INFECTION IN THE ELDERLY · Overview •Recognizing and treating infections in the elderly patient...

INFECTION IN THE ELDERLYΙδιαιτερότητες των λοιμώξεων στην τρίτη ηλικία

Γεώργιος Πετρίκκος

Παθολόγος – Λοιμωξιολόγος

• Ομότιμος Καθηγητής ΕΚΠΑ

• Κοσμήτορας Ιατρικής και Οδοντιατρικής Σχολής

Ευρωπαϊκού Πανεπιστημίου Κύπρου

[email protected] , [email protected]

mailto:[email protected]

Overview

• Recognizing and treating infections in the elderly patient can be particularly challenging because symptoms are often quite subtle and atypical in older adults.

• Recognize common atypical presentations of various geriatric infections

• Institute treatment in the elderly with respect to medication dosing and drug interactions

• Identify admission criteria and appropriate transitioning of care from the Emergency Department

Introduction

• Examples on nonspecific symptoms:- Generalized malaise

- Falls- - Changes in mental status or cognitive

impairment- - Anorexia

Introduction

• The classical manifestation of infection, fever, and leukocytosis, may be absent or blunted in 20-30% of serious elderly infections.

• In contrast to the young where fever is commonly attributed to a viral process, in the elderly it is associated with severe bacterial infections.

Adedipe A, Lowenstein R. Emerg Med Clin N Am 2006; 24(2):433-448.

Introduction -Epidemiology

• By 2020, patients aged 65 years old and older will constitute 16.3% of the population.

• Already, they account for over 15 million ED visits each year, and a large percentage of these visits are related to infection.

Caterino JM. Emerg Med Clin N Am 2008;26(2):319-343.

Introduction-mortality

• Infection is the primary cause of death in one-third of individuals aged 65 years and older and is a contributor to death for many others.

• Elderly patients have three times the mortality from pneumonia and five to ten times the mortality from urinary tract infection when compared with younger adults.

Introduction-Risk Factors

• Older adults are at greater infection risk due to immune senescence, comorbidities, and communal residence.

• Infection also has a marked impact on morbidity in older adults, exacerbating underlying illnesses and initiating functional decline.

These statistics make appropriate evaluation and treatment of the infected elderly an essential skill.


Risk Factors

• Aging is associated with:- - numerous chronic illnesses and comorbid conditions

- - polypharmacy and immunosuppressive medications

- - changes in the immune system that include a reduction of T-lymphocyte function and cell-mediated immunity

Risk Factors

• There is an impairment of the normal physiologic reserves seen in the elderly:

- - decreased cough reflex leading to aspiration pneumonia

- - impaired arterial and venous circulation

- - compromised wound healing, making cellulitis a common infection

Risk Factors

• Living environments, such as assisted living facilities and nursing homes, allow for the development of infection and foster the transmission of infectious agents.

• These facilities contribute to the rise and exposure of antibiotic-resistant bacteria (MRSA and VRE)

Risk Factors

• Invasive devices, which include indwelling urinary catheters, intravenous catheters, feeding tubes, and tracheostomies, are more common in the elderly.

• These devices compromise host defenses enabling bacteria to enter the body and cause infection.

Risk Factors

• Malnutrition, common in the nursing home population, is associated with a limited immune response and impaired wound healing.

• Polypharmacy is also frequently observed and can contribute to infection.

Antibiotic dosing should take into account reduced renal function with aging.

However, it is important that older adults with serious infection receive a first

antibiotic dose at the highest level with known safety profile.

Institutionalized older adults are at increased risk for antibiotic resistance,

particularly those with indwelling devices (bladder or vascular catheters,

gastrostomy tubes, etc).

'Antibiotic management'

https://www.uptodate.com/index.html#H1498031

Fever and Infection

• Elevated temperature is one of the most common complaints in the elderly and is present in approximately 10% of elderly ED visits.

• When fever is present, it is infectious in etiology approximately 90% of the time.

• It is important to note that criteria for fevers in the elderly are unique, and include elevations in body temperature from baseline of 1.3 °C or greater.

• Furthermore, hypothermia, a decrease in body temperature, is not an uncommon presentation of an underlying serious infection.


Fever and Infection

• The most accurate definition of fever in the elderly may be a change in temperature from the patient’s baseline.

• Elderly ED patients with a temperature of 37.2°C (99°F) or higher, or with an increase of 1.3°C (2°F) from baseline should be considered to be febrile.


Fever and Infection

• A temperature greater than 37.8 °C (100 °F) is associated with markers of serious illness over 75% of the time as determined by:

- - positive blood cultures

- - death within 1 month

- - the need for surgery or an invasive procedure

- - hospitalization for 4 or more days

- - the administration of IV antibiotics for 3 or more days

- - a repeat ED visit within 72 hours


Fever and Infection

• Fever in elderly ED patients is most commonly bacterial in origin.

• In several studies, it has been due to a viral cause in less than 5% of cases.


Fever and Infection

• Also consider the possibility of other potentially serious causes of fever which are present 10% of the time:

- - rheumatologic disease

- - thyroid storm

- - environmental exposure

- - medication-related events

- - malignancy


Fever and Infection

• Although fever often signifies the presence of serious illness in elderly patients, severe infection may also be present in the absence of fever.

• The failure to mount a febrile response to infection has been particularly noted in nursing home patients.


Bacteremia

• The presence of bacteremia in elderly patients with infection signifies a more severe disease state and greater risk of mortality.

• Blood stream infection is among the top ten causes of death in elderly patients in the U.S.


Bacteremia

• Risk factors:- increasing age

- - comorbid diseases: diabetes

cardiovascular disease

neuropsychiatric disease

malignancy

stroke

- - recent invasive procedure or instrumentation

- presence of indwelling catheters

Bacteremia

• Although fever is generally considered one of the cardinal signs of infection, numerous studies have demonstrated than an elevated temperature is often not present in elderly patients with blood stream infection

• As a result, the absence of fever cannot be taken as proof of the absence of bacteremia in this patient population.

Bacteremia

• The only independent predictors of bacteremia:- - altered mental status

- - vomiting

- - WBC band forms greater than 6%

- Elderly patients are likely to present with nonspecific signs and symptoms.


Bacteremia

• Laboratory testing fails to provide diagnostic certainty.

• Among the elderly with bacteremia, 20%-45% will have a normal WBC count.

• Relying on an increase in the erythrocyte sedimentation rate is also insensitive for the diagnosis of bacteremia in the elderly.


• Gastrointestinal and genitourinary sources of

bacteremia are more common in older adults, leading

to increased prevalence of infections due to Gram-

negative bacteria.

• Mortality is increased with bacteremia in older adults

versus young adults

Bacteremia

Bacteremia

• Lower respiratory infection: 10-34%

• Unknown source: 11-31%

• Intra-abdominal source: 9-20%

• Skin or catheter-related source: 9%


Bacteremia

• Gram-negative organisms: 70% cases

• Gram-positive organisms: 25% cases

• Anaerobes: < 10% cases

• Polymicrobial infections: 5-17%


Bacteremia

• Bacteremia in the elderly is associated with high mortality rates.

• Overall rates have been 20%-37% in most studies.


Pneumonia

• In the United States, pneumonia and influenza rank 6th among the leading causes of death.

• With advanced age, rates of morbidity and mortality for pneumonia increase dramatically.


Pneumonia- Epidemiology

• Nearly half of all cases of pneumonia involve patients > 65 years of age.

• Among nursing home residents, pneumonia is the second most common cause of infection.

• It is also the second most common cause of bacteremia in a nursing home.


Pneumonia – Predisposing factors

• Changes in the mucociliary transport system associated with age and smoking have a negative effect with clearing of bacterial pathogens.

• Changes in lung capacity, elasticity, and compliance are common with age.

Pneumonia: Pathogenesis

• Most cases are in fact related to microaspiration of bacterial pathogen colonizing the oropharynx.

• Ineffective clearing of mucus and secretions from the respiratory tract makes patient more susceptible to aspiration pneumonia.


Pneumonia - Microbiology

• Streptococcus pneumoniae- - most common isolate from sputum culture (20-30% of CAP

cases in the elderly).- - most common pathogen found in nursing home residents.



• Staphylococcus aureus- - more commonly associated with nosocomial infection

- - causes multilobar infiltration.

- - frequently associated with bacteremia.

- well-known manifestation of S aureus infection is the florid onset of pneumonia following recovery from influenza.



• Gram-Negative Bacilli- - rare in younger patients

- - more likely to affect nursing home residents compared with community dwellers

- - nearly 12% of pneumonias in patients from nursing homes

Pneumonia

• Classically, cough, especially productive cough, and fever are the hallmarks of respiratory tract infections.

• Other clinical manifestations of pneumonia include pleurisy and rigors.

• In the elderly patient the clinical presentation is similar; however, the rates of patients presenting with these manifestations change.

Pneumonia

• Although nearly 60% of patient with community-acquired pneumonia (CAP) presented with cough, only 34% of nursing home patients were noted to have a cough in the setting of pneumonia.

• Confounding this picture is the fact that only 60-75% of nursing home patients are febrile on presentation.


Community-acquired Pneumonia in the Elderly (CAP)

• The etiology of CAP pneumonia in the elderly is similar to that in young patients.

• Strep pneumoniae is the most common etiologic agent, accounting for approximately 50% of cases.

• Haemophilus influenzae and Moraxella catarrhalis are also relatively common.


Community-acquired Pneumonia in the Elderly

• Atypical agents such as Chlamydia pneumoniae, Mycoplasma, and Legionella pneumophilia are seen approximately 15% of the time in community-dwelling elderly persons, a lesser percentage than in younger patients.


Community-acquired Pneumonia in the Elderly

• Enteric gram-negative rods and Staphylococcus aureus are rarer pathogens and are more likely to be seen in the most severely ill patients.

• CAP developing after viral influenza has an increased chance of being caused of S aureus.


Nursing Home – and other Health Care –associated Pneumonias

• NHAP is clinically distinct from CAP in the elderly.

• It is associated with increased comorbidity, poorer functional status, and greater mortality.

• The mortality rate is 19-53% as compared with 8-14% in CAP.


HCAP

• Strep pneumoniae is still the most common organism, however enteric gram-negative rods, anaerobes, and Staph aureus are much more common in these patients.

• Pseudomonas rates have been 4-25% but as high as 52%.


Pneumonia – TreatmentCAP

• Elderly patients who develop CAP should receive:- a second-generation cephalosporin plus a macrolide

or

- a nonpseudomonal cephalosporin plus a macrolide

or

- monotherapy with a flouroquinolone


Pneumonia – TreatmentNHAP/HCAP

• Patients from nursing care facilities require appropriate antibiotic regimens to adequately cover multi-drug resistant organisms.

• Ideally antibiotic choice will include 2 drugs for gram-negative coverage as well as a drug for MRSA.


• The first gram-negative drug should be:- - an anti-pseudomonal cephalosporin (cefepime or

ceftazidime)

- - an anti-pseudomonal carbapenem (imipenem or meropenem) or

- - an anti-pseudomonal beta-lactam inhibitor (piperacillin-tazobactam)



• The second gram-negative drug should be:- an aminoglycoside (amikacin, gentamicin, or tobramycin)

or

- an anti-pseudomonal fluoroquinolone (ciprofloxacin or levofloxacin)



• If MRSA is a concern, vancomycin or linezolid is recommended.


Urinary Tract Infection

• Urinary tract infections (UTIs) encompass a spectrum of disease, from asymptomatic bacteriuria and cystitis, to pyelonephritis and urosepsis.

• UTIs are among the most common infections affecting the elderly.



• Among otherwise healthy geriatric patients living in the community, rates of UTI range from 5-30%, with higher rates seen with advanced age.

• Among institutionalized patients, the prevalence rates increase remarkably, between 17-55% of women and 15-31% of men.



• Anatomic variations during the aging process increase the risk of UTIs:

- - changes in prostatic function in men.

- - changes in vaginal flora associated with menopause in women.

- - elderly patients are more likely to have obstructive uropathy or anatomic changes related to childbirth or reproductive surgery.



•Other factors to consider include:- - higher rates of incontinence- - more frequent urologic instrumentation- - higher rates of catheterization- - comorbid diseases- - medications that alter bladder function



• Among young, healthy patients, the vast majority of UTIs are a result of Escherichia coli, Proteus mirabilis, Klebsiella pneumoniae, Enterococcus, Pseudomonas, and Staphylococcus species.

• Elderly patients have a lower incidence of E coliinfection and higher rates of polymicrobial infections.



• Patients with short-term urinary catheters are typically infected by a single organism, while long-term catheters are associated with polymicrobialinfections.

• The prevalence of gram-positve UTIs in geriatric patients has been increasing.



• The elderly often present with atypical symptoms of UTI:

- - malaise

- - anorexia

- - weakness

- - subtle mental status changes


Urinary Tract Infection Treatment

• Broad antibiotic coverage for a longer duration should be the cornerstone of any treatment plan.

• 7-10 days of treatment is preferred for women with symptoms for longer than 1 week, women with structural of functional changes, and for all men.²

• 14 days of treatment should be routine for elderly patients with pyelonephritis.



• Treatment of uncomplicated community-acquired UTI in the elderly is generally with a fluoroquinolone.

• Due to increased rates of resistance, TMP-SMX is not preferred as an empiric first-line agent.



• Alternative intravenous antibiotic therapies include:- - a fluoroquinolone

- - gentamicin plus or minus ampicillin

- - a third-generation cephalosporin plus or minus an aminoglycoside



• Patients who have an increased risk of drug-resistant organism or who are moderately to severely ill should be strongly considered for initial two-drug therapy to ensure effectiveness of the empiric regimen.

Asymptomatic bacteriuria is common and should not lead to antibiotic treatment.


• In patients with UTIs associated with chronic indwelling catheters, replacement of the catheter is associated with improved clinical outcomes and should be undertaken in the emergency department.


Influenza

• Although it affects all age groups, influenza causes the most severe disease in the elderly.

• Advanced age is associated with increased rates of influenza-related hospitalizations.


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Influenza

• 90% of deaths related to influenza occur in patients aged 65 years and over.

• As is true for pneumonia, the elderly may fail to demonstrate the classic signs of influenza.

• For example, many will not have fever or cough.



Influenza

• Secondary bacterial pneumonia may occur and is most commonly caused by Strep pneumoniae, Staph aureus, and Haemophilus influenzae.



Influenza - Treatment

• Oseltamivir (Tamiflu) and Zanamivir (Relenza) are recommended; however, Relenza is inhaled and may cause bronchospasm in patients with underlying lung disease.



• Tamiflu is given in the usual adult dosage of 75 mg orally twice daily for 5 days.

• Tamiflu should be renally dosed for patients with creatinine clearance less than 30 mL/min, with a recommended once daily regimen for those with clearance of 10-30 mL/min.



• Amantadine and rimantadine are not recommended due to the emergence of viral resistance as well as increased side effects in the elderly, particularly central nervous system side effects with amantadine.




• Due to the severe systemic effects and the severity of the respiratory illness, many elderly patients with influenza will require admission.

• For those patients being discharged, close follow-up is essential.



• Yearly influenza vaccination is recommended for all adults aged 50 years and older.

• Influenza vaccination of the community-dwelling elderly is associated with a 27% reduction in the risk of hospitalization and 48% reduction in the risk of death.




• Only the trivalent inactivated vaccine is approved for elderly patients.

• The live attenuated intranasal vaccine should only be used in healthy persons aged 5-49 years.


Cellulitis

• Cellulitis is more common, more severe, and is associated with increased mortality in the elderly compared with the younger population.

• Cellulitis in the elderly can often be attributed to chronic venous insufficiency, peripheral vascular disease, malnutrition and trauma.


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Cellulitis - Microbiology

• The microbiology is usually due to beta-hemolytic streptococci or S aureus.

• However, cellulitis complicated by diabetic ulcers or pressure ulcers may have different etiologies, and can include polymicrobial flora, Enterobacter, and anaerobes.



Cellulitis - Microbiology

• It has been widely established that bacterial resistance is on the rise.

• MRSA is an example of such resistant bacteria, and is more likely to occur in the elderly population.

• Once colonized with MRSA the rate of MRSA infection increases up to 25%, as does the risk of mortality.



Cellulitis - Treatment

• Treatment of cellulitis is dictated by:- - suspected organisms- - location of the cellulitis- - underlying comorbidities- - severity of the infection



•MSSA and streptococci:- - first-generation cephalosporin- - antistaphylococcal penicillins- - clindamycin in penicillin allergic patients




• Polymicrobial infections:

- broad spectrum antibiotics are indicated and must include coverage for gram-positive and gram-negative aerobes and anaerobes.




•MRSA:- - vancomycin- - linezolid- - quinupristin-dalfopristin (Synercid)



Meningitis

• Although the overall incidence of bacterial meningitis in the United States has decreased, the proportion of cases involving the elderly is currently increasing.

• The recognition of meningitis in the older patient may be more difficult, but as emergency physicians we must maintain a high level of suspicion, and consider bacterial meningitis as the etiology of acute illness.


Meningitis: Mortality

• Higher mortality figures are seen in elderly patients with meningitis, with case fatality rates averaging 20-25% for pneumococcal meningitis.

• Older patients who have severe neurologic impairment at presentation show morbidity and mortality rates approaching 50%.


Meningitis

• The most likely organisms to cause bacterial meningitis in the elderly:

- - S. pneumoniae- - Neisseria meningitides- - Listeria monocytogenes- - H. influenzae- - Gram-negative organisms

Meningitis

• Classic presenting symptoms of meningitis include fever, headache, neck stiffness, and photophobia.

• Other commonly encountered symptoms include lethargy, malaise, altered sensorium, seizures, vomiting, and chills.

Meningitis

• Although the older patient may exhibit any of these signs and symptoms, they are less often noted on presentation.

• Fever is a less frequently encountered finding when compared with younger patients, and nuchal rigidity is not universally present.


Meningitis

• Altered level of consciousness, respiratory symptoms, and seizures are more often found in elderly patients when compared with younger individuals.

• Among elderly patients admitted with meningitis, risk factors for death were found to be age over 60 years, obtunded mental status on admission, and seizures within the first 24 hours.


Meningitis - Treatment

• The objectives in the older patient with bacterial meningitis are prompt diagnosis and early institution of antibiotic therapy, which may improve patient outcome.

• If the possibility of bacterial meningitis is entertained after initial patient assessment, empiric antibiotic coverage should be initiated immediately.


• A combination of ampicillin plus a third-generation cephalosporin should be used for initial therapy, as these agents would be active against most species of S pneumoniae, L monocytogenes, aerobic gram-negative bacilli, H influenzae, and N meningitidis.



• The use of dexamethasone in the management of bacterial meningitis remains controversial.

• Dexamethasone, when given, should be administered 15-20 minutes before the first dose of antibiotics.


• All people who have had close contact with patients diagnosed with bacterial meningitis should be considered for prophylaxis.

• Rifampin 600 mg two times per day for four doses is adequate protection for N meningitides.

• Ciprofloxacin 500 mg orally as a single dose is an alternative.


Herpes Zoster

• Another skin infection seen more frequently in the elderly population.

• It is a disease confined to the skin and nervous system.

• Caused by the reactivation of the varicella-zoster virus (VZV).

Herpes Zoster

• VZV is responsible for pediatric chicken pox, and remains dormant in the dorsal root ganglia.

• What reactivates VZV remains unclear; however, it is usually a disease of the elderly and the immunocompromised.

• As cellular immunity decreases with aging, the incidence of herpes zoster increases.


Herpes Zoster

• Pain and paresthesias over a particular dermatome usually precede the characteristic rash.

• Prodromal pain is lancinating and is easily misdiagnosed as having cardiac, abdominal, and renal etiologies.

• Symptoms may last for several days before the hallmark lesions.

Herpes Zoster

Image Source: National Institutes of Health

Herpes Zoster

• Herpes zoster is a clinical diagnosis.

• Laboratory confirmation can be obtained via a culture of the vesicular fluid or by observing giant cells on Tzanck preparation.

Herpes Zoster

• A long-term sequela of herpes zoster is post-herpetic neuralgia.

• The incidence of post-herpetic neuralgia increases with age, with 50-75% of patients > 70 experiencing chronic pain over the involved dermatome.


Herpes Zoster - Treatment

• Antiviral therapy initiated within 72 hours of symptom onset decreases viral replication, nerve damage, duration of eruption, and pain.

• Administration of therapy after 72 hours may reduce the incidence of post herpetic neuralgia, but will not impact on the duration of symptoms.


Herpes Zoster - Treatment

•Antiviral agents used:- acyclovir- valacyclovir- famciclovir

• Immunizations should be maintained for tetanus, pertussis, pneumococcus, and

influenza.

• Zoster vaccine should be administered once to immunocompetent individuals age 60

or older, including patients who have a history of herpes zoster infection.

Immunizations

1. Fever is frequently absent in older adults with infection, particularly in frail older adults.

2. The absence of fever, therefore, does not exclude infection. 3. Many common infections do not present with classic symptoms in older adults.

For example, patients with pneumonia may not have respiratory symptoms, and patients with urinary tract infections may not have dysuria.

4. Instead of classic symptoms of infection, older adults with infections may present with confusion, delirium, anorexia, falls, or a general decline in functional status.

www.aging.arizona.edu

Conclusions (I)

Conclusions (II)

5. These patients are at higher risk of poor outcomes than are younger adults.

6. They are also at greater risk of infection with resistant organisms, necessitating the empiric use of broad-spectrum antimicrobial agents

FINAL COMMENT

Knowledge of these unique aspects of the infected elderly patient will aid the physician in providing optimal care to

this at-risk patient population.

References

1. Caterino JM. Evaluation and management of geriatric infections in the emergency department. Emerg Med Clin N Am 2008;26(2):319-343.

2. Adedipe A, Lowenstein R. Infectious emergencies in the elderly. Emerg Med Clin N Am 2006; 24(2):433-448.

3. del Portal DA, Shofer F, Mikkelsen ME, et al. Emergency department lactate is associated with mortality in older adults admitted with and without infections. Acad Emerg Med 2010;17(3):260-268.

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