Infective Endocarditis Quiz

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Questions and Answers

Which microorganism is the most common cause of subacute infective endocarditis following dental procedures?

Staphylococcus aureus

Staphylococcus epidermidis

Streptococcus viridans (correct)

Enterococcus faecalis

Which of the following is NOT a recognized risk factor for developing infective endocarditis?

Hypertension (correct)

Congenital heart disease

Rheumatic heart disease

IV drug use

What primarily causes bacteremia leading to infective endocarditis?

Airborne infections

Foodborne illnesses

Non-sterile injections (correct)

Zoonotic diseases

Staphylococcus aureus is primarily associated with which type of infective endocarditis?

Acute endocarditis Signup and view all the answers

Which factor is associated with a more severe course of infective endocarditis when untreated?

Staphylococcus aureus Signup and view all the answers

What are the major criteria for rheumatic fever?

Carditis Signup and view all the answers

Which of the following is a symptom associated with Sydenham's chorea?

Irregular, purposeless movements Signup and view all the answers

What is the most serious effect of rheumatic fever on the heart?

Rheumatic myocarditis Signup and view all the answers

Which of the following is NOT a minor criterion for diagnosing rheumatic fever?

Carditis Signup and view all the answers

What is a common cause of fibrinous (serofibrinous) pericarditis?

Rheumatic fever Signup and view all the answers

Which of the following complications can arise from repeated attacks of rheumatic fever?

Heart failure Signup and view all the answers

What is a potential cause of death related to rheumatic fever?

Pneumonia Signup and view all the answers

Which type of pericarditis is often associated with bacterial infections?

Suppurative pericarditis Signup and view all the answers

What is a common characteristic of Enterococcus faecalis in relation to infective endocarditis?

It is part of the normal flora of the human colon. Signup and view all the answers

Which pathogen is most closely associated with colorectal cancer in elderly patients?

Streptococcus gallolyticus Signup and view all the answers

What initiates the pathological process leading to the formation of vegetations in infective endocarditis?

Valvular endothelial damage. Signup and view all the answers

Which method is considered the standard test for diagnosing infective endocarditis?

Blood cultures Signup and view all the answers

In what specific circumstance are antibiotics administered as prophylaxis for infective endocarditis?

Patients with preexisting heart conditions during dental procedures. Signup and view all the answers

What clinical feature is NOT typically associated with infective endocarditis?

Hypertension Signup and view all the answers

What can happen if infective endocarditis is left untreated?

It can be fatal within a few weeks. Signup and view all the answers

Which of the following is considered less common as a pathogen in subacute infective endocarditis but may relate to poor dental hygiene?

HACEK organisms Signup and view all the answers

What is the primary causative organism of the disease described?

Viridans group of α-hemolytic streptococci Signup and view all the answers

What potential complications can arise from vegetations fragmenting?

Coronary artery embolism Signup and view all the answers

Which of the following is NOT a characteristic of vegetations observed in the disease?

Translucent and smooth Signup and view all the answers

What is the termination condition typically associated with the disease?

Congestive heart failure Signup and view all the answers

From which locations can organisms that cause the disease enter the bloodstream?

Dental sepsis and throat infections Signup and view all the answers

What type of degeneration is observed in the myocardium due to toxaemia?

Cloudy swelling and fatty degeneration Signup and view all the answers

Which of the following systemic symptoms may occur due to toxic lesions?

Clubbing of the fingers Signup and view all the answers

What can result from the organization of vegetations when treated with antibiotics?

Fibrosis and calcification Signup and view all the answers

What is the correct sequence of blood flow through the heart chambers?

Right atrium → Right ventricle → Pulmonary arteries → Lungs → Pulmonary veins → Left atrium → Left ventricle → Aorta Signup and view all the answers

Which age group is most commonly affected by rheumatic fever (RF)?

Children and young adults aged 5-15 years Signup and view all the answers

What factors increase the likelihood of developing rheumatic fever in developing countries?

Damp weather and low socioeconomic conditions Signup and view all the answers

What is the main cause of rheumatic fever following infection?

Group A beta-hemolytic streptococci Signup and view all the answers

What is a consequence of the autoantibodies produced in rheumatic fever?

Damage to human tissues due to cross-reactivity Signup and view all the answers

How long is the latent period after streptococcal infection before rheumatic fever can develop?

2-4 weeks Signup and view all the answers

What is the impact of long-term penicillin administration regarding rheumatic fever?

It prevents further attacks of streptococcal pharyngitis and RF Signup and view all the answers

Which of the following is NOT a characteristic of rheumatic fever?

It is primarily caused by viral infection Signup and view all the answers

What is a common pathological feature of acute infective endocarditis?

Suppurative inflammation with ulceration Signup and view all the answers

Which organs or structures can be involved with adherent mediastino-pericarditis?

Parietal pericardium and adjacent mediastinal structures Signup and view all the answers

Which of the following organisms is a common causative agent of acute infective endocarditis?

Streptococcus haemolyticus Signup and view all the answers

What complication may result from the organization of a pericardial lesion?

Constrictive pericarditis Signup and view all the answers

Which of the following best describes the vegetations associated with acute infective endocarditis?

Friable and yellow in color Signup and view all the answers

What is one of the types of non-infective endocarditis?

Non-infective thrombotic endocarditis Signup and view all the answers

Which structure can be constricted due to complications from pericardial lesions?

Orifice of the venae cava Signup and view all the answers

What causes the bacteria to reach the heart in cases of acute infective endocarditis?

Septic focus in the body Signup and view all the answers

Study Notes

Infective Endocarditis (IE)

IE is an infectious inflammation of the endocardium affecting heart valves.
Etiology: Bacteremia, often caused by dental procedures, surgery, distant primary infections, and non-sterile injections.
Risk Factors:
- Rheumatic heart disease
- Intravenous (IV) drug use
- Immunosuppression
- Prosthetic heart valve
- Congenital heart disease

Main Causative Pathogens

Streptococcus viridans:
- Normal flora of oral cavity and upper respiratory tract.
- Common cause of IE, especially in previously damaged heart valves, can be subacute.
Staphylococcus aureus:
- Affects healthy valves
- Usually fatal if left untreated, can cause acute IE
Staphylococcus epidermidis:
- Causes IE in patients with peripheral venous catheters, prosthetic heart valves, etc.
Enterococcus faecalis:
- Normal flora of human colon, urethra, and female genital tract
- Causes IE in patients with preexisting heart valve damage, is usually subacute.

Less Common Pathogens (Subacute IE)

Streptococcus gallolyticus:
- Normal flora of colon.
- Associated with colorectal cancer in the elderly and immunocompromised.
HACEK group (G-ve bacilli):
- Haemophilus
- Aggregatibacter
- Cardiobacterium
- Eikenella
- Kingella
- Associated with IV drug users who contaminate needles with saliva
- Poor dental hygiene and/or periodontal infections
Candida species:
- Normal flora of mucous membranes
- Causes IE in immunosuppressed patients.
- Associated with vascular catheters

Pathogenesis

Valvular Endothelial Damage: Damage from rheumatic fever, prosthetic valves, etc, creates turbulent blood flow.
- This leads to fibrin-platelet aggregates on the valve.
Bacteremia: Bacterial colonization of damaged valves.
- Further fibrin and platelet deposition leads to formations called vegetations.
- Eventually, valve destruction occurs with loss of function

Clinical Features

Constitutional symptoms: fatigue, fever/chills, and malaise
Signs of pathological cardiac changes: new or changed heart murmurs, heart failure signs
Possible manifestations of subsequent damage to other organs, such as glomerulonephritis, or septic embolic stroke

Lab Diagnosis (Before Antimicrobial Therapy)

Blood cultures: The standard test to determine the microbiologic cause of the disease.
- 5-day standard blood cultures allow for the recovery of most cultivable microorganisms, including Candida and fastidious HACEK organisms.
- Subculturing on solid media isolates the causative organism for further identification (morphology, biochemical reactions), and antibiotic susceptibility testing.
Serology
PCR

Prophylaxis

Antibiotics are typically administered only in specific situations like those with preexisting heart conditions undergoing dental or surgical procedures.

Prognosis

Untreated IE can be fatal within a few weeks.

Rheumatic Fever

Definition: Delayed complication of streptococcal pharyngitis/tonsillitis, usually occurring 2-4 weeks after the initial infection.
Etiology: Molecular mimicry—Antibodies formed against streptococcal M protein may cross-react with heart tissue, triggering inflammation.
Epidemiology: Peak incidence amongst 5-15 year olds. More common in developing countries.
Pathophysiology: Type II hypersensitivity reaction—Antibodies damage heart tissues.
Clinical Features (JONES criteria):
- Migratory polyarthritis
- Pancarditis (endocarditis, myocarditis, pericarditis)
- Subcutaneous nodules
- Erythema marginatum
- Sydenham chorea
Diagnosis: Jones criteria plus evidence of preceding streptococcal infection (GAS).
- Confirming GAS infection: elevated Antistreptolysin O (ASO) titers, positive rapid antigen test from throat swab.
Treatment: Bed rest is important, antibiotics to eradicate GAS, and symptomatic treatment for fever, arthritis, or cardiac issues.
Complications: Chronic rheumatic heart disease, and potentially death due to myocarditis or congestive heart failure.
Prevention:
- Early treatment of streptococcal pharyngitis (within 10 days of onset).
- Prolonged prophylactic antibiotic therapy (at least 5 years) after an episode.

Pericarditis

Definition: Inflammation of the pericardium, the sac surrounding the heart.
Types:
- Fibrinous (serofibrinous) pericarditis
- Suppurative pericarditis
Causes (Fibrinous Type): Rheumatic fever, lobar pneumonia, bronchopneumonia, tuberculous pericarditis, post-myocardial infarction, uraemia, diabetes mellitus.
Causes (Suppurative Type): Streptococcus, staphylococcus, meningococcus septicaemia, blood/lymphatic spread from pneumococcal lung infection, direct spread from empyema, osteomyelitis, subphrenic/liver abscess, penetrating chest wounds.
Pathological features (Suppurative): Suppurative inflammation with pus accumulation in the pericardial sac.
Complications (Suppurative): If survivors, heals by organization causing pericardial adhesions; leading to constrictive pericarditis or adherent mediastino-pericarditis.

Myocarditis

Definition: Inflammation of the myocardium (heart muscle).
Causes: Direct involvement by causal agents, toxin-mediated injury, local hypersensitivity reaction.
Types:
- Viral interstitial myocarditis
- Suppurative myocarditis
- Toxic myocarditis
- Hypersensitivity reactions
- Granulomatous myocarditis

Cardiomyopathy

Definition: Heterogeneous group of disorders marked by chronic myocardial dysfunction (uncertain cause).
Types: Classified into hypertrophic, dilated, and restrictive cardiomyopathy.
Further divide into primary (unknown etiology) and secondary (related to systemic disorders).

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Description

Test your knowledge on Infective Endocarditis (IE), its causes, risk factors, and main pathogens involved. This quiz covers essential details related to the condition and aims to enhance your understanding of its clinical aspects.