HTN Flashcards
what is an aneurysm
contrast true vs false aneurysms
localized abnormal dilation of a blood vessel
true= attenuated but intact vessel with a thinned ventricular wall
false= defect in the wall; leads to an extravascular hematoma that freely interacts with the extracellular space
What is an AV fistula
the direct connection between arteries and veins that bypass the capillary bed
can occur due to inflammatory necrosis of an adjacent vessel
problems with AV fistulas
if they rupture in the brain, could cause an intracranial hemorrhage
shunting of blood from arterial to venous circulation, increasing preload; leads to high output cardiac failure
associations of AV fistulas
the most common cause of ICH stroke in children
what is a berry aneurysm
weakened arterial elastic lamina and media, causing bulging at the arterial bifurcations
problems with berry aneurysms
if they rupture, can cause stroke
associations of Berry Aneurysms
HTN
connective tissue diseases
what is fibromuscular dysplasia
focal, noninflammatory, nonatherosclerotic fibrotic luminal narrowing in medium and large muscular arteries
Problems with fibromuscular dysplasia
fibrosis
focally thickened vessels and intimal hyperplasia that results in luminal stenosis, which leads to renovascular HTN
if rupture, can cause hemorrhage at the site of rupture
Associations of fibromuscular dysplasia
increased incidence in 1st degree relatives and young women
what stimulates the production of renin
- JG cells become activated by hypotension and hypovolemia
- Macula densa senses hyponatremia
- Activated Beta 1 receptors stimulate increased sympathetic tone
Results of RAAS activation
- Renin activates Angiotensin 1 to activate Angiotensin 2 via ACE
- Angiotensin 2 activates aldosterone and
- increases sodium reabsorption and water retention
- increases ADH release, making you thirstier
- activated Angiotensin 2 receptor signals arteriolar constriction
increases the extracellular volume and blood pressure
- aldosterone increases urinary secretion of potassium in the distal tubule and collecting ducts, lowering the serum potassium
differentiate essential vs secondary HTN vs malignant HTN
Essential HTN has no single identifiable cause
Secondary HTN has an underlying renal or adrenal cause
Malignant HTN- systolic > 200 and diastolic > 120, renal failure, retinal hemorrhage/ exudation and possible papilledema
contrast primary and secondary aldosteronism
Primary Aldosteronism (Conn syndrome) is an excess of aldosterone caused by autonomous overproduction, usually at the adrenal cortex. It is typically due to adrenal hyperplasia or adrenal adenoma.
Secondary Aldosteronism is a condition caused by increased renin secretion
compare and contrast the morphologic changes in benign HTN, hyperplastic arteriosclerosis and malignant HTN
Hyaline arteriolosclerosis: Arterioles show homogeneous, pink hyaline thickening with associated luminal narrowing
Hyperplastic arteriolosclerosis: vessels exhibit concentric, laminated (“onion-skin”) thickening of the walls with luminal narrowing, consisting of s_mooth muscle cells with thickened, reduplicated basement membrane_
Hyperplastic Arteriolosclerosis with necrotizing arteriolitis: same as above accompanied by fibrinoid deposits and vessel wall necrosis
Compare and contrast atherosclerosis and Monckeberg medial sclerosis
Atherosclerosis is arterial wall thickening and loss of elasticity that occurs in small arteries and arterioles ; can cause downstream ischemic injury
Monckeberg Medial Sclerosis is the calcification of muscular arteries involving the internal elastic membrane, do not encroach on the vessel lumen and are usually not clinically significant
greatest risk factor vs most common etiology of aneurysms
Greatest risk factor: atherosclerosis
Most common etiology: HTN
Morphologic features of cystic medial degeneration
- smooth muscle cell loss—or change in synthetic phenotype—leads to scarring (and loss of elastic fibers)
- inadequate extracellular matrix synthesis
- production of increasing amounts of amorphous ground substance (glycosaminoglycan
compare and contrast abdominal aortic aneurysms and thoracic aortic aneurysms with respect to:
- location, etiology and clinical features
Location
- AAA: below the renal arteries, but above the bifurcation into the iliac arteries
- TAA: Ascending Aorta
Etiology
- AAA: smoking, atherosclerosis, hypercholesterolemia and arterial HTN
- TAA: arterial HTN, bicuspid aortic valve, tertiary syphilis, connective tissue diseases, trauma and smoking
Clinical Features
- AAA: pulsatile abd mass, bruit on auscultation, lower back pain
- TAA: persistent cough, chest pressure thoracic back pain, difficulty swallowing and valve insufficiency
clinical features of syphilitic aneurysms
How do vessel dissections occur
blood separates the laminar plans of the media to form a blood-filled channel within the aortic wall
risk factors of aortic dissection
men 40-60y/o with h/o HTN
connective tissue abnormalities
syphillis
trauma
pathogenesis of an aortic dissection
- transverse tear of the aortic intima
- blood enters the media of the aorta and forms a false lumen within the intima-media space
- hematoma forms and propagates longitudinally downward
Clinical presentation of an aortic dissection
Sudden and severe tearing/ripping pain
Location: Anterior chest (ascending) or back (descending)
Interscapular or retrosternal pain
↑ BP
Asymmetrical blood pressure and pulse readings between limbs
Syncope, diaphoresis, confusion
