RAD 204 PATHOLOGY COLLEGE OF MEDICAL SCIENCES/RADIOLOGICAL SCIENCES DEP’T LECTURE 5: CARDIOVASCULAR PATHOLOGY WEEK OF OCTOBER 6, 2013 DR SHAI’ part 1 of.

RAD 204 PATHOLOGYCOLLEGE OF MEDICAL SCIENCES/RADIOLOGICAL

SCIENCES DEP’T

LECTURE 5: CARDIOVASCULAR PATHOLOGYWEEK OF OCTOBER 6, 2013

DR SHAI’

part 1 of 2

STRUCTURE & OBJECTIVES

Companion lecture to this lecture: link available on http://health141.yolasite.com/

you are required to have a print or e-version of the companion lecture during this lecture

congenital abnormalities of the heart

atherosclerosis, ischaemic heart disease, hypertension

valve disorders & aneurysms

diseases of the myocardium, pericardium

inflammatory and neoplastic disease

radiological diagnostics in cardiovascular pathology: FORMAL PROJECT 1 Due: November 5, 2013

mid term exam: 2nd week after Hajj holiday, in class, during class time. {mcq, short answer}

the projecthttp://emedicine.medscape.com/radiology

> CARDIAC

choose from list of cardiac imaging list and use (but do not copy/paste) this site, as ONE OF MANY credible references > submit a formal report with references on the pathology of the condition and a COMPREHENSIVE explanation of

imaging techniques used in the condition

radiological diagnostic and therapeutic interventions

OR

http://my.americanheart.org/professional/Education/Professional-Education_UCM_426265_WidgetListPage.jsp (MAIN PAGE) CLICK imaging techniques & application >> register and take this course

http://learn.heart.org/ihtml/application/student/interface.heart2/index2.html?searchstring=5670

register and complete course> take screen shot of your progress & results > submit

DUE NOVEMBER 5, 2013

mid term exam

WHEN: 2nd week after Hajj holiday

WHERE: in class, during class time

TOPICS: terminology, basic pathology, cell damage, repair, & response to injury, inflammation and healing, CVS pathology

STYLE: Multiple Choice Questions, Short Answer Questions, Read an Article & answer questions on the article

TIPS: see the http://health141.yolasite.com/ for lectures and articles

congenital heart abnormalities

define congenital

prevalence: 8/1000 live births

aetiology:

idiopathic/sporadic: most cases

maternal: rubella, alcohol abuse, intrauterine radiation, drugs eg thalidomide

genetic/ chromosomal: eg. Trisomy 21 {Down’s Syndrome}

clinical presentation: apparent at or shortly after birth ~heart

failure sequelae > cyanosis, dyspnoea, feeding difficulties, failure to thrive

types of congenital HD

abnormal shunting of blood b/w LEFT & RIGHT sides of heart

left - to - right more common b/c high pressure in lt heart

right - to left shunts from increased resistance to blood moving out of rt heart

obstruction to blood flow

left - to - right shuntsmalformations > shunting blood from left to right side of heart

commonest group of congenital heart abnormalities

from high pressure in lt. side

blood does NOT bypass lungs so no cyanosistype % of all CHD abnormalities

Ventricular Septal Defect 25-30

Atrial Septal Defect 10-15

Patent Ductus Arteriosus 10-15

AV Septal Defect 5

ventricular septal defects

VSD: defect of INTERventricular septum

INTERventricular septum: membranous (fibrous) portion & muscular portion

size & site of defect determines extent of shunt

presents as cardiac failure in infants or murmur in older children/adults

signs:

pansystolic murmur {flow from high pressure left ventricle to low pressure right ventricle during systole}

tachypnoea (increased respiratory rate)

indrawing of lower ribs on inspiration

Management: small defect : no treatment, close spontaneously. large defects: surgical repair.

atrial septal defectsfemales more than males 2:1

defect of INTERatrial causing shunting to RIGHT with enlargement of RT heart & pulmonary arteries

usually at fossa ovalis (incompletely closed ostium secundum defect)

clinical features: most children are symptom free for years, detected at routine clinical exam & CXR

some children dyspnoea, chest infections, cardiac failure, arrythmia (eg atrial fibrillation)

signs: from volume overload of rt ventricle

systolic flow murmur over pulmonary valve

wide splitting of 2nd Heart Sound (delayed closure of pulmonary valve, from increased stroke volume and Rt Bundle Branch Block)

diastolic rumbling murmur (increased flow across tricuspid valve)

Mgmt: surgical closure otherwise RV hypertrophy & pulm. hypertension

patent ductus arteriosuspersistence of embryological connection between AORTA & pulmonary trunk {Lt. main pulmonary artery}

OPEN ductus arteriosus in 10% CHD, females more than males

associated with maternal Rubella infection

EMBRYOLOGY: intra uterine life

ductus arteriosus allows Oxygenated Placental Blood to flow from Pulm. Artery to Aorta (BYPASSING LUNGS)

@ birth: pulmonary vasculature resistance declines, blood is diverted to lungs for oxygenation and ductus arteriosus closes within 1st few days of life

BUT: if ductus stays patent> blood continually shunted from aorta to pulm artery

up to 50% LV output may be recirculated through lungs, with increase work on heart

pda

clinical features: depends on size of the left - to right shunt

small shunts: asymptomatic , large: retarded growth & development > cardiac failure

signs: continuous ‘machinery’ murmur at HS2

mgmt: surgical in childhood

atrioventricular septal defect

septal defect with both atrial and ventricular component

from failure of endocardial cushions to fuse together

AV canal persists resulting in a single heart chamber, separated by abnormal valve leaflets

right - to - left shunts

result> blood bypasses lungs to enter systemic circulation > cyanosis

RT TO LTTetralogy of Fallot

commonest cause of cyanosis in < 1 yr olds, 1/2000 live births

tetra : FOUR

i) Ventricular Septal Defect

ii) Over riding aorta (receives blood from rt & lt ventricles)

iii) pulmonary stenosis (from thickening of subvalvar muscle or stenosis in valve cusps)

Rt Ventricular Hypertrophy

tetralogy of fallotAETIOPATHOGENESIS: defects from embryological abnormality in bulbar septum, which normally separates ascending aorta from pulm. artery, and which fuses with interventricular septum

pulm stenosis> inadequate perfusion of lungs

overriding aorta> receives blood from BOTH ventricles

net result: > systemic circulation w/ DEOXYGENATED blood > CYANOSIS

cyanosis: esp. after feeding or crying attack, results in growth stunting, digital clubbing, polycythaemia

children feel RELIEF from squatting

loud ejection systolic murmur: from VSD or PS

MGMT: surgical closure of septal defect, rechannel blood to aorta from LV

COMPLICATIONS: BACterial endocarditis, cerebral infarct/abcess

transposition of great arteries

malformation whereby connections between RT & LT ventricle, aorta, & pulm. artery are DISORDERED

aorta emanates from RV, pulm art from LV

prognosis: possible if there IS ONE OR MORE OF:

ASD

VSD

PDA

mgmt: surgical correction

persistent truncus arteriosus

EMBRYO: aorta & pulm art develop from same single tube (TRUNCUS ARTERIOSUS)

persistence: by failure of conotruncal RIDGES to fuse and descend towards ventricles

so, pulm. artery arises away from origin of undivided truncus

there is always: defective interventricular septum

undivided truncus overrides both ventricles and

receives blood from both sides.

tricuspid atresiarare, absent tricuspid orifice , always associated with:

Patent foramen ovale

VSD

Underdeveloped RV

Hypertrophy of LV

pathophysio: blood shunted from RA to LA, then small amount shunted from LV to RV via defect

some deoxygenated bloodenters systemic circulation > cyanosis

mgmt: surgical correction

obstructive congenital defects

COARCTATION OF AORTA

stenosis of aorta, at or just beyond ductus arteriosus

females 2: males 1, 1/4000 live births

clinical features form stricture of aorta

Hypertension (proximal to stenosis) > headache, dizzy

Hypotension (distal to stenosis) > weakness, low circulation

coarctation of aorta

BP raised in upper body, normal or low in legs

large pulsations in upper body, lower body weak pulses

systolic murmur

untreated:

LV failure from HTN, cerebral hemorrhage, bacterial endocarditis, dissection of aorta

ATHEROSCLEROSISARTERIOSCLEROSIS: thickening & loss of elasticity of arteries from ANY condition.

commonest type is AtheroSclerOsis {hardening or loss of elasticity due to atheroma formation}

involves intima of large - medium sized arteries

other type: Monckebergs medial calcific sclerosis: media of medium muscular arteries, esp in limbs, lumen size normal

other type: arteriolar sclerosis: thickening of walls of small arteries and arterioles

consequences of arteriosclerosis

vessel thickening: narrow lumen> poor tissue perfusion

inelasticity of vessels: vessel rupture > haemorrhage

altered endothelium: risk thrombosis* * define

• arteriosclerosis leads to MI, angina pectoris, stroke, TIA, ischaemic colitis, claudication

atherosclerosis• degenerative dz. of large & med arteries

• accumulation of lipids in intima (tunica intima) of arteries > cell reactions

• commonest : aorta (abd. aorta), coronary arteries, cerebral arteries, iliac/femoral art

• risk factors:

• constitutional: genetic traits, race, gender (up to 55 males more), age

• hard: hypercholesterolaemia (LDL), Hypertension, Diabetes mellitus, smoking

• soft: lack of exercise, obesity, stress & personality traits

pathogenesis • plaques > low grade chronic endothelial injury from risk

factors

• atheroma (atherosclerotic plaques) from:

• endothelial injury platelet adhesion to endo., diffusion of plasma proteins including LDL into intima of arteries, migration of monocytes into intima

• platelets release PDGF > proliferation of smooth muscle cells

• musc cells deposit excess collagen & elastin in intima

• macrophages phagocytose LDL and release free lipis

useful links

• http://www.brown.edu/Courses/Digital_Path/systemic_path/cardio.html

• https://web.duke.edu/pathology/Week13/Week13.html

hypertension• elevated blood pressure: important and treatable cause of cardiac

failure

• also a risk factor for atherosclerosis & cerebral haemorrhage

• DEFINITION: sustained rise of systemic BP > 160 mmHg and / or diastolic > 95 mmHg

• borderline hypertension: 140-160 mmHg systolic and/or 90-95 mmHg diastolic

• AETIOLOGICAL CLASSIFICATION:

• PRIMARY: essential / idiopathic: raised BP with age, 90% cases, raise peripheral vascular resistance (genetic, socio-economic, dietary, hormonal, neurological sns)

• SECONDARY: raised BP NO, renal disease, adrenal dz, endocrine dz, shunts, drugs, preeclampsia*

patho classification htn

• BENIGN: stable elevation BP/ years

• MALIGNANT: dramatic increase BP / short period time

benign• vessel changes gradually respond to persistent stable elevated BP

• histologically:

• hypertrophy & thickening of muscular media

• thickening of elastic lamina

• fibro elastic thickening of intima

• hyaline deposition in arteriole wall (hyaline arteriosclerosis)

• effects:

• reduced vessel lumen leads to tissue iscahemia

• rigidity leads to limited expansion

• fragility of vessels leads to haemorrhage

malignant

• acute destructive changes in walls of small arteries when BP SUDDENLY rises

• effects:

• necrosis of vessel wall (fibrinoid necrosis)

• infiltration by fibrin in vessels

• leads to lack of blood flow to kidney.

COMPLICATIONS OF HTN

• VASCULAR

• hyaline deposition in arteries

• fibrinous deposition in arteries

• HEART

• LV Hypertrophy

• BRAIN

• intracerebral haemorrhage: small vessel , microinfarct, fluid lacunae

• KIDNEY

• ischaemia of nephrons, chronic renal failure, benign hypertensive nephrosclerosis, renal failure

pulmonary hypertension• pulmonary arterial pressuRe > 30 mmHG

• precapillary, capillary, post capillary causes

• effects: transudation fluid from pulm capillaries INTO alveoli > dyspnoea, expectoration of blood stained watery fluid

• chronic effects: hyperplastic arteriosclerosis (muscular hypertrophy & dilation of pulm arteries),

• necrotizing arteriolitis: inc pressure in pulm arteries haemorrhae in alveolar spaces with haemosiderin laden macrophages

• cor pulmonale: RT ventriular hypertrophy from inc workload

ischaemic heart disease• condition caused by a reduction / cessation in blood supply to

myocardium ~myocardial ischaemia

• usually from atherosclerosis, sometimes from coronary emboli

• leading cause of death in western world

• results in 4 syndromes

• stable angina (chronic)

• unstable angina (Acute)

• myocardial infacrtion (acute)

• sudden cardiac death (acute)

angina pectoris• episodic chest pain, from ischaemia to

myocardium following exercise

• usually from stenosis of 1> coronary arteries, red. blood to myocardium

• stenotic coronary arteries are either:

• eccentric: fibrolipid plaques affect 1 side of wall, vasodilataory drugs may help

• concentric: colagenous plaques affect whole art wall, circumferential.

stable angina

• predictable , occurs at fixed level of exercise from inc. heart workload

• pain relieved in ~ 2 minutes of rest

• stenosis of at least 75% need to reproduce angina on exercise

unstable angina

• unpredictable, not related to exercise

• reflects reversible ischaemia due to variable luminal stenosis

• caused by variations in vasomotor tone by plaques or emboli causing occlusion

prinzimental angina

• vasospastic angina

• at rest

• from increase in coronary vasomotor tone

• unknown mechanism

• common in early morning

• severe but self limiting pain

• rarely lead to MI

mgmt angina

• avoid risk factors

• drug therapy ( nitrates, b blockers)

• surgery (coronary angioplasty, bypass)

myocardial infarction

• =necrosis of myocardium as a result of severe ischaemia

• COMMON, 15% of all deaths worldwide, 60% sudden deaths.

• middle age, 50 +, but 10 % in 35-50 yr olds

• features: chest pain, breathlessness, vomitting, collapse or syncope

• types:

• regional (90%) infarct in are supplied by ONE major coronary artery

• diffuse: (10%) cases, relates to overall myocardial poor perfusion

patho features

• macro: site of regional infarct shows circumferential necrosis from ppor perfusion

• histo: NECROSIS & Acute Inflammation

• necrotic tissue replaced by collagenous scar

• process takes ~ 7 weeks, necrosis causes enzyme release and proteins which are used as markers CK-MB, troponin T, lactic dehydrogenase*

outcomes of MI• IMMEDIATELY: sudden cardiac death

• Short Term:

• arrythmias (if involves conduction tissue)

• LV Failure: necrotic wall softens, cardiac dilation

• rupture: blood bursts into pericardial cavity

• papillary muscle dysfunction: 1 > valve leaflets canot close in systole

• mural thrombus: on the inflamed endocardium over infarcted area

• acute pericarditis: from inflammation over infarct surface

long term

• chronic Left hEART FAILURE: inadequate LV pumping action

• ventricular aneurysm: distension of weakened fibrotic part of LV

• recurrent MI: SECONDARY MI

• Dressler’s Syndrome: AutoImmune pericarditis, raised ESR

part 2 will be sent next week

• happy studying!