Introduction to Cardiovascular Infectious Disease

Question 1

Infectious Endocarditis

Answer 1

Inflammation of the inner lining of the heart (endocardium) caused by bacterial infection.

Most of the time this refers to an infection of the valves of the heart (most often the mitral or aortic valve).

Two variations of the infection – acute and subacute – each with distinct groups of microorganisms that cause disease.

Question 2

signs and symptoms of infectious endocarditis

Answer 2

fever, anemia, and an abnormal heartbeat
Abdominal or side pain is sometimes reported
patient may look very ill and may have petechiae (small red-to-purple discolorations), septic emboli, Roth’s spots, and splinter hemorrhages under the fingernails
In subacute cases, an enlarged spleen may develop.

Question 3

Septic emboli

Answer 3

Septic emboli with hemorrhage and infarction due to acute Staphylococcus aureus endocarditis

Question 4

Acute endocarditis

Answer 4

largely Staphylococcus aureus, sometimes Streptococcus pyogenes

Hectically febrile
Rapidly damages cardiac structures
Seeds infection in distal sites through sepsis
If untreated, progresses to death within weeks

103F to 104F fever often seen

Question 5

Subacute endocarditis

Answer 5

Streptococcal species (viridans), Enterococcal species

Indolent course of infection
Causes structural cardiac damage slowly
Rarely seeds infection at distal sites
Gradually progressive

usually less than 103 fever

Question 6

Infectious Endocarditis – Clinical Features

Answer 6

Generally nonspecific.

Initial diagnosis can be made through a patient presenting with a fever and valvular abnormalities.

behavior pattern that predisposes the patient to endocarditis (injection drug use).

blood cultures for bacteria that cause endocarditis, otherwise-unexplained arterial emboli, and progressive cardiac valvular incompetence.

Question 7

The Duke Criteria for infectious endocarditis

Answer 7

Highly sensitive and specific.

Positive result = 2 major criteria met, 1 major and 3 minor criteria met, or 5 minor criteria met.

trumped if alternative diagnosis is established, symptoms resolve and do not recur with less than 5 days of antibiotic therapy, or lack of histological evidence of endocarditis.

Possible infectious endocarditis is 1 major and 1 minor or 3 minor criteria are met.

Question 8

The Duke Major Criteria:

Answer 8

Positive blood culture (two separate cultures, or one for Coxiella burnetii)
Evidence of endocardial involvement

Question 9

The Duke Minor Criteria:

Answer 9

Predisposition (heart condition or injection drug use)

Fever above 38C (100.3F)

Vascular phenomena (arterial emboli, Janeway lesions, etc.)

Immunological phenomena (Osler’s nodes, Roth’s spots, rheumatoid factor, etc)

Microbiological evidence (positive blood culture, but not meeting major criterion, etc)

Question 10

Infectious Endocarditis – Portals of Entry (Primary Infection Sites):

Answer 10

Oral cavity
Skin
Upper respiratory tract

Question 11

Infectious Endocarditis - Local infection (in heart):

Answer 11

Mitral valve
Tricuspid valve (injection drug use)
Prosthetic valves

Question 12

Janeway lesion:

Answer 12

non-tender, small haemorrhagic lesions on the palms and soles.

Question 13

Osler’s nodes:

Answer 13

painful, red, raised lesions on the hands and feet. –immune complex disposition.

Question 14

Rheumatiod factor:

Answer 14

autoantibody associated with articular disease. Can be elevated in chronic hepatitis, bacterial endocarditis, leukemia, mono, SLE

Question 15

Treatment for acute endocarditis

Answer 15

gear towards a staph infections

1. Nafcillin or ozacillin +/- gentamicin or tobramycin
2. Vancomycin + gentamicin

Question 16

Treatment for subacute endocarditis

Answer 16

• gear towards a strep infection
  1. ampicillin/sublactam + gentamicin or tobramycin
  2. Vancomycin+ ceftriazone or tentamicin/tobramycin

Question 17

Treatment for endocarditis in penicillin allergic patients

Answer 17

1. Cephalosporin (3rd and 5th generation or carbapenems

2. vancomycin

Question 18

Staphylococcus aureus: classification

Answer 18

Gram +
cocci
catalase +
coagulase +

Question 19

Staphylococcus aureus: virulence factors

Answer 19

protein A (binds Fc portion of IgG)
coagulase (forms fibrin coat around the organism)
hemolysins and leukocidins (destroy RBCs and WBCs)
Hyaluronidase (breaks down connective tissue)
Staphylokinase (lyses formed clots)
Lipase (breaks down fat)

Question 20

Staphylococcus aureus: clinical presentaton

Answer 20

Most common cause of endocarditis
Localized skin/subcutaneous infection(most common skin infection) = impetigo, cellulitis, folliculitis, furuncles, carbuncles. Common infectious agent of surgical wounds.

Question 21

Streptococcus mutans: classification

Answer 21

gram +
cocci
catalase -
a-Hemolytic (is a member of strep viridans)
Bacitracin resistant

Question 22

Streptococcal viridans species: Infectious Endocarditis

Answer 22

2nd major cause; several oral species possible
Usually involves underlying mitral valve damage (rheumatic fever) which provides the site for bacterial colonization.
Viridans scan produce dextran for glycocalyx formation and surface adhesion proteins that assist colonization

Question 23

Enterococcus species: infectious endocarditis

Answer 23

3rd major cause
Usually preceded by bacteremia.
Most frequently found following genitourinary procedures in older men and obstetric procedures in younger women.
Virulence factors include pili, surface proteins, and extracellular enzymes like proteases and hyaluronidases.
Usually resistant to penicillin and carbepenems.

Question 24

Streptococcus pyogenes: classification

Answer 24

gram +
cocci
catalase -
Beta hemolytic
bacitracin sensitive

Question 25

Streptococcus pyogenes: Clinical Presentation

Answer 25

major cause of bacterial skin infections
Localized skin/subcutaneous infection = impetigo, erysipelas, cellulitis
Toxin-mediated = Toxic shock syndrome, necrotizing fasciitis

Question 26

Streptococcus pyogenes: mechanism of infection

Answer 26

Can colonize in the skin (following trauma) –> inflammation –> pustular lesions and honeycomb-like crusts (impetigo) at the site of inoculation. Deeper infections lead to erysipelas and cellulitis. Invasion from skin infections can lead not glomerulonephritis but not Rheumatic fever.

Question 27

Streptococcus pyogenes: virulence factors

Answer 27

Streptokinase (converts plasminogen to plasmin)
M protein (resists phagocytosis)
Hyaluronidase (breaks down connective tissue)
DNase (digests DNA)
Streptolysin O (destroys RBCs)
Streptolysin S (destroys WBCs)

Question 28

Rheumatic Heart Disease

Answer 28

Follows Streptococcus pyogenes pharyngitis in genetically predisposed individuals.

Mitral stenosis following pharyngitis with a rash is a definitive clinical indicator.

The damage to the heart muscle and valves is attributed to autoantibodies (antibodies to bacterial antigens cross-react with meromyosin in the heart). Type II hypersensitivity.

Question 29

Rheumatic Heart Disease: symptoms

Answer 29

Usually appear 2 to 4 weeks after strep infection
Pain swelling in large joints
Fever
Weakness
Muscle aches
Shortness of breath
Chest pain
Nausea and vomiting
Hacking cough
Circular rash
Lumps under the skin

Question 30

Rheumatic Heart Disease: Risks for aquiring

Answer 30

Strep throat infection (prolonged / untreated)
Prior case of rheumatic fever
Age 5 to 15 years old

Question 31

Rheumatic Heart Disease - Diagnosis

Answer 31

Blood Tests
Throat Culture
Echocardiogram
Chest x-rays
Electrocardiogram

Question 32

Rheumatic Heart Disease - Treatment

Answer 32

Penicillin based antibiotics
Aspirin
Corticosteroids
Rest

Question 33

Rheumatic Heart Disease - Prevention

Answer 33

Treat strep throat right away with antibiotics. Prevents the infection from developing into rheumatic fever.

People experiencing a sore throat and a fever lasting more than 24 hours should consult a physician.

Question 34

Myocarditis: definition

Answer 34

Inflammation of the myocardium (middle layer of the heart wall). Usually caused by a viral infection (Coxsackievirus B and Adenovirus (children)).

Chest pain, heart failure, and abnormal heart rhythms possible.

Question 35

Coxsackievirus A & B: classification

Answer 35

ssrna (+), group IV
nonsegmented
Icosahedral Nucleocapsid
Nonenveloped
Picornaviridae
Enterovirus

Question 36

Pericarditis: definition

Answer 36

Inflammation of the pericardium (sac-like membrane surrounding the heart). Typically an acute infection. Usually caused by a viral infection (Coxsackieviruses A and B, Echoviruses, and influenza virus). Viral pericarditis usually occurs during the summer months, coinciding with a higher incidence of enterovirus infections.

Chest pain associated with the irritated layers of the pericardium rubbing against each other.

Question 37

Rocky Mountain Spotted Fever caused by

Answer 37

Rickettsia rickettsii

Question 38

Rocky Mountain Spotted Fever: Typical symptoms include

Answer 38

fever, headache, abdominal pain, vomiting, and muscle pain. A rash may also develop, but is often absent in the first few days, and in some patients, never develops.

Question 39

Treatment for Rocky Mountain Spotted Fever

Answer 39

Doxycycline is the first line treatment for adults and children of all ages, and is most effective if started before the fifth day of symptoms

Question 40

What can cause Palm and Sole Rash:

Answer 40

RMSF
Syphillus
Coxsackievirus

Question 41

Obligate intracellular parasites that need host ATP to survive:

Answer 41

Chlamydiae and Rickettsiae

don’t know what this has to do with anything, but it’s there