The elderly can suffer significant morbidity or mortality if an infectious diagnosis is missed. The infectious syndromes listed in Table 2 are associated with significantly higher mortality in the older adult. Overall, infections account for up to 40% of all mortality in those 65 or older.²³ For these reasons, the emergency physician must consider infection, regardless of a fever, in the differential diagnosis of any senior presenting to the ED.



Although the potential etiologies of fever in the elderly are legion (see Table 3), numerous studies have identified respiratory, urinary tract, and soft-tissue infections as the predominant causes of fever in elderly who present to EDs.^5,24-28 These three types of infections account for 80% of secondary bacteremia in nursing home facilities.²⁹ The emergency physician can use the acronym PUS (Pneumonia, UTI, Soft Tissue) to remember these diagnoses when evaluating the febrile elderly patient.²⁴ Other diagnoses should be pursued when suggested by the history and physical exam or when an investigation of the "PUS" triad is negative.



Infectious syndromes are over-represented in the geriatric population. Forty percent of all cases of bacteremia and sepsis occur in the elderly, and are responsible for an estimated 60% of deaths. Gangrene of the appendix and gallbladder are more common in the elderly, while diverticulitis is found almost exclusively in the older patient. Sixty percent of tetanus and the majority of shingles occur in the elderly. Tuberculosis is also disproportionate, especially in nursing homes.³⁰

In formulating the differential diagnosis, it is important to consider the patient's functional status and living situation. Nursing home residents are more likely to develop nosocomial pneumonia, complicated urinary tract infection, or infected pressure ulcers than the independent elderly. For the recently hospitalized, consider a surgical wound infection or septic thrombophlebitis.³⁰