Cardiovascular 3

Question 1

acute rheumatic fever

Answer 1

acquired stenosis (failure of a valve to open completely, obstructing forward flow) is due to chronic (recurrent) rheumatic valvular disease. acute rheumatic fever is a systemic disease, usually in children, which follows a group A beta-hemolytic streptococcal pharyngitis. acute rheumatic fever (RF) produces myocarditis, pericarditis, arthralgia, or arthritis, erythema marginatum, subcutaneous nodules and other manifestations. the myocarditis is characterized microscopically by Aschoff bodies which are collections of mononuclear inflammatory cells and fibroblasts (essentially granulomatous inflammation)
recurrent bouts of RF eventually lead to severe fibrosis and calcification of the mitral valve and possibly other heart valves. the disease is thought to be due to production of antibodies against the streptococcal bacteria which cross react with various antigens in the heart, joints and other sites

Question 2

mitral valve stenosis

Answer 2

result of acute rheumatic fever (ARF)
group A b-hemolytic streptococcal pharyngitis
mostly affects children, 20% adults

Question 3

rheumatic carditis

Answer 3

pericarditis- fibrinous- around edge of heart itself
endocarditis- sterile vegetations- affecting valves- predominantly mitral
mycarditis- aschoff bodies (mononuclear cells and fibroblasts, form of granulomatous inflmmation)
stenosis- fibrosed the valve so much, unable to completely close- lead to regurgitation and insufficiency- lead to heart failure

Question 4

mitral valve regurgitation

Answer 4

regurgitation (insufficiency) refers to a valve that fails to close completely allowing backflow of blood. caused by variety of conditions including IHD and endocarditis.

Question 5

mitral valve prolapse

Answer 5

condition in which the leaflets balloon into the left atrium during left ventricular contraction (systole)
mild prolapse is very common and occurs in 5-10% of the general population and usually does not progress to valvular regurgitation.
severe prolapse may be associated with valvular regurgitation
some patients also experience chest pain and palpitations
some patients (3%) also experience chest pain and palpitations.
endocarditis, mitral regurgitation, thromboembol, atrial fibrillation and sudden death (rare) are potential complications.
in severe prolapse (also called floppy mitral valve) the valve cusps are large and microscopically show fragmentation, separation and loss of collagen (myxomatous degeneration)
floppy mitral valve may be an isolated abnormality or part of a systemic connective tissue disorder such as marfan syndrome

Question 6

aortic valve stenosis

Answer 6

fibrosis and calcification reduce the valve cusp mobility. this can be due to chronic rheumatic valvular disease (in these cases the mitral valve is almost stenotic) or may occur with advanced age (over 65 yrs)
bicuspid aortic valve is a common congenital malformation and these valves are predisposed to calcification and fibrosis beginning at about 40 years of age

Question 7

aortic valve regurgitation

Answer 7

the mechanisms include valve cusp destruction(endocarditis, rheumatic heart disease), weakened valve cusp (myxomatous degeneration-marfan) and dilation of aortic root (degeneration of the media of the aorta)

Question 8

infective endocarditis

Answer 8

usually caused by bacterial infection in a heart valve, although may also be caused by fungus or other unusual infections. predisposing factors include abnormal heart valves, prosthetic valves (10-20% of all IE cases), intravenous drug use, intracardiac shunts, diabetes, and immunosuppression.

Question 9

three factors important in pathogenesis of infective endocarditis

Answer 9

endocardial or endothelial injury due to abnormalities in blood flow
fibrin thrombi
organisms in the blood

Question 10

clinical manisfestations of infective endocarditis

Answer 10

fever, heart murmur, fatigue, anemia, arthralgia, myalgia, splinter hemorrhages (nail bed) and roth spots (retinal hemorrhages, not absolutely specific to IE)

Question 11

complications of infective endocarditis

Answer 11

rupture of chordae tendinae
spread of infection into myocardium or aorta
thromboembolism with infarction
septic thrombi with metastatic abscesses
valvular dysfunction and CHF

Question 12

acute endocarditis

Answer 12

short duration
virulent organism (staph aureus)
large friable vegetations
previously normal valve
prominent tissue destruction

Question 13

subacute endocarditis

Answer 13

longer duration
organism of low virulence (strep viridans)
small vegetations
previously abnormal valve
less tissue destruction

Question 14

vasculitis

Answer 14

caused by infection (usually due to direct spread of an adjacent infection, some microorganisms infect endothelial cells and cause vasculitis
other causes- mechanical trauma, toxins, caustic substances, radiation and immune complexes

Question 15

classification of vasculitis

Answer 15

large vessel- giant cell (temporal) arteritis, takayasu arteritis
medium vessel- polyarteritis nodosa (classic), kawasaki syndrome
small vessel- microscopic polyarteritis, wegener’s granulomatosis

Question 16

pathogensis of immune mediated vasculitis

Answer 16

1. immune complex formation- reaction to drugs or viruses
2. antineutrophilic cytoplasmic antibodies (ANCA)
   anti-myeloperoxidase (anti MPO)- perinuclear localization (formerly known as pANCA)- microscopic polyarteritis
   antiproteinase-3 (antiPR3)- diffuse cytoplasmic distribution (formerly known as cANCA)-wegener’s granulomatosis
3. antiendothelial cell antibodies- kawasaki disease
   4.cell mediated immunity

Question 17

giant cell (temporal arteritis)

Answer 17

etiology- unknown- t cell mediated?
clinical- fever, weight loss, headache, visual problems (including blindness), claudication of jaw (weakness when chewing due to decreased blood supply), pain and tenderness over temporal artery, polymyalgia rheumatiic
rare under the age of 50 years
pathology- granulomatous inflmmation with giant cells, fibrosis. eventually causes narrowing of vessel lumen, with decreased blood flow to affected tissues

Question 18

takayasu arteritis

Answer 18

etiology- unknown
clinical- thickening of the wall reduces blood flow in the major branches off the aortic arch (“pulseless disease” due to weak pulses in the arms)
usually affects young women- may be the same disease as temporal arteritis but in a younger pt
pathology- granulomatous inflammation with fibrosis involving the aortic arch and the arch branches

Question 19

polyarteritis nodosa

Answer 19

etiology- unknown in most cases- once up to 30% had hep B surface antigen in the serum, now <8% due to widespread immunizations
clinical- fever, weight loss, hematuria, renal failure, hypertension, absominal pain, melena. clinical presentation may be confusing due to involvement of multiple organs systems
pathology- haphazard and segmental involvement of medium and small muscular arteries. acute lesions show fibrinoid necrosis, thrombosis, neutrophils, aneurysms. with healing there is predominance of macrophages and plasma cells, progressive fibrous scarring
usual site of involvement are kidneys (85%), heart (75%), liver (65%) gi tract 50%

Question 20

kawasaki disease

Answer 20

etiology- suspected that a viral infection triggers a hypersensitivity reaction aka mucocutaneous lymph node syndrome
clinical- affects infants and young children (80% of patients <4yrs). fever, skin rash, mucous membrane lesions, skin rash cervical lymphadenopathy
usually self-limited but in 1-2% die with coronary artery vasculitis

Question 21

microscopic polyangiitis

Answer 21

etiology- often due to antigen-antibody complexes
clinical- fever, rash, joint swelling, pleural effusion, pulmonary infiltrates, myocarditis, GI bleeding, renal failure, presence of circulating antineutrophilic cytoplasmic antibodies (MPO ANCA). may be precipitated by drugs, microorganisms foreign proteins or tumor proteins
pathology- involves arterioles, capillaries, venules. fibrinoid necrosis, neutrophils (leukocytoclastic vasculitis)

Question 22

wegener granulomatosis

Answer 22

etiology- abnormal expression of proteinase 3 on endothelial cell surface, followed by ANCA binding and neutrophil activation, resulting in damage to endothelium and vessel
clinical- involves sinuses, lungs and kidneys (glomerulonephritis). associated with the presence of anti-neutrophilic cytoplasmic antibodies direct against proteinase 3(PR3-ANCA)
pathology- necrotizing granulomas with vasculitis

Question 23

thromboangiitis obliterans (buerger disease)

Answer 23

etiology- endothelial injury from a substance in cigarette smoke
clinical- usually begins before age 35. pain and ischemia in extremities
pathology- segmental acute and chronic vasculitis mainly in extremities with thrombosis

Question 24

dissecting aortic hematoma (aneurysm)

Answer 24

longitudinal tear of the aortic media which begins in the ascending aorta and extends variable distance proximal (toward the heart) and distal to the descending aorta
complications- severe hemorrhage from rupture, organ ischemia due to luminal compression by expanding hematoma
predisposing factors- hypertension, inherited connective tissue disorder ie marfan’s with medial degenration