Diebel's Website Flashcards

1
Q

What can microbial infections of the heart involve?

A

-Endothelial surface of the heart, the pericardial membranes, and the heart itself

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2
Q

How can pericardial and muscle infections present themselves?

A

They may have acute, subacute or chronic presentation.

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3
Q

What is infectious endocarditis?

A

Bacterial disease associated with sepsis and usually some underlying heart defect (either congenital, or prior ongoing chronic damage to the endocardium)

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4
Q

How does bacteria get to the heart?

A

It travels through the bloodstream and typically lodges itself on abnormal heart valves (native or prosthetic) or damaged heart tissue

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5
Q

What can happen on damaged heart tissue/valves?

A

Bacteria can grow to produce vegetations (collections of bacterial cells, platelets, fibrin, and inflammatory cells)

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6
Q

Who is particularly susceptible to infectious endocarditis?

A

IV drug users

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7
Q

What are portals of entry for IE pathogens to get into the bloodstream?

A
  • Oral cavity
  • Skin
  • Upper respiratory tract
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8
Q

What do most patients with IE have?

A

Positive blood cultures for the presence of bacteria in blood

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9
Q

What symptoms are associated with subacute onset IE?

A
  • Low grade fever
  • May or may not be accompanied by night sweats, chills, fatigue, malaise, generalized weakness anorexia, and lower back pain
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10
Q

What physical findings are associated with subacute onset IE?

A
  • Cardiac murmur
  • Conjunctival petechiae
  • Splinter hemorrhages in nails
  • Osler Nodes
  • Roth spots
  • Janeway lesions
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11
Q

What are common clinical features of IE?

A
  • Fever
  • Chills and sweats
  • Heart murmur
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12
Q

What are common laboratory features of IE?

A
  • Anemia
  • Elevated erythrocyte sedimentation rate
  • Elevated C-reactive protein level
  • Presence of rheumatoid factor
  • Circulating immune complexes
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13
Q

What are the top three Endocarditis cases in Injection Drug Users?

A
  • Staph. aureus 57%
  • Streptococci 12%= includes viridian’s streptococci, Streptococcus gallolyticus and other non-group A streptococci
  • Enterococci 9% - primarily enterococcus faecalis
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14
Q

What are the top three Native Valve Endocarditis (Nosocomial) bugs?

A
  1. Staph aureus 52% - methacillin resist. common
  2. Enterococci 16% - primarily enterococcus faecalis
  3. Streptococci 13% - includes viridian’s streptococci, Streptococcus gallolyticus and other non-group A streptococci
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15
Q

What are the top three Native Valve Endocarditis (Community Acquired) bugs?

A
  1. Streptococci - 40% - includes viridian’s streptococci, Streptococcus gallolyticus and other non-group A streptococci
  2. Staph. aureus - 28%
  3. Enterococci - 9% - primarily enterococcus faecalis
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16
Q

What drugs are used to treat IE?

A

Organism-specific.
Peptidoglycan synthesis inhibitors.
Ex: Penicillin G, Ceftriaxone, Vancomycin, Gentamicin, Ampicillin, Nafcillin or Oxacilling and Cefazolin

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17
Q

What is the MAJOR cause of myocarditis?

A

VIRUSES!

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18
Q

What are symptoms of myocarditis?

A
  • Flu-like illness with chest pain is common

- Other patients have arrhythmias and/or feel like they are having a heart attack

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19
Q

What are the most likely causative microorganisms for myocarditis?

A
  • Coxsackie B virus

- Adenovirus (particularly in children)

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20
Q

What is the MAJOR cause of pericarditis?

A

VIRUSES

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21
Q

What can also cause pericarditis?

A

Bacterial infections also occur by hematogenous spread, trauma, or cardiac surgery.

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22
Q

When does viral pericarditis usually occur?

A

-During spring and summer months, coinciding with higher incidence of enterovirus infections.

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23
Q

When is chest pain worse with pericarditis?

A

When patient is swallowing or supine. (this is the most common symptom)

24
Q

What is different about bacterial pericarditis (most pericarditis is viral)?

A

-Bacterial pericarditis tends to be more acute and severe and have a fever and tachypnea

25
Q

What is usually present with bacterial pericarditis?

A

-Concurrent infections of other systems (e.g. meningitis) are usually present

26
Q

What do ALL patients have with pericarditis??

A
  • Tachycardia and a characteristic three-component friction rub during the physical exam.
  • EKG changes are frequently found!
27
Q

What is used to establish etiology (find out cause) of pericarditis?

A

-Laboratory tests following pericardiocentesis are used to establish etiology

28
Q

What are the most likely causative microorganisms for pericarditis?

A
  • Coxsackie A virus
  • Coxsackie B virus
  • Echoviruses
  • Influenza virus
  • Staph. aureus
  • Strep. pneumoniae
  • H. influenzae
  • Neisseria meningitidis
29
Q

What does Rheumatic Heart Disease follow?

A

-Streptococcus pyogenes pharyngitis in genetically predisposed individuals.

30
Q

What is damaged in RHD?

A

-Frequently damage to the heart muscle and valves attributed to autoantibodies (type II hypersensitivity).

31
Q

What is the definitive clinical indicator for RHD?

A

Mitral stenosis following pharyngitis with a rash.

32
Q

What is the main microbial agent that causes RHD?

A

Streptococcus pyogenes

33
Q

What is the main course of colonizing bacteria for vascular catheter infections?

A

Bacteria on the skin, at the site of insertion of the catheter

34
Q

What enhances the colonization of catheter related bacteria?

A

Biofilm production

35
Q

What is the clinical presentation of intravascular catheter related infections?

A
  • 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
36
Q

What is the causative agent in intravascular catheter related infections?

A

Staphylococcus aureus

37
Q

What can aid in diagnosis of artificial valve, pacemaker and defibrillator infections?

A

Timing and onset of the infection after placement can aid in diagnosis.

38
Q

With prosthetic valves, what is the most predominant agent during the initial year following surgery?

A

Staphylococcus epidermis (50% of time)

39
Q

With prosthetic valves, what is the second most predominant agent during the initial year following surgery?

A

Staphylococcus aureus (20% of infections)

40
Q

With prosthetic valves, what is the most predominant agent after the initial year following surgery?

A

Streptococcus viridans group

41
Q

Where do infections occur with prosthetic valves?

A

Around the site of the implant

42
Q

What do valvular infections (prosthetic) usually have as part of an endocarditis?

A

They usually have a fever as part of an endocarditis syndrome as well as a heart murmur.

43
Q

Where do infections occur in Pacemaker and defibrillators?

A

-They can occur around the pocket of the implanted device or may involve electrodes or cardiac valves

44
Q

What causes infections within two weeks of implantation of a pacemaker or defibrillator?

A

Staph. aureus

45
Q

What causes infections from two weeks up to one year after implantation of a pacemaker or defibrillator?

A

Coag-negative Staphylococcus species.

[Esp. staph epidermis]

46
Q

What causes infections one year or more after implantation of a pacemaker or defibrillator?

A

Streptococcus viridian’s group

47
Q

What are clinical signs of electrophysiological device infections?

A
  • Variable:
  • -Involve pocket pain at implantation site
  • -Fever
  • -Chills
  • -Bacteremia
48
Q

What organisms are associated with artificial valve, pacemaker, and defibrillator infections?

A
  • Staph aureus
  • Staph epidermidis
  • Streptococcus species (viridians)
  • Enterococci
49
Q

What transmits RMSF?

A

Dog ticks and wood ticks

50
Q

Where does RMSF usually occur?

A

Mostly in Oklahoma, Missouri, Arkansas, Tennessee, North Carolina, and Delaware

51
Q

What is the pathogenesis of RMSF that leads to petechial rash?

A
  1. Tick inoculation
  2. Rickettsia spread through body in bloodstream
  3. The virus attaches to and is engulfed by vascular endothelial cells
  4. In vascular endothelial cells they multiply in the cytoplasm and spread to adjourning vascular cells
  5. Replication causes leakage of RBCs which produces a pink rash that develops into petechial rash.
52
Q

Where else can these petechial hemorrhages occur in RMSF?

A
  • Brain
  • Lung
  • Heart
  • Liver
  • Other visceral organs
53
Q

What do these hemorrhages in RMSF lead to?

A
  • Fever
  • Headache
  • Myalgia
  • Pneumonitis
  • Nausea
  • Vomiting
  • Abdominal pain
  • Cardiac arrhythmia
54
Q

When do the clinical symptoms of RMSF occur?

A

1-2 weeks following infection

55
Q

Who is most commonly affected with RMSF?

A

Children - but they usually have a milder disease

56
Q

What is the causative agent of RMSF?

A

Rickettsia rickettsii