Infectious Diseases

Educational Objectives

The goals of this program are to improve management of infections in older patients. After hearing and assimilating this program, the clinician will be better able to:

1. Describe differences in clinical presentation of infection between older patients and younger patients.

2. Discuss differences in treatment of pneumonia in older patients as outpatients, in the hospital, and in the nursing home.

3. Prevent and treat symptomatic urinary tract infections in nursing home patients.

Summary

Introduction: pneumonia, tuberculosis, urinary tract infection (UTI), endocarditis, cholecystitis, appendicitis, meningitis, sepsis, and septic arthritis associated with higher morbidity and mortality in older patients

Place of residence and associated infections: independent living in community — respiratory tract infections; influenza; community-acquired pneumonia (CAP); bronchitis; UTIs; intra-abdominal infections; secondary infections (eg, endocarditis, osteomyelitis, diabetic foot infections, central nervous system infections [rare]); acute-care facility — aspiration pneumonia; UTIs; intravenous (IV) site infections; pressure ulcers; syndromes confused with infection (eg, drug fever); long-term care facility — UTIs; aspiration pneumonia; influenza; skin and soft tissue infections; gastrointestinal (GI) infections; UTI — in young adults, usually caused by Escherichia coli; in older adults, can be caused by variety of pathogens (urine culture recommended)

Factors that cause high morbidity and mortality in older patients: low physiologic reserve; decreased host resistance; chronic illness or comorbidities; greater hospitalization rates, long-term care admissions, and adverse drug reactions; delayed diagnosis and treatment due to atypical presentation; increased number of procedures; delayed treatment response; impairments in barriers to infection — thinning of skin; diminished cough reflex; genitourinary (GU) tract changes (eg, prostate enlargement); comorbidities; polypharmacy (avoid use of sedating drugs in older patients); functional impairments (eg, loss of mobility); implantable devices (risk factor for multidrug-resistant organisms)

Immune function: T cells — changes in function, proliferation, receptor diversity, cytotoxicity, and interleukin-2 production; delayed-type hypersensitivity reactions; fewer naïve cells (ie, fewer T cells respond to new pathogens); many memory cells; B cells — antibody production affected by T cell function; more nonspecific antibodies and autoantibodies; fewer high-affinity antibodies; decrease in B lymphocyte function; decreased function of toll-like receptors on macrophages that recognize bacterial cell products and cell wall pieces; increased prostaglandin E2 production (immunosuppressive); natural killer cells (important in cancer surveillance and viral infections) appear to decrease

Clinical presentation of infection: altered mental status can be sole presenting finding in frail elderly patients; bacteremia — fever may be absent; tachypnea; pneumonia — fever, cough, or sputum production may be absent; intra-abdominal infection — failure to thrive; anorexia

Fever: baseline body temperature drops ≈1°F with age; some patients with infection do not reach 101°F; fever defined as persistent elevation in body temperature of ≥2°F, and oral temperature of ≥99°F on repeated measurement (particularly significant in setting of change in functional status); highly specific (temperature of 101°F in elderly usually associated with significant viral or bacterial infection); leukocytosis or left shift more significant in older patients than in younger patients; not sensitive for infection (20%-30% of older individuals afebrile); look for acute functional status change; C-reactive protein and procalcitonin levels increase with aging and infection, but not highly clinically useful; fever of unknown origin — most commonly caused by infection, inflammatory diseases, and neoplasms; lack of findings on most modern tests (eg, computed tomography [CT] of chest and abdomen)

Risks associated with antibiotics: pay attention to glomerular filtration rate; trimethoprim-sulfamethoxazole (TMP-SMZ) associated with increased risk for hyperkalemia in older patients on angiotensin-converting enzyme (ACE) inhibitors or angiotensin-receptor blockers (ARBs); linezolid associated with serotonin syndrome (avoid use in patients on serotonergic psychiatric medications); fluoroquinolones associated with tendon rupture; daptomycin associated with anemia and GI effects; tetracyclines associated with GI effects; ciprofloxacin and TMP-SMZ should not be used with warfarin due to increased risk for GI bleeding

Pneumonia: rate of hospital admissions, bacteremia, and nosocomial pneumonia per day of hospitalization higher in older patients; recent study suggests higher morbidity and mortality for pneumonia in nursing home patients not due to pathogens, but rather to frailty and underlying diseases of patients; pathophysiology — colonization of gram-negative bacilli or other pulmonary pathogens (eg, Streptococcus pneumoniae); important variables — virulence of colonizing pathogen, amount of aspiration, and integrity of host defenses; with greater debilitation, patients more likely to be colonized with gram-negative bacilli and Staphylococcus aureus; 40% to 60% of CAP due to S pneumoniae (lower in long-term care facilities and hospitals); in acute-care hospital, 35% of time due to gram-negative rods; heavy colonization of tongue may be risk factor in nursing homes; in hospitals, colonization of dental plaques may be risk factor; clinical signs — large study found fever response and pleuritic chest pain decrease, and tachypnea increases with age; confusion more likely to occur in patients with pneumonia in nursing home, compared to in community (chest pain less likely; hypotension more likely; 30- and 180-day mortality significantly higher)

Work-up of pneumonia: blood cultures (5%-15% positive; obtain before starting antibiotic); expectorated sputum; protected catheter brush; urine testing for Legionella pneumophila antigen; O2 saturation or arterial blood gas; complete blood count; renal function testing

Therapy: respiratory and nutritional support; fluid and electrolyte management; treatment of underlying diseases; encouragement of mobility (reduces length of stay and complications); aggressive early initiation of empiric antimicrobial therapy; ambulatory care — macrolides first-line therapy; respiratory fluoroquinolones; in hospitals — begin with broad-spectrum therapy, then narrow therapy after culture results obtained; respiratory fluoroquinolones; piperacillin-tazobactam; in nursing homes — amoxicillin-clavulanate; respiratory fluoroquinolones; intramuscular (IM) ceftriaxone or cefepime; newer macrolides; obtain detailed advanced directives; effects — initiating antibiotics within 8 hr, and obtaining blood cultures before initiating antibiotics lowers 30-day mortality

Prevention of pneumonia: statins do not appear to reduce incidence of CAP; increased risk associated with secondhand smoke, exposure to solvents, alcohol use, poor nutrition, and use of antipsychotic agents; consider improving oral hygiene; proton pump inhibitors may slightly increase risk for CAP; patients with gurgling breath sounds (sign of opiate and antipsychotic drug overdosing) often develop pneumonia; hospital practices — use bundle interventions for ventilator-associated pneumonia; hand hygiene; aspiration precautions; vaccines — routine revaccination not recommended; second dose for patients who received vaccine >5 yr previously and were <65 yr of age at time of vaccination; revaccination may be considered after 5 yr in patients who developed comorbidities; vaccinate patients 19 to 64 yr of age who have asthma or immunosuppression, or are smokers; pneumococcal conjugate vaccine significantly reduced pneumonia and meningitis in elderly patients

Influenza: mortality and morbidity rates poor; clinical presentation in elderly — cough; fever not always present; malaise; vaccine reduces hospitalization and death rates

Urinary tract infections: decreased bladder capacity; uninhibited bladder contractions; residual urine; prevalence of bacteriuria dependent on functional status, GU status, and underlying diseases; ratio of women to men in young patients 30:1, in elderly patients, 3:1; uncomplicated UTIs in older patients usually due to E coli (3-5 pathogens likely in UTI associated with long-term catheter use); Proteus infection associated with biofilm (difficult to eradicate); most bacteriuric patients (with or without pyuria) asymptomatic; fever without localizing symptoms in bacteriuric nursing home patients usually due to nonurinary source (risk for urosepsis higher if catheter in place); symptomatic UTI — dysuria; unexplained nonspecific complaints; unpleasant odor of urine not diagnostic of symptomatic UTI (usually due to dehydration); older patients presenting to acute-care hospital with upper tract infection may not be as easily managed as younger patients (older patients require monitoring); ≤90% of bacteriuric patients have pyuria, but 30% of nonbacteriuric patients have pyuria; treatment — catheter-associated asymptomatic bacteruria associated with renal scarring and other problems, but not treated unless patient symptomatic; treating asymptomatic bacteruria does not reduce symptomatic infections, and increases cost, drug toxicity, and antibiotic resistance; TMP-SMZ drug of choice if resistance ≤20% in community; nitrofurantoin, fosfomycin, and pivmecillinam recommended; β-lactam drugs not strongly recommended; treat women for ≥3 days (longer for men); recurrent and more complicated UTI treated with quinolone; in critically ill patients, use carbapenem (eg, imipenem, meropenem) and aminoglycoside; prevention — cranberry juice reduces bacteriuria but does not prevent symptomatic infection; vaginal estrogens for recurrent UTI in postmenopausal women reduce symptomatic UTI; treat bacteriuria before GU surgery; avoid indwelling bladder catheters; for patients who require catheterization try intermittent catheterization; catheter UTIs — antiseptics ineffective after few days; condom catheter less likely to result in symptomatic UTI; intermittent catheters; special catheters effective for short-term use; do not forget when patients have catheter in place; do not treat asymptomatic patients; ampicillin and aztreonam or aminoglycoside; many regimens possible; change catheter (drains bladder) and obtain culture

Methicillin-resistant S aureus (MRSA): firmly established as hospital pathogen; overall mortality and risk for hospitalization associated with colonization; poor functional status highly correlated with MRSA and surgery; inpatient treatment — ceftaroline (new cephalosporin; no effect on ampicillin-resistant enterococci); prevention measures (eg, isolation, hand washing) result in spectacular reduction in severe infections

Meningitis: individuals >35 yr of age do not develop aseptic meningitis; in older patients, almost always due to S pneumoniae or Listeria; small percentage due to S aureus, Staphylococcus epidermidis, or gram-negative rod; diagnosis — blood cultures may be positive 50% of time; CT not required before initiation therapy (lumbar puncture required); treatment — steroids controversial; repeat cerebrospinal fluid examination; minimum 2 wk of therapy

West Nile virus: severe in small children and patients >80 yr of age; diagnosis by IgM antibody testing; no effective treatment available; preventable by controlling mosquitoes

Shingles: painful; vaccine — approved by Food and Drug Administration for patients >50 yr of age; in short supply; expensive; results in ≈50% reduction of shingles and reduction of postherpetic neuralgia; treatment — antivirals helpful when given within 72 hr; steroids no longer routinely used, unless shingles severe and involves multiple dermatomes; vaccine ineffective for treatment

Clostridium difficile: stop offending antibiotics; treat with oral metronidazole or vancomycin (more recurrences with metronidazole); fidaxomicin associated with lower recurrence rate, but limited data about North American pulsotype strain; algorithm — for mild disease, use metronidazole; for moderate disease, use metronidazole or vancomycin (if patient has abdominal pain, cramping, or older age, use vancomycin); for severe disease, use vancomycin (IV vancomycin not highly effective; oral, nasogastric, or enema recommended); alternative therapy — cholestyramine ineffective; IV immunoglobulins not highly effective; monoclonal antibodies against toxins effective; probiotics effective for antibiotic-associated diarrhea, but ineffective for C difficile; toxoid vaccines in development; fecal transplantation effective

Readings

Anstey KJ et al: The role of cognitive and visual abilities as predictors in the Multifactorial Model of Driving Safety. Accid Anal Prev. 2012 Mar;45:766-74; Barbosa-Cesnik C et al: Cranberry juice fails to prevent recurrent urinary tract infection: results from a randomized placebo-controlled trial. Clin Infect Dis. 2011 Jan 1;52(1):23-30; Braitman KA, Williams AF: Changes in self-regulatory driving among older drivers over time. Traffic Inj Prev. 2011 Dec;12(6):568-75; Brandt LJ, Reddy SS: Fecal microbiota transplantation for recurrent clostridium difficile infection. J Clin Gastroenterol. 2011 Nov;45 Suppl:S159-67; Dow J, Jacques A: Educating doctors on evaluation of fitness to drive: impact of a case-based workshop. J Contin Educ Health Prof. 2012 Winter;32(1):68-73; Ewig S et al: CAPNETZ study group. Nursing-home-acquired pneumonia in Germany: an 8-year prospective multicentre study. Thorax. 2012 Feb;67(2):132-8; Falsey AR et al: Long-term care facilities: a cornucopia of viral pathogens. J Am Geriatr Soc. 2008 Jul;56(7):1281-5; Fischer HD et al: Hemorrhage during warfarin therapy associated with cotrimoxazole and other urinary tract anti-infective agents: a population-based study. Arch Intern Med. 2010 Apr 12;170(7):617-21; Gaines JM et al: Enhancing older driver safety: A driving survey and evaluation of the CarFit program. J Safety Res. 2011 Oct;42(5):351-8; Givens JL et al: Survival and comfort after treatment of pneumonia in advanced dementia. Arch Intern Med. 2010 Jul 12;170(13):1102-7; Kaplan V et al: Pneumonia: still the old man's friend? Arch Intern Med. 2003 Feb 10;163(3):317-23; Louie TJ et al: OPT-80-003 Clinical Study Group. Fidaxomicin versus vancomycin for Clostridium difficile infection. N Engl J Med. 2011 Feb 3;364(5):422-31; Manoff SB et al: Revaccination with a 23-valent pneumococcal polysaccharide vaccine induces elevated and persistent functional antibody responses in adults aged 65 or more years. J Infect Dis. 2010 Feb 15;201(4):525-33; Mourad O et al: A comprehensive evidence-based approach to fever of unknown origin. Arch Intern Med. 2003 Mar 10;163(5):545-51; Mundy LM et al: Early mobilization of patients hospitalized with community-acquired pneumonia. Chest. 2003 Sep;124(3):883-9; Takeshita T et al: Microfloral characterization of the tongue coating and associated risk for pneumonia-related health problems in institutionalized older adults. J Am Geriatr Soc. 2010 Jun;58(6):1050-7; Weinberg A et al: Influence of age and nature of primary infection on varicella-zoster virus-specific cell-mediated immune responses. J Infect Dis. 2010 Apr 1;201(7):1024-30; Weisfelt M et al: Community-acquired bacterial meningitis in older people. J Am Geriatr Soc. 2006 Oct;54(10):1500-7; Wong IY et al: The relationship between cognitive ability, insight and self-regulatory behaviors: Findings from the older driver population. Accid Anal Prev. 2012 Jul 2 [Epub ahead of print].

Disclosures

In adherence to ACCME Standards for Commercial Support, Audio-Digest requires all faculty and members of the planning committee to disclose relevant financial relationships within the past 12 months that might create any personal conflicts of interest. Any identified conflicts were resolved to ensure that this educational activity promotes quality in health care and not a proprietary business or commercial interest. For this program, members of the faculty and planning committee reported nothing to disclose.

Acknowledgements

Dr. Norman spoke at 39th Annual UCLA Family Practice Refresher Course, presented May 21-25, 2012, in Los Angeles, CA, and sponsored by the David Geffen School of Medicine at the University of California, Los Angeles, the UCLA Office of Continuing Medical Education, and the UCLA Department of Family Medicine. For course listings from these sponsors, visit www.cme.ucla.edu/courses/.

CME/CE INFO

Accreditation:

The Audio- Digest Foundation is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.

The Audio- Digest Foundation designates this enduring material for a maximum of 0 AMA PRA Category 1 Credits™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

Audio Digest Foundation is accredited as a provider of continuing nursing education by the American Nurses Credentialing Center's (ANCC's) Commission on Accreditation. Audio Digest Foundation designates this activity for 0 CE contact hours.

Lecture ID:

FP603401

Expiration:

This CME course qualifies for AMA PRA Category 1 Credits™ for 3 years from the date of publication.

Instructions:

To earn CME/CE credit for this course, you must complete all the following components in the order recommended: (1) Review introductory course content, including Educational Objectives and Faculty/Planner Disclosures; (2) Listen to the audio program and review accompanying learning materials; (3) Complete posttest (only after completing Step 2) and earn a passing score of at least 80%. Taking the course Pretest and completing the Evaluation Survey are strongly recommended (but not mandatory) components of completing this CME/CE course.

Estimated time to complete this CME/CE course:

Approximately 2x the length of the recorded lecture to account for time spent studying accompanying learning materials and completing tests.

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