Infective endocarditis Flashcards
What can cause damage to the endothelial lining of a valve?
Turbulent blood flow Electrodes Catheters Inflammation (rheumatic IE) Degenerative disease (Aortic stenosis)
what is infective endocarditis?
infection affecting the endocardial surface of the heart
usually the valves
what are the risk factors for infective endocarditis of a native valve?
Mitral valve prolapse Congenital heart disease Rheumatic heart disease Asymmetrical septal hypertrophy IV drug abusers Alcohol misusers Diabetics Medical devises such as catheters
what age group does IE mostly affect?
older patients
describe the pathophysiology of how infective endocarditis occurs.
Mechanical endothelial disruption exposes extracellular matrix protein which releases tissue factors.
This causes deposition of fibrin and platelets resulting in non bacterial throb endocarditis.
NBTEC facilitates bacterial adherence and infection resulting in vegetations.
what percentage of cases of IE are due to endothelial inflammation without valve lesion?
25%
describe the pathophysiological process of how IE occurs with endothelial inflammation without endothelial valve lesions.
Inflammation of endothelial cells causes expression of interns B1 family.
the interns are Transmembrane proteins which binds circulating fibronectin to proteins on their surface
Staph aureus carry fibronectin therefore binds to the surface resulting in vegetations.
what are causes of bacteraemia which can bring about IE?
Invasive procedures such as dental procedures requiring manipulation and perforating oral mucosa
GU and GI surgery
IV catheters
Extra cardiac infections
Non-invasive activities i.e. chewing and brushing teeth
Brushing teeth and chewing is a high/low grade bacteraemia of short/long duration but with high/low incidence
low grade
short duration
high incidence
name some of the organisms responsible to IE.
strep viridans staph aureus enterococci Staphylococci (coagulase -ve) haemophillus parainfluenzae actinobaccilus strep bovis fungi coxiella burnetii brucella species
what patients may have an atypical presentation of IE?
elderly and immunosuppressed
what is the subacute presentation of IE?
fever
non-specific symptoms
palpitation and immunologic/vascular phenomena
what is the acute presentation of IE?
fever
embolic signs/symptoms
or decompensated Heart failure
what are the common/non-sepcific symptoms of IE?
fever night sweats, malaise, fatigue, weight loss weakness arthralgia headache SOB
what are the clinical signs of IE?
cardiac murmor (regurgitant murmor) with signs of heart failure Janeway lesins Osler nodes Roth spot (eyes) Meningeal signs Splinter haemorrhages Cutaneous infarcts Vasculitic rash Immune complex deposition
what are janeway lesions?
Haemorrhage painless plaques
Occur mostly in the palms and soles
what are osler nodes?
small painful nodular lesion
Found on pads of fingers and toes
a woman present with painless lesions on her soles of her feet. what are these most likely to be?
Janeway lesions
a patinet presents with painful lesions on the pads of her fingers. what are these most likely to be?
osler nodes
what is the most frequent sign of IE?
pyrexia
what investigations are carried out for IE?
blood culture FBC U+E's (renal failure) Urinalysis ECG CXR Echo (transthoracic or transesophageal) MRI, PET-CT, Leucoyte SPECT/CT
why are U+E’s carried out?
to detect renal failure
why are FBC and CRP tests carried out?
for detection of elevated inflammatory markers
what may be observed in an ECG with someone with IE?
prolonged PR interval >200ms
4th degree heart block
