Rheumatic Fever and Endocarditis Quiz

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Questions and Answers

What type of disease is rheumatic fever considered?

Infectious disease

Acute immunologically mediated disease (correct)

Chronic degenerative disease

Autoimmune disease

Which age group is most commonly affected by rheumatic fever?

Infants aged 0-1 years

School-aged children aged 5-15 years (correct)

Adults aged 30-50 years

Elderly individuals over 65 years

What is not a major manifestation of rheumatic fever according to Jones' criteria?

Carditis

Arthritis

Chorea

Fever (correct)

Which of the following is a primary mechanism in the pathogenesis of rheumatic fever?

Cross-reactivity of antibodies with human tissue antigens Signup and view all the answers

Which parameter is a laboratory finding supporting the diagnosis of rheumatic fever?

Increased white blood cell count Signup and view all the answers

Which tissue is primarily affected by the autoimmune response in rheumatic fever?

Cardiac valves Signup and view all the answers

What type of inflammation does pancarditis refer to?

Inflammation of the heart layers including endocardium, myocardium, and pericardium Signup and view all the answers

What is the role of the M protein in the pathogenesis of rheumatic fever?

Promoting streptococcal adherence to host tissues Signup and view all the answers

What is a possible consequence of a mycotic aneurysm?

Weakening of the vessel wall Signup and view all the answers

Which condition is NOT commonly associated with raised ESR?

Healthy individuals Signup and view all the answers

Which diagnostic tool is most likely to show vegetations in cases of endocarditis?

Echocardiogram Signup and view all the answers

Which type of endocarditis is characterized by small, bland vegetations that do not cause destruction?

Non-bacterial thrombotic endocarditis (NBTE) Signup and view all the answers

Which procedure is important for prophylaxis in patients with cardiac abnormalities?

Antibiotic usage during dental or surgical procedures Signup and view all the answers

What is a common form of vegetative endocarditis involving the mitral valve?

Infective endocarditis Signup and view all the answers

What is a major difference between rheumatic endocarditis and Libman-Sacks endocarditis?

Rheumatic endocarditis is an autoimmune condition Signup and view all the answers

Which of the following is a characteristic feature of infective endocarditis?

Large, irregular, destructive vegetations Signup and view all the answers

What type of cells are characterized as 'caterpillar cells' in the context of Aschoff nodules?

Anitschkow cells Signup and view all the answers

In which part of the heart do Aschoff nodules typically form during myocarditis?

Myocardium Signup and view all the answers

What type of effusion is commonly associated with pericarditis due to Aschoff nodules?

Serous effusion Signup and view all the answers

What is the typical clinical feature of arthritis associated with rheumatic fever?

Joint pain that stops with aspirin Signup and view all the answers

What are the small vegetations called that may develop along the valve leaflets due to endocarditis in rheumatic fever?

Verrucae Signup and view all the answers

Which risk factor is least likely to contribute to the development of acute infective endocarditis?

Atrial fibrillation Signup and view all the answers

What is a key feature of vegetations associated with acute endocarditis compared to those seen in subacute endocarditis?

They are bulkier and occur on normal valves Signup and view all the answers

Which of the following is NOT a characteristic of Syndenham's Chorea?

Diminished coordination during sleep Signup and view all the answers

Which organism is primarily associated with the pathogenesis of acute infective endocarditis due to its virulence and ability to proliferate rapidly?

Staphylococcus aureus Signup and view all the answers

What type of necrosis is observed in Aschoff's nodules?

Fibrinoid necrosis Signup and view all the answers

What complication of infective endocarditis can result in the dislodgement of an artificial valve?

Dehiscence Signup and view all the answers

Which valves are most prone to developing severe lesions in the context of rheumatic fever?

Aortic and mitral valves Signup and view all the answers

Which symptom is most likely associated with the embolic complications of left-sided lesions in infective endocarditis?

Infarcts of brain and spleen Signup and view all the answers

In an immunocompromised patient, which condition is most likely to predispose them to acute infective endocarditis?

Neutropenia Signup and view all the answers

What morphological characteristic distinguishes the vegetations seen in acute infective endocarditis?

Friable and bulky Signup and view all the answers

Which of the following statements about the morphology of vegetations in infective endocarditis is accurate?

Acute endocarditis can cause perforation or erosion of valve leaflets Signup and view all the answers

What is a distinguishing characteristic of erythema marginatum compared to rheumatoid nodules?

It is typically flat with serpiginous margins Signup and view all the answers

Which condition is least likely to cause death as a result of acute rheumatic fever?

Chronic fatigue syndrome Signup and view all the answers

Which statement accurately reflects the chronic rheumatic heart disease outcomes?

70% of cases involve just mitral valve involvement Signup and view all the answers

What pathological feature is associated with rheumatic heart disease?

Permanent thickening and retraction of valve cusps Signup and view all the answers

Which of the following is considered a type of infective endocarditis?

Bacterial endocarditis Signup and view all the answers

What characterizes nonbacterial thrombotic endocarditis (NBTE)?

Sterile thrombi on cardiac valve leaflets Signup and view all the answers

In which condition would you most likely observe the presence of sterile thrombi on heart valves?

Nonbacterial thrombotic endocarditis Signup and view all the answers

What common long-term consequence is associated with chronic rheumatic heart disease?

Infective endocarditis Signup and view all the answers

Which of the following best describes the lesions associated with Libman-Sacks endocarditis?

Small sterile vegetations with fibrin and platelet thrombi Signup and view all the answers

What bacterium is known as a common causative agent of subacute bacterial endocarditis?

Streptococcus viridans Signup and view all the answers

What is a key factor in the pathogenesis of infective endocarditis?

Adhesion molecules on bacteria mediating adherence to injured endocardium Signup and view all the answers

Which condition is less likely to lead to platelet thrombi formation?

Healthy cardiac valves Signup and view all the answers

What is a common microscopic finding in lesions of Libman-Sacks endocarditis?

Fibrinoid necrosis and proliferation of capillaries Signup and view all the answers

How does acute infective endocarditis differ from subacute endocarditis?

Is associated with highly virulent pathogens Signup and view all the answers

What appearance do the vegetations of Libman-Sacks endocarditis typically have?

Warty or verrucous Signup and view all the answers

Study Notes

Rheumatic Fever and Rheumatic Heart Disease

Rheumatic fever is an acute, immunologically mediated, post-streptococcal, multisystem inflammatory disease.
It primarily affects the heart, joints, central nervous system, skin, and subcutaneous tissues.
It usually occurs 1-5 weeks after a streptococcal infection (group A β-hemolytic streptococcal infection).
The disease predominantly affects children aged 5-15 years.
Tissue lesions in rheumatic fever are sterile, meaning they don't contain streptococci.
Recurrence of rheumatic fever is always preceded by a streptococcal infection.

Pathogenesis

Rheumatic fever is a post-infectious immunologic disease resulting from the immune system's reaction to streptococcal antigens.
The body's antibodies cross-react with human tissue antigens, leading to inflammation.
Key antigens involved include the cell wall polysaccharide of group A Streptococcus, which can cross-react with cardiac valves.
The cell wall M protein shows cross-reactivity with sarcolemma and myosin in cardiac muscle.
The hyaluronate capsule of group A Streptococcus is identical to human hyaluronate present in joint tissues.
There may be autoantibodies in the brain that target basal ganglia and dopaminergic neurons.

Environmental Factors and Susceptible Hosts

Environmental factors like overcrowding and socioeconomic status can influence the risk of rheumatic fever.
Factors within the susceptible host, such as family history of the disease or genetic predisposition also play a significant role.
Repeated or continuous streptococcal infections increase susceptibility to rheumatic fever.

Clinical Manifestations

Cardiac: Pancarditis (inflammation of the endocardium, myocardium, and pericardium).
Extracardiac: Fever, arthritis (migratory polyarthritis), arthralgia, skin lesions (erythema marginatum, subcutaneous nodules), and chorea.

Jones Criteria for Diagnosis

To diagnose rheumatic fever, two major or one major and two minor criteria are needed.
Major criteria: Carditis, arthritis (migratory polyarthritis), chorea, subcutaneous nodules, and erythema marginatum.
Minor criteria: Clinical manifestations like fever, arthralgia, history of rheumatic fever or rheumatic heart disease. Laboratory findings like elevated acute-phase reactants (ESR, C-reactive protein, leukocytosis), prolonged PR interval on ECG. Supporting evidence of recent streptococcal infection (e.g., increased streptococcal antibody titers, positive throat culture for group A strep, or history of scarlet fever).

Morphology

Acute phase of rheumatic fever: Characterized by Aschoff nodules, which are small lesions:
- Foci of fibrinoid necrosis (immune complex reactions).
- Surrounding lymphocytes, macrophages, and plasma cells.
- "Activated" histiocytes (Anitschkow cells or Aschoff cells) with caterpillar-like appearance and central nuclei.
- Found in pericardium, myocardium, and valves.
- Eventually heal through fibrosis.
Microscopic appearance of Aschoff bodies: Spherical or fusiform structures with central necrosis, surrounded by lymphocytes (primarily T cells), scattered plasma cells, and activated macrophages.
Anitschkow cells have abundant cytoplasm and nuclei with centrally condensed wavy ribbon chromatin.

Pancarditis

Pericarditis: Aschoff nodules form in the pericardium, potentially causing pericardial effusion, and serous exudate.
Myocarditis: Aschoff nodules develop in the myocardium with interstitial oedema and mild inflammation, which can lead to left ventricular failure.
Endocarditis: Aschoff nodules lead to irregularities in valve surfaces, with fibrin and platelet aggregations forming small vegetations ("verrucae"), often along the valve lines. Aortic and mitral valves are most susceptible to significant damage.

Extracardiac Manifestations

Joints: Affects large joints like the knees, characteristically causing pain that subsides with aspirin.
Syndenham's Chorea: A disorder characterized by involuntary dance-like movements, which are commonly seen in patients with rheumatic fever. Restlessness, difficulty maintaining still posture, involuntary movements, disappearing during sleep, and some emotional instability are characteristic.

Subcutaneous Nodules

Painless nodules beneath the skin found on extensor surfaces of joints.
- Usually found on elbows or wrists.
Typically resolve within a few days to several weeks.

Erythema Marginatum

Flat or slightly raised, painless rash with pale centers and rounded or serpiginous margins.
Common in children.

Chronic Rheumatic Heart Disease (RHD)

Permanent valve deformity due to post-inflammatory fibrosis occurring 10-30 years after repeated acute RF attacks.
70% of cases have just mitral involvement; some have both mitral and aortic.
Endocarditis heals through progressive fibrosis; valvular leaflets fibrosis leads to stenosis. Cordae tendonae fibrosis leads to regurgitation.
Valves thicken and retract, often fusing and with calcium deposits.
Fibrous bridging across valvular commissures with calcification creates "fish mouth" stenosis.
Microscopic examination shows neovascularization and diffuse fibrosis that obliterates normal leaflet architecture.

Long-Term Outcome of RHD

Depends on chronic valve changes' severity.
Potential heart failure from mitral stenosis, mitral incompetence, or mixed mitral valve disease.
Susceptibility to infective endocarditis.
Left atrial thrombus formation can occur.

Types of Endocarditis

Non-infective (Non-microbial): Rheumatic heart disease, Libman-Sacks endocarditis (SLE), Non-bacterial thrombotic endocarditis (NBTE).
Infective (Microbial): Primarily bacterial or fungal.

Non-bacterial Thrombotic Endocarditis (NBTE)

Characterized by the deposition of small, sterile thrombi on cardiac valve leaflets.
Occurs more commonly in mitral valves in debilitated patients (cancer or sepsis), often in those with mucinous adenocarcinomas.
Sterile, bland, non-destructive vegetations.
Doesn't cause tissue destruction nor show inflammation.

Endocarditis of Systemic Lupus Erythematosus (Libman-Sacks Endocarditis)

Occurs in approximately 10% of patients with lupus.
Lesions from immune complex deposition.
Affects mitral and tricuspid valves, as small (1-4 mm), sterile vegetations.
Appear warty (verrucous) in appearance.
Microscopically, composed of fibrin and platelet thrombi with fibrinoid necrosis. Capillaries and infiltration by histiocytes, plasma cells, lymphocytes, and neutrophils occur in the endocardium.

Infective Endocarditis (IE)

Microbial infection affecting heart valves or mural endocardium.
Leads to vegetation formation (thrombotic debris and microorganisms), and often destroys underlying cardiac tissue.
Classified into acute (ABE) and subacute (SABE) forms.

IE Pathogenesis

Bacteria entering the bloodstream implant on cardiac valves or endocardium due to surface adhesion molecules.
Bacteria preferentially lodge on damaged valves (especially in RHD and congenital heart disease) over healthy ones
Conditions causing stress to valves lead to endothelial damage, favoring platelet thrombi formation, which then get infected by circulating bacteria.

Sub-acute Bacterial Endocarditis

Damage to the pre-existing valve leads to platelet-fibrin deposits and thrombotic vegetations.
Bacteria invade thrombotic vegetations and slowly proliferate causing gradual valve destruction.
Poorly virulent causative agents like Streptococcus viridans.

Acute Bacterial Endocarditis

Patients with normal valves affected by highly virulent causative agents (e.g., Staphylococcus aureus).
Bacteria enter the bloodstream resulting in rapid proliferation of organisms on heart valve leading to necrosis and valve destruction.
Rapidly forming vegetations depend on both virulence of the organism and the size of the bacterial invasion. Host immunity plays a role as well.

Risk Factors for IE

Rheumatic heart disease, congenital heart malformations, other cardiac malformations, and various other heart conditions.
Iatrogenic factors like prosthetic valves, indwelling catheters; immunocompromised patients.
Infections like neutropenia, AIDS or, IV drug use.

IE Morphology

Macroscopic: Friable (easily disintegrating), bulky vegetations that are bacteria laden.
- Vegetations can be single or multiple and range in size from millimeters to centimeters.
Microscopic: Acute endocarditis vegetations tend to be bulkier, can cause perforation or erosion of the valve leaflet, and potentially spread to myocardial abscesses. Subacute endocarditis vegetations tend to be smaller, don't usually cause perforation, and extend to adjacent mural endocardium. IE shows mixed inflammatory cells and colonies of bacteria.

IE Complications

Cardiac: Valvular insufficiency, myocardial abscess, perforation of IV septum, suppurative pericarditis.
Embolic: Left-sided lesions (brain, spleen, kidneys, limbs), and less commonly mycotic aneurysms in vessels. Right-sided lesions can affect the lung. Artificial valve dislodgement also a risk.

IE Diagnosis

Clinical suspicion based on known risk factors, unexplained fever, septicemia, heart failure, and embolic infarcts.
Investigations include raised ESR, white blood cell count, normochromic, normocytic anaemia, and blood cultures to identify the causative organism (if no antibiotics are being taken).
Echocardiogram may show vegetation.

Major Forms of Vegetative Endocarditis

Information on the location, pathogens, and microscopic/pathological features of different endocarditis types.

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Description

Test your knowledge about rheumatic fever and related cardiac conditions in this quiz. Answer questions about its pathology, manifestations, age groups affected, and diagnostic features. Ideal for medical students and healthcare professionals looking to reinforce their understanding of these topics.