Cardiovascular Infections Flashcards
What is endocarditis?
inflammation of the endocardium => needs to have both (1) active bacteremia and (2) structurally defective valves (e.g., prosthetic valve)
What are the risk factors for endocarditis?
IV drug use and IV catheters (bacteremia); prosthetic valves, severe stensosis, and regurgitation (structural heart disease)
Which pathogens are responsible for endocarditis?
Strep viridians and other Strep species (causes sub-acute/indolent infection: days-weeks) and Staph aureus (causes acute infection: hours-days)
What are the S and S of endocarditis due to Strep species?
affinity for pharynx and gums, appear in chains or pairs in Gram stains, subacute onset, low grade fever, fatigue, murmur => slow valve destruction
What are the S and S of endocarditis due to Staph aureus?
due to IV drug use or surgical procedures, cocci in clusters in Gram stain, acute onset, high grade fever, shaking, chills, murmur => rapid valve destruction
What is the composition of a valvular vegetation?
fibrin, platelets, RBCs, bacteria, WBCs => causes valve destruction and can lead to systemic emboli
How does endocarditis present?
fever, night sweats, new or worsening murmur => may also have symptoms of septic embolism
What is the complication of vegetation on a right-sided valve (i.e., tricuspid)?
pulmonic emboli
What is the complication of vegetation on a left-sided valve?
emboli can go anywhere => may see Roth spots (emboli on the retina), Janeway lesions (emboli on the palms with inflammation of blood vessels), Osler nodes (red, painful nodes on the fingers), or splinter hemorrhages (dark lines in the nail beds)
What distinguishes endocarditis from myocarditis?
myocarditis is usually accompanied by CHF => S and S include fever and chest pain
What distinguishes endocarditis from pericarditis?
pericarditis does not cause a murmur and never occurs without pain
What is the best initial workup for endocarditis?
blood cultures - endocarditis is impossible without systemic bacteremia (95% sensitive) => negative result more likely to be false negative (Abx was given too soon)
What is the best imaging test for endocarditis?
trans esophageal ECHO (TEE) - more sensitive than transthoracic ECHO (TTE) but TTE is less invasive, so start with TTE and perform TEE if TTE is negative but you have a high clinical suspicion of endocarditis
Why is TEE better for visualizing left-sided endocarditis?
enters closer to left-sided valves, so is easier to visualize left-sided damage
What establishes a Dx of endocarditis?
1 + blood culture AND vegetations visualized on ECHO
How can you establish a Dx of endocarditis if blood cultures are negative?
document presence of fever, risk factors, embolic phenomena AND vegetations on ECHO
What is the empiric Abx Tx for endocarditis?
vancomycin (covers Staph, including MRSA, but not reliable for Strep) + IV Ampicillin (for Strep) - Gentamycin can be added for synergism => change Abx based on sensitivity when culture results are available
How long should Abx be continued for Tx of endocarditis?
4-6 weeks of IV Abx (vegetations take a long time to treat) => PT may need surgery for ruptured valve and embolism
When is prophylactic Abx Tx for endocarditis warranted?
PT must be undergoing high risk procedure and have both (1) significant valvular defect (prosthetic valve, previous endocarditis, unrepaired/partially repaired cyanotic heart defect) AND (2) risk of bacteremia: dental work or respiratory tract work with blood (tooth extraction, root canal, dental cleaning, biopsy, tonsillectomy)
What is the recommended prophylaxis for endocarditis?
amoxicillin or clindamycin (single dose before procedure)
What is pericarditis?
infection/inflammation of the pericardium
What causes pericarditis?
anything that affects or damages the heart and irritates the pericardium - viral infection (most common), autoimmune disorders, malignancy, metabolic causes, chest trauma
What is the typical presentation of pericarditis?
fever, friction rub, murmur, and pleuritic (sharp and stabbing) chest pain that is relieved by sitting forward - worse laying down or taking a deep breath (pericardium is stretched)
What is a risk associated with pericardial effusion?
cardiac tamponade (compression of heart due to build up of fluid in pericardial sac) - rate of fluid accumulation is more important than the amount
What is the best initial test for pericarditis?
ECG demonstrates the electrical activity of the heart - should be the first test for any type of chest pain (rules out MI)
When would you use an ECHO in a PT with suspected pericarditis?
ECHO shows structural changes in the heart - use it to rule out pericardial effusion (fluid in the pericardial sac - won’t hear a friction rub, sounds will be muffled due to fluid)
What are the typical ECG changes in pericarditis?
diffuse (seen in multiple leads) concave ST elevations and PR depressions
What is the Tx for pericarditis?
supportive with first presentation: NSAIDs with or without Colchicine (side effects of diarrhea and abdominal pain) - steroids if insufficient response to NSAIDs => should resolve in 2-6 weeks
Which valve is most commonly affected in IV drug users with endocardits?
tricuspid
What are the S and S of myocarditis?
chest pain, arrhythmia, symptoms of heart failure (SOB, lower extremity edema)
