Hypertension

HYPERTENSION

2. Hypertension
Elevated blood pressure
Sustaineddiastolicpressuregreaterthan90mmHg,ora
sustainedsystolicpressureinexcessof140mmHg.
systolicbloodpressureismoreimportantindetermining
cardiovascularrisk
Hypertensionisacommonhealthproblemwithoccasionally
devastatingoutcomes
Ittypicallyremainsasymptomaticuntillateinitscourse.

3. Hypertension
Elevated blood pressure
Itcontributestothepathogenesisofcoronaryheartdisease
andcerebrovascularaccidents,cardiachypertrophyand
heartfailure(hypertensiveheartdisease),aorticdissection,
andrenalfailure.
Themechanismsofhypertensioninthevastmajorityof
peopleremainunknown;"essentialhypertension“.
Theprevalenceandvulnerabilitytocomplicationsincrease
withage;theyarealsohigherinAfricanAmericans.
Reductionofbloodpressuredramaticallyreducesthe
incidenceanddeathratesfromIHD,heartfailure,and
stroke

4. Pathogenesis of Hypertension
Ninetypercentto95%ofhypertensionisidiopathic
(essentialhypertension),whichiscompatiblewithlonglife,
unlesscomplicationsupervenes.
Mostoftheremainderof"benignhypertension"is
secondarytorenaldiseaseor,narrowingofrenalartery,
(atheromatousplaque,renovascularhypertension).
Infrequently,hypertensionissecondarytodiseasesof
theadrenalglands,suchasprimaryaldosteronism.
Cushingsyndrome,pheochromocytoma,orother
disorders.

5. Pathogenesis of Hypertension
About5%ofhypertensivepersonsshowarapidlyrising
bloodpressurethatifuntreatedleadstodeathwithin1or2
years.
Termedacceleratedormalignanthypertension,
Theclinicalsyndromeischaracterizedbysevere
hypertension(diastolicpressureover120mmHg),renal
failure,andretinalhemorrhagesandexudates,withor
withoutpapilledema(swellingoftheopticdisc).
Itmaydevelopinpreviouslynormotensivepersonsbut
moreoftenissuperimposedonpreexistingbenign
hypertension,eitheressentialorsecondary.

6. Types and Causes
of Hypertension
(Systolic and
Diastolic)
 Essential Hypertension (90% to 95% of Cases)
 Secondary Hypertension
RENAL
Acute glomerulonephritis
Chronic renal disease
Polycystic disease
Renal artery stenosis
Renal vasculitis
Renin-producing tumors
ENDOCRINE
Adrenocorticalhyperfunction(Cushing syndrome, primary
aldosteronism, congenital adrenal hyperplasia, licorice
ingestion)
Exogenous hormones (glucocorticoids, estrogen [including
pregnancy-induced and oral contraceptives],
sympathomimeticsand tyramine-containing foods,
monoamine oxidaseinhibitors)
Pheochromocytoma
Acromegaly
Hypothyroidism (myxedema)
Hyperthyroidism (thyrotoxicosis)
Pregnancy-induced
CARDIOVASCULAR
Coarctationof aorta
Polyarteritisnodosa
Increased intravascular volume
Increased cardiac output
Rigidity of the aorta
NEUROLOGIC
Psychogenic
Increased intracranial pressure
Sleep apnea
Acute stress, including surgery

7. Essential Hypertension
contributing factors
Alterationsinrenalsodiumhomeostasisand/orvesselwall
toneorstructureunderlieessentialhypertension
Bothincreasedbloodvolumeandincreasedperipheral
resistancecontributetotheincreasedpressure.

8. Essential Hypertension
Essentialhypertensionresultsfromaninterplayofmultiple
geneticandenvironmentalfactorsaffectingcardiacoutput
and/orperipheralresistance.
Geneticfactors:Allelicvariationsinthegenesencoding
componentsoftherenin-angiotensinsystem.
Hypertensionisassociatedwithpolymorphismsin
boththeangiotensinogenlocusandtheangiotensinII
typeIreceptorlocus.
Environmentalfactors:modifytheexpressionofany
underlyinggeneticdeterminantsofhypertension;stress,
obesity,smoking,physicalinactivity,andheavy
consumptionofsaltareallimplicated.

10. Vascular Pathology in Hypertension
Inadditiontoacceleratingatherogenesis,hypertension-
associateddegenerativechangesinthewallsoflargeand
mediumarteriescanpotentiatebothaorticdissectionand
cerebrovascularhemorrhage.
Hypertensionisalsoassociatedwithtwoformsofsmall
bloodvesseldisease:
hyalinearteriolosclerosis
hyperplasticarteriolosclerosis

11. HyalineArteriolosclerosis
Characterizedby
Diffuse,homogeneous,pinkhyalinethickeningofthe
wallsofarterioles.
Lossofunderlyingstructuraldetailandnarrowingofthe
lumen
Occurstypicallyinelderlypatients.
Advancedlesionsareseeninpersonswithdiabetes
mellitusand/orwithhypertension.

12. HyalineArteriolosclerosis
Hyalinearteriolosclerosisistypicallyseeninkidneys.
Endothelialinjurycausesleakageofplasmacomponents
acrossvascularendothelium,andexcessiveextracellular
matrixproductionbysmoothmusclecells.
Thisprocessisassociatedwithluminalnarrowingthat
mayinduceischemicinjury
Afferent&efferentarteriolesinkidney→benign
nephrosclerosis

13. HyalineArteriolosclerosis
Markedly thickened arteriole to the lower right of
this glomerulus

14. HyalineArteriolosclerosis
Arteriolar wall is hyalinized and the lumen is
markedly narrowed

15. HyperplasticArteriolosclerosis
Concentriclaminated(onionskin)arteriolarthickeningwith
reduplicatedbasementmembraneandsmoothmuscle
cellsproliferation.
Commonlyassociatedwithmalignanthypertension
Leadstoluminalnarrowing
Frequentlyassociatedwithfibrinoidnecrosis
(necrotizingarteriolitis).
Later,thevascularwallshypertrophyduetohyperplasia
ofSMCsandsometimesthisoccursalongwith
necrosisofthevesselwall.

16. HyperplasticArteriolosclerosis
Onion skin appearance
Narrow Lumen
Onion Skin Thickening
Of arterioles.

17. HyperplasticArteriolosclerosis
(Onion-Skinning) causing luminal obliteration (arrow)

18. HyperplasticArteriolosclerosis
Fibrinoid necrosis

19. Hypertensive heart disease (HHD)
Basicsfordiagnosis
Historyofhypertension
Leftventricularhypertrophyintheabsenceofother
causesaccountingforhypertrophy
Thestimulusforhypertrophyispressureoverload

20. Hypertensive heart disease (HHD)
StagesofHHD
CompensatedHHD:
Withhypertrophyanadequatecardiacoutputis
maintained.
DecompensatedHHD:
Thicknessofmusclewallincreasedemandfor
oxygen,decreasecompliance,androleof
hypertensiononatheroma,allcontributeto
decompensatedHHDandeventualdilatation.

21. Hypertensive heart disease (HHD)
Gross
Compensatedstage.....Concentrichypertrophy
Decompensatedstage.........Dilatation
Bothstages,heartweightincreased
Histology:Largefiberswithlargenuclei,laterinterstitial
fibrosis.
HHDCausesdeath
CHF
Increasedriskofsuddencardiacdeath
Renaldisease,stroke
Drugcontrolleadstoregressionofhypertrophy.

22. Corpulmonale
Corpulmonaleconsistsofrightventricularhypertrophy
anddilationduetopulmonaryhypertensioncausedby
primarydisordersofthelungparenchymaorpulmonary
vasculature.
Generally,rightventriculardilationandhypertrophy
causedbycongenitalheartdiseaseorbyleftventricular
failureareexcludedbythisdefinition.

23. Corpulmonale
Corpulmonalemaybeacuteorchronic.
Acutecorpulmonalemostcommonlyfollowsmassive
pulmonaryembolismwithobstructionof>50%ofthe
pulmonaryvascularbed.
Chroniccorpulmonaleoccurssecondarytoprolonged
pressureoverloadcausedbyobstructionofthe
pulmonaryvasculature,orcompressionorobliteration
ofseptalcapillaries(resultingfromemphysema,
interstitialpulmonaryfibrosis,orprimarypulmonary
hypertension).

24. Corpulmonale
Inacutecorpulmonaletherightventricleisusuallydilated
butdoesnotshowhypertrophy;ifanembolismcauses
suddendeaththeheartmayevenbeofnormalsize.
Chroniccorpulmonaleischaracterizedbyrightventricular
(andoftenrightatrial)hypertrophy.Inextremecasesthe
thicknessoftherightventricularwallmaybecomparable
toorevenexceedthatoftheleftventricle.
Whenventricularfailuredevelopstherightventricleand
atriummayalsobedilated.Suchdilationmaymaskright
ventricularhypertrophy.