Download GRS8InfectiousDiseases_v1

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INFECTIOUS
DISEASES
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OBJECTIVES
Know and understand:
• Factors that influence immune function in older adults
• Ways in which infectious diseases may present
atypically in older patients
• Criteria for initiating antibiotic therapy for residents of
long-term-care facilities
• How to diagnose and manage infectious diseases
that are common in the older adults
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TOPICS COVERED
• Predisposition to Infection
• General Principles for Diagnosis and
Management of Infections
• Epidemiology, Diagnosis, and Management
of Specific Infectious Syndromes
• Fever of Unknown Origin
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CONSEQUENCES OF INFECTION
Mortality—Infection is
a major cause of
death in older adults
Morbidity—Infection
often exacerbates
underlying illness or
leads to
hospitalization
Infection
40%
All
other
causes
60%
Major cause of death
in adults  65 years
AGE-RELATED ALTERATIONS
IN IMMUNE FUNCTION
• Immune response declines with age, a phenomenon
known as immune senescence
• The main features are depressed T-cell responses
and depressed T-cell/macrophage interactions
• B cells produce antibodies with lower affinity 
weakened immunogenicity of vaccines
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IMPACT OF COMORBIDITY
ON IMMUNE FUNCTION
• The impact of comorbidities on innate immune
function and host resistance is greater than the
impact of age itself
• Comorbid diseases also indirectly complicate
infections (eg, community-acquired pneumonia
in an older adult with multiple comorbidities
often requires hospitalization)
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IMPACT OF NUTRITIONAL STATUS
ON IMMUNE FUNCTION
•
On hospital admission, global undernutrition is
present in 30%–60% of patients 65 years
•
11% of older outpatients suffer from undernutrition, mostly due to reversible conditions such
as depression, poorly controlled diabetes mellitus,
and medication side effects
•
Some nutritional interventions may boost immune
function in older adults, but results vary with the
population studied and the supplements used
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LONG-TERM CARE CONSIDERATIONS
• Residence in a nursing facility puts older adults at
risk of epidemic diseases such as influenza
• Widespread antibiotic use increases likelihood of
infection by antibiotic-resistant organisms
• Resistance issues are worsened by:
 Debilitated host
 Close proximity of residents
 Poor staff compliance with prevention strategies (eg,
influenza immunization)
 Difficulties with infection control implementation
• Maintaining up-to-date immunizations is critical
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ATYPICAL PRESENTATION
• Older adults may present without typical signs and
symptoms, even if the infection is severe
• Fever may be absent in 30%–50% of frail older adults
with serious infections
• Fever in older nursing-home residents can be
redefined as:
 Temperature >2°F (1.1°C) over baseline, or
 Oral temperature >99°F (37.2°C) on repeated measures, or
 Rectal temperature >99.5°F (37.5°C) on repeated measures
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ANTIMICROBIAL MANAGEMENT
• Drug distribution, metabolism, excretion, and
interactions can be altered with age
• Even in the absence of disease, aging is associated
with a reduction in renal function
• Antibiotic interactions occur with many medications
commonly prescribed for older adults
• Risk factors for poor adherence include poor cognitive
function, impaired hearing or vision, multiple
medications, and financial constraints
SUGGESTED MINIMUM CRITERIA
FOR INITIATION OF ANTIBIOTIC THERAPY
IN THE LONG-TERM-CARE SETTING (1 of 2)
Condition
Minimum criteria
Urinary tract infection,
without catheter
Fever AND one of the following: new or
worsening urgency, frequency, suprapubic
pain, gross hematuria, CVA tenderness,
incontinence
Urinary tract infection, with
catheter
Fever OR one of the following: new CVA
tenderness, rigors, new-onset delirium
Skin and soft-tissue infection
Fever OR one of the following: redness,
tenderness, warmth, new or increasing
swelling of affected site
CVA = costovertebral angle
SUGGESTED MINIMUM CRITERIA
FOR INITIATION OF ANTIBIOTIC THERAPY
IN THE LONG-TERM-CARE SETTING (2 of 2)
Condition
Respiratory infection
Minimum criteria
 Fever > 102°F (38.9°C) AND RR > 25 or
productive cough
 Fever > 100 < 102°F AND RR > 25, pulse > 100,
rigors, or new-onset delirium
 If afebrile but with COPD: new or increased
cough with purulent sputum
 If afebrile without COPD: new or increased
cough AND either RR > 25 or new-onset delirium
Fever without source of  New-onset delirium or rigors
infection
 If antibiotics instituted as a diagnostic test (not
recommended), discontinue in 3–5 days if no
improvement and evaluation negative
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BACTEREMIA AND SEPSIS
• Older patients with bacteremia are less likely
than younger adults to have chills or
sweating, and fever is commonly absent
• GI and genitourinary sources of bacteremia
are more common than in younger adults
• Mortality rate with nosocomial gram-negative
bacteremia: 5%–35% in younger adults,
37%–50% in older patients
MANGEMENT OF BACTEREMIA
AND SEPSIS
• Similar in older and younger patients
• Rapid administration of antibiotics aimed at
the most likely sources is essential
• Early “goal-directed” therapy for volume
resuscitation has proven benefit
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PNEUMONIA: EPIDEMIOLOGY
• Patients  65 account for over 50% of cases
• Cumulative 2-year risk for long-term-care
residents is about 30%
• Mortality in older patients is 3 to 5 that of
younger adults
• Comorbidity is the strongest independent
predictor of mortality
CAUSES OF PNEUMONIA IN
O L D E R A D U LT S
• Streptococcus pneumoniae predominates
• Gram-negative bacilli (eg, Haemophilus influenzae,
Moraxella catarrhalis, Klebsiella spp.) are more
common than in younger adults, particularly in those
with COPD and nursing home residents
• Staphylococcus aureus and respiratory viruses
commonly cause community-acquired pneumonia in
nursing-home residents
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COMMUNITY-ACQUIRED PNEUMONIA
Infectious Diseases Society of America guidelines
suggest the following as first-line therapy for adults
over 60, with or without comorbidity:
• β-lactam/β-lactamase combination or advancedgeneration cephalosporin (ceftriaxone or
cefotaxime), with or without a macrolide
• Alternatively, one of the newer fluoroquinolones with
enhanced activity against S. pneumoniae
(levofloxacin, moxifloxacin, gemifloxacin)
NURSING HOME AND
HOSPITAL-ACQUIRED PNEUMONIA
• Initial regimens should be broadly inclusive, followed
by step-down therapy to narrower coverage if the
causative agent is identified
• For MRSA-colonized patients or patients in units with
high rates of MRSA, initial regimens should include
vancomycin or linezolid until MRSA is excluded
• Patients with improving hospital-acquired pneumonia
not caused by nonfermenting gram-negative bacilli
(eg, Pseudomonas, Stenotrophomonas) can receive
short courses of antibiotics (8 days)
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REDUCING THE RISK OF PNEUMONIA
• Immunization
• Smoking cessation
• Aggressive treatment of comorbidities (eg,
minimizing aspiration risk in post-stroke
patients, limited use of sedative hypnotics)
• System changes with attention to infection
control may be particularly effective in the
nursing home
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INFLUENZA
• Annual flu vaccination is recommended for all adults
 FDA approved high-dose vaccine for adults ≥ 65 yr, which
produces higher antibody responses, but unknown if this
provides better clinical protection
• Treatment with neuraminidase inhibitors is most
effective if initiated within 48 hours of symptom onset
• Oseltamivir (oral) is easier to use than zanamivir
(inhaled)
• Older adults appeared to be less susceptible to the
H1N1 pandemic of 2009 but are more likely to be
hospitalized for H1N1 than younger adults
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URINARY TRACT INFECTION (UTI)
• One of the most common illnesses in older adults
• As in younger adults, gram-negative bacilli are most
common
• Older adults are more likely to have resistant isolates,
such as Pseudomonas aeruginosa, and gram-positive
organisms, including enterococci, coagulase-negative
staphylococci, and Streptococcus agalactiae
• Additional organisms in patients with indwelling
catheters include enterococci, S. aureus, and fungi,
particularly Candida spp.
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ASYMPTOMATIC BACTERURIA
•
Affects up to 15% of women in the community
and 40% of women in nursing homes
•
Incidence in men is approximately half that in
women
•
Treatment is not recommended
 No clinical benefit
 Associated with adverse effects, expense,
C. difficile colitis, and potential for selection of
resistant organisms
LOWER-TRACT UTI (CYSTITIS)
IN OLDER WOMEN
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• Characterized by dysuria, frequency, and urgency
• 3‒7 days of therapy sufficient for uncomplicated cystitis
• Fluoroquinolones (FQs) more efficacious than TMP-SMX
in recent trials (TMP-SMX resistance usually >10%–20%)
• Options in some settings are amoxicillin (particularly for
enterococcal infection) and first-generation
cephalosporins for patients with FQ intolerance
• Culture not required unless first-line therapy fails
UPPER-TRACT UTI (PYELONEPHRITIS)
IN OLDER WOMEN
• Characterized by fever, chills, nausea, and flank pain;
commonly accompanied by lower-tract symptoms
• Requires 7–21 days of therapy
• Consider IV antibiotics for patients with suspected
urosepsis, those with upper tract disease due to
relatively resistant bacteria such as enterococci, and
those unable to tolerate oral medications
• Culture and sensitivity data should be obtained in
most cases
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UTI IN OLDER MEN
• Causative organisms and treatment choices are similar
to those for older women
• Usually due to obstructive prostatic disease or
functional disability; 14 days of therapy needed
• If prostatitis is suspected, 6 weeks of therapy is
usually required
• Culture and sensitivity data should guide therapy for
virtually all UTIs in older men
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TUBERCULOSIS: EPIDEMIOLOGY
• Patients 65 account for 25% of active cases in US
• In long-term-care residents, prevalence of skin-test
reactivity is 30%–50%, due to high rates of exposure in
the early 1900s
• Thus, most active cases in older adults are due to
reactivation
• Primary infection is of particular concern in nursinghome outbreaks
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TUBERCULOSIS: PRESENTATION
• Older adults may present with fatigue, anorexia,
decreased functional status, or low-grade fever
instead of classic symptoms
• Lung involvement common (75%); pneumonic
processes in older adults should raise suspicion
• Older patients are more likely than younger adults to
have extrapulmonary disease
• Virtually any body structure can be involved, and that
organ system can account for the major presenting
symptom
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TUBERCULOSIS: SKIN TESTING
• Induration ≥15 mm 48 to 72 hours after placement of a
5-tuberculin-unit PPD is a positive test in all situations
• Induration ≥10 mm is considered positive in nursinghome residents, recent converters (previous PPD <5
mm), immigrants from countries with high endemicity
of TB, underserved US populations, and people with
specific risk factors
• Induration 5 mm is considered positive in HIVinfected patients, patients with a history of close
contact with people with active TB, and those with
chest radiographs consistent with TB
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TUBERCULOSIS: MANAGEMENT
• Treatment of active TB is similar to that in
younger adults
• Regardless of age, anyone with a positive PPD
should be treated with isoniazid for 9 months if:
 They have never been treated in the past
 Active disease is excluded
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INFECTIVE ENDOCARDITIS
• In older adults, associated with degenerative
valvular disorders and prosthetic valves
• Treatment is IV antibiotics for 4–6 weeks
• Consider surgery for severe valvular dysfunction,
recurrent emboli, marked heart failure, myocardial
abscess, fungal endocarditis, or failure of antibiotics
to sterilize blood cultures
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PROSTHETIC DEVICE INFECTIONS
• Device removal usually required for cure
• Early and prolonged antibiotic intervention (for
months), combined with aggressive surgical
drainage, may be successful if symptoms have been
present only for a brief duration
• When full functionality is the goal, the best course is
device removal and administration of antibiotics for
6–8 weeks, followed by reimplantation
• Administration of prophylactic antibiotics other than
for heart valves remains controversial
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SEPTIC ARTHRITIS
• More likely in joints with underlying pathology
• Early arthrocentesis is indicated in any mono- or
oligoarticular syndrome, to exclude infection
• S. aureus is the most likely pathogen
• Aggressive antibiotic therapy should be combined
with serial arthrocentesis in uncomplicated cases
• Surgical drainage required when conservative
strategy fails
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OSTEOMYELITIS
• S. aureus is the predominant organism
• GI and genitourinary flora are more common than
in younger adults, so a specific microbiologic
diagnosis is useful
• Infections of pressure ulcers and diabetic foot
infections commonly require surgical consultation
plus aggressive antimicrobial therapy aimed at
mixed aerobic and anaerobic bacteria
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HIV INFECTION AND AIDS
• Heterosexual activity is the primary mode of infection
in older adults
• Untreated older adults progress to AIDS more rapidly
than young adults, but response to HAART is similar
• Management is similar to that used for younger adults,
except that more aggressive CVD prevention is
warranted
• HIV is probably the most treatable infectious cause of
dementia and much more likely to reverse with
therapy than syphilis (which is more commonly tested)
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BACTERIAL MENINGITIS
• Older adults account for most meningitis-associated
fatalities
• Ceftriaxone or cefotaxime, plus vancomycin, are
recommended as empiric therapy until a specific
isolate can be tested for antimicrobial susceptibility
• Ampicillin is the drug of choice for Listeria spp.
• More resistant gram-negative rods (eg, Pseudomonas
spp.) require ceftazidime or an extended-spectrum
penicillin, with or without intrathecal aminoglycoside
therapy
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NEUROSYPHILIS
• Possible underlying process in stroke or
dementia; also consider in unilateral deafness,
gait disturbances, uveitis, and optic neuritis
• Positive CSF serology (Venereal Disease
Research Laboratory test) may be diagnostic,
but the sensitivity is only 75% in most series
• Optimal treatment is penicillin G
REACTIVATED VARICELLA ZOSTER
VIRUS (HERPES ZOSTER, SHINGLES)
• Advancing age is the major risk factor
• The most disabling complication, postherpetic
neuralgia, is common in older adults
• Zoster vaccine is recommended for all
immunocompetent adults ≥ 60 yr old and
reduces the risk of zoster and post-herpetic
neuralgia by >50%
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FACIAL NERVE PALSY (BELL’S PALSY)
• Associated with at least 3 infectious causes: herpes
simplex virus, varicella zoster virus, and Borrelia
burgdorferi (which causes Lyme disease)
• If facial nerve palsy occurs as part of an episode of
varicella zoster virus, antiviral treatment is indicated
and corticosteroids should be administered as well
• If Lyme disease is suspected on a clinical basis:
 Oral amoxicillin, 500 mg 4 times per day for 14 days; or
 Oral doxycycline, 100 mg twice per day for 14 days; or
 IV ceftriaxone, 2 g per day for 14 days
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GASTROINTESTINAL INFECTIONS
• Can present diagnostic dilemmas in the absence of
fever or elevated WBC counts; a high index of
suspicion is necessary
• Diagnostic aids:
 Intra-abdominal infection—CT or labeled WBC study
 Cholecystitis, appendicitis, abscess—ultrasound
 Ischemic bowel—often requires angiography or
flexible sigmoidoscopy
• Treat infectious diarrhea as in younger adults
CLOSTRIDIUM DIFFICILE
INFECTION
• Recent increase in incidence and severity,
especially in older adults
• First-line treatment:
 Metronidazole in mild to moderate disease
 Vancomycin in severe disease
• Relapse is more common in older adults and may
require tapering the vancomycin dose
• Prevention: Avoid unneeded antibiotics and reduce
duration of needed antibiotic use
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FEVER OF UNKNOWN ORIGIN
• Defined as temperature >38.3°C (101°F) for at least 3
weeks, undiagnosed after 1 week of medical evaluation
• About one third of cases are due to treatable infections,
especially intra-abdominal abscess, bacterial
endocarditis, and tuberculosis
• Collagen vascular diseases are more common causes
than in younger patients (about 30% of cases)
• Neoplastic disease accounts for another 20% of cases
EVALUATING FEVER OF UNKNOWN
ORIGIN IN OLDER ADULTS (1 of 2)
1. Confirm fever; conduct thorough history (include travel, MTB
exposure, drugs, constitutional symptoms, symptoms of giant cell
arteritis) and physical exam. Discontinue nonessential medications.
2. Initial laboratory evaluation: CBC with differential, liver enzymes,
ESR, blood cultures  3, PPD skin testing, TSH, antinuclear
antibody. Consider antineutrophilic cytoplasmic-antibody or HIVantibody testing.
3. a) Chest or abdomen or pelvic CT scan—if no obvious source; or
b) Temporal artery biopsy—if symptoms or signs are consistent with
giant cell arteritis or polymyalgia rheumatica and increased ESR; or
c) Site-directed work-up on basis of symptoms or laboratory
abnormalities, or both.
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EVALUATING FEVER OF UNKNOWN
ORIGIN IN OLDER ADULTS (2 of 2)
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4.
If 3a is performed and no source is found, then 3b, and vice versa.
5.
a) BM biopsy—yield best if hemogram abnormal—send for H&E,
special stains, cultures, or
b) Liver biopsy—very poor yield unless abnormal liver enzymes or
hepatomegaly.
6.
Indium-111 labeled white blood cell or gallium-67 scan—nuclear
scans can effectively exclude infectious cause of FUO if negative.
7.
Laparoscopy or exploratory laparotomy.
8.
Empiric trial—typically reserved for antituberculosis therapy in rapidly
declining host or high suspicion for tuberculosis (ie, prior positive
PPD).
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SUMMARY
•
Immune function and host resistance are compromised
in older adults as a consequence of both immune
senescence and comorbid disease
•
A redefinition of fever should be considered in the frail
older patient
•
There are suggested criteria for initiating antibiotic
therapy in residents of long-term-care facilities
•
Careful selection of first-line therapy is warranted in
older patients with pneumonia
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CASE 1 (1 of 4)
• A 78-year-old man is admitted to the hospital because
he has had cough, shortness of breath, and fever for
the past 3–4 days.
• He was hospitalized 3 months ago for a similar
episode; at that time he was treated with ceftriaxone
and doxycycline.
• History includes hypertension, hyperlipidemia, and mild
cognitive impairment.
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CASE 1 (2 of 4)
• Temperature is 38.1°C (100.6°F) and blood pressure is
155/80 mmHg. Heart rate is 101 beats per minute,
respiratory rate is 22 breaths per minute, and O2
saturation is 95% on 2 L of oxygen via nasal cannula.
• Radiography of the chest shows bilateral lower lobe
infiltrates.
• Laboratory results are normal except for WBC count of
15,700/μL and creatinine level of 1.0 mg/dL.
• On admission, the diagnosis is community-acquired
pneumonia.
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CASE 1 (3 of 4)
Which of the following antibiotics would be most effective?
A. Ceftriaxone
B. Levofloxacin
C. Ceftriaxone plus doxycycline
D. Azithromycin
E. Doxycycline
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CASE 1 (4 of 4)
Which of the following antibiotics would be most effective?
A. Ceftriaxone
B. Levofloxacin
C. Ceftriaxone plus doxycycline
D. Azithromycin
E. Doxycycline
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CASE 2 (1 of 3)
• A 67-year-old man is preparing to undergo
colonoscopy with polypectomy for a polyp detected on
recent capsule endoscopy.
• History includes coronary artery disease and aortic
valve stenosis.
• The patient experiences hives when he takes
penicillin. He does not recall whether he has taken
cephalosporins in the past.
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CASE 2 (2 of 3)
Which of the following is most appropriate in terms of
endocarditis prophylaxis for this patient?
A. Oral clindamycin
B. Oral azithromycin
C. Oral moxifloxacin
D. Intravenous cefazolin
E. No prophylaxis
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CASE 2 (3 of 3)
Which of the following is most appropriate in terms of
endocarditis prophylaxis for this patient?
A. Oral clindamycin
B. Oral azithromycin
C. Oral moxifloxacin
D. Intravenous cefazolin
E. No prophylaxis
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CASE 3 (1 of 3)
• In January, a 73-year-old nursing-home resident is
evaluated because he has had fever, headache, nasal
congestion, nonproductive cough, shortness of breath,
and malaise since the previous day.
• A rapid influenza test from a nasal swab is positive for
influenza A.
• Another resident has had similar symptoms for 2 days.
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CASE 3 (2 of 3)
Which of the following should be offered to
the other nursing-home residents?
A. Rimantadine
B. Amantadine
C. Oseltamivir
D. Zanamivir
E. Peramivir
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CASE 3 (3 of 3)
Which of the following should be offered to
the other nursing-home residents?
A. Rimantadine
B. Amantadine
C. Oseltamivir
D. Zanamivir
E. Peramivir
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GRS Slides Editor:
Annette Medina-Walpole, MD, AGSF
GRS8 Chapter Authors:
H. Keipp Talbot, MD, MPH
Kyle Widmer, MD
GRS8 Question Writer:
Vera P. Luther, MD
Medical Writers:
Beverly A. Caley
Faith Reidenbach
Managing Editor:
Andrea N. Sherman, MS
Copyright © 2013 American Geriatrics Society
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