Archive for April, 2008
Posted by Alex
Chronic fatigue syndrome (CFS) is characterized by at least 6 months of exceptional fatigue, with several associated chronic symptoms. Chronic diseases that would exclude the diagnosis of CFS include untreated hypothyroidism, sleep apnea, chronic active hepatitis, any psychotic disorder, dementia, anorexia nervosa or bulimia nervosa, recent substance abuse, and severe obesity. Bipolar affective disorder excludes a diagnosis of CFS, but nonpsychotic unipolar major depression or anxiety disorders do not. As so defined, patients with CFS represent a small fraction (1 to 3%) of all patients seeking medical care for the complaint of chronic fatigue.
Patients with CFS may be of any age, of either sex, and from all walks of life; the typical patient is a 35-year-old white woman. The onset is often sudden, frequently after an acute “viral” syndrome. In unusual cases, CFS follows in the wake not of a nondescript “flulike” illness but of a well-defined acute infectious illness, including acute infectious mononucleosis and Lyme disease (despite adequate antibacterial therapy and the resolution of Lyme disease-specific symptoms).
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Posted by Alex
Definition
Classic polyarteritis nodosa (PAN) is a multisystem, necrotizing vasculitis of small and medium-sized muscular arteries in which involvement of the renal and visceral arteries is characteristic. PAN does not involve pulmonary arteries, although bronchial vessels may be involved; granulomas, significant eosinophilia, and an allergic diathesis are not part of the classic syndrome. The term microscopic polyangiitis (microscopic polyarteritis) discribes the necrotizing vasculitis with few or no immune complexes (pauci-immune) affecting small vessels (capillaries, venules, or arterioles). Since necrotizing arteritis involving small and medium-sized arteries may also be present, it shares features with classic PAN except that glomerulonephritis is very common in microscopic polyangiitis, and pulmonary capillaritis often occurs.
Incidence And Prevalence
Pan is an uncommon disorder. The mean age at onset in reports of PAN is 48 years, and the male-to-female ratio is 1.6:1.
Pathophysiology And Pathogenesis
The vascular lesion in classic PAN is a necrotizing inflammation of small and medium-sized muscular arteries. The lesions are segmental and tend to involve bifurcations and branchings of arteries. They may spread circumferentially to involve adjacent veins. However, involvement of venules is not seen in classic PAN and, if present, suggests microscopic polyangiitis or the polyangiitis overlap syndrome (see below). In the acute stages of disease, polymorphonuclear neutrophils infiltrate all layers of the vessel wall and perivascular areas, which results in intimal proliferation and degeneration of the vessel wall. Mononuclear cells infiltrate the area as the lesions progress to the subacute and chronic stages. Fibrinoid necrosis of the vessels ensues with compromise of the lumen, thrombosis, infarction of the tissues supplied by the involved vessel, and, in some cases, hemorrhage. As the lesions heal, there is collagen deposition, which may lead to further occlusion of the vessel lumen. Aneurysmal dilatations up to 1 cm in size along the involved arteries are characteristic of classic PAN. Granulomas and substantial eosinophilia with eosinophilic tissue infiltrations are not characteristically found and suggest allergic angiitis and granulomatosis (see below). online canadian pharmacy
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Posted by Alex
Definition
Giant cell arteritis (also called temporal arteritis) is an inflammation of medium – and large-sized arteries. The disorder most frequently involves one or more branches of the carotid artery, particularly the temporal artery. The disorder is a systemic disease which can involve arteries in multiple locations.
Incidence And Prevalence
Giant cell arteritis has a high incidence in Scandanavia and in regions of the United States with large Scandanavian populations, compared to a lower incidence in southern Europe. The annual incidence rates in individuals 50 years of age and older range from 0.49 to 23.3 per 100,000 population. It occurs almost exclusively in individuals older than 55 years; however, well-documented cases have occurred in patients 40 years old or younger. It is more common in women than in men and is rare in blacks. Familial aggregation has been reported, as has an association with HLA-DR4. In addition, genetic linkage studies have demonstrated an association of giant cell arteritis with alleles at the HLA-DRB1 locus, particularly HLA-DRB1*04 variants. The disease is closely associated with polymyalgia rheumatica, which is more common than giant cell arteritis. In Olmsted County, Minnesota, the annual incidence of polymyalgia rheumatica in individuals 50 years of age and older is 52.5 per 100,000 population. Read the rest of this entry »
