Infective Endocarditis

Question 1

summarise the features of infective endocarditis?

Answer 1

Feverroth spots, osler nodes, new onset murmur, janeway lesions, anaemia, splinter haemorrhages, emboli

Buzzwords: Prosthetic valve, dental procedures, vegetation on echo, indwelling catheter, R side of heart

FEVER + NEW MURMUR= INFECTIVE ENDOCARDITIS UNTIL PROVEN OTHERWISE NO PAIN= MORE SEPSIS

Question 2

define infective endocarditis?

Answer 2

infection of intracardiac structures ( mainly heart valves)

Question 3

summarise the epidemiology of endocarditis?

Answer 3

UK Incidence: 16-22/1 million per year

Question 4

what are the most common organisms that cause infective endocarditis?

Answer 4

Streptococci (40%) - mainly a-haemolytic S. viridans and S. bovis

Staphylococci (35%) - S. AUREUS (most common) and S. epidermidis

Enterococci (20%) - usually E. faecalis

Question 5

what other organisms can cause endocarditis but are not routinely checked for on a blood test?

Answer 5

HACEK- may present with a negative blood culture as not routinely checked for ▪ Haemophilus ▪ Actinobacillus ▪ Cardiobacterium ▪ Coxiella burnetii ▪ Eikenella ▪ Kingella ▪ Chlamydia Histoplasma, Candida, Aspergillus (fungal)

Question 6

what are the other causes of endocarditis?

Answer 6

SLE (Libman-Sacks endocarditis), malignancy

Question 7

outline the pathophysiology of endocarditis?

Answer 7

vegetations form when organisms deposit on the heart valves during a period of bacteraemia

vegetations are made up of platelets, fibrin and infective organisms they destroy valve leaflets, invade myocardium or aortic wall leading to abscess cavities

Activation of the immune system can lead to the formation of immune complexes -> vasculitis, glomerulonephritis, arthritis

Question 8

What are the risk factors for infective endocarditis?

Answer 8

Abnormal valves (e.g. congenital, calcification, rheumatic heart disease) - streptococci associated with this

Prosthetic heart valves – can occur during surgery or later (most likely cause is coagulase-negative staph epidermis)

Turbulent blood flow (e.g. patent ductus arteriosus)

Recent dental work/poor dental hygiene (source of Strep viridans)

Dermatitis

IV injections/ drug use (often R-sided vulvular involvement and more likely to have Staph aureus, strep, polymicrobial infections)

Renal failure

Organ transplantation

DM

Post-op wounds

Pneumonia

Malignancies I.e. colorectal cancer is associated with strep bovis

Chronic cholecystitis

Question 9

what are the presenting symptoms of infective endocarditis?

Answer 9

Fever with sweats/chills/rigors

• NOTE: this might be relapsing and remitting
• Minor part of duke’s criteria

Malaise

Night sweats

Anorexia

Weight loss

Arthralgia

Myalgia

Confusion

Headache

Skin lesions

Ask about recent dental surgery or IV drug use

Question 10

what are the signs of infective endocarditis?

Answer 10

• Pyrexia • Tachycardia • Signs of anaemia • Clubbing • Any new murmur or changing previous murmur • Frequency of heart murmurs: ○ Mitral > Aortic > Tricuspid > Pulmonary • Splenomegaly Vasculitic Lesions due to immune complex depositions as the vegetations get dislodged Embolic phenomena: emboli may cause abscesses in different organs- Janeway lesions (painless macules on the palms which blanch on pressure) – JANE NO PAIN ON PALM

Question 11

what are the signs of infective endocarditis which are specifically due to vasculitic lessons due to immune complex depositions as the vegetations get dislodged?

Answer 11

Roth spots on retina

petechiae on pharyngeal and conjunctival mucosa

oslers nodes

Splinter haemorrhages

Glomerulonephritis

Question 12

summarise the prognosis for patients with infective endocarditis?

Answer 12

• FATAL if untreated 15-30% mortality even WITH treatment - even higher with prosthetic valves

Question 13

what is modified Duke criteria for infective endocarditis?

Answer 13

definitive infective endocarditis: 2 major or 1 major and 3 minor or all 5 minor criteria

Question 14

what are the appropriate investigations for infective endocarditis?

Answer 14

bloods

urinalysis blood culture

ECG

Echo- SHOULD BE PERFORMED AS EARLY AS POSSIBLE IN ALL SUSPECTED CASES

Blood Culture – maj clinical criteria if 2 sep blood culture sets are positive

Question 15

what can be seen in the bloods in infective endocarditis?

Answer 15

FBC - high neutrophils

normocytic anaemia

High ESR/CRP

U&Es – provide baseline assessment

A lot of patients with infective endocarditis tend to be rheumatoid factor positive – minor criteria in Duke’s LFTs

Question 16

what can be seen in the urinalysis in infective endocarditis?

Answer 16

Septic emboli are most common complications of IE – can demonstrate active sediment assisting the diagnosis

Microscopic haematuria Proteinuria

Question 17

what may be seen on the ECG in infective endocarditis?

Answer 17

long PR interval at regular intervals (when infection progresses to conduction system disease)

Question 18

what may be seen on the echo in infective endocarditis?

Answer 18

SHOULD BE PERFORMED AS EARLY AS POSSIBLE IN ALL SUSPECTED CASES

Transthoracic or transoesophageal (produces better image)

May show vegetation but only if >2mm

Question 19

what are the possible complications of infective endocarditis?

Answer 19

• Valve incompetence – valve disintergrating
• Intracardiac fistulae or abscesses
• Aneurysm
• Heart failure
• Renal failure
• Glomerulonephritis
• Arterial emboli from the vegetations shooting to the brain, kidneys, lungs and spleen and bowel
• Complete heart block

Question 20

outline a management plan for infective endocarditis?

Answer 20

Question 21

what is the major criteria for diagnosing infective endocarditis?

Answer 21

positive blood culture

• typical organism in 2 separate cultures or
• persistently positive blood cultures eg 3>12h apart ( or majority if more than 3) or
• single positive blood culture for coxiella

Endocardium involved

• positive echocardium ( vegetation. abscess, pseudoaneurysm, dishiscence of prosthetic valve) or

abnormal activity around prosthetic valve on PET/ CT or SPEC/CT or

Paravalvular lesions on cardiac CT

Question 22

what is the minor cirteria for infective endocarditis?

Answer 22

predisposition ( cardiac lesion, IV drug abuse)

fever more than 38

vascular phenomena ( emboli, janeway lesions)

immunological phenomena ( glomerulonephritis, osler’s npdes)

positive blood culture that doesnt meet major criteria