Cardio Flashcards
state two infections can that affect the heart in children?
infective endocarditis
acute rheumatic fever
what congenital heart conditions can occur with IE?
ventricular septal defects
patent ductus arteriosus
aortic valve abnormalities
tetralogy of fallot
what is the triad features of IE?
endothelial damage
platelet adhesion
microbial adherence
what happens to the bacteria once they attach to the lesion of damaged endothelial ?
the bacteria are protected within the vegetation from phagocytic cells and host defense mechanisms and so can proliferate easily
what specific surface receptor does organisms that cause IE have ?
surface receptors to fibronectin that allow the microbe to adhere to the thrombus at the outset
what organisms commonly cause IE?
Staphylococcus Aureus, Streptococcus Viridans
what are the HACEK organisms?
Haemophillus, Actinobacillus, Cardiobacterium, Eikenella and Kingella
state some features of IE?
persistent low grade fever
heart murmur
splenomegally
- petechiae, oslers nodes, laneway lesions, splinter haemorrhages (embolic phenomena)
PE, haematuria (due to glomerular nephritis), cerebral emboli, roth spots on the retina
what investigations should be done for IE?
blood cultures
Echo
what criteria is used for diagnosing IE?
Dukes criteria
in order to confirm diagnosis how many major or minor should be present ?
2 major
1 major and 3 minor
5 minor
what are the minor criteria for dukes criteria?
predisposing heart condition
fever
vascular phenomena
immunological phenomena (roths, oslers, GN, RF)
+ blood cultures
echo findings
what are the two major criteria of the dukes criteria?
+ blood cultures for endocarditis (2 separate cultures take 12hrs apart)
evidence of endocardial involvement
what three factors increase the possible need for surgical intervention?
vegetation (>1.5cm, mobile, increase of size) valvular dysfunction perivalvular extension (new heart block, large abscess despite management, valvular rupture)
what are the antibiotics commonly used to treat IE?
IV penicillin or IV ceftriaxone for 4 weeks
or/and
IV gentamicin for 2 weeks
what antibiotic is used for methicillin IE?
vancomycin for 6 weeks
what antibiotics are used for HACEK organisms IE?
ceftriaxone along with gentamicin for 4 weeks
what are fungal IE treated with?
amphotericin B
what increases the risk of IE?
acquired valvular heart disease hypertrophic cardiomyopathy previous IE structural congenital heart disease valvular replacement
what usually precedes acute rheumatic fever?
2-4 weeks after pharyngitis
what organism most commonly causes acute rheumatic fever?
streptococcus pyogenes
why can pharyngitis cause acute rheumatic fever?
cross-reactivity to group A β-haemolytic streptococcus (GAS)
what gender is most affected by rheumatic fever?
females
is streptococcus pyogenes a gram negative cocci?
no
- gram positive cocci
what are the two cytolytic toxins produced by strep pyogenes?
streptolysin O and S.
what is the pathophysiology of rheumatic fever?
strep pyogenes contain M proteins in their cell wall
B cells produce anti-M protein antibodies which cross react with tissues in the body
this is exacerbated by production of activated cross reactive T cells
what are risk factors of rheumatic fever?
extremes of age poverty overcrowding FHx D8/17 B cell antigen positivity
what criteria is used for rheumatic fever?
revised jones diagnostic criteria
what valve in the heart is most affected by rheumatic fever?
mitral
what two things are required for diagnosis of rheumatic fever?
- +throat culture for strep pyogenes or raised anti streptolysin A or anti-deoxyribonuclease B titre
- 2 major criteria or 1 major and 2 minor
what is the major criteria for rheumatic fever? SPECS
Sydenham’s chorea Polyarthritis Erythema marginatum Carditis Subcutaneous nodules
what is the minor criteria for rheumatic fever? CAPE
CRP or ESR – Raised acute phase reactant
Arthralgia
Pyrexia/Fever
ECG – Prolonged PR interval
what are the DD for rheumatic fever?
septic arthritis
reactive arthropathy
infective endocarditis
myocarditis
what two things is reactive arthritis associated with ?
urethritis
conjunctivitis
what ECG changes might be seen with myocarditis ?
saddle ST segments or T wave changes
what investigations can be done for rheumatic fever?
Bloods - FBC, CRP, ESR, culture rapid antigen detection test throat culture anti streptococcal serology ECG CXR ECHO
what might the ECG show for rheumatic fever?
prolonged PR interval
what is the management of rheumatic fever ?
Antibiotics e.g. benzathine benzylpenicillin
aspirin
assess for emergency valve replacement
what prophylaxis can be given for rheumatic fever?
intramuscular Benzathine benzylpenicillin every 3-4 weeks, oral Phenoxymethylpenicillin twice daily, oral sulfadiazine daily, or oral azithromycin (in penicillin allergy)
