W3 Systemic Infective Endocarditis Flashcards
Infective Endocarditis (IE)
What is it?
How is it classified? 3
What is the etiology? 4
—infection of the cardiac endothelium, seen as vegetations
Classified
—clinical course, or
—host substrate, or
—organism
Etiology
—pts have existing cardiac abnormalities
—MV prolapse w/ MR is leading
—rheumatic HDisease
—congenital HDisease
IE of the NATIVE valve
—which pathogen responsible for majority?
—which pathogens make up 3%?
—right sided IE due to what? Which pathogen?
—strep & staph (80%)
HACEK, gram neg, in normal flora of URT (3%)
—haemophilus
—actinobacillus
—cardiobacterium
—eiknella
—kingella
right sided IE
—IV drug users
—staph (60%)
IE of the PROSTHETIC valve
Responsible for how many cases?
When is the greatest risk
Which organism is causative for infection <2 months ?
10-20% of IE cases
—greatest risk w/i first 6mo after implantation
—w/i 2 months = staph
—>2 mo is typical of native valve IE
IE pathogenesis
Describe 3 main steps
What are 3 complications/progressions?
- Endothelial injury
—immune complex deposition OR turbulent blood flow due to regurgitation lesions (valve disorders): left sided regurg valves more affected b/c higher pressure system - Platelets + fibrin adhere to damaged tissue which is known as a non bacterial thrombotic endocarditis
- Bacteria in bloodstream INFECT this nidus forming a VEGETATION. Fibrin covers the organisms and protects them from host defences. They multiply.
bacteria comes from trauma to mucosa, skin surfaces (oropharyngeal, IV drug use, GI tract etc)
gram + more common
complications/progression
—vegetations can cause valve coaptation & rupture»_space; worsening regurg
—vegetation can embolise»_space; organ ischemia distally
—can extend into valve ring, conduction system, myocardium etc
IE
What are the clinical S/S for:
Acute: microorganism, disease course?
Subacute: microorganism, disease course?
What are the hallmark findings? 2
—subtle to fulminant CHF
—acute»_space; valve destruction in days to weeks (staph)
—explosive/rapid illness w/ high fever & rigours
—subacute»_space; evolves over weeks to months (strep viridans) in pts w/underlying disease
—low grade fever, fatigue, anorexia, weakness, myalgias, night sweats (can be mistaken for UTI or flu)
HALLMARK: fever & new murmur
IE: physical signs — 5
- New murmur w/ aortic > mitral > tricuspid
- Neuro: cerebral emboli, encephalopathy, meningitis
- These findings relating to emboli/immune complex (stigmata)
—mucosal petechiae
—splinter haemorrhages
—osler nodes (painful, fingers/toes, “osler ouch”)
—Roth spots (retinal hem)
—Janeway lesions (erythematous, macular, non tender, palms/soles)
—splenomegaly - Fundoscopic exam chorioretinitis or endophthalmitis
-
Systemic embolization
—kidney (flank pain, hematuria, renal failure)
—lung infarction (septic PE/pneumonia)
—aneurysm
IE — what labs do you order? 4
—blood cultures to Isolde microorganism
—CBC: leukocytosis, normocytic-normochromic anemia
—elevated ESR, CRP (inflammation)
—UA w/ microhematuria
IE diagnostics, what would you see on
EKG
CXR
What is the best test sensitivity wise ?
EKG
—conduction disturbances
—prolonged PR interval
CXR
—signs of HF (pulm edema, effusions)
Transthoracic ECHO
—visualise valves for vegetation (65% sensitivity)
TEE
—>90% sensitivity and should be performed if IE is suggested
—detects vegetations, posterior valves, right side heart structures, perforations better than TTE
CT/MRI
—for pts w/ CNS complications
—detect metastatic infection
Cath
—To assess coronaries
IE
What is the Duke criteria?
Definite, possible and rejected
Major 4
Minor
DEFINITE
—pathologic:
1. microorganisms found on culture or histologic examination of vegetation / a vegetation has embolised
2. Pathological lesions, vegetations or abscess confirmed by histo exam showing active endocarditis
—🔑clinical:
—2 major
—OR 1 major and 3 minor
—OR 5 minor**
POSSIBLE
—1 major criterion, 1 minor criterion
—3 minor
REJECTED
—firm alt dx
—resolution of IE syndrome w/ abx therapy <4d
—no path evidence of IE at surgery/autopsy w/abx <4d
—does not meet criteria above
🔑MAJOR “BRET”
—Blood culture positive 🩸
—Regurgitation murmurNEW
—Endocardial involvement 💪🫀
—TEE positive for IE 😮
MINOR
—predisposition
—fever >38 C
—vasc phenomena: arterial emboli, pulm infarcts, intracranial haemorrhage, conjunctival hemorrhage,
—some microbiological evidence
IE: Duke Criteria
Major : “BRET”
Minor
MAJOR “BRET”
—blood culture for IE, 2 separate cultures
—regurgitation murmur (new)
—endocardial involvement
—TEE positive for IE
MINOR
—predisposition, IV drug use
—fever >38C
—vasc phenomena : major arterial emboli, septic pulm infarts, mycotic aneurysm, intracranial hem, conjunctival hem, Janeway lesions
—immunologic phenomena: glom.nephritis, Osler nodes, Roths,
—microbiological evidence
IE
Medical therapy
Surgery
ABX prophylaxis: what are the 4 risk groups
When should they all receive proph?
General rule for proph?
—abx should be bactericidal
—if fulminant, do not delay abx as you obtain cultures
—6w IV dosing to sterilise vegetation
—anticoags do not prevent embolisation related to IE
Surgery
—abx + valve replacement and cardiac reconstruction = higher survival rates than abx alone
—debride infected tissue
—remove non viable tissue
—reconstruct affected area
—restore the valve
ABX prophylaxis: 2Ps, 2Cs
—Prosthetic heart valves
—Prior IE
—Cardiac transplantation pts that develop valvulopathy
—Congenital heart disease
—amoxicillin or cephalexin w/PCN allergy
—if any of these risk groups receive dental procedures that involve gingival manipulation should receive proph abx
PROSTHETIC - PRIOR - POST - PROCEDURE - congenital
—recommended for procedures occurring in the context of infection
—tonsillectomy
—bronchoscope w/ incision of mucosa in pts w/ infection
—surgical procedure of skin/MSK
IE: abx proph
Syncope
SBP and MAP ?
Causes: 3
—as short as 6-8 secs can precipice syncope
—SBP <70 or
—MAP <40
Causes
—cardiac: structural vs arrhythmic
—non-cardiac: neurocardiogenic, carotid hypersensitivity, situational, orthostatic, subclavian steal syndrome, vertebrobasilar disease
—LOC: seizure, hypoglycaemia, hypoxemia, psychogenic
Syncope
Examination, what are you checking?
Diagnostics?
—BP and orthostatic BP
—HR
—carotid bruits, cardiac murmus, periph pulses, neuro
Diagnositcs
—EKG
—ECHO (structural)
—Head CT if LOC
—blood work for cardiac enzymes, CBC, chem panel
Syncope — etiology 4
-
Neurocardiogenic
—most common
—autonomic overactivity triggered by stimuli (blood) 🩸 followed by fall in vasc resistance w/o rise in CO»_space; prodromal SX -
Situational 😵💫
—causes vagal reflex vasodilation which decreases blood return to the heart (peeing, pooping, playing an instrument, coughing) -
Carotid sinus syncope 🤵
—uncommon
—pressure on carotid sinus
—shaving, turning head, tight collar -
Orthostatic 👵🏻
—elderly people when standing
—systolic drops >20mmHg (normal is 5-15)
—dehydration, meds, diabetes, alcohol, varicose veins
Syncope — neuro evaluation
Syncope
What is the tilt table test?
Syncope
Treatment 4
- Non-pharmacologic
—behaviour change, avoid triggers
—tilt training
—counter-pressure maneuver can raise periph vasc resistance and BP - Medical
—correct electrolyte imbalances
—discontinue QT prolong meds
—anti-arrhythmias if vent. Tachy.
—for autonomic dysfunction: Florinef to increase volume or midi drive to inc periph resistance - Devices
—pacemaker
—defibrillators - Surgical
—for pts for mechanical cardiac causes from LVOT obstruction relating to HOCM or aortic stenosis
