Keywords: Chapter 10, Blood Vessels

Allergic granulomatosis

A systemic vasculitis with prominant eosinophilia seen in young patients with asthma.
Aneurysm
Localized dilatations of arteries caused by a congenital or acquired weakness in the media.
Aneurysm, atherosclerotic
Usually affects the abdominal aorta; develops as a result of destruction and weakening of the media by atheromatous changes. Often contains a mural thrombus.
Aneurysm, congenital
There is a focal congenital defect in the arterial wall leading to a vascular aneurysm also known as a berry aneurysm. These occur mainly in the circle of Willis or one of the main branches. Subarachnoid hemorrhage, sometimes fatal, is a dreaded complication.
Aneurysm, dissecting
Actually a hematoma in the wall of an artery - usually the aorta. Splitting of the media occurs, blood enters the split through a tear in the intima. There is a weakening of the connective tissue of the media - cystic medial necrosis. It may be a complication of Marfan's syndrome. The majority of patients have a history of hypertension.
Aneurysm, mycotic
These lesions are caused by significant weakening of the blood vessel wall by infection.
Aneurysm, syphilitic
Uncommon lesion; usually affects the ascending aorta and arch. Microscopically, there is endarteritis and periarteritis of the vasa vasosum, with obliterative changes, leading to focal necrosis and scarring of the media and disruption of the elastic lamellae and weakening of the wall. Under the pressure of blood pumped from the left ventricle, the ascending aorta and arch dilate.
Angiitis, hypersensitivity
A broad category of inflammatory vascular lesions, presumed to be a response to exogenous substances such as bacterial products or drugs.
Angioplasty
A procedure by which a narrowed artery, usually a coronary artery is dilated by the inflation of a balloon catheter.
Angiosarcoma
A malignant neoplasm of blood vessels, occurring most commonly in subcutaneous, soft tissues, but also in internal organs such as liver and spleen.
Arteriosclerosis
Vascular changes characterized by thickening and loss of elasticity of arterial walls. Similar changes in arterioles are known as arteriolosclerosis. It may be seen in patients with chronic hypertension, and, to a lesser degree, as part of the aging process.
Arteriosclerosis, hyaline
The blood vessel walls take on a glassy, "hyaline" appearance. This change reflects mild or "benign" hypertension and are particularly seen in kidneys.
Arteriosclerosis, hyperplastic
This change refers to the concentric rings of increased connective tissue and smooth muscle giving the arteries an onion-skin appearance. Such changes signify acceleration of the hypertension.
Arteriosclerosis, Monckeberg's medial sclerosis
Seen in older persons. Affects medium-sized and large arteries and consists of degenerative calcification of media. Cause is not known; not of great clinical significance. Can accompany atherosclerotic changes.
Arteritis
Inflammation of arteries.
Arteritis, infectious
In most cases this is caused by the direct invasion of arteries by infectious agents - usually bacteria or fungi, such as in the neighborhood of abscesses or pneumonic lesions. Associated thrombosis will cause infarction.
Arteritis, Takayasu
An inflammatory disorder of large arteries, classically the aortic arch and its major branches with localized stenosis or occlusion; also known as "pulseless disease". An auto-immune basis has been proposed. It is most common in young women, similar to other auto-immune disorders.
Arteritis, temporal, (giant cell or granulomatous arteritis)
Focal, chronic, granulomatous inflammation of the temporal arteries. It can occasionally involve other cranial arteries, the aorta and its branches. Grossly, the affected artery is cord like with nodular thickening and narrowing of the lumen. Microscopically, there is granulomatous inflammation of the media and intima with varying admixtures of chronic and acute inflammatory cells, histocytes and giant cells. A thrombus may be present. It is most common in older adults.
Atheroma
Necrotic mass of lipid in the center of an atherosclerotic lesion. This term is now also used for the entire atherosclerotic lesion.
Atheromatous plaque
The characteristic lesion of atherosclerosis, consisting of a fibrous cap and an atheroma.
Atherosclerosis
a disease of large and medium-sized arteries that result in the progressive accumulation within the intima of smooth muscle cells and lipids.
Atherosclerosis, complicated lesions of
Include thrombosis, neovascularization of the fibrous cap, thinning of media, calcification and ulceration of the basic lesion i.e. the atheromatous plaque.
Atherosclerosis, complications of
i) Acute occlusion, usually due to hemorrhage into a plaque, or thrombosis: this will cause infarction e.g. coronary artery and myocardial infarct. ii)Chronic narrowing of vascular lumen; causing chronic ischemia and sometimes atrophy e.g. kidney. iii) Aneurysm formation, iv) Embolism of atheromatous material (cholesterol embolism).
Atherosclerosis, risk factors for
Any factor with a doubling in the incidence of ischemic heart disease. This includes 1) hypertension, 2) blood cholesterol level, 3) cigarette smoking, 4) diabetes, 5) increasing age and male sex, 6) physical inactivity and stressful life patterns.
Atherosclerosis; hypotheses of atherogenesis
Bacillary angiomatosis
A distinct non-neoplastic proliferation of small blood vessels in the skin, lymph nodes and visceral organs of patients with HIV infection or other immunosuppressed states. Caused by small bacteria Bartonella henselae. Responds to antibiotic therapy and should be distinguished from Kaposi's sarcoma.
Buerger disease, (thromboangiitis obliterans)
An occlusive, inflammatory disease of the medium-sized and small arteries in the distal arms and legs. Patients are usually young or middle-aged male smokers. Symptoms typically include intermittent claudication (cramping, muscular pain following exercise, relieved by rest). Microscopically, there is acute inflammation of arteries with thrombosis and obliteration of lumen.
Deep venous thrombosis (DVT)
refers to both phlebothrombosis and thrombophlebitis. Predisposing factors include prolonged bed rest, reduced cardiac output as in the post-operative or post-partum period, congestive cardiac failures. The most dreaded complication is pulmonary embolism.
Familial hypercholesterolemia
An autosomal dominant disease with a defect in the LDL receptors resulting in markedly increased cholesterol level and an increased incidence of early onset of atherosclerosis and its complications.
Fatty streak
flat or slightly elevated intimal lesions containing intra and extra-cellular lipid. May be the initial lesion of atherosclerosis.
Fibromuscular dysplasia
A non-inflammatory thickening of large and medium sized muscular arteries causing stenosis. This is most significant in the renal arteries where it is a cause of secondary hypertension.
Fibrous cap
This is a part of the typical atherosclerotic lesion and consists of a layer of fibrous tissue in the intima covering the lipid rich atheroma.
Gangrene
A clinical term used to indicate ischemic necrosis (coagulative type) with superimposed bacterial infection and leukocyte accumulation.
Glomus tumor (glomangioma)
a benign, painful tumor of the glomus body, (neuromyoarterial receptor which is sensitive to temperature and regulates arterial flow). Typically, these tumors are small, reddish blue and occur most commonly in the distal fingers and toes. Histologically, there is a mixture of branching vascular channels and nests of glomus cells.
Hemangioendothelioma
A vascular tumor composed of endothelial cells, considered to be intermediate between benign hemangiomas and frankly malignant angiosarcomas. Histologically, several variants are described, based on the predominant cell type - spindle cell, epithelioid etc. In general, surgical excision is curative; rarely do these tumors metastasize.
Hemangioma
Common congenital vascular lesions usually occurring in skin, but may be found in internal organs. Their true origin is uncertain - are they true neoplasms or hamartomas? Capillary hemangiomas are composed of vascular channels the size of normal capillaries. Those that are present in newborns often regress by the age of 5 years. Cavernous hemangiomas consists of large vascular channels. These do not regress.
Hemangiopericytoma
Rare malignant neoplasm thought to arise from pericytes, smooth muscle cells external to the walls of capillaries and arterioles.
Hypertension
Defined by the WHO as a systolic pressure greater than 160 mm Hg or a diastolic pressure greater than 90, or both. The etiology of most cases is unknown - "essential" or primary hypertension.
Hypertension, malignant, (accelerated)
A state of hypertension resulting in rapidly progressive vascular compromise resulting in symptomatic diseases of brain, heart or kidney. Pressures are usually greater than 160/110. Blood vessels show fibrinoid necrosis or concentric hyperplasia of smooth muscle-cells ("onion-skin" changes).
Intimal cell masses
These are thickened white areas at branch points in the arterial tree. Microscopically they are composed mainly of smooth muscle cells and connective tissue, but no fat. Relationship to subsequent atherosclerosis is suggested.
Kaposi sarcoma
A malignant tumor derived from endothelial cells. A sporadic form exists,; but now it is more likely to be the epidemic form in association with AIDS. Clinically, painful purple to brown skin lesions are present. Histologically, a mixture of capillaries and spindle cells is present with inflammatory changes and hemosiderin. It may be widely disseminated at the time of death; but is not usually the cause of death.
Kawasaki syndrome, (muco-cutaneous lymph node syndrome)
An acute disease of infancy and early childhood with fever, rash, conjunctival and oral lesions, lymphadenitis and pathologically an acute necrotizing vasculitis. Coronary arteries affected in 70% of patients, with aneurysm formation. Thought to be of viral etiology.
Lymphedema
Occurs when there is obstruction to Lymphatics as in scarring, tumor, parasites (Filaria).
Multiple hemangiomatous syndromes
Angiomatous lesions present in two or more tissues e.g, -von Hippel-Lindau syndrome - hemangiomas in brain and retina; - Sturge-Weber syndrome - vascular lesions in brain and skin.
Phlebothrombosis
Venous thrombosis not initiated by inflammation.
Polyarteritis nodosa (PAN)
An acute, necrotizing vasculitis affecting mainly medium-sized arteries. The lesions are patchy and consist of an area of fibrinoid necrosis and acute inflammation sometimes with thrombosis and small aneurysms. Common sites are kidneys, heart, skeletal muscle and skin.
Raynaud phenomenon
Intermittent attacks of ischemia of fingers or toes due to intense arterial vasospasm, often precipitated by cold or emotional stimuli.
Thrombolytic therapy
Thrombolytic enzymes such as tissue plasminogen activator or streptokinase are infused directly into the obstructed artery to lyse the thrombus. Used in coronary arteries or leg arteries.
Thrombophlebitis
Inflammation and secondary thrombosis of veins, usually small veins as part of a local reaction to bacterial infection.
Varicose veins
Enlarged and tortuous blood vessels. Occurs most commonly in the legs. Predisposing factors include older age, female sex, heredity, posture and obesity. There is dilation and elongation of the veins as well as incompetence of venous valves. Examples of varicose veins at other sites include hemorrhoids, (rectal), esophageal varices and varicocele (scrotum).
Vasculitis
Inflammation and necrosis of blood vessels, including arteries, veins and capillaries. The damage may be due to infectious agents, mechanical trauma, radiation or toxins; often no specific etiologic factor is identified. the pathogenesis is thought to involve immune mechanisms such as deposition of immune complexes, direct attack by circulating antibodies etc.
Vasculitis, leukocytoclastic
A form of hypersensitivity angiitis, confined predominantly to the skin and presenting as purpuric lesions. Microscopically, there is fibrinoid necrosis of small vessels and an acute inflammatory reaction and extravasated red cells. Clinically presents as purpura.
Wegener granulomatosis
A systemic necrotizing vasculitis of unknown etiology characterized by granulomatous lesions of the respiratory tract (nose, sinuses and lungs) and renal glomerular disease. The majority of patients have anti-neutrophilic cytoplasmic antibodies (ANCA) in the blood suggesting that these antibodies activate neutrophils to attack blood vessels. Clinical features include those of sinusitis, pneumonitis, hematuria, proteinuria and nonspecific symptoms such as rashes, muscular and joint pains. Pathologic changes include vasculitis, granulomatous inflammation and large zones of necrosis