3.1 Pathology of Hypertension
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3.1 Pathology of Hypertension
According to WHO, what is Hypertension and what is borderline?
Arterial blood pressure greater than 160/95
Borderline = 140-160/90-95
What are some 7 notable risk factors for Hypertension?
Race - blacks
Alterations in the Renin-Angiotensin System
Excess Salt Intake
What are the causes of Secondary Hypertension?
Acute Brain Lesions
What is the tumor of the adrenal medulla that produces and secretes Catecholamines?
What is Pheochromocytoma?
Tumor of the adrenal medulla that produces and secretes Catecholamines (NE and E)
Which results in massive BP increases, along with Tachycardia, sweating and anxiety
Where is the morphologic consequences of HTN most likely seen in?
Peripheral vessels (Kidneys, brain, eye)
What occurs due to a consequence of the concentric hypertrophy of the left ventricle?
Heart becomes enlarged (cardiomegaly)
Increases in thickness from a normal 1.2 cm to about 2.0 - 2.5 cm
In Hypertension, the heart becomes enlarged due to a consequence of what?
Concentric hypertrophy of the left ventricle
All 3 layers involved
What is the histologic changes seen in the heart after hypertension?
All muscle fibers are thickened, enlarged with prominent
box-car shaped nuclei
What is a common finding of the heart after hypertension?
Interstitial myocardial fibrosis
What is the #1 cause of RHF?
Left Heart Failure
What is Benign Nephrosclerosis and what does it cause?
Long standing HTN (benign HTN) causes hyalinization of the arterioles and fibrosis of the small arteries, especially of the kidneys
What percentage of patients with "benign hypertension" has Hypertensive nephrosclerosis?
What can Hypertensive Nephrosclerosis eventually lead to?
End-Stage Renal Disease (chronic renal failure)
What is the pathology of Benign Nephrosclerosis?
Kidneys are bilaterally atrophic
Cortical surfaces have a subcapsular granularity with focal scarring
Cortex is thin on sectioning
Microscopically, what does the kidneys look like during Benign Nephrosclerosis?
Many glomeruli appear normal
Others have an ischemic change, with thickening and wrinkling of the glomerular capillary tuft
What happens to the glomerular capillary tuft found in Benign Nephrosclerosis?
Tuft is obliterated by a dense, eosinophilic globular mass of collagen and matrix material scarring that leads to many sclerosed glomeruli w/in Bowman's Capsule
What is the pathology of the convoluted tubules in Benign Nephrosclerosis?
Tubular atrophy with surrounding interstitial fibrosis and chronic inflammation
In hypertension, what do the larger arcuate and interlobular arteries of the renal blood vessel pathology look like?
Fibrotic thickening of the intima
In hypertension, what do the arterioles of the renal blood vessel pathology look like?
Concentric hyaline thickening of the walls w/ loss of smooth muscle cells (Hyaline Arteriolosclerosis)
Clinically, what does malignant hypertension look like?
Marked elevation in BP w/ diastolic pressures greater than 130 mmHg
What is the proposed pathogenesis of Malignant Hypertension?
Related to injury to the endothelium b/c of high pressures causing leakage of plasma into the injured walls resulting in fibrinoid necrosis
What is the gross pathology of malignant hypertension?
Size of the kidneys vary with duration of the disease
Cut surface reveals obscured corticomedullary junctions w/ small red punctate areas of hemorrhage
Occasionally there are small cortical infarcts due to thrombosis
What is the histologic pathology of malignant hypertension?
Fibrinoid necrosis of the blood vessel walls w/ concentric hyperplasia of smooth muscle cells in renal arterioles (onion skin arteriolitis)
Leads to Hyperplastic Arteriolosclerosis w/ luminal obliteration
What is Hypertensive Encephalopathy?
Vascular changes in the brain that usually cause acute and chronic ischemia leading to thromboses of small cerebral arterioles w/ fibrinoid necrosis (Lacunar Infarcts)
Where are the sites of intercerebral hemorrhage?
Basal Ganglia-Thalamus (75%)
What are the features of hypertensive retinopathy?
Arteriolar narrowing leading to AV Nicking
Flame-shaped retinal hemorrhages
Edema of the optic disk
"Star Exudates" that radiate from the macula
Cotton wool spots
In hypertensive retinopathy, what causes arteriolar narrowing in the Retina?
Arteriolosclerosis accompanies long-standing hypertension and causes progressive thickening of the retinal arterioles which narrows their lumen and causes tortuosity of their shape
In Hypertensive Retinopathy,what is Arteriovenous Nicking?
At sites where the thickened arterioles cross the veins, the veins appear kinked or crimped
In AV Nicking, what is copper wiring?
Narrowed lumen of the retinal arterioles ↓ the visibility of the blood column and makes it appear at first orange or copper in color
In AV Nicking, what is silver wiring?
As blood columns eventually becomes completely obscured, light reflected from the sclerotic vessels appears as silver threads (wirings)
In Hypertensive Retinopathy, what is cotton wool spots?
Fluffy, white bodies in the retina
Ischemia results in swollen axons w/ cytoplasmic bodies that resemble cotton on fundoscopy