Vascular pathology Flashcards
What are the three layers of the arterial wall?
Intima, media and adventitia
What are the basic clinical findings in vasculitis?
1) nonspecific symptoms of inflammation (fever, fatigue, weight loss and myalgias)
2) symptoms of organ ischemia depending on which blood vessel the vasculitis is affecting
What are the types of large-vessel vasculitis? medium-vessel vasculitis? small-vessel vasculitis?
Large vessel (aorta and major branches) - Temporal (Giant Cell) arteritis, Takayasu arteritis Medium vessel (muscular arteries that supply organs) - polyarteritis nodosa, Kawasaki disease, Buerger disease Small vessel (arterioles, capillaries) - Wegener granulomatosus, microscopic polyangiitis, Churg-Strauss syndrome, Henoch-Schonlein Purpura (HSP)
Temporal Giant Cell arteritis is a vasculitis that affects what size arteries? Which arteries does temporal giant cell arteritis usually affect? What clinical symptoms does the patient present with? What are the histological characteristics? What is the treatment?
Affect large size blood vessels, classically the branches of the external carotid artery. If the temporal artery is affected, the patient presents with headache. If the opthalmic artery (branch off maxillary artery) is affected, the patient presents with visual disturbances. If lingual or facial arteries are affected, the patient presents with jaw claudication (pain in the jaw or ear while chewing). Biopsy of affected segment shows giant cells and intimal fibrosis. A negative biopsy does not rule out the disease. The treatment is corticosteroids.
Takayasu arteritis is a vasculitis that affects what size arteries? Which arteries does Takayasu arteritis usually affect? What clinical symptoms does the patient present with? What is the treatment?
Takayasu arteritis affects large vessels, classically the aortic arch and its branches. Presents as visual or neurologic disturbances and a weak or absent pulse in the upper extremities. Treat with corticosteroids.
Polyarteritis Nodosa is a vasculitis that affects what size arteries? How does it classically present? What does it look like on imaging?
Medium sized vessels. It presents in young adults as hypertension (renal artery involvement), abdominal pain with melena (mesenteric artery involvement) and skin lesions. The skin lesions have alternating parts of fibrinoid necrosis and healed fibrosis, producing a “string of pearls” appearance.
Kawasaki disease is a vasculitis that affects what size arteries? What type of person typically presents with it? What are the signs and symptoms? What are the treatments?
Kawasaki disease affects medium sized blood vessels. It classically affects Asian children less than 4 y/o. It commonly affects the coronary arteries leading to myocardial infarction or aneurysm with rupture. Treatment is aspirin (only time you give aspirin to a child!) and IVIG
Buerger disease is a vasculitis that affects what size arteries? What are the clinical symptoms? What risk factors is it associated with?
Buerger disease is a vasculitis of the medium sized blood vessels. Its symptoms are ulceration, gangrene and autoamputation of fingers and toes. It is highly associated with smoking.
Wegner’s granulomatosis is a vasculitis that affects what size arteries? What does it look like histologically? What organs does it usually involve? What symptoms does this lead to?
Wegners affects small sized arteries. It is large necrotizing granulomas with adjacent necrotizing vasculitis. Serum c-ANCA levels are elevated. It commonly effects the nasopharynx, lungs and kidneys leading to sinusitis or nasopharyngeal ulcerations, hemoptysis with bilateral nodular lung infiltrates and hematuria due to glomerulonephritis.
How is microscopic polyangiitis similar to Wegners granulomatosis? How is it different?
Both are small sized vessel vasculitis involving the lung and kidney (hemoptysis and hematuria). However MP doesn’t have nasopharynx involvement while WG does. MP doesn’t have granulomas while WG does. MP has elevated p-ANCA while WG has elevated c-ANCA.
What is Churg-Strauss syndrome? What cell type is elevated? What histological marker is present?
Churg-Strauss syndrome is a necrotizing granulomatous vasculities involving arteries of the heart and lungs. Eosinophils are typically elevated. Serum p-ANCA levels are elevated.
What is the pathogenesis of Henoch-Schonlein Purpura? What are the symptoms? After what disease does this typically occur?
Vasculitis due to IgA immune complex deposition. Usually presents with palpable purpura on buttocks and legs, GI pain and bleeding and hematuria. HSP usually follows an upper respiratory tract infection.
What is the difference between primary and secondary hypertension?
Primary hypertension (95% of cases) has no known etiology but risk factors include age, race, stress, obesity and a high-salt diet. Secondary hypertension (5% of cases) is caused by renal artery stenosis which decreases blood flow to the glomerulus. This decrease is sensed by the juxtaglomerular cells which respond by secreting renin. The renin-angiotensin system produces angiotensin II which increases blood pressure (leading to HTN) by two mechanisms 1) contracts arteriole smooth muscle, increasing total peripheral resistance and 2) stimulating release of aldosterone which increases sodium and water retention in the kidneys
What is arteriosclerosis? What three patterns give rise to it?
ArterIOsclerosis is a hardening of the arteries due to thickening of the blood vessel wall. Hardening arises in three different ways:
atherosclerosis - formation of intimal plaques
arterIOLOsclerosis - narrowing of small arterioles
Monckeberg medial calcific sclerosis
How do atherosclerotic plaques form? What arteries are the most frequently involved? What are the common complications of atherosclerosis?
Chromic injury to the endothelium allows lipids/cholesterol to leak into the intima. Lipids are oxidized and then consumed by macrophages. Because of all the ingested lipids, these macrophages are termed “foam cells.” Factors released from macrophages and the blood vessel wall stimulate smooth muscle cell recruitment and proliferation and ECM production, enclosing the necrotic lipid core in a fibromuscular cap.
Frequently involved arteries
abdominal aorta, coronary arteries, popliteal arteries, internal carotid arteries, vessels of the circle of Willis
complications:
The intimal plaque (atheroma) is a raised lesion that obstructs blood flow causing ischemia. If the plaque ruptures, it can cause thrombosis, stroke or infarction. Weakening of the vessel wall can lead to an aneurysm.
What are the two types of arteriolosclerosis? How does each type lead to a narrowing of the small arterioles? What are the causes of each type of arteriolosclerosis?
Hyaline arteriolosclerosis - proteins leak into the vessel wall producing vascular thickening and luminal narrowing. Caused by long standing benign hypertension or diabetes
hyperplastic arteriolosclerosis - hyperplasia of the smooth muscle cells produces vascular thickening and luminal narrowing. Caused by malignant hypertension.
What is Monckeberg medial calcific sclerosis?
calcification of the media layer of medium sized arteries. Does NOT cause luminal narrowing so it is clinically silent and non-obstructive. Usually seen as an incidental finding on x-ray or mammography
What is aortic dissection? What are the complications? What are the causes of aortic dissection? How does this condition present?
When an intimal tear allows blood to spread longitudinally in the media layer.The complications are 1) rupture through the adventitia and massive hemorrhage 2) cardiac tamponade (hemorrhage into the pericardial sac).
Two main causes: 1) hypertension results in hyaline arteriolosclerosis of vaso vasorum. A lack of blood supply to the media causes atrophy and weakens the wall. 2) inherent weakness of connective tissue in the media from Marfan’s syndrome or Ehlers-Danlos syndrome. Patients present with a sudden, excruciating, tearing pain that radiates to the back.
What are the major causes of a thoracic aneurysm? an abdominal aneurysm?
Both are because the aortic media isn’t getting enough nutrients so it atrophies
thoracic - tertiary syphilis causes endarteritis of the vaso vasorum, resulting in atrophy and weakness of the aortic wall.
abdominal - atherosclerosis increases the diffusion barrier to the media, resulting in atrophy and weakness of the aortic wall
What is the major complication of a thoracic aneurysm? an abdominal aneurysm?
thoracic - dilation of the aortic valve root, resulting in aortic valve insufficiency, compression of structures in the mediastinum (lungs, esophagus), thrombosis/embolus, rupture
abdominal - rupture, compression of local structures, thrombosis/embolus
What is aortic valve insufficiency/aortic regurgitation? What is the most common cause?
When the aortic valve does not close properly so some of the blood that was pumped out during systole goes back into the left ventricle during diastole. It is most commonly caused by aortic root dilation.
What are the three vascular tumors? Are they benign or malignant? What tissues do they usually affect?
hemangioma - benign tumor of blood vessels in the skin or liver
angiosarcoma - aggressive malignant tumor of endothelial cells in the skin, liver or breast. Polyvinyl chloride exposure is associated with liver angiosarcoma
kaposi sarcoma - low-grade malignant tumor of endothelial cells in the skin. Associated with human herpes virus 8. Typically seen in older, eastern european males, AIDS patients, transplant recipients.
