing ASD?
Transthoracic echocardiogramas it provides information regarding both the size of ASD, and direction of blood flowing through the defect (using Doppler). It is also able to approximate the pulmonary artery pressure.
