CVS-Infections Flashcards
What are the infections of the CVS?
1) Pericarditis (infection of the pericardium)
2) Myocarditis (infection of the myocardium)
3) Endocarditis (infection of the endocardium)
What is meant by endocarditis?
- An infection of the endocardial surface of the heart (usually bacterial), commonly affecting the heart valves (mitral mostly)
What are the risk factors of infective endocarditis?
1) Having a prosthetic valve
2) Aortic stenosis
3) Any congenital heart disease
4) Chronic rheumatic heart disease
5) Any valvular abnormality
What are the microorganisms that can cause IE?
1) Staphylococci (most common cause):
- Mainly staph.Aureus (it can cause acute IE in native “healthy” valves, use vancomycin as it is MRSA)
- Staph.Epidermis (when there is a prosthetic valve)
- History of health care contact and drug injection are the two important risk factors,
2) Streptococci:
- Usually after oral activity
- Viridans streptococci, S.mitis. S.sanguis, S.oralis (found in the oral cavity)
- S.bovis (associated with colon carcinoma)
3) Gram -ve rods (part of the normal oral flora)
A) HACEK group (They are “fastidious and do not grow well”)
1) Haemophilus aphrophilus
2) Actinobacillus actinomycetemcomitans
3) Cardiobacterium hominins
4) Eikenella corrodens
5) Kingella kingae
- They cause IE in already damaged valves or underlying heart diseases
B) Pseudomonas aeruginosa (due to IV abuse)
What are the classifications of IE
1) Native valce endocarditis
1a) Acute
- Accompanied by high fever, systemic toxicity, and death can occur in hours to days (commonly caused by staphylococcus aureus)
1b) Subacute
- Due to a previous valvular disease
- Has a slow, indolent course, low-grade fever, night sweats
- Caused by streptococci (viridans group)
2) Prosthetic valve endocarditis
- Accounts for 10-20% of IE
2a) Occurs within 2 months of surgery, Usually hospital-acquired, Caused by staph.epidermidis
2b) Occurs after 2 months post-surgery, usually community-acquired, caused by enterococci and streptococci
3) IE in IV drug users
- S.Aureus is the most common pathogen
- Pseudomonas can be a cause to
- It usually involves the tricuspid valve
What is the pathogenesis of infective endocarditis?
1) Endothelial damage
2) Platelet-fibrin aggregation creates a sterile vegetation
3) Transient bacteremia and adherence of microbes
4) Microbial proliferation, invading the endocardial surface
5) Metastatic infection of visceral organ
- Basically, the organism enters the blood, adheres to the endocardium, causes an infective vegetation
What is the pathology of IE?
1) It has a vegetative lesion
2) The lesion is composed of platelets, fibrin, microorganisms, and inflammatory cells
What is the clinical presentation of IE?
FROM JANE
- Constitutional symptoms
1) Fever (consistent)
2) Fatigue
3) Malaise
4) Dyspnea, Cough, Chest pain
5) Toxicity (consistent)
Combination with signs of pathological cardiac changes
1) Heart failure signs
2) Murmur (consistent)
- Manifestations of subsequent damage to other organs
- Skin lesions
1) Janeway lesions
2) Osler node (Immunological)
3) Nail Bed hemorrhage (splinter hemorrhage)
4) Emboli (SNC, Skin, Spleen, Kidneys, Skeletal System “can cause stroke or sepsis)
5) Roth spots (immunological)
6) Glomerulonephritis
How to diagnose IE?
1) Clinical presentation
2) Duke criteria
- Major (Positive blood culture, echocardiogram)
- Minor (clinical features like fever)
3) Blood cultures (main)
4) Echocardiography (Main)
- Transthoracic
- Transesophageal
How to take a blood culture for IE?
- It is a definitive diagnosis of IE, at least 3 sets (1 aerobic and 1 anaerobic bottle for each set) of blood cultures must be taken in an aseptic technique from different body sites
- You collect 20ml per sample 1 (diluent) :5
What is the proper management of endocarditis?
1) Antimicrobial therapy
- Initially empirical therapy
- High-dose parenterally (Injections)
- Continuous for 4-6 weeks
- You must continue the treatment and take a blood culture and not stop the treatment until the culture is negative
2) Prophylaxis (treatment before the definitive diagnosis) is given in specific cases like in patients with preexisting heart conditions undergoing dental or surgical procedures
What is meant by myocarditis?
- The inflammation of the myocardium, clinically manifested by chest pain, arrhythmias, or congestive heart failure
- Most of the time it is associated with VIRAL infections (Coxsackie B, enteroviruses, adenoviruses, parvovirus B19, Human Herpes 6, Dengue virus)
What is menat by pericarditi?
- It is the inflammation of the pericardium caused by a variety of infectious agents
- Classified as (Acute, Recurrent, or Chronic)
- Mainly viral
Describe the enterococci bacteria
1) Gram-positive
2) Colonizes the GI
3) Grows in high sodium concentrations and bile salts
4) Catalase negative, PYR positive, Resists bile and optochin
5) Like E.faecalis and E.faecium
6) Causes infection from the patient’s own flora (UI, IE, WOUND INFECTIONS, PERITONITIS)
8) iT IS BECOMING RESISTANT
Which bacteria can cause IE through artificial valves?
1) Within 2 months of surgery: Staphylococcus Epidermidis (usually hospital-acquired)
2) After 2 months of surgery: enterococci and streptococci (Usually community-acquired)
Which bacteria can cause IE through IV abuse?
Mainly S.aureus, but it can also be due to Pseudomonas
- Involves the tricuspid valves usually
Which bacteria can cause IE in native valves?
S.Aureus
- Causes acute IE
Which bacteria can cause IE through Oral activity?
Streptococci (viridans, S.mitis, S.sanguis, S.oralis)
- Causes a subacute IE
Which bacteria can cause IE through the colon?
Streptococcus Bovis
Which bacteria can cause IE in damaged valves/diseased hearts?
HACEK
