CPR 7.13 Bacterial, Viral, and Parasitic Cardiac Infections

Question 1

Define cardiomyopathies.

Answer 1

a heterogeneous group of diseases that have a direct effect on cardiac structure, myocardial function, or myocardial electrical properties.

Question 2

Define Pericarditis and outline the most common viral and bacterial causes as well as the relative prevalence between these types.

Answer 2

• infection of the pericardium
• Enteroviruses Coxsackie B virus. More common.
• Staphylococcus aureus, Mycobacterium tuberculosis, Streptococcus pneuoniae, Borrelia burgdorferi. Rare, usually extension of bacterial pneumonia.

Question 3

Sharp sub-sternal chest pain worse with inspiration or laying supine. Fevers, chills, sweats, SOB, difficulty swallowing is most indicative of what?

Answer 3

Viral Pericarditis

Question 4

Describe the symptoms of bacterial pericarditis.

Answer 4

Same as viral Pericarditis symptoms with addition of flu-like symptoms for extended periods of time. Chest pain not as prevalent

Question 5

Describe diagnostic steps for viral pericarditis

Answer 5

Pericardial Friction Rub. Myocardial enzymes may be elevated (look like MI). PMHx, EKG/ECG, echocardiogram, CXR (fluid accmulation can cause it to appear larger). EMB: not done that often anymore because of risks). PCR,

Question 6

Describe diagnostics of bacterial pericarditis

Answer 6

Patient history is most important part of determining whether Pericarditis has bacterial cause. (untreated pneumoia, recent surgery, immunosuppresion..

Question 7

What is the treatment of viral vs. bacterial pericarditis?

Answer 7

Viral: Supportive treatment. Anti-inflammatories, diuretics, low salt diet, reduced activity. Anti-Arrhythmic drugs.
Bacterial: Antibiotics to treat specific bacteria responsible.

Question 8

Define myocarditis and name the most common viral, parasitic, and bacterial causes as well as the relative prevalence of each type.

Answer 8

• Inflammation of the myocardium.
• Viral: Most Common. Enteroviruses (Coxsackie B virus).
• Parasite: Trypanosoma cruzi
• Bacteria: Rare (Pulmonary Infection Bacteria). Staphylococci, Steprtococci, (Borrelia burgdoferi),

Question 9

Describe the range and examples of Sx in myocarditis

Answer 9

Cardiac Sx start 7-10 days after systemic illness. May have chest pain. Abnormal heartbeat, fatigue, fever, myalgias, sore throat, joint pain/swelling, leg swelling, fainting, SOB.

Question 10

What is the commonly infected population, and frequent diagnostic tests for myocarditis?

Answer 10

often in newborns, adolescents, or young adults. 2/3 male. ST elevation and T wave reversion. Largely same as Pericarditis

Question 11

Treatment for myocarditis?

Answer 11

Supportive treatment. Anti-inflammatories, diuretics, low salt diet, reduced activity. Anti-Arrhythmic drugs.

Question 12

Name 2 factors that contribute to development of myocarditis.

Answer 12

HIV

Post GAS infection

Question 13

Catalse Negative, Beta-Hemolytic is an example of what bacterial species? What can this cause?

Answer 13

Streptococcus pyogenes. GAS
Rheumatic fever (RHD)

Question 14

Define endocarditis and the general mechanism by which this occurs.

Answer 14

Bacterial infection of the endothelial lining of the heart, usually the heart valves. Bacteria in bloodstream attach to the heart valves.

Question 15

Differentiate between common causes of endocarditis in Native/Late Prosthetic valve infections vs. Early Prosthetic valve infections.

Answer 15

(a) Native Valve or Late Prostethtic valve infection: Oral Streptococci (Strep. Viridans) most common.
(b) Early Prosthetic Valve: Staphylococcus aureus.

Question 16

Describe the catalase test and hemolytic status of Strep. Viridans.

Answer 16

(These are Catalase Negative, α-hemolytic).

Question 17

What are some common pre-disposing factors for infective endocarditis?

Answer 17

Patents unaware of CHD’s, Waning immune system. Dental work or poor dentition. Heart murmur (damaged valves), Prosthetic valves, IV drug users (bacteremia), Intravascular device, Over 60 yoa, male.

Question 18

Describe the most common Sx present of infective endocarditis

Answer 18

Fever, heart murmur, Non-specific Sx (weight loss, chills, fatigue, malaise, nausea, vomiting, night sweats. Peripheral splinter hemorrhages (nail beds), Osler’s Nodes (tender lesions on palms, fingertips, feet), Roth’s spots (hemorrhage in the eye).

Question 19

What diagnostic tests are run for suspected endocarditis and why is this method required?

Answer 19

-Blood cultures, 3 in a 24 hour period (because healthy individuals will often have transient bacteremia.

Question 20

How can HACEK group bacteria be distinguished as a les common cause of Infective endocarditis?

Answer 20

Gram Negative causes of bacterial endocarditis, more rare than Gram Positive.
(a) These are gram negative and fastidious, part of normal flora of oral cavity.

Question 21

Describe the general treatment as well as outcomes for endocarditis

Answer 21

Antibiotics (25-50% mortality, this is so high beause older and immunocompromised people are most commonly infected).

Question 22

How can a bacterial infection cause rheumatic fever?

Answer 22

Pharyngeal infection from Strep Pyogenes with M protein that is similar to myosin in humans can cause an immune response and therefore lead to inflammation of heart muscle.

Question 23

Describe Strep pyogenes in terms of Catalase test and hemolytic status.

Answer 23

Catalase negative, Beta-hemolytic.

Question 24

What are the Sx of Rheumatic fever?

Common population infected?

Answer 24

joint pain, subcutaneous nodules especially on joints, Myo/Peri-carditis, CHF, SOB, heart murmur, annular rash over trunk and arms. Typicaly 5-15 years old, more prevalent in developing world.

Question 25

How is rheumatic fever most effectively treated?

Answer 25

Early treatment of GAS pharyngitis. Supportive treatment of Sx. Surgery on heart valves with RHD.

Question 26

What causes Chagas disease?

Answer 26

Trypanosoma cruzi hemoflagellate

Question 27

What is the vector for Chagas parasite?
What geographical area is it located in.
In what ways can this parasite be spread?

Answer 27

Triatomine bug “kissing bug.” Blood sucking insect that feeds on both humans and other animals.

1. Location: Mexico, Central and South America.
2. Can also be acquired through blood products, organ transplant, or congenitally.

Question 28

What is the clinical presentation for Chagas disease?

Answer 28

Chagoma (indurated area of erythema and swelling with local lymphadenopathy.

1. Ramana’s sign: painlss edema of eyelid if that is point of entry.
2. Chronic: Inflammation due to persistent parasites, not AI. Causes thinning of ventricular walls, biventricular nelagement, apical aneurysms, mural thrombi.

Question 29

How is the Chagas disease diagnosed in:

• Acute phase
• Chronic phase

Answer 29

1. Acute: Detect parasites in blood. Giesma stained thin and thick blood smears.
2. Chronic: Serology detection of IgG antibodies that bind to T.cruzi antigens.
   (a) RIPA: sensitive and specific confirmatory test for detecting antibodies.
3. Travel history is important.

Question 30

Preventative treatment of Cahgas disease?

Drugs?

Answer 30

Reduction f vector by spraying insecticdes, Plasetering walls, Serologic screening of blood donors, Safe travel. Benznidazole and Nifurtimox (acute) but have severe side effects.