Infective endocarditis Flashcards
What is infective endocarditis?
Infective endocarditis is an endovascular infection of cardiovascular structures, including cardiac valves, atrial and ventricular endocardium, large intrathoracic vessels and intracardiac foreign bodies, e.g. prosthetic valves, pacemaker leads and surgical conduits.
How does damaged endocardium predispose someone to IE?
Damaged endocardium promotes platelet and fibrin deposition which allows organisms to adhere and grow, leading to an infected vegetation. Valvular lesions may create non-laminar flow, and jet lesions from septal defects or a patent ductus arteriosus result in abnormal vascular endothelium.
Which valves are most commonly affected in IE?
Aortic and Mitral valves in non drug users
Which valves are most commonly affected in IVDUs?
Right sided heart lesions (tricuspid and pulmonary)
What are cardiac risk factors for IE?
- Mitral valve prolapse
- Congenital Heart Disease
- Aortic stenosis
- Aortic regurgitation
- Mitral regurgitation
- Rheumatic Heart Disease
- Prosthetic heart valve
- Cardiac Surgery
What are non-infective risk factors for IE?
- IVDU
- Indwelling medical devices
- Diabetes mellitus
- AIDS
- Chronic skin infection, burns
- GU infection
- GI lesions
- Organ transplant
- Homelessness
- Pneumonia
- Poor dental hygeine/dental work
If someone presented with a new murmur and a fever, what might you suspect?
IE until proven otherwise
What organisms can cause IE?
- Strep. viridans
- Enterococci
- Staph aureus/epidermidis
- HACEK organisms
- Coxiella burnetti
- Chlamydia
- Candida
- Aspergillus
- Histoplasma
What are symptoms of infective endocarditis?
- Malaise
- Pyrexia (90%)
- Rigors
- Night sweats
- Weight loss
- Headache
What signs might be seen in someone with infective endocarditis?
- Septic signs
- New/changing pre-existing cardiac murmur
- Skin lesions
- Roth’s spots
- Spenomegaly/splenic infarct
- Embolic phenomena
- Glomerulonephritis/AKI
What are septic signs seen in IE?
- Fever
- Rigors
- Night sweats
- Splenomegaly
- Clubbing
- Malaise/Weight loss
What is the following?
Clubbing of the fingers and toes
What can valvular vegetations do to the valve?
- Valve destruction
- Valve regurgitation
- Valve obstruction
What is the following?
Osler’s nodes - Tender, red-purple, slightly raised, cutaneous nodules often with a pale surface. Most frequently found over the tips of the fingers and toes, but can be present on the thenar eminences and are often painful.
What is the cause of the following?
Osler’s nodes - result from the deposition of immune complexes. The resulting inflammatory response leads to swelling, redness, and pain that characterize these lesions.
What is the following?
Janeway Lesions - Non-tender, haemorrhagic macules or papules often found on the palms or soles – especially on thenar or hypothenar eminences
What causes the following?
Janeway Lesions - thought to be caused by septic micro-emboli deposited in peripheral sites, which causes microabscesses of the dermis with marked necrosis and inflammatory infiltrate not involving the epidermis
What are signs of long standing infection in infective endocarditis?
- Anaemia
- Clubbing
- Splenomegaly
What are the following?
Splinter haemorrhages - Small, red-brown lines of blood seen beneath the nails. They run in line with the nail and look like splinters caught underneath the nail.
What causes the following?
Splinter haemorrhages - In bacterial endocarditis, this sign is thought to be caused by emboli creating clots in capillaries under the nail, resulting in haemorrhage.
What skin lesions are found in Infective endocarditis?
- Osler’s nodes
- Janeway lesions
- Splinter haemorrhages
- Petechiae (most common)
What is the following?
Roth spots - oval retinal haemorrhages with a pale centre located near the optic disc
What causes the following?
Roth spots - insult causes rupturing of the retinal capillaries, followed by extrusion of whole blood, leading to platelet activation, the coagulation cascade and a platelet fibrin thrombus. The fibrin appears as the white lesion within the haemorrhage.
It is suggested that in subacute bacterial endocarditis, thrombocytopenia secondary to a low-grade disseminated intravascular coagulopathy can prompt capillary bleeding in the retinal vasculature.
Why can AV block occur in IE?
Aortic root vegetations can prolong PR interval, and if serious can cause complete AV block
