Are the elderly more susceptible to infections?
Older adults become more susceptible to infections due to several
factors. As people get older, it is more frequent that they have comorbid
conditions, such as diabetes, renal insufficiency and arthritis. Many comorbid
conditions, both the number and type of comorbid conditions, predispose people
to infections. Often, when people age, there is immunosenescence, which means
that the immune system doesnt function as well or as vigorously. The
combination of increased comorbid conditions and the decrease in activity of
the immune system can make people more prone to infections. The other syndrome
that occurs when people become old is frailty. When people become frail, their
body mass index drops and they have a harder time functioning independently, in
terms of their daily living activities. They become more prone to falls and
injuries. All of these things predispose older people to infections. There is
an increased association with being older and an increased risk of infection,
but it probably has more to do with how successfully some people age. Some
people age and they remain active and healthy, and individuals such as that
probably do not have an increased risk of infections. But individuals who
become frailer and more dependent on others for maintaining their health status
and their daily activities, their risk for infections increases greatly.
Keith S. Kaye, MD
Are infections in the elderly more common in places such as nursing
homes, or are they prevalent in the entire elderly population?
What you start seeing is that people who need a lot of assistance or
have comorbid conditions are more likely to end up in assisted living
facilities or nursing homes. So, some of the highest-risk older adults are in
nursing homes. I do think that there is an association between increased age in
general and infection risk. You have to be careful not to lump all older adults
into one single category. Older people in general may be at increased risk for
infection, but there are certainly subsets of older adults, some of whom that
are at increased risk and some of whom really are not.
What special considerations are there when treating infections in the
Treating infections in older adults is a special niche. One thing that
needs to be considered is the side effects and tolerability of the medications.
Sometimes, in older adults, their metabolism and their clearance of medications
changes as they get older. Also, they are often on other medications.
Sometimes, they can be susceptible to side effects of medications, so the side
effect profile of medications must be taken into account when treating
infections in the elderly. You want to take into account the other medications
they are taking and also their renal function and how well you dose the
medication. Other side effects of antibiotics include Clostridium
difficile, which ironically, is caused by antibiotic use. We used to think
that antibiotics were harmless. If there is any concern about whether or not
people might have an infection, particularly those adults who are in
institutions such as nursing homes, we need to be more thoughtful about who
really needs antibiotics. It used to be that if a patient had a positive
culture in their urine, you treated it regardless. But now, we have to think
about whether someone truly has an infection or is just colonized, as
antibiotics use can lead to superinfections.
What are some of the best ways to prevent infections in the elderly?
There are a few different ways. One is vaccination. We have a good
vaccine program nationally, but our vaccination rates are suboptimal for a
developed country such as the US. Yearly influenza vaccinations are necessary.
Influenza not only causes the flu, but in older adults particularly, it causes
superinfections with bacterial pneumonia. Getting the flu vaccine and making
sure that older adults are up-to-date on their pneumococcal vaccination are
important. In institutional settings, such as in hospitals and nursing homes,
good hand hygiene by staff and avoiding the spread of pathogens from one
patient to another is important. The final thing is for older adults to stay
active. The longer they can remain independent and function without needing
hands-on assistance or needing feeding tubes or urinary catheters will decrease
the risk of infections, as well.
Is it difficult to diagnose infections in the elderly?
Infections in the elderly can present in atypical ways. A lot of times,
older adults may not have a fever as readily as individuals who are younger.
The fever may be lower grade. Sometimes, signs of infections might be a change
in mental status or poorer functioning. Things such as the cough associated
with pneumonia may not be as recognizable. The other issue with older adults,
particularly when there is dementia or other comorbid conditions that may
interfere with the accuracy or ability to interpret their history, you
cant get a good history of what hurts or what is bothering them. It can
be a challenge to figure out if they have an infection or to determine what
type of infection they have. Sometimes, standard tests such as chest X-rays
might initially not be positive because the patient is dehydrated and pneumonia
cant be seen. This can be confusing. Once individuals are hydrated or in
the hospital for a while, things may become more obvious. So symptoms can be
atypical and underwhelming; also, the history can be difficult to elicit and
some tests such as X-rays may not be as sensitive to detect abnormalities in
older adults. by Emily Shafer