Transcript Blood Vessels-2

Blood Vessels-2
Dr Suneet Kumar
Hypertension
• Sustained increase in
diastolic BP > 90 mm Hg
and/or a systolic BP >140
mm Hg
• Idiopathic (Essential)
primary HTN (95%)
• Secondary
Hypertension (5%)
Secondary causes
•
Renal disease
–
Acute glomerulonephritis, chronic renal
disease, Polycystic disease; Renal artery
stenosis, renal artery fibromuscular
dysplasia, Renal vasculitis, renin-producing
tumors
Rare Causes:
•
Endocrine
–
–
–
•
Adreno-cortical hyperfunction: Cushing
syndrome, Primary aldosteronism,
Congenital adrenal hyperplasia, Licorice
ingestion
Estrogen: PIH, Oral contraceptives
Pheochromocytoma, acromegaly,
hypothyroidism (myxedema),
hyperthyroidism (thyrotoxicosis)
Cardiovascular
–
Coarctation of aorta, Polyarteritis nodosa
(or other vasculitis)
Regulation of blood pressure
Pathogenesis of essential hypertension
Factors influencing development of HTN
• Genetic defects
– Increases sodium concentration in
SMCs of peripheral resistance
arterioles
– Sodium opens calcium channels
– Increased smooth muscle
contraction  increase in TPR
• Reduced renal sodium excretion
– Sodium retention → increase in
ECF volume, → increases CO →
increases TPR
• Activation of RAA system
– Which increases CO and TPR
• Increased sympathetic nervous
system activity
– Most important ; increases TPR
• Medications
– Decongestants
– Appetite suppressants
– NSAIDS (block vasodilator effect of
PG)
– Estrogen (increase
angiotensinogen synthesis in liver)
• Environmental factors
– Can modify genetic determinants
– Stress, obesity, smoking, physical
inactivity, and heavy consumption
of salt
Clinical manifestations
• Asymptomatic:
For a long time
• Symptomatic
– Morning headaches that
subside before noon,
blurred vision, sweating &
chest pain
• Signs
– HT
retinopathynarrowing of
the vessels
– Increased amplitude of
point of maximal impulse
(PMI) from LVH & S4
•Heart
–Concentric LV
hypertrophy muscle is
thicker, O2 demand increases,
heart is prone to arrithmias;
CCF, MI
•Blood vessels
–Accelerated atherosclerosis
–Aneurysm, rupture,
dissection, stroke.
•Brain
– Intra-cerebral hemorrhage
•Kidney
–Chronic renal failure
The heart has to do much
more work. It does not
expand. Preload increases,
and heart rate increases.
Vascular pathology
• Hyaline arteriosclerosis
• Hyperplastic
arteriosclerosis (Onion
skinning)
Malignant (Accelerated) Hypertension
•Markedly elevated BP
(systolic > 200 & diastolic >
120 mm Hg) causing endorgan damage
–Headache and dramatic
elevations of BP, which get
worse as time goes by.
•Medical emergency
–Untreated patients die
within 2 yrs from renal
failure, intra-cerebral
hemorrhage or CHF.
•Fundoscopy examination
–Retinal hemorrhages,
exudates, papilledema
Morphology
• Kidney
– Petechial hemorrhages
– Flea-bitten appearance
• Microscopy
– Hyperplastic
arteriosclerosis (“onion
skin”)
– Necrotizing arteriolitis
• Fibrinoid necrosis of
vessel walls
Aneurysm
• Localized abnormal
dilation of a blood vessel
or wall of heart
• Causes
– Weakened vessel wall due
to
• Congenital defect (EhlerDanlos syndrome)
• Systemic disease
(Hypertension)
• Atherosclerosis
• Infection
• Trauma
• Most common etiology
• In ascending aorta
– Dissecting aortic aneurysm
extending proximally
• In distal aorta (thoracic &
abdominal) and in
extremities
– Atherosclerosis
Aneurysm
• Types
– Saccular (spherical)
– Fusiform (spindle
shaped)
– Dissecting aneurysms
• Significance
– Enlarge and rupture
– Thrombosis and
embolism
– Erosion/compression of
surrounding structures
Abdominal aortic aneurysms
•Due to atherosclerosis
•Sites
–Abdominal aorta, below
renal arteries
–Lack of vasa vasorum below
renal artery orifices
•Cause
–Intrinsic/acquired defect in
structural components of wall
•Age > 50 years
•Sex- M:F- 5:1
•Symptoms
–Asymptomatic or a pulsatile
mass
–Mid-abd to lower back pain
•Signs
–Abdominal bruit on
auscultation (50%)
•Complication
–Rupture (Most common)
–C/F- Abrupt severe back
pain; ↓ BP
•Lab diagnosis
–Abdominal USG- Gold
standard
Aneurysm
•Gross
–Saccular or fusiform
–Atheromatous ulcers with
mural thrombi
•Mycotic abdominal aortic
aneurysms
–Microorganisms, especially
Salmonella gastroenteritis
•Complications
–Thrombosis
–Embolization of thrombus
–Rupture
•Syphilitic aneurysm
Tertiary stage of syphilis
–Obliterative endarteritis of
vasa vasorum & aortitis
•Site- Thoracic aorta
•Gross
–“Tree barking”- Intimal
roughening
•Complications
–Rupture
–Aortic insufficiency
–Narrowing of coronary ostia
Berry Aneurysm
•Site
–Cerebral artery at bifurcations
of Circle of Willis
–Anterior communicating artery
with ACA
•Cause
–Congenital (absence of internal
elastic membrane & muscular
wall)
–Associated with
•PCKD (10-15%)
•Coarctation of aorta (Increased
pressure in cerebral vessels)
•C/F
–Headache, stiff neck
(meningeal irritation) & death
•Gross
–Saccular, 5-10 mm to > 3 cm;
may be multiple
•Complication
–Rupture→ subarachnoid
hemorrhage
Dissecting Aneurysm
•Entry of blood from vessel lumen
enters an intimal tear & dissects
through layers of media
•Etiology
–Degeneration (cystic medial
necrosis) of tunica media
–Loss of elastic and smooth
muscle fibers
•Predisposing factors
–Hypertension
–Marfan’s syndrome (fibrillin
defect)
–Ehler-Danlos syndrome
(collagen defect)
–Pregnancy (↑ed plasma
volume)
–Cu deficiency (cofactor in
lysyl oxidase)
–Coarctation of aorta (wall
stress)
–Trauma
There is a tear (arrow) located
7 cm above the aortic valve and
proximal to the great vessels
in this aorta with marked
atherosclerosis. This is an
aortic dissection.
Dissecting aneurysm
• Symptoms
– Severe tearing pain
• Acute onset chest pain;
radiates to back
– May compress & obstruct
aortic branches (eg. renal
or coronary arteries)
• Labs
– Chest X-ray- Mediastinal
widening
• Increased aortic diameter
(80% cases)
– Retrograde arteriography
• Gold standard test
Proximal (type A) lesions
•Dissections within 1st 10 cm of
proximal aorta (ascending
aorta)
•Most common; most
dangerous
Type B lesions
•Dissections that do not
involve ascending aorta
•Begin below sub-clavian
artery
•Less common; better
prognosis
Question
•
A.
B.
C.
D.
E.
A 55-year-old man has had a BP of 165/105
mm Hg for many years and has not bothered
to treat this condition. His most likely cause
of death will be from:
Cerebral hemorrhage (stroke)
Aortic aneurysm rupture
Congestive heart failure
Chronic renal failure
Intracranial arterial aneurysm rupture
Question
•
A.
B.
C.
D.
E.
A 45-year-old man dies suddenly and unexpectedly.
Immediate cause of death is found to be a
hemorrhage in right basal ganglia region. M/S
examination reveal that his renal artery branches
have concentric endothelial cell proliferation which
markedly narrows the lumen, resulting in focal
ischemia and hemorrhage of the renal parenchyma.
An elevation in which of the following substances in
his blood is most likely to be associated with these
findings?
Ammonia
Calcium
Cholesterol
Renin
Troponin I