Week 3: CV pathology diseases of blood vessels I & II Flashcards
Describe capillary vascular malformations.
- malformed dilated capillaries in skin. Not a neoplasm.
- usually present at birth, vary in size, grows in proportion to child’s growth
1. Nevus simplex (macular stain) - aka salmon patch,stork bite, angel kiss
- blanchable pink-red patches
- common at nape of neck, forehead between eyebrows, eyelids
- most disappear within 1st year of life
- may be more intense with crying
2. Naevus Flammeus - “port wine”
- common in head/neck, dermatomal dist. for facial lesions
- pink to red macules at birth, persist and darken with age, may become ticketed, irregular and nodular
Describe hemangiomas of Infancy (HOI)
- benign vascular neoplasm
- 50% present at birth as red macule,papule, 50% appear in first few months of life
- 2/3 in head/neck
- Two phases: rapid growth for 6-12 months, then slow involution over years
- most follow benign course
- can have visceral involvement
Describe venous malformations.
- superficial or deep
- pain common, esp with deeper lesions.
- venous stasis and activation of altered endothelium may cause localized coagulopathy–>phlebothrombosis common
Descrive arteriovenous malformations (AVM).
- abnormal communication between artery and vein that bypasses capillary bed
- brain is most common site, greatest clinical significance. Can hemorrhage, cause seizure, headache, progressive neurological deficit
- In large AVMs, can have high output cardiac failure from decreased peripheral resistance and compensatory increase in SV and CO
Describe lymphatic malformations.
- commonly occurs as lymphatic-venous malformations or capillary-lymphatic malformations
- cervicofacial and axilla region most common
- can be associated with trisomy 13,18,21 and Turner syndrome
Describe coarctation of the aorta.
- narrowing of the aorta at the level of ductus arteriosis/ligamentum arteriosum
- Two types:
1) pre-ductal (infantile): less common and more severe. Narrowin is proximal to ductus arteriosus, heart failure in early life often. patent ductus arteriosus.
2. )post ductal (adult): less severe. narrowing is distal to ligamentum arteriosum. Hypertension in upper body and weak pulses/hypotension in lower with potential ischemia. Large intercostal arteries as collateral circulation.
Describe hereditary hemorrhagic telangiectasia.
- autosomal dominant vascular disorder that manifests later in life, not congenital, genetically predetermined
- variety of manifestations
- diagnostic criteria: epistaxis, telangiectasias, visceral history, family history
- can have secondary iron deficiency anemia
List in descending order from the most severely affected, the vessels affected by atherosclerosis and their major clinical consequences.
- abdominal aorta-aneurysm
- proximal coronary artery - MI, chronic ischemic heart dz
- descending thoracic aorta - aneurysm
- popliteal artery -gangrene
- internal carotid artery - cerebral infarct
- circle of willis vessels- cerebral infarct
What are complicated lesions (atherosclerosis)?
-advanced plaques that undergo certain changes which are particularly significant clinically, including: focal erosion, ulceration or rupture of fibrous cap–>thrombosis and micro emboli, hemorrhage, aneurysmal dilation, calcification
Describe the fatty streak in atherosclerosis?
- aggregates of foam cells (LDL in macrophages), T cells, SMCs, aggregated platelets
- 1st grossly visible lesion in development of atherosclerosis
What is atherothrombosis?
-atherosclerotic plaque disruption with superimposed thrombosis (leading cause of mortality in Western world)
Define aneurysm.
=pathologic dilution of a segment of a blood vessel or wall of the heart
- True aneurysm=dilation of all three intact, but often attenuated vessel wall layers
- false aneurysm=rupture of the intimal and medial layers, with resulting dilation created by extravasation of blood into the adventitia
What are 3 subtypes of aneurysm, based on shape or location or cause.
- Abdominal aortic aneurysm: most common. mostly caused by advanced atherosclerosis with erosion of IEL and plaque expansion leading to medial destruction. Or caused by connective tissue disease. Saccular or fusiform.
- Mycotic aneurysms: infection of vessel wall, mostly caused by septic embolus in infective endocarditis. Also secondary to neighboring bacterial infection.
- Syphilitic: tertiary syphilis.
What are 3 different shapes of aneurysms?
- saccular: assymmetric, spherical
- berry: small intracranial saccular aneurysms. develops over time due to underlying congenital weakness of vessel media
- fusiform: progressive, symmetrical dilation of complete vessel circumference.
Describe aortic dissection. Risk factors?
- definition: intimal tear allowing blood to enter vessel wall and dissect along laminar planes of aortic media, forming false channel.
- plane of dissection: outer 1/3 of media–> weakened external wall can lead to rupture
- common site: ascending aorta above aortic ring, then descending aorta below ligamentum arteriosum
- risk factors: age>70, hypertension, male, atherosclerosis, connective tissue disease
- major complications: acute aortic regurg, MI, cardiac tamponade from rupture into pericardium, potential cerebral/renal/mesenteric infarct
How is aortic dissection classified?
-Type A: ascending aortic lesion only or ascending and descending aortic lesion
-Type B: descending aortic lesion only
risk of rupture greater in Type A
What are histological findings in aortic dissection?
-medial degeneration=patchy loss of elastic fibers and SMCS replaced by myxoid (glycoprotein).
Define hypertension. How is it classified?
-typically defined as systolic pressure>140 and/or diastolic >90mmHg
-95% is primary, idiopathic, essential HTN
-rest is secondary, e.g. renal abnormalities
Classification
-Benign: no symptoms, longstanding mild/moderate
-malignant: aka hypertensive crisis or emergency, severe HTN with acute end organ damage. Bp usually >200/140 mmHg. Rapid onset.
Describe the morphological changes due to hypertension in large arteries.
- elastic fiber degeneration from tissue fatigue w/ thinning and fragmentation of fibers. lower damping ability of vessels to compensate for mechanical stress
- intimal hyperplasia
- medial SMC hypertrophy and increased ECM deposition
- vessel dilation—>potential aneurysm/dissection
Describe the morphological changes due to hypertension in small arteries/arterioles.
-autoregulation: leads to vasoconstriction due to high bp to protect capillary beds. If chronic, leads to remodeling
-Eutrophic inward remodeling: most common, smaller lumen, no change in medial cross sectional area. Essential HTN.
-Hypertrophic inward remodeling: less common. ECM deposition with increase in medial cross sectional area. worse prognosis. assoc with advanced HTN.
VASCULAR CONSEQUENCES
-mechanical stress: loss of structural integrity, leakage across endothelium, fixed luminal narrowing, luminal obliteration
-Organs: heart, brain, kidneys vulnerable. May lead to renal hypotension—>increase renin–>angiotensin–>aldosterone, worsened HTN
Describe Benign Nephrosclerosis.
-assoc. w/ benign HTN
EARLY
-vasoconstriction by SM contraction. No microscopic changes
LATER
-arteries: myointimal thickening, IEL changes, medial hypertrophy
-arterioles: hyaline thickening of vessel walls (leakage of plasma proteins across injured ECs and deposition of ECM/basement membrane constituents)
-luminal narrowing and decreased perfusion–>chronic ischemia->nephropathy–>patchy scarring
-interstitial fibrosis with little or no inflammation.
-granular appearance of kidney, areas of scarring (contracted) and raised areas of preserved parenchyma
-affects afferent arteries
Describe malignant nephrosclerosis.
-associated with malignant HTN.
ACUTE phase
-medial fibrinoid necrosis
-eosinophilic lesion secondary to EC injury, minimal inflammation, platelet deposition–>may cause thrombosis, ischemia, infarct
HEALING phase
-onion skinning and intimal fibrosis
-concentric SMCs and ECM deposition, hyperplastic AS
-severe luminal narrowing/obliteration—>ischemic atrophy, capillary rupture
Grossly: flea bitten kidney, petechial hemorrhages
What is vasculitis?
- inflammation of vessel walls
- important to distinguish between infectious and non infectious causes
- non infectious due to: immune complex deposition, ANCA (anti neutrophill cytoplasmic antibodies), and anti endothelial cell antibodies
How is vasculitis classified?
- Large vessel
- Giant cell arteritis -granulomas
- Takayasu aortitis -granulomas - Medium vessel
- Polyarteritis nodosa (assoc. w/ Hep B) -PMN, fibrinoid necrosis
- thromboangiitis obliteran (tobacco smoker)-granulomas - Small vessel
- Henoch-Schonlein Pupura (HSP)
- Wegener’s -granuloma
- microscopic polyangiitis -PMN and fibronoid necrosis
- Churg-Strauss syndrome - eosinophils
Describe Giant Cell Arteritis
- most common vasculitides
- diagnosed in >50 yo (commonly >70), Caucasians
- affects arteries in head: swollen, red, tender
- pathology: nodular thickening due to intimal hyperplasia, intimal/medial granulomatous inflammation w/ giant cells, fragmentation of IEL
- may have thrombosis
- clinical: throbbing, headache, ocular symptoms common
Describe Takayasu Aortitis
- like Giant Cell arteritis except in young people
- granulomatous vasculitis of aorta or major branches
- women, asians, under 50 yo
Describe polyarteritis nodosa (PAN)
-multiple organs involved, spares lungs, medium sized vessels
-rare, in young adults 40-60yo
-immune complex reaction, assoc with Hep B
-Acute lesions: PMNs w/ fibrinoid necrosis, inflammation, microaneurysms w/ potentially palpable superficial nodule
—>thrombosis and infarct
-Chronic lesions: Mononuclear cells, scarring and fibrotic thickening, compromise or obliterate lumen
CLINICAL: depends on organ involvement
Describe microscopic polyangiitis.
- vasculitis of capillaries, small arterioles and small venules
- inflammatory response dominated by PMNs
- can affect vessels anywhere, most have kidney involvement
- palpable cutaneous purpura
- looks like PAN except for small vessels
Describe Henoch-Schonlein Purpura.
- most common vasculitis in kids
- related to IgA immune complex deposition
- triggers: Upper Resp infection, drugs/allergies, insect bites, immunizations
- PMN infiltration of small vessels,
- palpable purpura, mostly butt and lower extremities
Describe thromboangiitis obliterans
- heavy tobacco smokers
- often leads to ischemia and gangrene of the extremities
- focal acute and chronic inflammation, and thrombosis of medium and small sized arteries
Describe Reynaud Phenomenon.
- arterial vasospasm and ischemic changes of digits on the hands and feet following cold or emotional stress
- paroxysmal discoloration of fingers, toes, tips of nose/ears
- young, healthy women
- Primary RP: histologically normal in early stages, may have intimal thickening and thrombus formation in later stages
- Secondary RP (secondary to disease, e.g. lupus): vascular endothelial damage and inflammation common, thrombus and/or hemorrhage may occur, ulceration and gangrene
What is lymphangitis?
-bacterial infections may spread into and through lymphatics–>dilated lymphatics filled with PMNs/Macrophages, cellular debris, and bacteria
Describe angiosarcoma.
- rare, aggressive neoplasm from vascular or lymphatic endothelium
- can be anywhere, skin, breast, and liver common
- liver angiosarcomas associated with carcinogen exposure
Describe granuloma pyogenicum
- rapidly growing pedunculated red nodule on the skin, gingival or oral mucosa
- often follows trauma
