Robbins Essential Pathology PDF: Heart Chapter

128 CHAPTER 8 Heart A B C D...

128 CHAPTER 8 Heart A B C D Fig. 8.13 Myxomatous degeneration of the mitral valve. There is promi- Fig. 8.12 Calcific valvular degeneration. (A) Calcific aortic stenosis of a nent hooding with prolapse of the posterior mitral leaflet (arrow) into the previously normal valve (viewed from above the valve). Nodular masses left atrium; the atrium also is dilated, reflecting long-standing valvular of calcium are heaped up within the sinuses of Valsalva (arrow). Note insufficiency and volume overload. The left ventricle is shown on the that the commissures are not fused, as in rheumatic aortic valve stenosis right in this four-chamber view. (Courtesy of William D. Edwards, MD, (see Fig. 11.19C). (B) Calcific aortic stenosis occurring on a congenitally Mayo Clinic, Rochester, Minnesota.) bicuspid valve. One cusp has a partial fusion at its center, called a raphe (arrow). (C and D) Mitral calcification, with calcific nodules within the annulus (attachment margin) of the mitral leaflets (arrows). (C) Left atrial view. (D) Cut section demonstrating the extension of the calcification into Clncal Features. Mos paens are asympomac; e vavuar abnor- the underlying myocardium. Such involvement of adjacent structures may s dscovered ncdenay on pysca examnaon. A mnory o near the interventricular septum can impinge on the conduction system. paens as papaons, dyspnea, or aypca ces pan. Auscuaon dscoses a mdsysoc cck, somemes w a regurgan murmur. Clncal Features. In severe dsease (aorc vave orce reduced o 20% e cnca course s usuay bengn, oug ere s an ncreased rsk o 30% o norma), cronc oulow obsrucon may rase et venrcuar o necve endocards (see aer) and approxmaey 3% o paens pressures o 200 mm Hg or more, causng et venrcuar yperropy. he deveop emodynamcay sgncan mra regurgaon and conges- yperroped myocardum s prone o scema and sysoc and dasoc ve ear aure, usuay oowng rupure o e cordae or vave ea- dysuncon, eadng o congesve ear aure. Once angna, congesve es. Treamen requres repar or repacemen o e mra vave. ear aure, or syncope appears, e prognoss s poor, w dea usu- Rheumatic Valvular Disease ay occurrng wn 5 years. he reamen s surgca repacemen o e dseased vave. Rheumatic heart disease is the cardiac manifestation of rheumatic fever, an acute immunologically mediated multisystem inamma Myxomatous Mitral Valve Disease tory disease that occurs after group A β-hemolytic streptococcal In myxomatous degeneration of the mitral valve, one or both infections. mitral leaets are “oppy” and prolapse, ballooning back into the e rggerng necon ypcay nvoves e par ynx. Mra se- left atrium during systole. noss, wc s vruay aways caused by reumac ear dsease, s Prmar y mtra vave proapse s a orm o myxomaous degener- due o vavuar nlammaon and scarrng. e ncdence o reumac aon afecng 0.5% o 2.4% o adus. I s one o e mos common ear dsease as decned n many pars o e Wesern word over e orms o vavuar ear dsease; women are afeced amos seven mes pas severa decades, due o mproved socoeconomc condons, rapd more oten an men. dagnoss and reamen o srepococca par yngs, and a decne n e vruence o many srans o group A srepococc. However, n Pathogeness. he eoogy s usuay unknown (dopac). Rarey,  s ow ncome counres and economcay depressed areas n e Uned a manesaon o a connecve ssue dsorder, parcuary Maran syn- Saes, reumac ear dsease s an mporan pubc ea probem, drome. As dscussed n Caper 6, Maran syndrome s mos commony and  remans e mos common cause o acqured vavuar dsease n caused by muaon n e gene encodng brn. e word. Morphology. ere s baoonng (oodng) o e afeced mra Pathogeness. Anbodes agans e M proens o ceran srepo- eales (Fg. 8.13), wc are enarged, redundan, ck, and rub- cocca srans cross-reac w proens ound n e myocardum and ber y. he endnous cords are eongaed and nned, and may cardac vaves. ese anbodes are oug o cause njur y by ac- rupure. On soogc examnaon, e vave sows deposon o vang compemen and Fc recepor–bearng ces (e.g., macropages). myxomaous (mucod) maera. CD4+ T ces a recognze srepococca pepdes and os angens  CHAPTER 8 Heart 129 aso appear and may ec cyokne-medaed nlammaor y responses. reumac ear dsease w vave dysuncon nvovng e mra Ony abou 3% o paens neced w srepococc deveop reumac vave n 95% o cases; 25% o ese cases aso afec e aorc vave. ever, suggesng a os genec varans may nluence suscepby. Fbross o e mra vave eales (Fg. 8.14C o E) eads o uson o e commssures and severe mra senoss. Fbross and uson Morphology. In acue reumac ever, ere are nlammaor y oc o e cordae endneae may aso occur, urer exacerbang vave afecng a varey o ssues, ncudng a ree ayers o e ear. dysuncon. W g mra senoss, e et arum progressvey Acue cardac nvovemen may ead o one or more o e oowng: becomes daed owng o pressure overoad.    Percardts assocaed w a brnous exudae    Myocardts n e orm o scaered Ascof bodes wn e Clncal Features. Acue reumac ever s mos common n c- nersa connecve ssue; paognomonc Ascof bodes dren, bu rs aacks aso occur n adus. Two o ree weeks ater (Fg. 8.14A) conss o coecons o ympocyes (prmary T e na necon, ere s one o wo conseaons o sympoms: ces), scaered pasma ces, and pump, acvaed macropages (1) mos commony, a mgraor y arrs n one or more jons oten (Ansckow ces) w assocaed brnod necross accompaned by cards; or (2) n abou 20% o paens, neuroogc    Vavus, resung n brnod necross and brn deposon sympoms, mos noaby Sydenam corea (S. Vus dance), car- aong e nes o cosure, oten assocaed w sma rom- acerzed by nvounar y movemens, musce weakness, and emo- boc vegeaons (Fg. 8.14B). ona dsurbances. Fever may aso be seen n some cases. here s Percards and myocards may ead o oca scarrng bu no varabe nvovemen o e skn (ras and subcuaneous nodues). perssen abnormaes. In conras, vavus oten eads o cronc hroa cuures are negave wen sympoms begn, bu serum ers A B C D E Fig. 8.14 Rheumatic heart disease. (A) Microscopic appearance of an Aschoff body in acute rheumatic carditis; there is central necrosis associated with a circumscribed collection of mononuclear inflammatory cells, including some activated macrophages with prominent nucleoli and central wavy (caterpillar) chromatin (arrows). (B) Acute rheumatic mitral valvulitis superimposed on chronic rheumatic heart disease. Small veg- etations (verrucae) are visible along the line of closure of the mitral valve leaflet (arrows). Previous episodes of rheumatic valvulitis have caused fibrous thickening and fusion of the chordae tendineae. (C and D) Mitral stenosis with diffuse fibrous thickening and distortion of the valve leaflets, commissural fusion (arrows), and thickening and shortening of the chordae tendineae. There is marked left atrial dilation as seen from above the valve (C). (D) Anterior leaflet of an opened rheumatic mitral valve; note the inflammatory neovascularization (arrow). (E) Surgically removed specimen of rheumatic aortic stenosis, demonstrating thickening and distor- tion of the cusps with commissural fusion. (E, From Schoen FJ, St John-Sutton M: Contemporary issues in the pathology of valvular heart disease, Hum Pathol 18:568, 1967.) 130 CHAPTER 8 Heart o anbodes agans srepococca angens (e.g., srepoysn O or Sma romb a orm a ses o pacemaker nes, ndweng vascuar DNase) usuay are eevaed. Cnca sgns o cards ncude percar- caeers, or damaged endocardum provde a ere so or bacera da rcon rubs, cardac daon, mra nsuicenc y, and congesve seedng and ensung endocards. Increased suscepby o bacera ear aure, bu ess an 1% o paens de o acue reumac ever. necons (e.g., secondar y o neuropena and nravenous drug abuse) he dagnoss s made based on evdence o pror srepococca nec- aso ncreases e rsk and adversey afecs oucomes. on n conjuncon w e ypca cnca eaures descrbed earer. he causave organsms var y dependng on e underyng rsk ac- Ater acue dsease subsdes, reacvaon may occur w subsequen ors. From 50% o 60% o cases o endocards o damaged or deormed srepococca necons, causng addona njury o e ear (cards) vaves are caused by Streptococcus vrdans, a componen o e norma and mra vave (mra senoss). W mra senoss, ara daon oten ora lora. By conras, e more vruen Stapyococcus aureus (com- eads o ara braon, ncreasng e rsk o mura romb n e et mon o e skn) can aack eay as we as deormed vaves and s arum and romboembosm. Cronc pumonary venous congeson responsbe or 10% o 20% o cases overa;  aso s e major ofender produces e pumonary vascuar and parencyma canges o et-sded n necons occurrng n nravenous drug users. Many oer bacera ear aure; w me, rg venrcuar yperropy and rg-sded speces, oten commensa n e ora cavy, and even ung on occason ear aure may ensue. In addon, scarred and deormed vaves are more prove o be e cupr. In abou 10% o cases, no organsm s soaed suscepbe o necve endocards. Mra vavuopasy or surgca repar rom e bood, probaby because organsms embedded wn vegea- or repacemen o dseased vaves can oresa many o ese compcaons ons are reeased no e bood n ver y sma numbers. and as greay mproved e ouook or ese paens. Seedng o e bood w mcrobes s e proxmae cause. hs may occur due o an obvous or occu necon, a dena or surgca procedure, njecon o conamnaed maera no e boodsream Infective Endocarditis by nravenous drug users, or rva njures. Anboc propyaxs Infective endocarditis is a microbial infection of the heart valves or s crca n paens w predsposng acors (e.g., prosec ear the endocardium marked by the presence of vegetations composed vaves) undergong dena or surgca procedures. of thrombus and organisms that lead to varying degrees of damage to underlying cardiac tissues. Morphology. In acue endocards, buky and poenay desruc- he aora, aneur ysma sacs, oer bood vesses, and prosec ve vegeaons conanng brn, neurops, and mcroorgansms devces may aso become neced. Mos cases are caused by bace- are presen on e ear vaves (Fg. 8.15). e aorc and mra ra necons. Inecve endocards s cassed as acue or subacue vaves are e mos common ses o necon excep n nrave- based on e empo and severy o e cnca course. nous drug users, n wc e rcuspd vave s requeny nvoved.    Acute endocardts reers o desrucve necons by gy vruen Vegeaons somemes erode no e underyng myocardum o organsms a may nvove prevousy norma vaves. Morbdy produce an abscess (rng abscess) (see Fg. 8.15B). Sepc embo and moray are sgncan, even w approprae anboc er- are sed rom e rabe vegeaons, eadng o sepc narcs and apy and/or surger y. abscess ormaon were ey odge. Seedng o e vesse was may    Subacute endocardts reers o necons by organsms o ow vr- ead o e deveopmen o mycotc aneurysms (see Caper 7). Sub- uence n a prevousy abnorma ear, usuay nvovng scarred or acue endocards ecs ess vavuar desrucon and s assocaed deormed vaves. e onse s nsdous and even wen unreaed w ormaon o vegeaons, cronc nlammaor y nraes, and e course s proraced over weeks o mons. Mos paens vavuar bross and caccaon. recover ater approprae anboc erapy. Pathogeness. Acqured srucura abnormaes o ear vaves (suc C ln cal Feature s. Fe ver s  e mos cons se n s g n o  ne c  ve as reumac mra senoss, mra vave proapse, and aorc senoss) endo c ard s, bu  may be abs e n n sub a c ue d s e as e ( p ar  c u  ary as we as prosec ear vaves predspose o necve endocards. n oder adu s), n w  c on y v ague sy mpoms suc as  a  gue, A B Fig. 8.15 Infective endocarditis. (A) Subacute endocarditis caused by Streptococcus viridans on a previously myxomatous mitral valve. The large, friable vegetations are denoted by arrows. (B) Acute endocarditis caused by Staphylococcus aureus on a congenitally bicuspid aortic valve with extensive cuspal destruction and ring abscess (arrow).  CHAPTER 8 Heart 131 weg  oss, and a  u  ke sy ndrome are ound. By con ras , ac ue endo c ard s o en as a sor my ons e w   r ap d y d e veop ng e ver, c  s, and we a k ness. Mur murs are pres en n 90 % o p a  e n s w   e -sde d esons. M cro e mb o  c an g ve r s e o p ee c  ae, na  bed and re na  emor rages, p an ess er y emaous pam or s oe LA LA Ao Ao esons, or p an u    nger  p no du  es. T e d ag nos s s con   r me d by p os ve bo o d c u ures and  e  d e n    c a  on o vege  a  ons by e co c ardog rapy. he prognoss depends on e necng organsm and e exen LV o compcaons. Adverse sequeae ncude gomeruoneprs due LV o rappng o angen–anbody compexes n gomeru (see Cap- er 11), sepcema, arryma (rom nvason no e underyng myocardum and conducon sysem), and sysemc embozaon. Let unreaed, necve endocards generay s aa. Approprae ong-erm (6 weeks or more) anboc erapy and/or vave repace- Nor mal Dilated cardiomyopathy men reduce moray raes. For necons nvovng ow-vruence organsms (e.g., S. v rdans), e cure rae s 98%, and or S. aureus necons, cure raes range  rom 60% o 90%; owever, w nec- ons due o aerobc gram-negave bac or ung, a o paens umaey succumb. LA LA Ao Ao Nonbacterial Thrombotic Endocarditis Nonbaceria romboic endocardiis (NBTE) is caracerized by e deposiion of sma (1 o 5 mm), serie, nondesrucive romboic LV LV masses on cardiac vaves (Suppemena eFg. 8.3). Prevous vavuar damage s no a prerequse. Indeed,  ypcay occurs on prevousy norma vaves. Dseases assocaed w genera deby or wasng are assocaed w an ncreased rsk or NBTE, as are ypercoaguabe saes (e.g., cronc dssemnaed nravascuar coagu- Hyper trophic Restrictive aon, yperesrogenc saes, and underyng magnances, parcuary cardiomyopathy cardiomyopathy mucnous adenocarcnomas) and endocarda rauma (e.g., ndweng Fig. 8.16 The three major forms of cardiomyopathy. Dilated cardiomy- caeer). he oca efec on e vave s usuay rva, bu embo rom opathy leads primarily to systolic dysfunction, whereas restrictive and NBTE esons can cause narcs n e bran, ear, and oer organs. hypertrophic cardiomyopathies result in diastolic dysfunction. Note the NBTE esons aso ncrease e rsk o necve endocards. changes in atrial and/or ventricular dilation and in ventricular wall thick- ness. Ao, aorta; LA, left atrium; LV, left ventricle. CARDIOMYOPATHIES AND MYOCARDITIS These diseases are characterized by cardiac myocyte dysfunction    Inerted gene defects. Daed cardomyopay s eredar y n 20% that may be coned to the myocardium (primary) or may be a o 50% o cases. Muaons n over 50 genes ave been mpcaed, cardiac manifestation of a systemic disorder (secondary). usuay w auosoma domnan nerance. Genes a encode Incuded among e dverse dseases a ead o myocye dysuncon cyoskeea proens or proens a nk e sarcomere o e cyo- are necous, mmunoogc, meaboc, and genec dsorders. hose a skeeon are mos commony nvoved, ypcay by muaons a are nlammaory n naure are generay consdered orms o myocards, resu n oss-o-uncon. wereas ose a are nonnlammaory a no e caegory o cardo-    Infecton. Coxsackevrus B and oer enerovruses are occason- myopaes, wc can be urer subdvded no ree more or ess ds- ay deeced n e myocardum o end-sage daed cardomyop- nc uncona and paoogc paerns (Fg. 8.16 and Tabe 8.3): ay, and nsances n wc necous myocards as progressed    Daed cardomyopay o daed cardomyopay ave been documened. By e me o    Hyperropc cardomyopay dagnoss, nlammaon s absen.    Resrcve cardomyopay    Acoo and oter toxns. Rarey, acoo abuse s assocaed w e O ese paerns, daed cardomyopay s mos common and deveopmen o daed cardomyopay, by unknown mecansms. resrcve cardomyopay eas common. Toxc agens, suc as doxorubcn and reaed cemoerapeuc drugs, can aso cause daed cardomyopay. Dilated Cardiomyopathy    Perpartum cardomyopaty. Daed cardomyopay occurs ae n Dilated cardiomyopathy is characterized by progressive cardiac gesaon or severa weeks o mons posparum. he eoog y s dilation and contractile (systolic) dysfunction. unceran and may be muacora. Approxmaey a o ese paens sponaneousy recover norma uncon. Pathogeness. A dagnoss, daed cardomyopay as usuay pro-    Iron overoad. Daed cardomyopay can be seen n e seng o gressed o end-sage dsease marked by ear aure secondar y o poor eredar y emocromaoss, cronc nefecve emaopoess, or myocarda conracy. he damage a cumnaes n end-sage mupe red ce ransusons due o njur y caused by ron depos- daed cardomyopay can be naed by nered abnormaes or on n e ear and ron-medaed producon o reacve oxygen by envronmena exposures, as oows: speces.  CHAPTER 8 Heart 131.e1 t C A Supplemental eFig. 8.3 Nonbacterial thrombotic endocarditis (NBTE). (A) Nearly complete row of throm- botic vegetations along the line of closure of the mitral valve leaflets (arrows). (B) Photomicrograph of NBTE, showing bland thrombus, with virtually no inflammation in the valve cusp (c) or the thrombotic deposit (t). The thrombus is only loosely attached to the cusp (arrow). 132 CHAPTER 8 Heart Table 8.3 Cardiomyopathies: Functional Patterns and Causes Secondary Myocardial Functional Left Ventricular Mechanisms of Heart Dysfunction (Mimicking a Pattern Ejection Fraction Failure Causes Cardiomyopathy) Dilated