Infective Endocarditis (pathology)

Question 1

What is infective endocarditis?

Answer 1

Inflammation of the endocardium (inner layer of the heart)

• Usually involves the valves
• Vegetations = platelets+ fibrin+ microorganisms

Question 2

What are the risk factors for infective endocarditis (8)?

Answer 2

• Prosthetic valves (mechanical & biological) but native valves most affected
• Cardiac devices (pacemakers, defibrillators)
• Intravenous drug users
• Congenital heart disease
• Rheumatic valve disease
• Mitral valve prolapse
• Immunosuppression
• Heath care associated IE- central lines

Question 3

What are the symptoms of infective endocarditis?

Answer 3

• Embolic stroke with haemorrhagic conversion
• Pyogenic brain abscess
• Septic pulmonary emboli
• Splenic infarcts
• Peripheral (finger) infarcts
• Valve dysfunction (perforation/vegetation)

FEVER + NEW HEART MURMUR

Question 4

What are the signs of infective endocarditis (9)?

Answer 4

• Osler’s nodes (painful)
• Janeway’s lesions (no pain)
• Roth spots (central retinal haemorrhage)
• Splinter haemorrhage
• Anemia (Discoloration of conjunctiva + Angular stomatitis-cracks at the edge of the mouth)
• Raised JVP
• Bradycardia
• Low BP
• Crackles

Question 5

What are the investigations of infective endocarditis?

Answer 5

Blood culture + Echo (vegetations, +/- stenosis/regurgitation)
Bloods
-	CRP
- 	high WBC
-	anaemia 
- 	urea and electrolytes
Urine dip stick
-	Haematuria 
Blood cultures
-	AT LEAST 3 SETS,30 min apart from 3 different sites= confirm that bacteraemia is persistent and spread out 
-	Essential before starting antibiotics 
*Association with cancer- colonoscopy 
Imaging 
-	Transthoracic echo
-	Transoesophageal echo
-	CT/MRI 
-	PET (F-FDG or leucocyte labelled SPECT/CT)
Modified Duke Criteria 
-	Definite IE 
•	2 major 
•	1 major+ 3 minor
•	5 minor
-	Possible IE (1 major + 1 minor or 3 minor)

Question 6

What are the medical treatments for infective endocarditis caused by streptococcus?

Answer 6

Penicillin G (or vancomycin if allergic to beta lactam)
- 4 weeks without prosthetic valve
- 6 weeks with prosthetic valve
Strep viridans ↑ penicillin sensitivity= better prognosis than staph aureus

Question 7

What are the medical treatments for infective endocarditis caused by staphylococcus?

Answer 7

• Native valves
  • Flucloxacillin 4-6 weeks
• Prosthetic valves
  + Rifampicin and Gentamycin for 6 wee

Question 8

What is the empirical treatment (all valves) for infective myocarditis?

Answer 8

• Ampicillin+ flucloxacillin+ gentamicin (for gram -ve)
• Vancomycin+ gentamicin (penicillin allergy)
  • Better response to treatment in native valves

Question 9

What is the surgical treatment for infective myocarditis? What are the criteria for surgery?

Answer 9

Criteria: 
-	HF+ valvular dysfunction 
-	Uncontrolled infection
-	Prevention of embolism (vegetation > 10 mm)
-	Renal failure 
Replacement > repair 
IV Abx for 6 weeks post-op