Flashcards in Chapter 10 - Vascular Disorders Deck (128):
What are chylomicrons and when are they absent?
Chylomicrons: diet-derived TGs; absent during fasting
How does the density of chylomicrons compare to that of all lipoproteins?
Chylomicrons least dense (protein 2%) of all lipoproteins
What do chylomicrons require for assembly and secretion? What cell type secretes chylomicrons? Once secreted, where to chylomicrons go?
Require apoB48 for assembly/secretion from enterocytes → lymphatics
Describe how nascent chylomicrons become mature chylomicrons.
Nascent chylomicrons obtain apoCII/apoE from HDL
What are chylomicrons a source of?
Chylomicrons: source FAs + glycerol
What does capillary lipoprotein lipase do?
CPL: chylomicrons → chylomicron remnants (↓↓TG)
What induces the synthesis of CPL?
CPL synthesis induced by insulin
What activates CPL in the fed state?
CPL activated by apoCII
Where is CPL located?
CPL in adipose, muscle, myocardium
What removes chylomicron remnants?
Remnants removed by apoE receptors in liver
What is VLDL?
VLDL: liver-derived TG
Describe VLDL synthesis.
G3P + 3 FAs → TG → VLDL
What is important in the synthesis and secretion of VLDL?
ApoB100 important in synthesis/secretion VLDL
What is VLDL a source of? Where are TGs synthesized and stored?
VLDL: source FAs + glycerol; TG synthesis liver, TG stores in adipose
What are the substrates and products in the reactions catalyzed by CPL?
CPL: VLDL → IDL → LDL
What does CETP do?
CETP transfers TGs from VLDL → HDL; HDL transfers CH → VLDL
How does an increase in VLDL affect HDL-CH?
↑VLDL causes ↓HDL-CH
What does VLDL form with the standing chylomicron test?
VLDL forms infranate with standing chylomicron test
VLDL: turbid infranate; more protein than chylomicrons
What formula is used to calculate VLDL concentration?
VLDL = TG ÷ 5
What is the cause of plasma or serum turbidity?
Plasma/serum turbidity due to ↑↑TG; VLDL and/or chylomicrons
What do chylomicrons form with the standing chylomicron test?
Chylomicrons: supranate (less protein than VLDL)
From what is LDL derived? What does LDL transport?
LDL: derives from VLDL; transports CH
What do small dense LDL particles increase the risk of?
Small dense LDL particles: ↑risk for atherosclerosis, CAD
What is the formula for calculated LDL?
Calculated LDL = CH − HDL − TG/5
How do chylomicrons affect the calculated LDL?
Chylomicrons falsely ↓calculated LDL
How do chylomicrons affect the calculated VLDL?
Chylomicrons falsely ↑calculated VLDL
What are the functions of cholesterol?
CH: cell membranes, hormones, bile salts/acids
What is not required for accurate serum cholesterol?
Fasting not required for accurate serum CH
Which cholesterol is the "good cholesterol"?
HDL-CH: “good CH”
What are the factors that increase HDL?
↑HDL: nicotinic acid (best), exercise; diet alterations not effective
What are the functions of HDL?
HDL: source of apoCII and apoE
HDL: removes CH from plaques/fatty streaks for disposal in liver
HDL is measured as what?
Measured as HDL-CH
How does increased VLDL affect HDL-CH?
↑VLDL causes ↓HDL-CH
What is arteriosclerosis?
Arteriosclerosis: thickening of arterial wall; loss of elasticity
What is medial calcification?
Medial calcification: dystrophic calcification of muscular arteries (uterine, radial)
Describe the epidemiology of atherosclerosis.
Atherosclerosis: men > women; ↑with age
What are the risk factors for atherosclerosis?
Risk factors: HTN, DM, smoking, hyperlipoproteinemia
What are the first steps in the pathogenesis of atherosclerosis?
Atherosclerosis: endothelial cell injury; platelets/macrophages pivotal roles
What are the causes of endothelial cell injury?
Endothelial injury: HTN, smoking, homocysteine, oxidized LDL
What is the cell response to endothelial injury?
Macrophages infiltrate intima; release cytokines
Platelets induce inflammatory responses in leukocytes/endothelial cells
What are foam cells?
Foam cells: macrophages, SMCs with CH
What is the pathognomonic lesion of atherosclerosis?
Fibrous plaque: pathognomonic lesion atherosclerosis
What does the fibrous cap overlie?
Fibrous plaque overlies necrotic core
What is CRP a marker of?
CRP: marker disrupted/inflammatory fibrous plaques
What is the most common site of atherosclerosis? What does this site not have?
Abdominal aorta: MC site atherosclerosis; no vasa vasorum
What are the complications of atherosclerosis?
Complications: aneurysms, thrombosis/infarction, HTN (renal artery), cerebral atrophy, PAD
What is claudication?
Claudication: key sign of PAD; “angina” in peripheral arteries (pain relieved by resting)
What are the signs and symptoms of PAD?
PAD: dependent rubor, cool skin, poor healing, ↓hair/nail growth, ↓pedal pulses, bruits over femoral/popliteal arteries
What are the 5 P's of acute peripheral artery vessel occlusion?
5 P’s: pain, pallor, paresthesias, paralysis, pulselessness
How is PAD diagnosed?
Dx: ABI ratio, angiography, duplex ultrasonography
What is arteriolosclerosis?
Arteriolosclerosis: hardening of arterioles
What is NEG and where does it occur with respect to arteriolosclerosis? What results from NEG in arteriolosclerosis?
NEG: glucose attaching to proteins in basement membrane; leaky membrane
What are the causes of hyaline arteriolosclerosis?
Hyaline arteriolosclerosis: diabetes mellitus, hypertension
What is the cause of hyperplastic arteriolosclerosis? What is the pathologic finding?
Hyperplastic arteriolosclerosis: malignant HTN; onion skinning renal arteriole
What is an aneurysm?
Aneurysm: vessel weakening and outpouching
What is the most common vessel aneurysm?
AAA MC vessel aneurysm
Where are AAAs usually located?
AAA below renal artery orifices
What is the pathogenesis of an AAA?
AAA: atherosclerosis weakens wall
What are the clinical findings of a ruptured AAA?
AAA rupture triad: left flank pain, hypotension, pulsatile mass
How is an AAA diagnosed?
Dx AAA: ultrasonography, CT, angiography
What is the most common peripheral aneurysm? What is this aneurysm's epidemiology? Where is it located?
Popliteal aneurysm: male dominant; behind knee; MC peripheral aneurysm
Name the fungi that commonly invade vessels and weaken them.
Fungal invaders: Aspergillus, Candida, Mucor
Name the bacteria that invade vessels and weaken them.
Bacterial invaders: B. fragilis, P. aeruginosa, Salmonella spp.
Where are cerebral berry aneurysms typically found?
Cerebral berry aneurysm: circle of Willis, base of brain
What are the risk factors for a cerebral berry aneurysm?
Risk factors: HTN any cause, coarctation, atherosclerosis
Where is the most common site for a cerebral berry aneurysm?
MC site is junction of communicating branch with ACA
What is important in the pathogenesis of a cerebral berry aneurysm?
Vessel lacks internal elastic lamina and smooth muscle
What results from the rupture of a cerebral berry aneurysm? What is the clinical finding?
Rupture: subarachnoid hemorrhage; “worst headache I ever had”
What is the pathogenesis of an aortic arch aneurysm?
Aortic arch aneurysm: tertiary syphilis; vasa vasorum vasculitis
What is very characteristic of endarteritis obliterans?
Endarteritis obliterans: plasma cell infiltrate very characteristic
What is a clinical finding of a syphilitic aneurysm? What is the cause of this finding?
Syphilitic aneurysm: AV regurgitation; dilation of aorta and valve ring
What are the clinical findings of AV regurgitation?
AV regurgitation: early diastolic murmur; wide pulse pressure produces bounding pulses
What causes an Austin Flint murmur? What needs to be done as a result?
Austin Flint murmur: blood dripping onto anterior MV leaflet; valve (aortic) must be removed
What is the most common cause of death in Marfan syndrome and EDS?
Aortic dissection: MCC death in Marfan syndrome/EDS
Describe the genetics of Marfan syndrome.
Marfan syndrome: AD, missense mutation in fibrillin synthesis
What are the clinical findings in Marfan syndrome.
Marfan syndrome: arachnodactyly, dislocated lens, MVP, AV regurgitation, eunuchoid
Describe the pathogenesis of an aortic dissection.
Aortic dissection: CMD; elastic tissue fragmentation
What are the risk factors of an aortic dissection?
Risk factors: Marfan/EDS, HTN, pregnancy, coarctation of aorta
What are the clinical findings of an aortic dissection? What is the most common cause of death in the setting of an aortic dissection?
Aortic dissection: pain radiates into back; absent pulse
Aortic dissection: AV regurgitation, cardiac tamponade MCC death
Describe the saphenous vein system.
Superficial saphenous → perforator branch → deep veins → back to right heart
Where are the locations of varicose veins?
Locations: superficial saphenous vein, distal esophagus, anorectal region, left scrotal sac
What is the most common clinical manifestation of chronic venous insufficiency?
Superficial varicosities: MC clinical manifestation of chronic venous insufficiency
What are the risk factors for superficial varicosities in the lower extremities?
Risk factors: female; family history; pregnancies; prolonged standing; obesity; elderly
What is the pathogenesis of superficial varicosities in the lower extremities?
Valve incompetence of perforator branches; reversal of blood flow to superficial saphenous
Superficial varicosities in the lower extremities may be secondary to what?
2° superficial saphenous veins: DVT with reversed blood flow to superficial veins
What is the most common cause of venous thrombosis? What is another cause of venous thrombosis?
Venous thrombosis: MCC stasis blood flow; hypercoagulability
Where is the most common site of venous thrombosis?
Venous thrombosis: MC site lower extremity; veins in calf, popliteal/femoral veins
What are the signs of an acute calf DVT?
Acute calf DVT: swelling, pain, pitting edema
What is a sign of chronic DVT?
Stasis dermatitis: sign of chronic DVT
What area is affected by stasis dermatitis? What are the clinical findings in stasis dermatitis?
Stasis dermatitis: medial malleolus; hemorrhage/orange discoloration; ulcers
What is superficial thrombophlebitis associated with?
Superficial thrombophlebitis: occult DVT
What are the causes of superficial thrombophlebitis?
Causes: IV cannulation veins, infection (S. aureus), pancreatic cancer, hypercoagulable state
What are the clinical findings of superficial thrombophlebitis?
Superficial thrombophlebitis: pain, tenderness, erythema of overlying vein
What is the pathogenesis of SVC syndrome?
SVC syndrome: compression by primary lung cancer; usually small cell carcinoma
What are the clinical findings of SVC syndrome?
Discoloration of face, arms, shoulders; retinal hemorrhages; stroke
What is the pathogenesis of thoracic outlet syndrome?
TOS: compression neurovascular compartment in neck
Who is commonly affected by TOS? What are the causes of TOS?
Common among weight lifters (tight scalene muscles); cervical rib
What are the clinical findings of TOS?
Arm falls asleep at night; numbness/paresthesias; + Adson test
Describe the structure of lymphatic vessels. This structure predisposes these vessels to what?
Lymphatics: incomplete basement membranes; infection, tumor invasion
Describe the clinical findings of acute lymphangitis. What is acute lymphangitis associated with?
Acute lymphangitis: S. pyogenes cellulitis; red streak up lymphatics
What is lymphedema?
Lymphedema: lymphatic fluid in interstitial space
What are the causes of lymphedema?
Radiation post–radical mastectomy, congenital, Turner syndrome, filariasis
What is the most common cause of lymphedema worldwide?
Filariasis MCC lymphedema in world
What are the clinical findings of lymphedema?
Lymphedema: pitting edema early; nonpitting in advanced cases
What does ANCA stand for?
ANCA: antibodies against cytoplasmic components of neutrophils
What is an example of a c-ANCA type of vasculitides?
c-ANCA: Wegener granulomatosis
What are examples of p-ANCA type of vasculitides?
p-ANCA: microscopic polyangiitis, Churg-Strauss syndrome
What is the gross appearance of small vessel vasculitis? What is this appearance a sign of?
Small vessel vasculitis: palpable purpura; acute inflammation
What are the clinical findings of medium vessel vasculitis?
Medium-sized vessel vasculitis: thrombosis, aneurysms
How does large vessel vasculitis present?
Large vessel vasculitis: absent pulse, stroke
Essential hypertension accounts for what percentage of all hypertension cases?
Essential HTN: 85% of all HTN cases
What does SBP correlate with?
SBP: SV, aorta compliance
What are the primary determinants of stroke volume?
SV: preload, afterload, contractility of heart
What does vessel elasticity determine?
Vessel elasticity determines aortic compliance
How does aortic compliance change with age?
Aortic compliance ↓with age
Who is primarily affected by systolic hypertension? What causes systolic hypertension?
Systolic HTN: >60 years old; loss of aortic compliance
What causes an increase in SBP?
↑SBP: ↑preload, ↑contractility, ↓aortic compliance
What causes a decrease in SBP?
↓SBP: ↓preload, ↓contractility, ↑afterload (aortic stenosis)
What does DBP correlate with?
DBP: blood volume in aorta while heart fills in diastole
What does DBP depend on?
DBP depends on tonicity of smooth muscle PVR arterioles and HR
What causes an increase in DBP?
↑DBP: vasoconstriction in PVR arterioles, ↑blood viscosity, ↑HR
What causes a decrease in DBP?
↓DBP: vasodilation PVR arterioles, ↓blood viscosity, ↓HR
How does excess sodium affect plasma volume, stroke volume and SBP?
↑Sodium retention: ↑PV → ↑SV → ↑SBP
How does excess sodium affect the PVR arterioles and DBP?
↑Sodium retention: ↑vasoconstriction PVR arterioles → ↑DBP
Describe the pathogenesis of essential hypertension.
Essential HTN: genetic factors reduce renal sodium excretion
Secondary hypertension accounts for what percentage of all hypertension cases? What are the leading causes of secondary hypertension?
2° HTN: 15% of cases; renovascular HTN and drugs are leading causes
What are the complications of hypertension in descending order?
Complications of HTN, descending order: acute Ml, stroke, renal failure