Infective Endocarditis Flashcards
Learning outcomes
So basically how you get it, and what the presentation, investigation and treatment is
What is infective endocarditis?
Infective endocarditis is a form of endocarditis. It is an inflammation of the inner tissues of the heart, the endocardium, usually of the valves. Can involve the interventricular septum, chordae tendinae and intra cardiac devices.
How does infective endocardiits affect men and women?
Affects men more than women with a ratio of 2:1
Women have a worse prognosis
What percentage of IE patients have underlying structural heart disease?
Around 25%
What are the cardiac risk factors for infective endocarditis?
What are the predisposing valvular lesions in patients with IE?
What are the non-cardiac risk factors for patients with IE?
How does infective endocarditis arise?
Valvular surface is damaged as a result of turbulent blood flow. As a result, platelets and fibrin adhere to the underlying collagen surface and create a sterile fibrin-platelet vegetation. Bacteraemia leads to colonisation of the thrombus and perpetuates further fibrin deposition and platelet aggregation, which develops into a mature infected vegetation.
What are the ways bacteraemia can arise?
- Extra-cardiac infections
- Invasive procedures (e.g. oral, abdominal, genitourinary surgery
intravascular catheters)
- Gingival disease – easy access for bugs to enter blood stream
- Activities of daily living (brushing teeth and bowel movements)
What are the different modes of acquisition?
Health care related - (nosocomial - occuring within the hospital - if over 48 hours after hospitilisation)
Non - nosocomial (if the signs and symptoms appear less than 48 hours after admission - usually as a result of home based nursing, IV therapy, haemodialysis if less than 30 days before onset, acute care facility if 90 days before onset, resident in nursing home)
Community - acquired
IVDA (intravenous drug abuse)
What are the symptoms of infective endocarditis?
What is this sign of infective endocarditis?
Splinter haemorrhages
What is this sign of infective endocarditis?
Vasculitic rash
Petechial (a small red or purple spot caused by bleeding into the skin)
What is this sign of infective endocarditis?
Roth spots
What is this sign of infective endocarditis?
Osler’s nodes
What is this sign of infective endocarditis?
Janeway lesions (Pathognomonic) (specifically characteristic or indicative of a particular disease or condition)
macular means spots
Ecchymotic means: the escape of blood into the tissues from ruptured blood vessels marked by a livid black-and-blue or purple spot or area - differs from petechiae only because the spots are greater than 3 mm
What are the signs of infective endocarditis?
Congestive cardiac failure
Immune complex deposition:
splinter haemorrhages
vasculitic rash
Roth Spots
Osler’s nodes
Janeway lesions
nephritis
Embolic Phenomena (vegetation embolises - absess forms in the place it lands)
Focal neurological signs (Focal neurologic signs also known as focal neurological deficits or focal CNSsigns are impairments of nerve, spinal cord, or brain function that affects a specific region of the body, e.g. weakness in the left arm, the right leg, paresis, or plegia.)
Peripheral embolus :
renal
cerebral
splanchnic
vertebral
Pulmonary Embolus
When is there a high index of suspicion?
When there is
FEVER
NEW MURMUR
KNOWN IE CAUSATIVE ORGANISM
PROSTHETIC MATERIAL
PREVIOUS INFECTIVE ENDOCARDITIS
CONGENITAL HEART DISEASE
NEW CONDUCTION DISORDER
IMMUNOCOMPROMISED
IVDA
When are signs asbsent for IE?
- elderly
- after antibiotic treatment
- immunocompromised
- IE involving less virulent / atypical organisms
What are the relevant investigations for IE?
Markers for infection for inflammation / infection (Full blood count, neutrophilia, CRP ESR)
Urinary and electrolyte tests - searching for nephritis, infection and sepsis
Blood Cultures (before starting antibiotics)
Urinalysis - looking for blood - if so - nephritis
ECG - looking for conduction delay
CXR - looking for heart failure and pulmonary abscess - sign of embolisation
Echocardiogram - transthoracic or transoesophageal
When would you need a transoesophageal echo?
When the TTE is normal and the clinical suspicion is high
OR
When the TTE/TOE is normal but the suspicion of IE remains high - repeat echo at 7/10 days as initial vegetation may have been too small to see.
OR
TTE is positive and you need to assess complications, abscesses and measure the size of the vegetation.
When is repeat TTE and TOE needed?
If there is a new complication e.g
new murmur
persisting fever
embolism
heart failure
abscess
atrioventricular block
OR
To assess ongoing treatment (silent complications and vegetation size) / treatment success on completion (valve morphology and cardiac function)
What are the possible ways you get negative blood cultures even when IE is positive?
If there has been prior antibiotic use
If there are fastidious organisms present
If there are intracellular bacteria
What are the common bacteria responsible for IE?
85% of all IE:
streptococci
enterococci
staphylococcus
How does streptococci viridians enter the blood?
Orally
What are the health care associated microbiological causes of IE?
Staph aureus
Coagulase negative staph (staph epidermis)
Which bacterial cause of IE is most common among intravenous drug users?
Staph aureus
What bacteria is most likely to infect native valve?
Strep viridians
What bacteria is most likely to infect a prosthetic valve?
Staph epidermis
Give exmamples of fastidious organisms
Nutritionally variant streptococci
Fastidious Gram –ve bacilli – HACEK group
Haemophilus parainfluenzae, H. aphrophilus, H. paraphrophilus, H. influenzae, Actinobacillus actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, Kingella kingae, K. dentrificans
Brucella
Fungi
Give examples of intracellular bacteria
5% of all IE
Coxiella burnetii
Bartonella
Chlamydia
How do you check for intracellular bacteria?
Serology, PCR, Gene amplification, Cell culture
What are the major findings of the modified DUKE criteria in the diagnosis of IE?
Blood cultures positive for IE
Evidence of endocardial involvement
When is blood culture for IE considered positive?
Typical organisms consistent with IE from 2 separate blood cultures
Persistently positive blood cultures have organisms consistent with IE
Single positive blood culture for coxiella burnetti
What is the modified duke criteria - minor?
What is diagnosis according to modified duke criteria?
Definite: 2 major
1 major and 3 minor or 5 minor
Possible:
1 major and 3 minor
What is treatment for IE?
Antibiotics and maybe surgery
What is the benefit of using aminoglycosides in conjunction with beta lactams and glycopeptides (cell wall inhibitors)?
Synergistic
Bacetericidal
Shortern duration of therapy
What are the likely infective organisms for native valves and the corresponding treatment?
staphylococci
streptococci
HACEK species
Bartonella spp.
What is the treatment for native valve infection?
Plus potentially IV vancomycin (if penicillin allergic/severe sepsis or MRSA)
What is the treatment for native valve infection and sepsis
Gentamicin
Vancomycin
What is the treatment for infection of prosthetic valves?
Rifampicin, gentamicin and vancomycin
What are the likely infective organisms for prosthetic valve infections?
MSSA
MRSA
non - HACEK - ve pathogens
What are the potential side effects of gentamicin?
Ototoxic and nephrotoxic
What are the continuous investigations that are required?
Fullblood count
U and E’s
CRP
ECG (1-2 days)
Echo (weekly)
When is a fungal infection likely?
Prosthetic valve endocarditis
IVDA
Immunocompromised
What are the likely organisms for fungal infections?
Candida
Aspergillus
What is mortality like for fungal infective endocarditis?
Mortality is high (over 50%)
What is treatment for fungal IE?
Dual anti-fungals
Valve replacement
Often maintained long term
Sometimes for life (on antifungals)
What are the potential complications of IE? (also the indications for surgery)
Heart Failure
Fistula formation
Leaflet perforation
Uncontrolled infection
Abscess formation
AV heart block
Embolism
Prosthetic valve dysfunction / dehiscence
What is the most common indication for surgery?
Heart failure - refractory pulmonary oedema
What is meant by an uncontrolled infection?
Persisting fever, +ve blood cultures >7-10 days
- inadequate antibiotic treatment
- resistant organisms
- infected lines
- locally uncontrolled infection
- embolic complications – absess?
- extracardiac site of infection
- adverse reaction to antibiotics – can cause fever
What are the organisms that produce large vegetations?
•staph, strep bovis, candida – cause huge vegetations
When would you operate an embolism?
If the embolism and the vegetation is greater than 10mm
OR
Isolated vegetation is greater than 15 mm
What is the most severe form of IE?
Prosthetic valve endocarditis
10-30% of all cases
Poor Prognosis (20-40% in-hospital mortality)
What is recommended before removal of an intracardiac device?
IV antibiotics for as long as possible before removal
What is prophylaxis for IE?
Limited to highest risk patients (highest incidence and highest risk of adverse outcomes from IE)
Antibiotic prophylaxis should be reduced
Good oral hygiene & regular dental review are of particular importance
What are the cardiac conditions at highest risk of IE?
Acquired valvular heart disease:
- stenosis
- regurgitation
Valve replacement
Structural congenital heart disease
- surgically corrected / palliated structural conditions
- excluding
- isolated ASD
- fully repaired VSD or PDA
- closure devices that are endothelialised
Hypertrophic cardiomyopathy
Previous IE
What are risky procedures that may have to be avoided?
Body piercing and tattooing
Puts patients at risk of IE
DO NOT OFFER
Look
Which infective organism is responsible for acute and sub acute IE?
Acute: days and weeks (staph aureus)
Subacute: Weeks and months (strptococci)
What is treatment for Staph?
MSSA:
Native valve: Flucloxacillin - 4 weeks
Prosthetic valve: Flucloxacillin, rifampicin and gentamicin - 4 weeks
MRSA:
Native valve: Flucloxacillin, rifampicin - 4 weeks
Prosthetic valve: Vancomycin, rifampicin - 6 weeks and gentamicin - more than weeks
