Cardiovascular system infections Flashcards
What is transient bacteremia?
self-resolving in patients with no underlying illness, immune deficiency or turbulent cardiac blood flow
What type of bacteremia is characterized by “direct inoculation of the blood stream; nosocomial or IV drug user”
Primary bacteremia
What is secondary bacteremia?
microorganism causing infection at another site incase the bloodstream and disseminate via the circulation to other body areas (hematogenous spread)
What is sepsis?
life-threatening organ dysfunction due to a dysregulated host response to infection
What does SOFA measure?
respiratory, hepatic, cardiovascular, renal , CNS, and platelet dysfunction
What is the endocardium?
thin lining inside the chambers of the heart
What is the muscle tissue of the heart called?
the myocardium
What is the pericardium?
The thin double layered sac that encloses the heart
In Canada people who develop endocarditis it is usually caused by _
bacteria
Myocarditis and pericarditis are typically aligned with _ infections
viral
What is rheumatic fever?
A rare complication of streptococcal pharyngitis infections, autoimmune reaction lasting about 3 months
What population is most commonly affected by rheumatic fever?
children between 5-15 and adults in developing countries, as well as in indigenous northern regions
What are the four types of possible autoimmune reactions that can result from rheumatic fever?
- carditis
- polyarthritis
- erythema marginatum
- chorea
How is rheumatic fever treated?
anti-inflammatories, diuretics, bed rest
What is the method of continued prevention for someone with no residual heart disease?
penicillin (IM), once monthly for a minimum of 10 years or until 25 (because at that point the likelihood of developing strep is low)
What is the method of continued prevention for someone with residual heart disease?
penicillin (IM), once monthly until 40-45 years old, but often continued for life (because body has proven it cannot handle it)
Why are patients with a rheumatic heart valve at an increased risk of complications associated with bacteremia?
Increased risk due to the turbulent blood flow at the site of the damaged valve (can cause erosions and damage to the endocardium, can then lead to the ability for platelets and fibrin to bind, making it easy for bacteria to adhere)
Minor fibrin and platelet deposition can occur on the low pressure side of the damaged valve causing_
non-bacterial thrombotic endocarditis (NBTE)
What is endocarditis?
infection and inflammation of the endocardium; commonly affects the heart valves - mitral and aortic (especially in IV drug users)
What type of endocarditis is associated with non-virulent bacteria such as viridans streptococci?
subacute endocarditis
What is the differentiating symptom between subacute and acute endocarditis?
sepsis in acute endocarditis
What are peripheral manifestations of endocarditis?
splinter hemorrhages, Osler’s nodes, conjunctival petechiae, Roth’s spots, Janeway lesions
What are the risk factors of abnormal valves mainly associated with subacute infective endocarditis?
prosthetic valve, mitral valve prolapse, rheumatic valve, congenitally abnormal valve
In the case of developing endocarditis in the hospital from a central venous catheter, what heart valve would most be affected?
tricuspid valve
What is the Duke Criteria for diagnosis of endocarditis?
Definitive IE: 2 major OR 1 major and 3 minor OR 5 minor
What are two of the major criteria for endocarditis diagnosis?
- positive blood culture (2 separate but positive samples)
- evidence of endocardial involvement (hearring murmur or visual)
What are the five minor criteria for endocarditis?
- predisposition
- clinical symptoms
- vascular phenomena
- immunologic phenomena
- positive blood culture not meeting major criteria
What is the treatment protocol for endocarditis?
the appropriate antimicrobial therapy (bactericidal) administered parenterally (long duration, 4-6 weeks), valve replacement in severe cases, recurrent embolism or in cases of fungal endocarditis
Which type of heart infection is most associated with pediatric cases?
myocarditis
What does myocarditis look like in older adults?
it progresses slowly; progressive heart failure and dilated cardiomyopathy
What does myocarditis look like in children?
acute symptoms - cardiogenic shock, acute heart failure and sudden death
When causes pain to accompany myocarditis?
Pain is reported in those with concomitant pericarditis…if it is just the heart muscle there will be no sharp stabbing pain
Inflammatory cardiomyopathy is most often associated with a _ infection of the myocardium and infiltration of cardiac muscle by _
viral; T-lymphocytes
What else can cause myocarditis and pericarditis besides viruses?
medications
What ensures full recovery from myocarditis?
early identification and treatment
What is the treatment for myocarditis?
Same as for heart failure= ACE inhibitors, diuretics, beta blockers
What do you want to avoid in the treatment of myocarditis?
NSAIDS - induced fluid retention (due to vasoconstriction of blood vessels in the kidney and resulting retention of sodium and potassium) makes the heart work harder
What will occur if symptoms of myocarditis persist for more than 2 weeks to months?
permanent dilated cardiomyopathy (just like an 85 year old who has a heart attack), increase risk for heart attack and stroke
What are the infectious causes of pericarditis?
viruses are the most causative pathogen, appears 2-3 weeks post “flu-like” illness (enteroviruses, influenza, HIV)
What are some common symptoms of pericarditis?
sharp, stabbing chest pain caused by rubbing of two layers of the pericardium, pain worsens when lying down, with deep breaths, swallowing and coughing, sitting upright or forward relieves pain
How can one differentiate the pain of a heart attack from pericarditis?
Pain improves from sitting upright or leaning forward, in a heart attack nothing will help the pain
What are the three diagnostic findings of pericarditis?
- abnormal heart sounds (layers rubbing)
- abnormal ECG (due to inflammation)
- echocardiogram - appearance of fluid surrounding the heart
T/F: you don’t need the pericardium to live
True
Persistent bacteremia is suggestive of _ infections such as endocarditis or _ infections
intravascular; catheter-related
What are the 2 most common reasons for heart murmurs?
- narrowing or leaking valves
2. presence of abnormal passages through which blood flows in or near the heart
What colour top blood collection tube is used for aerobic specimen?
green top
What is the colour top of blood collection tube for anaerobic specimen?
orange top
T/F: MRSA is not transmitted by the airborne route
true; contact route
What is an indicator of bacterial growth in the bottle of blood specimens?
CO2 production in the bottom of the bottle where CO2 is able to diffuse down, there will also be a colour change
What type of bacteria is catalase positive?
staphylococci (gram positive)
What type of bacteria is catalase negative?
streptococci (gram negative)
