Ch 32 Alterations of cardiac function

Rheumatic Fever Pathology

• Acute rheumatic fever (ARF) develops following a pharyngeal infection by group A beta-hemolytic streptococci
• Streptococcal skin infections do not progress to ARF because they lack the antigenic molecules of pharyngitis-causing strains, resulting in a different immune response
• ARF impacts the heart, joints, CNS, and skin via abnormal immune responses to streptococcal M proteins that cross-react with normal tissues
• Antibodies against the GlcNAc antigen in streptococci cross-react with laminin, a protein around heart cells and valves
• Autoimmunity and intense inflammation lead to lesions in connective tissues, particularly the heart, joints, and skin
• Inflammation can subside without treatment, causing damage and increasing susceptibility to recurrent ARF with subsequent streptococcal infections
• Repeated ARF attacks lead to chronic changes in organs through scarring, granulomas, and thromboses
• Approximately 10% of ARF cases develop into rheumatic heart disease (RHD)
• Genes like HLA-DR 1 and HLA-DR 6 are implicated in RHD, suggesting a genetic role in severe chronic disease
• RHD starts as carditis, primarily affecting the endocardium, including heart valves
• Endocardial inflammation causes valve leaflet swelling and erosion, leading to deposits of platelets and fibrin
• Valves lose elasticity, leaflets adhere, and involved structures undergo scarring and shortening over time
• Myocardial inflammation results in localized fibrin deposits known as Aschoff bodies, surrounded by necrosis
• Pericardial inflammation commonly involves serofibrinous effusion

Rheumatic Fever Etiology

• Rheumatic fever, a systemic inflammatory disease, arises from a delayed immune response to group A beta-hemolytic streptococci
• Untreated ARF can result in scarring and deformity of cardiac structures, leading to rheumatic heart disease (RHD)
• Crowding and poor hygiene are environmental risk factors
• A genetic predisposition may be a factor as the condition tends to run in families.
• Individuals with prior ARF attacks are more susceptible to recurrent episodes
• Most often occurs in children aged from 5 to 15

Rheumatic Fever Clinical Manifestations

• Common symptoms of acute rheumatic fever include fever, lymphadenopathy, arthralgia, nausea, vomiting, epistaxis, abdominal pain, and tachycardia
• Major manifestations: carditis, acute migratory polyarthritis, chorea, and erythema marginatum, occur singly or in combination, 1-5 weeks post-streptococcal pharyngitis infection

Rheumatic Fever Diagnosis

• Diagnosis relies on the Jones Criteria, combining clinical signs and symptoms with lab evidence of systemic inflammation
• Elevated C-reactive protein or erythrocyte sedimentation rate, correlated with physical findings, support the diagnosis
• Positive throat cultures for group A beta-hemolytic streptococci are important but may be negative at the rheumatic attack's onset
• Most streptococci strains produce streptolysin-O, leading to increased antibodies as the immune system responds
• Elevated white blood cell count, erythrocyte sedimentation rate, and CRP at the onset of cardiac or joint symptoms indicate acute inflammation
• Echocardiography is recommended for ARF suspects to detect subclinical carditis

Rheumatic Fever Treatment

• Antibiotic treatment within the first 9 days of beta-hemolytic streptococcus infection can usually prevent rheumatic fever
• Therapy involves antibiotics to eradicate streptococcal infection, typically a 10-day regimen
• NSAIDs are used to reduce inflammation of carditis and arthritis.
• Severe carditis may require cardiac glycosides, diuretics, and bed rest
• Surgical repair of damaged valves may be needed for chronic recurrent rheumatic fever or carditis
• Active disease is determined when murmurs resolve/cardiac status stabilizes, major manifestations disappear, the individual is afebrile, and the erythrocyte sedimentation rate normalizes
• A rheumatic recurrence will develop in 50% to 65% of children if they have another group A streptococcal infection.
• Continuous prophylactic antibiotic therapy for up to 5 years is necessary to prevent recurrence of acute rheumatic fever

Rheumatic Fever Complications

• Carditis occurs in approximately 50% of patients with acute rheumatic fever, a few weeks post-infection
• Earliest indication can be an undetected murmur from mitral/aortic valve dysfunction
• Chest pain results from pericardial inflammation that may have an audible friction rub
• Extra heart sounds, heart block, atrial fibrillation, and a prolonged PR interval, can be associated with chronic heart disease
• Endocardial inflammation can manifest as valvular diseases. (stenosis & regurgitation)
• Acute migratory polyarthritis of more than one joint, occurs in ~60-80% of individuals with rheumatic fever
• Synovial joints may be involved
• 2 or more joints are simultaneously or successively involved, each being symptomatic for ~2-3 days, while overall polyarthritis continues for up to 3 weeks
• Palpable subcutaneous nodes can often develop over bony prominences and along extensor tendons
• Sydenham chorea, or St. Vitus dance, is a neurological disorder marked by sudden involuntary movements (more common in girls)
• It is self-limiting, needing dopamine receptor blockers and antiepileptic medications in severe cases
• Erythema marginatum, a distinctive truncal rash, appears alongside acute rheumatic fever.

Infective Endocarditis Pathology

• At least 3 elements are required to develop infective endocarditis: endocardial damage, blood-borne microorganism adherence, and formation of infective endocardial vegetations

Infective Endocarditis Etiology

• Infective endocarditis refers to infections and inflammation of the endocardium, especially the heart valves and has ~15,000 new cases/year in the U.S.
• The most common cause are bacteria, especially streptococci, staphylococci, and enterococci

Infective Endocarditis Clinical Manifestations

• This condition may be acute, subacute or chronic
• It can lead to valvular dysfunction and other manifestations (lungs, eyes, kidneys, bones, joints, CNS)
• The indications and symptoms can result from inflammation/infection, systemic microemboli or immune complexions
• Pertinent findings include fever, murmurs and petechial lesions (skin, conjunctiva, oral mucosa)
• Other physical findings include: Osler nodes/Janeway lesions, weight loss, back pain, night sweats
• Can result to more CNS, splenic, and renal issues

Infective Endocarditis Diagnostics

• To diagnose, assess for persistent bacteremia, new murmurs, vascular complications, and examine appropriate EKG and echocardiogram
• Organ scans can be conducted when emboli are expected

Infective Endocarditis Treatments

• Usually will require antimicrobial therapy for up to 4-6 weeks (starting with IV antibiotics and ending with oral antibiotics)
• Two antibiotics simultaneously are sometimes given to prevent resistance
• Other drugs or surgery may be needed to treat possible heart failure secondary to valvular dysfunction
• For those with certain heart valve conditions, preventative antibiotics are only suggested for certain high-risk individuals (hx of IE, prosthetic valves, specific heart defects, etc.)

Raynaud Phenomenon and Disease

• Raynaud phenomenon and disease are characterized by attacks of vasospasm in the small arteries and arterioles of the fingers and, less commonly, the toes
• Clinical manifestations include: changes in skin color, and sensation caused by ischemia (pallor, numbness, and the sensation of cold) and attacks tend to be bilateral

Varicose Veins

• Varicose veins are a common condition affecting more than 25 million Americans and are superficial veins in which blood has pooled (typically involve the saphenous veins of the legs)
• Caused by (1) trauma to the saphenous veins that damages one or more valves, or (2) gradual venous distension caused by the action of gravity on blood in the legs.
• Risks factors include standing for long periods, wearing constricting garments, or crossing legs
• In terms of progressing, it can result to chronic venous insufficiency, venous stasis ulcers, and infection