Pitfalls in the Diagnosis and Therapy of Infections in Elderly Patients – A Mini-Review

Abstract

Extended life expectancy is paralleled by an increasing number of patients older than 65 years suffering from severe infections. Infections in this group of patients are generally more severe and associated with an increased risk of death. This is related to several factors which are discussed in this review. Specifically, immunosenescence and an atypical presentation of infection-associated symptoms with a subsequent delay of diagnosis and initiation of antimicrobial treatment are cornerstones in this dilemma. In addition, comorbidities and comedications, a changing spectrum of pathogens with a higher percentage of multiresistant pathogens, and more importantly, an altered pharmacokinetics of antimicrobial drugs are further contributing factors to the adverse outcome of infections in elderly subjects. Infections in the elderly demand special attention in terms of diagnosis and treatment. As the mortality rates are high, special emphasis must be put on preventive measures including effective vaccination strategies and establishment of hygiene standards to prevent transmission of multiresistant pathogens among elderly patients, both in health care centers and nursing homes.

Challenges with Diagnosing and Managing Sepsis in Older Adults

“…Age-related changes in the immune system, otherwise known as immunosenescence, increase the vulnerability of the older adult to contract an infection but decrease the older adults’ immune response 7 . There are multiple, complex factors that contribute to immunosenescence and increase the risk of older adults in acquiring sepsis 8 .…”

“…Older adults experience a decrease in circulating thyroid hormone levels. Decreasing thyroid hormone levels have been linked to decrease in natural killer cell activity, which provides additional rationale for the blunting of the immune response to novel antigens 7,22 . With all of these factors affecting immunosenescence, older adults are at an elevated risk of infection.…”

“…The most common example is the presence of altered mental status, which is a nonspecific marker of infection in older patients and does not necessarily indicate a nervous system infection as it would in younger adults. Other examples of unique symptoms of infection in older patients include: lethargy, tachypnea, loss of appetite, dehydration, weakness, dizziness, falls, and incontinence 7,23,24 . Finally, due to the presence of multiple comorbid conditions and an increased incidence of delirium in this patient population, it can be challenging to acquire a thorough history of present illness that would normally assist in the initial diagnosis of infection 25 .…”

“…Older adults with urinary tract infections often present with confusion and they are less likely than younger adults to present with the classic symptoms of urinary frequency and pain 25 . Moreover, older adults with pneumonia are more likely to present with generalized weakness, falls, and hypoxemia, rather than the typical symptoms of fever and chest pain 7,25 .…”

“…The underlying problem assessing temperature in older adults is the fact that the body’s baseline temperature changes with age and can often times be 0.6–0.8° C lower in older adults than in younger adults 26 . Additionally, there is a decreased temperature response to infection as a result of decreased cytokine production, decreased sensitivity of the hypothalamus to cytokines, and poor peripheral thermoregulation 7 . Malnutrition also leads to a decreased temperature response to infection 7 .…”