endocarditis

Question 1

what is the basic principles of endocarditis

Answer 1

inflammation of the endocardium (valve, papillary muscles) that lines the surface of the heart
usually due to bacterial infections
endovascular infection of cardiovascular structures, including cardiac valves, atrial and ventricular endocardium, large intrathoracic vessels and intercardiac foreign bodies eg prosthetic valves, pacemakers etc

Question 2

how can you divide endocarditis

Answer 2

infective: subacute, acute and prosthetic

noninfective

Question 3

explain non infective endocarditis

Answer 3

Nonbacterial thrombotic endocarditis/Marantic

• sterile vegetations that arise with hypercoagulable state or underlying adenocarcinoma
• vegetrations arise on mitral valve along lines of closure and result in regurgitation

Libman-Sacks Endocarditis

• sterile vegetations associated with SLE
• vegetations present on surface and under surface (both sides) of mitral valve
• result in mitral regurgitation

Question 4

explain infective endocarditis

Answer 4

S. viridans

• most common cause
• subacute
• low virulence organism, infects previously damaged valves
• results in small vegetations that do not destroy the valve
• pathogenesis –> damaged endocarditis surface develops thrombotic vegetations (platelets and fibrin) and transient bacteriemia leads to trapping of bacteria in vegetations (eg dental work)

S aureus

• most common cause in IVDU
• high virulence organism, infect normal valves (tricuspid hard to grow

Question 5

what are the clinical features of endocarditis

Answer 5

• fever
• murmur –> vegetatons –> disrupt flow
• janeway lesions –> septic embolisation
• Osler nodes –> painful
• anemia of chronic disease –> chronic inflammation
• splinter hemorrhage

Question 6

what are the lab findings in infective endocarditis

Answer 6

• positive blood cultures
• anemia of chronic disease - macroscopic
• TEE is useful for detecting lesions on valves

Question 7

what is the aetiology of infective endocarditis

Answer 7

• consequences of two factors (presence of organisms in blood and abnormal cardiac endothelium facilitating their adherence and growth)
• bacteraemia due to - patient specific reasons (poor dental hygeine, IV drug use) and associated with diagnostic or therapeutic procedures (Eg dental treatment IV cannulae, cardiac surgery)
• damaged endocardium promotes platelet and fibrin deposition which allows organisms to adhere and grow, leading to an infected vegetatoin
• vascular lesions –> create non-laminar flow and jet lesions from septal defects or a patent DA –> abnormal vascular endothelium
• aortic and mitral valves most commonly affected

Question 8

what is the clinical presentation of infective endocarditis

Answer 8

• dependent on organism and presence of predisposing cardiac conditions
• may occur as a chronic or subacute illness with low grade fever and nonspecific symptoms

high clinical suspicion

• new valve lesions/(regurgitation) murmur
• embolic event(s)
• sepsis of unknown origin
• haematuria, glomerulonephritis and suspected renal infarct
• fever + prosthetic + IVDU + newly developed ventricular arrhythmia

Low clinical suspicion
- fever + none of above

Question 9

what is the diagnositic criteria of infective endocarditis

Answer 9

Major Criteria

• positive blood culture for IE (typical bacteria)
• persistently positive blood culture
• positive serological test for Q fever
• ECHO evidence of endocardial involvement
• new valvular regurgitation

Minor Criteria

• predisposition
• fever
• valvular phenomena
• immunological phenomena: Osler nodes
• microbiol evidence
• ECHO

Question 10

what are the clinical features of infective endocarditis

Answer 10

general: malaise, clubbing
cardiac: murmurs, cardiac failure
arthralgia: 25%
pyrexia: 90%
skin lesion: oslers nodes, splinter haemorrhage, janeway lesions, petechiae
eyes: roth spots
splenomegaly
neurological: cerebral emboli
renal: haematuria

Question 11

what investigations would you order in infective endocarditis

Answer 11

blood cultures
serological tests
FBC: decrease HB, increased WBC, decreased platelets
Urea and Electrolytes: increased urea and creatinine
liver biochem: increased serum alk phos
inflam markers: increased ESR and crative protein
urine: proteinuria and haematuria
ECG: PR prolongation/heartblock
CXR: pulmonary oedema in left side disease, pulmonary emboli
transthoracic ECHO:
Transoesophageal ECHO

Question 12

what is the treatment for infective endocarditis

Answer 12

• location = prolonged course of ABx 4-6 weeks - should respond 48 hours evidence by decreased fever, serum markers of infection and relief of systemic symptoms of infection – failure –> consider perivalvular extension of infection and abscess, drug reaction, nosocomial infection, PE