Diebel's Website Flashcards
What can microbial infections of the heart involve?
-Endothelial surface of the heart, the pericardial membranes, and the heart itself
How can pericardial and muscle infections present themselves?
They may have acute, subacute or chronic presentation.
What is infectious endocarditis?
Bacterial disease associated with sepsis and usually some underlying heart defect (either congenital, or prior ongoing chronic damage to the endocardium)
How does bacteria get to the heart?
It travels through the bloodstream and typically lodges itself on abnormal heart valves (native or prosthetic) or damaged heart tissue
What can happen on damaged heart tissue/valves?
Bacteria can grow to produce vegetations (collections of bacterial cells, platelets, fibrin, and inflammatory cells)
Who is particularly susceptible to infectious endocarditis?
IV drug users
What are portals of entry for IE pathogens to get into the bloodstream?
- Oral cavity
- Skin
- Upper respiratory tract
What do most patients with IE have?
Positive blood cultures for the presence of bacteria in blood
What symptoms are associated with subacute onset IE?
- Low grade fever
- May or may not be accompanied by night sweats, chills, fatigue, malaise, generalized weakness anorexia, and lower back pain
What physical findings are associated with subacute onset IE?
- Cardiac murmur
- Conjunctival petechiae
- Splinter hemorrhages in nails
- Osler Nodes
- Roth spots
- Janeway lesions
What are common clinical features of IE?
- Fever
- Chills and sweats
- Heart murmur
What are common laboratory features of IE?
- Anemia
- Elevated erythrocyte sedimentation rate
- Elevated C-reactive protein level
- Presence of rheumatoid factor
- Circulating immune complexes
What are the top three Endocarditis cases in Injection Drug Users?
- Staph. aureus 57%
- Streptococci 12%= includes viridian’s streptococci, Streptococcus gallolyticus and other non-group A streptococci
- Enterococci 9% - primarily enterococcus faecalis
What are the top three Native Valve Endocarditis (Nosocomial) bugs?
- Staph aureus 52% - methacillin resist. common
- Enterococci 16% - primarily enterococcus faecalis
- Streptococci 13% - includes viridian’s streptococci, Streptococcus gallolyticus and other non-group A streptococci
What are the top three Native Valve Endocarditis (Community Acquired) bugs?
- Streptococci - 40% - includes viridian’s streptococci, Streptococcus gallolyticus and other non-group A streptococci
- Staph. aureus - 28%
- Enterococci - 9% - primarily enterococcus faecalis
What drugs are used to treat IE?
Organism-specific.
Peptidoglycan synthesis inhibitors.
Ex: Penicillin G, Ceftriaxone, Vancomycin, Gentamicin, Ampicillin, Nafcillin or Oxacilling and Cefazolin
What is the MAJOR cause of myocarditis?
VIRUSES!
What are symptoms of myocarditis?
- Flu-like illness with chest pain is common
- Other patients have arrhythmias and/or feel like they are having a heart attack
What are the most likely causative microorganisms for myocarditis?
- Coxsackie B virus
- Adenovirus (particularly in children)
What is the MAJOR cause of pericarditis?
VIRUSES
What can also cause pericarditis?
Bacterial infections also occur by hematogenous spread, trauma, or cardiac surgery.
When does viral pericarditis usually occur?
-During spring and summer months, coinciding with higher incidence of enterovirus infections.
When is chest pain worse with pericarditis?
When patient is swallowing or supine. (this is the most common symptom)
What is different about bacterial pericarditis (most pericarditis is viral)?
-Bacterial pericarditis tends to be more acute and severe and have a fever and tachypnea
What is usually present with bacterial pericarditis?
-Concurrent infections of other systems (e.g. meningitis) are usually present
What do ALL patients have with pericarditis??
- Tachycardia and a characteristic three-component friction rub during the physical exam.
- EKG changes are frequently found!
What is used to establish etiology (find out cause) of pericarditis?
-Laboratory tests following pericardiocentesis are used to establish etiology
What are the most likely causative microorganisms for pericarditis?
- Coxsackie A virus
- Coxsackie B virus
- Echoviruses
- Influenza virus
- Staph. aureus
- Strep. pneumoniae
- H. influenzae
- Neisseria meningitidis
What does Rheumatic Heart Disease follow?
-Streptococcus pyogenes pharyngitis in genetically predisposed individuals.
What is damaged in RHD?
-Frequently damage to the heart muscle and valves attributed to autoantibodies (type II hypersensitivity).
What is the definitive clinical indicator for RHD?
Mitral stenosis following pharyngitis with a rash.
What is the main microbial agent that causes RHD?
Streptococcus pyogenes
What is the main course of colonizing bacteria for vascular catheter infections?
Bacteria on the skin, at the site of insertion of the catheter
What enhances the colonization of catheter related bacteria?
Biofilm production
What is the clinical presentation of intravascular catheter related infections?
- Non-specific system manifestations including fever and chills
- Local manifestations like erythema, tenderness and swelling
- A purulent discharge can sometimes be ovserved at the catheter exit site
What is the causative agent in intravascular catheter related infections?
Staphylococcus aureus
What can aid in diagnosis of artificial valve, pacemaker and defibrillator infections?
Timing and onset of the infection after placement can aid in diagnosis.
With prosthetic valves, what is the most predominant agent during the initial year following surgery?
Staphylococcus epidermis (50% of time)
With prosthetic valves, what is the second most predominant agent during the initial year following surgery?
Staphylococcus aureus (20% of infections)
With prosthetic valves, what is the most predominant agent after the initial year following surgery?
Streptococcus viridans group
Where do infections occur with prosthetic valves?
Around the site of the implant
What do valvular infections (prosthetic) usually have as part of an endocarditis?
They usually have a fever as part of an endocarditis syndrome as well as a heart murmur.
Where do infections occur in Pacemaker and defibrillators?
-They can occur around the pocket of the implanted device or may involve electrodes or cardiac valves
What causes infections within two weeks of implantation of a pacemaker or defibrillator?
Staph. aureus
What causes infections from two weeks up to one year after implantation of a pacemaker or defibrillator?
Coag-negative Staphylococcus species.
[Esp. staph epidermis]
What causes infections one year or more after implantation of a pacemaker or defibrillator?
Streptococcus viridian’s group
What are clinical signs of electrophysiological device infections?
- Variable:
- -Involve pocket pain at implantation site
- -Fever
- -Chills
- -Bacteremia
What organisms are associated with artificial valve, pacemaker, and defibrillator infections?
- Staph aureus
- Staph epidermidis
- Streptococcus species (viridians)
- Enterococci
What transmits RMSF?
Dog ticks and wood ticks
Where does RMSF usually occur?
Mostly in Oklahoma, Missouri, Arkansas, Tennessee, North Carolina, and Delaware
What is the pathogenesis of RMSF that leads to petechial rash?
- Tick inoculation
- Rickettsia spread through body in bloodstream
- The virus attaches to and is engulfed by vascular endothelial cells
- In vascular endothelial cells they multiply in the cytoplasm and spread to adjourning vascular cells
- Replication causes leakage of RBCs which produces a pink rash that develops into petechial rash.
Where else can these petechial hemorrhages occur in RMSF?
- Brain
- Lung
- Heart
- Liver
- Other visceral organs
What do these hemorrhages in RMSF lead to?
- Fever
- Headache
- Myalgia
- Pneumonitis
- Nausea
- Vomiting
- Abdominal pain
- Cardiac arrhythmia
When do the clinical symptoms of RMSF occur?
1-2 weeks following infection
Who is most commonly affected with RMSF?
Children - but they usually have a milder disease
What is the causative agent of RMSF?
Rickettsia rickettsii
