INTRODUCTION

Diseases caused by infectious pathogens are a major cause of illness and death among the elderly. Many of the most serious infectious diseases have a predilection for those at the extremes of age – individuals with relatively deficient immune function. In addition, infections common to persons of all ages can be devastating when they occur in those of more advanced age. Elderly individuals also are frequently found in environments, such as hospitals and nursing facilities, where antibiotic-resistant organisms are prevalent and indwelling catheters breech the protection offered by an intact integument. On the other end of the functionality spectrum, many older individuals are active and may spend their postretirement years traveling to locales where they are exposed to exotic organisms. Similarly, many elders are sexually active and remain at risk for sexually transmitted infections, especially when establishing new intimate partnerships.

Compounding their increase in risk of infection, older individuals may suffer from delays in diagnosis as their infections often present atypically. Infectious diseases in older persons frequently present without fever or leukocytosis and can be challenging to detect and localize – especially in those who suffer from cognitive impairments. Therefore, the diagnostic approach must be modified when the patient is elderly, and the clinician must appreciate the unique characteristics of this growing population.

THE ELDER HOST

Immune function changes with age and during advanced age can begin to falter. Both humeral and cellular immunity can wane during senescence.