Rheumatic Heart Diseases

RHEUMATIC FEVER Acute, recurrent inflammatory disease in children 5-15 yrs old (rarely adults) Characterized by inflammatory changes in the fibrous tissue of different organs mainly the heart and joints. Predisposing factors: Are damp weather, overcrowding, poor housing and low socioeconomic conditions. These factors predispose to upper respiratory tract infections. Sites of Lesions: Rheumatic lesions occur mainly in the fibrous stroma of the heart, joints, ligaments and tendons. Less commonly the lesions affect the skin, brain, serous membranes, arteries and lung.

Pathogenesis of RF It is an autoimmune collagen disease, occurs 10-20 days after untreated throat infection by group A, -hemolytic Streptococcus Increased immune response to streptococcal antigens elicits antibodies to form that cross-react with heart & valve tissue Similar antigenic groups are shared by Streptococcus and heart/valve tissues

Morphology of Acute Rheumatic Fever Acute Rheumatic Carditis ( Pancarditis) Myocarditis Pericarditis Endocarditis: a- Mural b- Valvular

Acute Rheumatic Myocarditis The characteristic lesions are the Aschoffs nodules, affect mainly the left side of the heart and in particular the posterior wall of the left atrium. Aschoff’s Nodule Gross: Seldom seen by the naked eye as grayish nodules 1-2mm in diameter in the connective tissue, mostly paravascular. Microscopic Foci of fibrinoid necrosis surrounded by lymphocytes, macrophages, occasional plasma cells and Aschoff’s cells Aschoff’s cells are modified histiocytes with abundant amphophilic cytoplasm and round or ovoid nucleus. Aschoff’s giant cells: large multinucleated Aschoff’s cells Old lesions heal by fibrosis in months to years

Rheumatic myocarditis Aschoff’s nodule Aschoff’s cell Rheumatic myocarditis

Acute Pericarditis Fibrinous pericarditis develops with scanty serous exudate in the pericardial sac and excess fibrin deposit on the visceral and parietal pericardium giving the "bread and butter appearance". Pericarditis heals by organization.

Acute Rheumatic Endocarditis Mural Endocarditis: : Aschoffs nodules develop mainly on the posterior wall of the left atrium. Healing of the lesion by fibrosis ends in a white fibrous patch called "MacCallum's patch". Valvular Endocarditis: I- Acute rheumatic valvulitis affects mainly the mitral and aortic valves. The cusps are swollen due to inflammatory oedema and show foci of fibrinoid necrosis and infiltration by histiocytes, lymphocytes and plasma cells (Aschoffs nodules are uncommon). The endothelium at the line of contact of the inflamed cusps undergoes degeneration and necrosis due to the sustained trauma at every heartbeat. On the rough surface multiple, firm, adherent, small vegetations 1-3 mm indiameter form. They develop on the atrial surface of the mitral and tricuspid valves and on the ventricular surface of the aortic and pulmonary valves. The vegetations may also form over the cordae tendinae and the posterior wall of the left atrium

Acute rheumatic valvulitis (small pale vegetations)

Chronic Rheumatic Valvulitis: The vegetations undergo organization and the inflamed cusps heat by fibrosis. The cusps appear fibrotic, thick, and irregular and may show calcified patches. The cordae tendinae are fibrosed, thick and short. If the cusps adhere together during the acute inflammatory stage, healing results in stenosis of the valve. If no adhesions occur the cusps retract during healing causing incompetence of the valve - Microscopically the cusps show abnormal vascularization, fibrosis, hyalinosis and sometimes calcification.

Chronic Rheumatic Valvulitis: Chronic rheumatic mitral valvulitis causes stenosis more often than regurgitation, and it is the most common cause of mitral stenosis. It occurs more frequently in females than in males. In mitral stenosis, the valve leaflets and chordae tendinae are thick, rigid, and inter-adherent. The mitral orifice is narrowed to a slit-like channel, sometimes designated a "fish-mouth" deformity. In mitral regurgitation, the deformed mitral leaflets are retracted (the effects are previously described).

Chronic Rheumatic Valvulitis: Chronic aortic valvulitis is encountered more often in males than in females. Aortic valve disease is almost invariably associated with an element of mitral valvulitis. In patients with aortic stenosis, the valve cusps are thickened, firm, and adherent to each other, and the resultant aortic valve orifice is reduced to a rigid, triangular channel. Fibrosis of the valve leaflets may also cause them to retract toward the aortic wall, resulting in aortic regurgitation

Chronic rheumatic valvulitis Fused cusps and thickened chorda tendinae Mitral stenosis Fish-mouth deformity Chronic rheumatic valvulitis

Clinical Features The predominant clinical manifestations of acute rheumatic fever are those of arthritis and carditis. After repeated attacks of acute RF, permanent valve deformity due to post-inflammatory fibrosis; may occur 10-30 yrs MV valve affected 1st in (70% of cases) Mitral plus aortic valves affected in (25% of cases) The arthritis, which is much more common in adults than in children, preferentially occurs in larger joints and tends to involve different joints sequentially (migratory polyarthritis)

Long-term Outcome of RHD Depends on severity of chronic valve changes May develop heart failure due to mitral stenosis, mitral incompetence or mixed valve disease. Right-sided heart valves only affected after right-sided pressure rises due to left sided valve disease Infective endocarditis Left atrial thrombus formation Rx - valvuloplasty or valve replacement

ENDOCARDITIS Inflammation of the valvular endocardium Types: Definition: Inflammation of the valvular endocardium Types: I- Infective endocarditis: - Acute infective endocarditis. - Subacute infective endocarditis. II- Non-infective endocarditis: - Rheumatic endocarditis - Atypical verrucous endocarditis - Non-infective thrombotic endocarditis

Infective Endocarditis (IE) Infective endocarditis , a serious disease designates infection of the cardiac valves or mural surface of the endocardium, resulting in the formation of bulky thrombotic masses, containing bacteria termed vegetations. Virtually any type of microorganism is capable of causing endocarditis, although most cases are caused by bacteria. Infective endocarditis has traditionally been subdivided into acute and sub-acute forms. In the era of antibiotics, however, therapy often modifies the morphology and clinical progression of disease, thus blurring the distinction between acute and subacute cases.

Infective Endocarditis (IE) Acute Infective Endocarditis Causative organisms: Virulent bacteria e.g. streptococcus haemolyticus, staphylococcus aureus, pneumococci and gonococci. Pathogenesis: - Acute infective endocarditis is a part of a septicaemic condition. -The source of bacteria is a septic focus in the body as puerperal sepsis, acute osteomyelitis, carbuncle, pneumonia or gonococcal infections. -Bacteria reach the heart by the blood stream and attack the healthy valves usually in cases with poor resistance.

Infective Endocarditis (IE) Acute Infective Endocarditis Morphology The affected valve shows suppurative inflammation, ulceration with perforation and vegetations. The vegetations are: Bulky, friable, yellowish and septic. Present on both surfaces of the cusps. Their fragmentation causes pyaemia.

Acute bacterial endocarditis of mitral valve (friable vegetation with ulceration and perforation of the cusps)

Acute bacterial endocarditis of aortic valve (friable vegetation with ulceration and perforation of the cusps)

Infective Endocarditis (IE) Subacute Infective Endocarditis Causative organisms: Streptococcus viridans in 95% of the cases. Rarely haemophilus influenza, E. coli and others. Pathogenesis: The organisms enter the blood stream from dental sepsis and throat infections during mastication, dental extraction and tonsillectomy (bacteraemia). They invade valves predisposed to infection by: Chronic rheumatic valvulitis. Congenital malformations as bicuspid aortic valve, pulmonary stenosis septal detects ... etc. On top of prosthetic valves. These predisposing factors cause roughness of the cusps upon which minute platelet thrombi form. The bacteria lodge in the thrombi multiply and invade the cusps.

Infective Endocarditis (IE) Subacute Infective Endocarditis: Pathological Lesions: I. Cardiac Lesions: Vegetations develop mainly on the mitral and aortic valves as they are the valves commonly affected by rheumatic valvulitis. The vegetations are bulky, polypoid, friable and easily detached. They are grey, reddish or brown in colour. Vegetations develop on any surface of the cusps, cordae tendinae and may extend over the posterior wall of the left atrium over the MacCallum's patch. The myocardium shows cloudy swelling and fatty degeneration due to toxaemia

Infective Endocarditis (IE) Subacute Infective Endocarditis: Pathological Lesions: II. Embolic Lesions: Vegetations fragment and form emboli causing: (1) Infarcts: In the spleen, kidney and brain. (2) Retinal necrosis and blindness: Due to embolism in the retinal artery. (3) Coronary artery embolism: Rare. (4) Mycotic aneurysms: Occur commonly in the cerebral and mesenteric arteries, rarely elsewhere. They result from mild inflammation in the vascular wall induced by the emboli, followed by fibrosis. The weak fibrosed part dilates slightly forming a small aneurysm. (5) Focal glomerulonephritis: resulting from entrapment of immune complexes in the glomeruli as hypersensitivity to bacterial antigen.

Subacute bacterial endocarditis (vegetation on top of Ch. Rh Subacute bacterial endocarditis (vegetation on top of Ch.Rh.valvulitis)

Subacute bacterial endocarditis (vegetation on top of Ch. Rh Subacute bacterial endocarditis (vegetation on top of Ch.Rh.valvulitis)

NON-BACTERIAL, THROMBOTIC (MARANTIC) ENDOCARDITIS Nonbacterial thrombotic endocarditis is characterized by the deposition of small masses aseptic vegetations on the leaflets of the cardiac valves, commonly in cachectic patients. Grossly, multiple small nodules along the lines of valve closure, similar to the valvular lesions of acute rheumatic fever. The mitral valve is the most common site, followed by the aortic valve.

Libman-Sacks Endocarditis The term Libman-Sacks endocarditis refers to sterile small vegetations that may develop on the cardiac valves of patients with systemic lupus erythematosus. These lesions occur most frequently on the ventricular surfaces of the mitral and tricuspid valves but can also involve other endocardial surfaces.