Infective Endocarditis And Intro To Antithrombotics

Question 1

Bacterial Infective Endocarditis
What empiric treatment should be recommended? 2
Which common organisms are you covering? 3
What are you doing in the meantime? 2 things
Duration of abx treatment?
Route?

Answer 1

—bactericidal
—staphylococci, streptococci, enterococci
—vanco + ceftriaxone
—vanco + ampicillin/sulbactam (Unasyn)
—repeat blood cultures every 1-2 days!
—ID CONSULT!
—4-6 weeks depending on organisms, valve type, response etc
—IV abx via PICC + home infusions after discharge

Question 2

What are the main organisms that causes IE in order of most common to least common

Answer 2

1. Viridans strep
2. Enterococci
3. Staph aureus
4. Coag neg staph
5. Gram neg bacilli HACEK
6. Fungi

Question 3

Infective endocarditis
How would you treat if
Viridans streptococci
Or
Enterococci
3 agents

Answer 3

—Penicillin G (gram +)
—ceftriaxone for viridans (gram+)
—ampicillin for enterococci (gram + entero)
because remember, cephalosporins do not cover any enterococcus species so ceftriaxone won’t work
—+/- gentamicin (gram - )

Question 4

Infective endocarditis
How would you treat if the organism was
Staph aureus, MRSA, MSSA?
Coag-neg staph? If also prosthetic valve? What do you add on?

Answer 4

MSSA: nafcillin, oxacillin, cefazolin
MRSA: vanco or dapto
Coag-neg: vanco +/- gentamicin +rifampin if prosthetic valve

Synergy:
In treating complicated MRSA infections, many clinicians combine vancomycin with another agent, such as gentamicin, in the expectation of a more rapid bacteriologic response based on a synergistic interaction be- tween the two antibiotics

Question 5

Infective endocarditis
Treatment for gram neg organisms (HACEK)
Funghi?

Answer 5

ceftriaxone

consider surgery too

Fungi → antifungals such as nystatin for candida or voriconazole for aspergillosis

Question 6

Endocarditis
When is prophylaxis needed?

Which procedures?

Answer 6

2Ps and 2Cs
1. Prosthetic heart valve
2. Previous endocarditis infection
3. Cardiac transplantation recipients w/ valvulopathy
4. Congenital heart disease

Procedures
—dental
—respiratory → tonsillectomy
—soft tissue

Question 7

Endocarditis prophylaxis
Which are the oral and parenteral preferred agents?
What if there is a PCN allergy?
When do you administer?

Answer 7

PO
1. Amoxicillin preferred
2. Cephalexin if PCN allergy

Parenteral
1. Ampicillin, cefazolin or ceftriaxone preferred
2. Cefazolin or ceftriaxone if PCN allergy

1 time doses given 30-60 mins prior to procedure

Question 8

Infective endocarditis
When is anticoagulation indicated? When is it not indicated?

Answer 8

—contraindicated for native valves! → risk of intra cerebral haemorrhage from mycotic aneurysms or emboli

—uninflected prosthetic valves typically require anticoagulation

Question 9

Antithrombotics (layman: blood thinners)
What are examples of:
Antiplatelets
Anticoagulants
Fibrinolytic

Side effects & contraindication?

Answer 9

Antiplatelets
1. COX/prostaglandin inhibitors aspirin
2. ADP inhibitors clopidogrel, ticagrelor
3. PDE/adenosine uptake inhibitors dipyridamole, cilostazol
4. Glycoprotein IIb/IIIa inhibitors

Anticoagulants
1. Heparin (antithrombin activator)
2. Warfarin (vitamin K antagonist)
3. Direct thrombin inhibitors (dabigatran)
4. Factor Xa inhibitors (rivaroxaban, apixaban, enoxaparin)

Fibrinolytics
1. T-PA derivatives
2. Streptokinase

Side effects and contrainidcation
BLEEDING!!!!!

Question 10

Familiarise yourself with the MOA for Antiplatelets

Question 11

Aspirin (ASA, acetylsalicylic acid)
MOA
AKA?
Duration of action?
How does aspirin compare to other COX inhibitors such as NSAIDs?

Answer 11

MOA
—irreversibly acetylates the cycle-oxygenase (COX enzyme) to inhibit synthesis of thromboxane A2 which is the prostaglandin that stimulates platelet aggregation
—COX or prostaglandin-inhibitor

Duration of action
—platelets can’t make more COX-1
—effect on existing platelets is permenant
—effects last several days, 3-5, until new platelets form

NSAIDs
—have a reversible effect
—they don’t acetylate the COX enzyme so effects only last a few hours

note: NSAIDs may interfere w/ ASA if taken together. If NSAID is taken first, prevents ASA from inhibited COX-1 so it won’t have the same effect

Question 12

Aspirin ASA
What are the common indications?

What are the key toxicities? What’s the favourite one?

3 contraindications

Answer 12

Common indications
—primary & secondary prophylaxis of CV events
—VTE prevention
—thromboprophylaxis post carotid endarterectomy or stenting or heart valve repair
—analgesic, antipyretic, anti-inflammatory properties

Key toxicities
—🤮GI upset, ulcers, perforation (ALL NSAIDs & ASA)
—👂hearing loss, tinnitus

Contraindications
—🥴hypersensitivity
—👧children recovering from chickenpox (Reye Syndrome)
—😮‍💨asthma, rhinitis, nasal polyps

Question 13

Aspirin Pearls
What is the dose to know:
Baby aspirin
LT CVD prevention
Post CVD event

Answer 13

81mg = low dose or baby aspirin

162mg daily most commonly used for LT CVD prevention often in combo w/ antiplatelets

325mg acute phase post CVD event

Other pearls
—chewable → better bioavailability
—enteric coating may prevent GI upset
—coformulation exists w/ omeprazole
—rectal suppository also exists
—double check aspirin allergy, may not be legit
—found in combinations such as Alka-seltzer! So watch out for hypersensitivities and additive effects

Question 14

Salicylate toxicity
In which setting could they occur?
What are the mild s/sxs? And severe?

Answer 14

—serum salicylate levels can rise quickly in hospital setting

—MILD ➡️ N/V, tinnitus, vertigo, tachypnea, tachycardia

—Severe ➡️ acidosis, agitation, delirium, hallucinations, convulsions, lethargy, stupor