Infective Endocarditis Flashcards
What is infective endocarditis?
It is the infection of the endocardial surface of the heart involving the heart valves +/- Mural endocardium +/- septal defect
What are the 4 main complications of infective endocarditits?
Valvular failure
Heart failure
Sepsis
Embolic disease
One of the major complications of IE is embolic disease. What could this lead to?
Stroke, MI, mycotic aneurysm, AKI, Liver injury, distal embolus (blue toe syndrome)
What side of the heart is more affected in IE?
Which valve is most effected?
Left side > Right side (95% are left sided)
Mitral > Aortic valves
Explain the pathophysiology of infective endocarditis
The endocardial surface or valves become infected after exposure to microemboli from bacteria or fungi circulating in the blood stream. Previously damaged tissue (previous IE, surgery) or non-native valves predispose to this infection
These organisms proliferate in the evolving thrombus + Persistent shedding into the blood stream causes an immune response resulting in symptoms
Vegetations in the valves causes valvular destruction and failure
What are the RFs for infective endocarditis?
Patient factors:
Age>60
Immunocompromised (DM, chemo, splenectomy, sickle cell, transplant, HIV)
Pathology:
Congenital/Structural heart disease
Valvular heart disease
Previous IE
Bowel Cancer
Procedure:
IVDU
Surgical procedure (valvular replacement, stent, and even if not cardiac)
Termination of pregnancy
Haemodialysis
Failure of aseptic technique
What is the most common organism causing IE?
What is the most common organism causing IE in Prosthetic valves?
What is the most common organism causing subacute IE?
What is the most common organism causing IE in a patient with lower GI/GU disease and bowel malignancy?
Staph aureus is the most common
Strep epidermidis and aureus are most common in prosthetic valves
Strep viridans is most common in subacute disease
Enterococci (Faecalis and Faecium) for GI/GU disease and bowel malignancy
What are the organisms that are most likely involved in IE?
Staph aureus is the most common
Strep epidermidis and aureus are most common in prosthetic valves
Strep viridans is most common in subacute disease
Enterococci (Faecalis and Faecium) for GI/GU disease and bowel malignancy
Coxiella (needs only 1 positive culture)
Fungi in immunocompromised patients
HACEK group in 2% of cases
What murmurs are most a/w IE?
AR or MR are most associated with IE (remember left sided and vegetations)
Are Osler nodes painful or painless?
Where are they typically located?
Painful and palm, pads of fingers and toes
Are Janeway lesions painful or painless?
Where are they typically located?
Painless (and haemorrhagic) on the palms of hand and soles of foot
Go through the signs and symptoms of IE
Symptoms: Fever, night sweats, anorexia, weight loss, Myalgia
In advanced disease, HF: SOB/dyspnoea, PND, orthopnoea, chest pain, cough with pink, frothy sputum
Signs: FROM JANE
Fever
Roth Spots
Osler Nodes
(New) Murmur - typically left sided
Janeway lesions
Anaemia
Nailbelt haemorrhages
Embolic (Stroke, MI, mycotic aneurysm, AKI, Liver injury, distal embolus)
+ clubbing, poor dentition, and scars of previous cardiac surgery on closer inspection
+ Splenomegaly on palpation (mild)
What are the major criteria in Duke’s criteria?
Major:
a) Blood cultures: 2 separate cultures of typical organisms
or 1 culture of coxiella
b) Imaging:
TOE ECHO 2V2A: showing vegetations or valvular perforation or Abscess or Aneurysm/pseudoaneurysm
Cardiac CT: Paravalvular lesions
PET CT FDG: Abnormal activity around prosthetic valve
What are the minor criteria in Duke’s criteria?
Minor Criteria:
a) Fever >38
b) Microbiology evidence but inadequate for major
c) Predisposing factors (tissue damage, previous IE…)
d) Vascular phenomena (emboli/thrombosis)
e) Immunological phenomenon (osler’s, Janeway lesions, Glomerulonephritis)
What is required for a Definite IE dx vs probable?
Definite if:
a) Pathological evidence on histology of vegetations or intracardiac abscess
b) 2 major criteria
c) 1 major + 3 minor
d) all 5 minor
Probable if:
a) 1 major + 1 minor
b) 3 minor
Fully explain Duke’s criteria in the diagnosis of IE
Definite if:
a) Pathological evidence on histology of vegetation or intracardiac abscess
b) 2 major criteria
c) 1 major + 3 minor
d) all 5 minor
Probable if:
a) 1 major + 1 minor
b) 3 minor
Major Criteria:
a) Blood cultures: 2 separate cultures of typical organisms
or 1 culture of coxiella
b) Imaging:
TOE ECHO 2V2A: showing vegetations or valvular perforation or Abscess or Aneurysm/pseudoaneurysm
Cardiac CT: Paravalvular lesions
PET CT FDG: Abnormal activity around prosthetic valve
Minor Criteria:
a) Fever >38
b) Microbiology evidence but inadequate for major
c) Predisposing factors (tissue damage, previous IE…)
d) Vascular phenomena (emboli/thrombosis)
e) Immunological phenomenon (osler’s, Janeway lesions, Glomerulonephritis)
What investigations would you like to order if you are suspecting IE?
Bedside: ABG/VBG, ECG, Urine dipstick/urinalysis (source of sepsis and signs of kidney injury)
Bloods:
FBC -> Hb anaemia, raised WCC, low platelets in sepsis, DIC
CRP -> elevated
U&E -> AKI (end-organ failure from sepsis or emboli) + for medications or contrast
LFTs -> Liver injury due to emboli
Imaging:
ECHO (for valvular vegetation and perforation + abscess, aneurysm/pseudoaneurysm)
Cardiac CT (paravalvular lesions)
PET CT FDG (Abnormal activity around prosthetic valve)
+
CT/MRI brain for emboli and infarcts
What echo will you use for IE?
Initially TTE the TOE. TOE required to visualise vegetations and or
What will you find on urinalysis showing kidney disease? (not necessarily as a complication of IE)
Oliguria/anuria
Proteinuria
Haematuria
Casts (RCC, WCC, granular)
What is the prophylactic antibiotic regimen given to patients at risk of IE? e.g. prosthetic valve, prior IE, heart defects, immunocompromised…
When is it indicated?
2g amoxicillin 30-60 minutes prior to
1) High risk dental procedures
2) Interventions on infected mucosa (Resp, GU, derm)
What preventative measures can you advise the patient about (IE)?
1) Good dental hygeine
2) 2g amoxicillin 30-60 minutes prior to
1) High risk dental procedures
2) Interventions on infected mucosa (Resp, GU, derm)
What is the antibiotic regimen for a native valve IE?
Native: 2-6 weeks IV
Subacute: amoxicillin/benzyl + Gentamicin
Acute or IVDU: Vancomycin + Gentamicin
What is the antibiotic regimen for a prosthetic valve IE?
Prosthetic: >6 weeks IV
Vancomycin + Gentamicin + Rifampicin
Half of those with IE will require surgical intervention.
What are the absolute indications for surgical management? Be specific
What is the surgical management of IE?
Severe aortic or mitral regurg.
Atrial or Mitral Vegetations >10mm after 1 embolic episode
Atrial or Mitral Vegetations > 15mm regardless
Uncontrolled infection despite AB
Surgical repair involving valve repair, reconstruction, replacement (nothing specific)
What is the subacute/acute management for IE?
Pharmacological:
Prolonged antimicrobrial therapy (2-6 weeks in native valve and >6 weeks in prosthetic valve) according to antimicrobial guidelines
Native: 2-6 weeks IV
Subacute: amoxicillin/benzyl + Gentamicin
Acute or IVDU: Vancomycin + Gentamicin
Prosthetic: >6 weeks IV
Vancomycin + Gentamicin + Rifampicin
Surgical repair involving valve repair, reconstruction, replacement
What is the chronic management of IE?
1) Good dental hygeine
2) 2g amoxicillin 30-60 minutes prior to
1) High risk dental procedures
2) Interventions on infected mucosa (Resp, GU, derm)
Continuous antibiotic prophylaxis if required in high risk patients
What are the complications of IE?
Cardiac:
HF
Re-infection
Aortic abscess causing AV block
Valvular failure
Non-Cardiac:
Embolism causing Stroke, Splenic infarct, distal ischaemia (blue toe), MI, Limb ischaemia, PE, mesenteri ischaemia…
AKI
Glomerulonephritis
Embolism complicated up to 50% of cases decreasing to 20% post-AB therapy. It is associated with the size and mobility of vegetation. What period of time is the risk of embolism highest?
First 2 weeks
