An all-encompassing definition of aging has yet to be forthcoming, because of the diversity of phenomena associated with this process.<sup>7 Blumenthal H.T. Biology of aging Care of the Geriatric Patient in the Tradition of E V Cowdry St. Louis: C V Mosby Co. (1983). 

Cliccare qui per andare alla sezione Riferimenti</sup> With the aging process there is a steadily increasing susceptibility to ultimately fatal disease. It is an interesting observation, however, that the diseases to which humans ultimately succumb do not greatly alter their predetermined life span.<sup>7 Blumenthal H.T. Biology of aging Care of the Geriatric Patient in the Tradition of E V Cowdry St. Louis: C V Mosby Co. (1983). 

Cliccare qui per andare alla sezione Riferimenti</sup> Respiratory tract infections are a major cause of disease and death in the elderly and have been recognized as being so for many years. The important effects of age on the symptoms and clinical presentation of pneumonia were accurately described by Sir William Osler many years ago, in his textbook of medicine.<sup>62 Osler W. Principles and Practice of Medicine   New York: Appleton (1892). 

Cliccare qui per andare alla sezione Riferimenti</sup> Initially described as the “Captain of the Men of Death,” pneumonia became known, perhaps more philosophically, as the “friend of the aged.”<sup>62 Osler W. Principles and Practice of Medicine   New York: Appleton (1892). 

Cliccare qui per andare alla sezione Riferimenti</sup> Pneumonia in the elderly is often noted to be more severe than in younger patients; the aged need to be admitted more often to hospital and have longer hospital stays, more complications, and, most importantly, a higher mortality rate. <sup>19 Esposito A.L. Pneumonia in the elderly Respiratory Infections. Diagnosis and Management New York: Raven Press (1994).  257-274

Cliccare qui per andare alla sezione Riferimenti, 22 Fein A.M., Feinsilver S.H., Niederman M.S. Atypical manifestations of pneumonia in the elderly Clin Chest Med 1991 ;  12 : 319-336

Cliccare qui per andare alla sezione Riferimenti</sup> In many studies, it is not simply chronologic age per se that has been shown to impact negatively on the manifestations of pneumonia in the elderly, but rather the underlying comorbid illness that is frequently present. In most studies of pneumonia, an age of 60 or 65 years has been used as the cut-off to describe elderly patients.