The Western journal of medicine
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Elderly persons are prone to more frequent or greater morbidity and higher mortality from selected infectious diseases than the average population. Factors that may affect this increased predilection or poorer prognosis include environmental exposure, normal physiological changes of aging, coexistence of chronic diseases and alteration of host defense mechanisms. Infections to which the aged are particularly vulnerable are pneumonia, influenza, tuberculosis, urinary tract infection, Gram-negative bacteremia, intra-abdominal sepsis, soft tissue infection, infective endocarditis, bacterial meningitis, bacterial arthritis and herpes zoster infection.
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Platelets play an important role in hemostasis, and alterations in platelet function may be the cause of abnormal bleeding in a wide variety of congenital and acquired clinical disorders. Platelet dysfunction may be classified as disorders of (1) substrate connective tissue, (2) adhesion, (3) aggregation and (4) platelet-release reaction. The congenital defects of platelet function, although uncommon, have provided important insights into platelet physiology and pathophysiology and, as a group, are less common, better characterized and more readily classified than the acquired defects. ⋯ A specific diagnosis often requires measurements of the factor VIII and von Willebrand factor complex and other tests of platelet function. Some of these tests may be available only in specialized laboratories. Therapy for bleeding episodes resulting from platelet dysfunction is directed at (1) removing or treating the underlying cause of the platelet disorder; (2) replacing the missing plasma cofactors needed to support normal platelet function (such as by the transfusion of cryoprecipitate in patients with von Willebrand disease, and (3) transfusing functional platelets in the form of platelet concentrates in patients with disorders of intrinsic platelet dysfunction.