CPC 4 Flashcards
Define stenosis and insufficiency. Which is more likely to present accutely?
failure of the valve to open completely, impedes forward flow
insufficiency results from failure of a valve to close completely, allowing reversed flow
valvular insufficiency can be caused by many processes, some of which are acute, whereas stenosis is almost always due to chronic abnormality of the valve cusp
Contrast the age of presentation for senile calcific aortic stenosis v. stenotic bicuspid valve
senile calcific aortic stenosis 70s-90s
bicuspid aortic valves (greater than normal mechanical stress) 50s-70s
Describe how calcific lesions are deposited on the valve.
may be connected to chronic injury due to hyperlipidemia, hypertension, inflammation and other factors
definitely differs from atherosclerosis in the abnormal valve contain cells resembling osteoblasts that synthesize bone matrix proteins and promote the deposition of calcium salts
Describe the classic morphology of calcific aortic stenosis.
heaped-up calcified masses within the aortic cusps that ultimately protrude through the outflow surfaces into the sinuses of Valsalva, preventing the opening of the cusps, free edges are not normally involved
calcific process begins at valvular fibrosa (pts of max. cusp flexion, near their attachment); commissural fusion is not usually seen
narrowing from 4 cm2 to .5-1 cm2
Describe the microscopic features of a senile calcific stenotic valve.
layered architecture of valve is preserved, functional area is decreased, causing outflow obstruction
What are late complications of bicuspid aortic valve?
aortic stenosis or regurgitation
infective endocarditis
aortic dilation and or dissection (structural abnormalities of the aortic wall commonly accompany bicuspid aortic valve, even when the valve is hemodynamically normal)
Describe the morphology of a bicuspid aortic valve.
usually the two functional cusps are of unequal size, with the larger cusp having a midline raphe (common site of calcific deposits), resulting in incomplete commissiural separtaion during development, less frequently cusps are equal size with absent raphe
What process may lead a bicuspid aortic valve to become incompetent.
as a result of aortic dilation, cusp prolapse of infective endocarditis
How could you distinguish bicuspid valve from fusion occurring during rheumatic disease?
in acquired deformity, the fused commissure produces a conjoined cusp that is generally twice the size of nonconjoined cusp, the mitral valve is generally normal in congenital bicuspid aortic valve
Contrast rheumatic fever and rheumatic heart disease.
fever: an acute, immune response to group A streptococci M proteins that cross-react with host tissues that occurs a few weeks after an episode of group A strep pharyngitis, CD4 T cells specific for streptococcal peptides also react with self proteins int eh heart and produce cytokines that activate macrophages; acute rheumatic carditis is a frequent manifestation during the active phase of fever and may progress over time to chronic rheumatic heart disease
HD: characterized principally by deforming fibrotic valvular disease particularly mitral stenosis
Name and describe the focal inflammatory lesions that are found in the heart during RHD.
aschoff bodies are distinctive lesions of teh heart which consist of foci of lymphocytes (primarily T cells) occasional plasma cells and plump activated macrophages called anitschkow cells (pathognomonic)
What is a “caterpillar cell”?
anitschkow cells have a central round to ovoid nuclei in which the chromatin is disposed in a central, slender, wavy ribbon; these bess are nicknamed caterpillar cells
aschoff bodies may be found in any of the three layers of the heart, causing pericarditis, myocarditis or endocarditis
Where would you find vegetations in a patient with rheumatic heart disease
verrucae are found along the lines of closure, inflammation of the endocardium and left sided valves typically results in fibrinoid necrosis within the cusps or along the tendinous cords, with the verrucae overlying these areas
What are MacCallum plaques?
irregular thickenings indued by subendocaridal lesions, perhaps exacerbated by regurgitant jets, usually in the left atrium
What are the cardinal changes in the mitral valve in chronic rheumatic heart disease?
valve leaflet thickening with commissural fusion
shortening (fish mouth or buttonhole stenoses)
thickening and fusion from tendinous cords
What is the squaquelae that follows mitral stenosis by rheumatic heart disease?
left atrium progressively dilates and may harbor mural thrombi, in the appendage or along the wall (can embolize)
long standing congestion causing pulmonary vascular and parenchymal changes and in time lead to right ventricular hypertrophy
Describe the microscopic view of mitral leaflets in rheumatic heart disease.
acute inflammation eventually leads to diffuse fibrosis and neo-vascularization that obliterate the originally layers and avascular leaflet architecture, Aschoff are rarely seen long after the initial infection
What type of immune reaction is Rheumatic Fever?
combination of antibody and T cell mediated reactions
What are the clinical manifestations of acute rheumatic fever?
acute carditis: pericardial rub, weak heart sounds, tachy, and arrhthymias
migratory polyarthritis in which one large joint after another becomes painfully swollen for a period of days then subsides spontaneously
Briefly characterize infective endocarditis.
colonization or invasion of the heart valves or the mural endocardium by a microbe, leads to the formation of vegetations composed of thrombotic debris and organisms, often associated with the destruction of the underlying cardiac tissues
aorta, aneurysmal sacs, other blood vessels and prosthetic devices can also become infected
Contrast acute infective endocarditis and sub-acute infective endocarditis.
acute: usually infection of previously normal heart valve by a highly virulent organism that produces necrotizing, ulcerative destructive lesions (requires surgery, often deadly)
sub-acute infective endocarditis: orgs of lower virulence causing insidious infections of deformed valves that are less destructive , often cured with antibiotics
What are common antecedent disorders that can predispose to endocarditis?
rheumatic heart disease, mitral valve prolapse, degenerative calcific valvular stenosis, bicuspid aortic valve, prosthetic valves and unprepared and repaired congenital defects
Differentiate the causative organisms of endocarditis based on the patients risk factors
abnormal valves: viridans streptococci
IV drug users: S. aureus
prosthetic valve: coagulase-negative staphylococci
other common bacteria: enterococci Haemophilus Actinobacillus Cardiobacterium Eikenella Kingella (commensals in the oral cavity)
Describe the morphological hallmarks of infective endocarditis.
friable, bulky, potentially destructive vegetations containing fibrin, inflammatory cells and bacteria or other organisms on the heart valves (aortic and mitral valves are the most common sites of infection)
vegetations can erode the underlying myocardium and produce abscess, emboli can be shed from the vegetations (which can develop septic infarcts of mycotic aneurysms)
What is the long term course of vegetations of sub-acute infective endocarditis?
often have granulation tissue indicative at healing at their bases, with time fibrosis, calcification and a chronic inflammatory infiltrate can develop
What are the clinical features of infective endocarditis?
acute: rapidly developing fever, chills, weakness and lassitude, fever in the elderly may be slight or absent
complications begin within the first few weeks of onset including murmurs or immune complex deposition causing glomerulonephritis
Duke criteria look at things like micro-thromboemboli; erythematous or hemorrhagic non-tender lesions on the palms or soles, subcutaneous nodules in the pulp of digits and retinal hemorrhages
What does atherosclerosis have to do with pulmonary hypertension?
it is unusual to find atherosclerosis in the pulmonary veins, or any veins unless they are under high pressure
What are the typical associations with the following murmurs: crescendo-decrescendo murmur holosystolic murmur diastolic rumble wheezes and crackles
crescendo-decrescendo: aortic stenosis
holosystolic murmur: mitral regurgitation
diastolic murmur: aortic stenosis
wheezes and crackles: edematous airways causing airway obstruction
What lesion is associated with fish mouth/button hole valve?
bicuspid aortic stenosis
Patients with bicuspid aortic valve are at increased risk for dilation of aortic root and aneurysms of the ascending aorta, what is the pathological change often seen in the aortic wall of these patients.
cystic medial degeneration (disorganization of the elastin fibers) which is classically seen in Marfans, HTN and bicuspid valve
