Pneumonia in the elderly.

However it is assessed, pneumonia is more important in the elderly than in any other age group. For community acquired or nosocomial pneumonia elderly adults far exceed any other age group with 97% of all pneumonia deaths occurring in this age group. Increasingly pneumonia in the immunocompromised elderly is also being seen. The factors which determine the increased frequency of pneumonia in the elderly include social effects, immune changes and physiological changes in the lungs. These are compounded by the effects of the high frequency of chronic disease in this group. The clinical presentation of pneumonia is slightly different in the elderly and this, together with the presence of underlying disease, may make diagnosis difficult; however, focal signs in the chest are nearly always present. Streptococcus pneumoniae is the most important cause of community acquired pneumonia in the elderly followed by Haemophilus influenzae and the influenza viruses. In contrast to younger adults Mycoplasma pneumoniae infection is rarely identified. The role of Gram-negative enterobacteria is unclear, with some studies suggesting that this is the most frequent pathogen, others finding no cases at all. The pathogens causing nosocomial pneumonia are similar to those in younger adults. Management is more difficult because of the effects of underlying diseases, altered drug pharmacokinetics and drug interactions and the outcome is significantly worse with 25% of adults with community acquired pneumonia dying in recent prospective studies.