Geriatric Infectious Diseases: Current Concepts on Diagnosis and Management

Thomas T. Yoshikawa, MD; Dean C. Norman, MD

J Am Geriatr Soc. 2017;65(3):631-641.

Abstract and Introduction

Abstract

New information on infectious diseases in older adults has become available in the past 20 years. In this review, in-depth discussions on the general problem of geriatric infectious diseases (epidemiology, pathogenesis, age-related host defenses, clinical manifestations, diagnostic approach); diagnosis and management of bacterial pneumonia, urinary tract infection, and Clostridium difficile infection; and the unique challenges of diagnosing and managing infections in a long-term care setting are presented.

Introduction

Since the first review on the topic of infections in the aging population published in this journal in 1985, new information on infectious diseases in older adults has become available.^[1] In this review, the discussion will be focused on three major areas: The general problem and approach to the diagnosis and management of infections in older adults (geriatric infectious diseases); management of three specific geriatric infectious disease that are especially common, important, or relevant to older adults in the ambulatory, hospital, and long-term care settings; and general concerns about geriatric infectious disease in long-term care facilities (LTCFs).

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Table 1. Antibiotic Therapy of *Clostridium difficile* Infection According to Severity of Disease and for Recurrent Infection ^59,62,66,74
Severity	Treatment
Initial episode
Mild
≥3 loose stools, no to mild abdominal pain, afebrile	Outpatient if not in hospital for another reason; metronidazole, 500 mg orally 3 times/day for 10–14 days. Monitor hydration, electrolyte and renal status
Moderate
≥3 loose stools; moderate abdominal pain or tenderness; nausea.	Hospitalize. Check hydration, electrolyte, and renal status. May require intravenous fluids.
Evidence of volume depletion (e.g., altered sensorium; decreased renal function); mild to moderate leukocytosis	Vancomycin, 125 mg orally 4 times/day, 10–14 days. Metronidazole, 500 mg orally 3 times/day, 10–14 days as alternative therapy.
Severe
≥3 loose stools with blood fever; severe abdominal pain; vomiting Ileus; may be hypotensive; altered renal function; low albumin level; leukocytosis	Hospitalize. Intravenous fluids. Insert nasogastric tube for vancomycin, 500 mg 4 times/day (or use rectal enema) with or without intravenous metronidazole. Or fidaxomicin, 200 mg orally 2 times/day, 10 days
Severe, complicated
Hypotensive; respiratory distress; toxic megacolon; ileus; peritonitis	Antibiotics for intra-abdominal sepsis. Surgery for subtotal colectomy
Recurrent infection
First recurrent infection	Vancomycin, 125 mg orally 4 times/day for 14 days if initial therapy was metronidazole; fidaxomicin, 200 mg orally 2 times/day for 10 days if initial therapy was vancomycin
Subsequent recurrent infections	Pulsed-dose, tapered regimen with vancomycin;^a fecal microbiota transplant

^aThere are several different regimens. One example with oral vancomycin is 125 mg every 6 hours for 14 days; then 125 mg every 12 hours for 7 days, 125 mg once a day for 7 days, 125 mg every other day for 8 days, and 125 mg every 3 days for 15 days.

Table 2. Approach to Diagnosis and Management of Infections in Long-Term Care Facilities
1. Suspected Infection Typical symptoms and signs may be absent. Unexplained decline in functional status, increasing confusion, falling, delirium, reduced oral intake, urinary incontinence. Fever, defined as: Single oral temperature >100°F (>37.8°C) Repeated oral temperatures >99°F (>37.2°C) or rectal temperatures >99.5°F (>37.5°C) An increase in temperature of >2°F (>1.1°C) over baseline temperature. 2. Evaluation of Individual Nursing assistant or nurse records vital signs (temperature, blood pressure, pulse, respiratory rate) as well as oxygen saturation using a pulse oximeter. Clinical evaluation by nurse should include mental status (delirium), hydration status, presence of cough (with or without sputum production); presence of abdominal pain, tenderness or distention; identification of skin ulcers or wounds; and presence of indwelling bladder catheter. Findings are communicated to the healthcare provider on call. 3. Healthcare Provider Determine whether there is advance directive regarding decisions on extent of evaluations. Based on clinical data provided, initial decision may be to transfer individual to the nearest emergency department for further evaluation or direct admission. If individual's status is stable but infection is suspected AND select laboratory or radiological testing can be obtained, then the following should be ordered within 12–24 hours: Complete blood count including differential white blood cell count. A white blood cell count of 14,000 cells/μL or a band neutrophil >6% or ≥1,500 cells/μL warrants careful assessment for bacterial infection. Urinalysis and urine culture (for suspected urinary tract infection). Chest radiograph (for suspected pneumonia), Deep wound culture for purulent soft tissue wound (e.g., infected pressure ulcer). Stool for culture, parasite examination, and Clostridium difficile toxin (for diarrhea). 4. Management In an individual who the healthcare provider determines has an infection (e.g., pneumonia, urinary tract infection, infected pressure ulcer) but is clinically stable enough to remain in the long-term care facility, antibiotic therapy can be initiated with drugs that normally would be prescribed for treatment of that infection on an outpatient (ambulatory care) basis. (See text sections on Pneumonia, Urinary Tract Infection, and Clostridium difficile Infection as examples.) Preventive interventions should also be implemented, especially influenza and pneumococcal vaccinations.

Source: High K, Bradley SF, Gravenstein S et al. Clinical practice guideline for the evaluation of fever and infection in older adult residents of long-term care facilities: 2008 update by the Infectious Diseases Society of America. Clin Infect Dis 2009;48:149–171.