Term
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Definition
| an acute immunologically mediated inflammatory disease that follows group A strep pharyngitis |
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Term
| how does rheumatic fever occur? who is usually affected by it? |
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Definition
| *antibodies against the M proteins of certain streptococci cross react with tissue glycoproteins in the heart, joints, other tissues (strep infection induces an autoimmune response against self antigens). typically RF affects younger people. |
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Term
| why is rheumatic fever less prevalent in the US? |
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Definition
| if strep infections are recognized soon enough, they can be treated with antibx, and the complications of RF can be avoided |
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Term
| what are tests that can indicate the presence of strep throat? |
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Definition
| *streptolysin O, DNase B, and hyaluronidase. elevated sedimentation rates are also a clue. |
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Term
| does everyone with a strep infection get RF? |
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Definition
| no, only a minority of infected pts develop RF - indicating a genetic susceptibility influencing the hypersensitivity response |
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Term
| what are the long term changes associated with strep/rheumatic fever? |
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Definition
| chronic sequelae usually occur after inadequate tx of acute RF and can result in progressive fibrotic changes to the valves and the chordae tendineae |
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Term
| what is one of the most common chronic sequelae associated with RF? |
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Definition
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Term
| what are some of the other changes in the heart from mitral stenosis (which can occur as a result of RF)? |
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Definition
| left atrial enlargement or dilation, the potential for thrombus formation (mural thrombi can form and then fragment due to abnormal changes in blood flow - causing strokes), pulmonary edema, and R-sided heart failre (cor pulmonade/RVH) |
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Term
| where is RH more commonly seen? |
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Definition
| in areas of the world lacking access to aggressive antibx therapy |
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Term
| what are other parts of the body besides heart valves associated with strep/RF? |
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Definition
| strep throat is severe, (usually w/white exudates and a higher fever), other portions of the heart can also be affected; the endocardium w/the valves, the myocardium with aschoff bodies and anitschkow cells, and fibrinous pericarditis on the outside (proteinaceous material) |
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Term
| why is RF considered a pancarditis? |
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Definition
| RF typically affects all 3 layers of the heart |
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Term
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Definition
| areas of fibrinoid necrosis (as opposed to coagulative) that are present w/in the myocardium, surrounded by a chronic mononuclear cell inflammation |
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Term
| what are anitschkow cells? |
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Definition
| large histiocytes/macrophages w/vesicular (bubbly) nuclei and basophilic cytoplam that are found in ashcoff bodies. the nucleus tends to have an owl's eye appearance and when cross sectioned, the nuclei tend to look like caterpillars |
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Term
| what happens as RF progresses to the pericardium? can this be heard? |
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Definition
| fibrinous pericarditis may cause a friction rub, however it may typically resolve w/out significant scarring. this rub is often audible |
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Term
| what are the most commonly involved valves in RF? |
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Definition
| the *aortic and mitral* valves, where the endocardium accumulate relatively small vegetations along the lines of closure (can lead to a murmur) |
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Term
| what are the clinical features of RF? |
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Definition
| migratory polyarthritis of the large joints (not usually the hands), carditis, subcutaneous nodules in the skin, erythema marginatum of the skin (appears as a ring-like rash, similar to lyme disease), and sydenham chorea (which is a series of rhythmic purposeless movements) |
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Term
| when does acute rheumatic fever occur? can it reactivate? who does this affect most often? |
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Definition
| 10 days - 6 weeks after an episode of pharyngitis, there is an increased vulnerability to reactivation of the disease with subsequent pharyngeal infections. usually children between 5-15 yrs are affected |
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Term
| what characterizes acute changes associated with RF? are they destructive? can they occur simultaneously with chronic changes? |
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Definition
| wart-like excrescences on the closure of the mitral valve that are usually not destructive. acute changes can also occur along with chronic changes ushc as fusion of the chordae tendinae (esp people with a genetic vulnerability for RF) |
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Term
| how does an aschoff body appear histologically? |
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Definition
| a large area of fibrinoid necrosis in the myocardium containing anitschkow bodies (appear as owl's eyes/caterpillars in cross section) |
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Term
| what characterizes chronic RF? is the damage reversible? |
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Definition
| generally the clinical manifestations do not show up for years after the initial episode of RF. it typically involves the mitral and aortic valves and can cause stenosis as well as regurgitation. usually damage due to chronic RF is irreversible |
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Term
| what is the most **common cause of mitral stenosis? |
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Definition
| RF related mitral valvulitis |
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Term
| how might pts with RF present cardiologically in general? is either sex more often affected? |
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Definition
| pts may present with pulmonary changes, CHF, and/or R-sided heart failure. women do tend to be more affected than men |
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Term
| what is the fish mouth deformity? |
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Definition
| the fish mouth deformity of the mitral valve or "button hole" is one possible complication of chronic RF in the heart, where scarring changes the appearance of the valve |
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Term
| how can RF affect the L atrium? |
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Definition
| the L atrium can become dilated and hypertrophies if the mitral valve is stenotic - leading to congestion in the lungs - which then makes the R ventricle work even harder, possibly creating RVH and failure (cor pulmonale) |
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Term
| how can dilation of the L atrium lead to thrombi? |
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Definition
| as the atrium dilates, the blood will not flow as well against the stenotic mitral valve, causing the flow to be turbulent - leading to thrombi, such as mural thrombi that may embolize into systemic circulation (causing stroke-like changes, transient ischemic attact, or *arrhythmias - if conduction areas are involved) |
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Term
| what is long term prognosis for chronic RF? |
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Definition
| highly variable, damage can be significant - resulting in valvular replacement and long term sequelae from a hypertrophied heart |
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Term
| what are mccallums plaques? |
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Definition
| fibrotic changes of the heart wall due to diseased valves hitting it consistently |
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Term
| how can RF affect blood supply to the heart? |
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Definition
| neovascularization can occur in the valves, which are not typically well vascularized |
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Term
| what determines the necessity of valve replacement due to RF? |
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Definition
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Term
| what is chronic aortic valvulitis? does it affect one sex more often? can it co-present with other conditions? |
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Definition
| aortic stenosis (thick/firm/self adherent) or regurgitation (fibrosis/retratction) can often coexist w/mitral valvulits and LVH and is more common in males. |
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Term
| can aortic stenosis become calcific? is this usually symptomatic? |
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Definition
| yes, fibrosis of the valve leaflets can lead to calcification and can be associated with LVH. this is usually asymptomatic |
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