Pneumonia in the Elderly Patient
Author: Scott T. Wilber, MD, Assistant Professor of Emergency Medicine, Northeastern Ohio Universities College of Medicine, Associate Director, Emergency Medicine Research Center, Summa Health System, Akron, OH.
Peer reviewer: Varnada A. Karriem-Norwood, MD, Assistant Professor of Emergency Medicine, Emory University, Atlanta, GA.
Pneumonia is a disease that continues to have a significant effect on older persons. There are an estimated 1.7 million annual physician visits for pneumonia in patients older than age 65, costing $4.8 billion per year to treat.1 Pneumonia is the fourth leading cause of hospitalization and the fifth leading cause of death in patients older than age 65.2 As the number of persons in this age group grows, emergency medicine physicians will face the increased burden of this disease in the geriatric population.
At the same time, the emergency physician is faced with changes in the management of pneumonia. It is no longer sufficient to diagnose pneumonia in elderly patients, admit them, and let the admitting physician decide which antibiotics to prescribe. As a result of recent studies, there will be increasing pressure to manage patients with pneumonia as outpatients. Knowing which elderly patients with pneumonia are appropriate for outpatient management will allow the emergency physician to respond to these pressures in a pro-active, patient-centered manner. Additionally, the prompt administration of antibiotics (within 8 hours of patient presentation) will be evaluated as an indicator of the quality of pneumonia care. This requires the emergency physician to have an understanding of resistance patterns and knowledge of newer antibiotics.
This article reviews the important epidemiology of geriatric pneumonia. Differences in the etiologies and clinical features of pneumonia in this age group will be discussed. Most importantly, diagnosis and treatment will be emphasized, with special attention given to decision making for the practicing emergency physician.
— The Editor
Epidemiology
The incidence of pneumonia requiring hospitalization in persons older than age 65 is more than 2%, and is five times higher than any other age group.3 The incidence is higher in males, and increases with age.2 One-third of physician visits for pneumonia in patients older than age 65 result in hospital admission (> 700,000 admissions in 1998),3 and 42% of patients older than 65 years of age who have pneumonia are seen in an emergency department (ED).1
Following a long period of declining mortality from pneumonia in the antibiotic era, mortality rates for pneumonia have increased in the past two decades.4 One explanation for this is the growth in the size of the elderly population. The risk of death from pneumonia increases with age.2,5 Pneumonia is the sixth leading cause of death in those ages 65-74 years, the fifth in those 75-84 years, and the fourth in those older than age 85. In the United States, 75,000 persons older than age 65 died from pneumonia in 1996, which was exceeded only by heart disease, malignancy, cerebrovascular disease, and chronic obstructive pulmonary disease (COPD) as the cause of death in this population.2 Elderly patients who initially survive pneumonia are twice as likely to die in the next 10 years than those without pneumonia.6
Pathogenesis
For pneumonia to develop, microorganisms must gain access to the epithelium of the lower respiratory tract and establish infection. Rarely, pathogens may access the lower respiratory tract via hematogenous or direct spread. More commonly, organisms are directly inoculated into the lower respiratory tract, either through bacterial colonization of the upper respiratory tract mucosa with subsequent aspiration or direct inhalation of aerosolized microorganisms into the lower respiratory tract. Typical bacterial pneumonias generally gain access to the lower respiratory tract by colonization and aspiration. Given the high content of bacteria in oropharyngeal secretions, aspiration of as little as 0.01 cc of oropharyngeal secretions is enough to initiate pneumonia, and up to 50% of average people aspirate small amounts of oropharyngeal secretions while sleeping.7 Factors that increase the risk of oropharyngeal colonization and aspiration are common in the elderly.8-10 These and other risk factors for pneumonia in this population are shown in Table 1.
|
Table 1. Risk Factors for Pneumonia in Elderly Patients8-10 |
| • Impaired mucociliary transport Smoking Chronic bronchitis Increased age |
| • Recent hospitalization |
| • Nursing home residence |
| • Poor nutrition |
|
• Enhanced oropharyngeal colonization Inability to ambulate Inability to perform ADLs Declining clinical status Underlying cardiac or respiratory disease Incontinence Neoplastic disease Broad-spectrum antibiotics |
|
• Aspiration Cerebrovascular disease Ineffective cough reflex Altered level of consciousness Alcoholism Sedative medications CNS disease Dysphagia Esophageal dysfunction NG or ET tubes |
Aerosolized microorganisms also may gain access to the lower respiratory tract via direct inhalation. This is the common method by which viruses, atypical bacteria, mycobacteria, and fungi initiate pneumonia. Mycobacteria are particularly concerning, as the inhalation of as few 5-50 organisms may produce disease.7
There are numerous host defenses that prevent the development of pneumonia. Salivary flow, epithelial cell loss, coughing, and sneezing help remove microorganisms from the upper respiratory tract. Mucociliary transport removes secretions and microorganisms from the conducting airways, but this function declines in the elderly, smokers, and those with chronic bronchitis.7 Once organisms gain access to the lower respiratory tract, local humoral defenses (IgA and IgG) and alveolar macrophages may prevent infection.
Microbial Etiology
The microbial etiology of community-acquired pneumonia (CAP) in older patients differs from that found in younger patients. (See Table 2.) Streptococcus pneumoniae is the most common pathogen; it is responsible for up to 50% of cases in which a microbial etiology is found.8,11-13 Infection by the typical bacterial pathogens Haemophilus influenzae, Staphylococcus aureus, and Moraxella catarrhalis also are more common in elder adults compared to younger patients.8,12
|
Table 2. Microbial Etiologies |
| • Streptococcus pneumoniae |
| • Haemophilus influenzae |
| • Aerobic gram-negative bacilli |
| • Staphylococcus aureus |
| • Viruses |
| • Anaerobes |
| • Moraxella catarrhalis |
| • Mycoplasma pneumoniae |
| • Legionella species |
| • Chlamydia pneumoniae |
| • Mycobacterium tuberculosis |
Older patients have an increased risk of pneumonia due to aerobic gram-negative bacilli.8,12 This group includes Escherichia coli and Enterobacter, Acinetobacter, Klebsiella, Serratia, Proteus, and Pseudomonas species. Oropharyngeal colonization and subsequent pneumonia from these organisms is increased in patients with incontinence, underlying cardiopulmonary or neoplastic disease, those on broad-spectrum antibiotics, and patients with declining functional status.8-10
Pneumonia from Legionella species is more common in patients whose illness requires hospitalization for pneumonia.12 Other atypical pathogens include Mycoplasma pneumoniae and Chlamydia pneumoniae. A recent study showed an increased prevalence of M. pneumoniae infections in patients older than age 65, whereas C. pneumoniae infection occurred less commonly in this group.11 Polymicrobial and anaerobic pneumonias also are more common in patients requiring hospitalization for their pneumonia.12
Important viral causes of lower respiratory infection in the elder population include influenza, parainfluenza, and respiratory syncytial virus. Influenza causes significant morbidity and mortality in this age group. The major complications of influenza include influenza pneumonia and secondary bacterial pneumonia. Streptococcus pneumoniae and Staphylococcus aureus are the most common pathogens in this setting.
It should be noted that even in studies that attempt to determine the etiology of pneumonia, no microbial etiology is found in 40-60% of patients, despite extensive testing.8,11,12 In these same studies, multiple organisms are found in 2-5% of patients.8,11,12
Clinical Features
Clinical features attributed to typical bacterial pneumonias include the sudden onset of fever and chills, dyspnea, pleuritic chest pain, cough with purulent sputum, and physical findings of tachypnea, tachycardia, and signs of consolidation on chest examination. Fatigue, anorexia, headache, and myalgias also may be present.
Older patients generally have a longer duration of symptoms, and the prevalence of all of the above symptoms is lower than in younger patients.8,14 It is important to remember that older patients with pneumonia often lack cough or fever. Also, in contrast to younger patients, the elderly may commonly present with vague, nonspecific complaints. These include weakness, falls, confusion, delirium, anorexia, abdominal pain, or functional decline.8,9
Vital sign abnormalities in patients with pneumonia include fever, tachycardia, and tachypnea. Tachypnea is more commonly found in the geriatric patient, with 65% having a respiratory rate of 30 or higher.8,14 Fever, defined as a temperature greater than 38°C, is found in only 30% of patients greater than age 65.14 However, one-fourth of patients older than age 65 who do present with fever will have pneumonia.15
Physical examination of the chest may provide clues to the diagnosis of pneumonia. Inspection of the chest may show asymmetric chest expansion. Tactile fremitus is elicited by palpating the chest wall while the patient speaks. Tactile fremitus will be increased in patients with pneumonia, but decreased in the presence of pleural effusions or pneumothorax. Dullness to percussion may be present in pneumonia or pleural effusion.
Auscultation of the lungs should be performed with the patient upright and breathing normal tidal volumes, if possible. Normal, vesicular breath sounds may be replaced by bronchial breath sounds in the area of pneumonia. Consolidation of the lung may produce increased transmission of whispered or normal speech, known as whispered pectoriloquy or bronchophony, respectively. Similarly, a change in the sound of vowels from "e" to "a," known as egophony, may occur.16 Crackles, or rales, are nonmusical lung sounds that may occur in patients with pneumonia.
The value of the chest examination is diminished by low agreement between physicians. Interobserver reliability is poor for tactile fremitus and whispered pectoriloquy and fair to good for dullness to percussion, wheezes, and rales.16,17 Lack of cooperation in elders presenting with confusion, altered mental status, or weakness may further diminish the value of the physical examination.
For these reasons, the ability to diagnose pneumonia based solely on history and physical examination is limited. Decision rules have been developed to predict pneumonia based on history and physical examination, but they have low sensitivity and specificity for the diagnosis of pneumonia. Physician judgment is more sensitive than the decision rules.16,18
It has been classically taught that "typical" pneumonias can be differentiated from "atypical" pneumonias by history and physical examination. However, studies show that clinical features are neither sensitive nor specific for determining the etiology of pneumonia.12,13,19
Although fever generally resolves within 3-5 days with treatment, a significant number (35-85%) of patients still have some symptoms of pneumonia after one month.13,20,21
Diagnosis
Pneumonia is a clinical and radiographic diagnosis, and no other laboratory studies are required. Patients diagnosed with pneumonia should have some of the symptoms of acute infection noted previously (most studies require at least 2) accompanied by the presence of an acute infiltrate on chest radiograph or ausculatory findings consistent with pneumonia.13
Chest Radiography
In addition to its usefulness in diagnosing pneumonia, the chest x-ray also is helpful in evaluating for other causes of lower respiratory tract symptoms, and assessing the severity and complications of pneumonia. Ideally, a posteroanterior (PA) and lateral chest x-rays should be performed in geriatric patients in whom the diagnosis of pneumonia is considered. Anteroposterior (AP) portable chest x-rays may be easier to perform in the geriatric population, but result in a decrease in the quality of the radiograph.9 Although the occasional outpatient may be treated without a confirmatory radiograph, this approach is discouraged in published clinical guidelines, primarily based on the limitations of physical examination in diagnosing pneumonia as noted above.12,13
The radiographic appearance of pneumonia has traditionally been divided into lobar, bronchopneumonia, and interstitial patterns.22 However, these patterns are of limited usefulness in determining the etiology of pneumonia.8,12,13,22 For instance, traditional teaching suggests pneumococcal pneumonia causes a lobar infiltrate; studies, however, suggest that the different radiographic patterns occur somewhat equally in this type of pneumonia.22,23 In addition, radiologists cannot reliably distinguish viral from bacterial pneumonia.22,24 As in the physical examination, the interpretation of chest radiographs is limited by interobserver variability.22,25
Many patients who present with lower respiratory tract symptoms do not have pneumonia.13,18 The chest x-ray can suggest other common causes of lower respiratory tract symptoms in older patients, such as congestive heart failure, malignancy, atelectasis, pleural effusion, or pulmonary embolism or infarct.13
A widely held axiom is that chest x-rays may be negative in patients with dehydration,8,26 a common finding in geriatric patients with pneumonia. There is little clinical evidence to support this theory, and animal studies have yielded conflicting results.22 Similarly, it has been suggested that elderly patients with pneumonia less commonly have infiltrates on initial chest x-rays as compared to younger patients.8,9,27
Multilobar disease is a risk factor for death in patients with pneumonia, as is the presence of a pleural effusion. Parapneumonic effusions may be sterile or may represent empyema, an infection of the pleural space. Other complications of pneumonia seen on chest x-ray include abscess formation and mass lesions with resulting post-obstructive pneumonia.
Laboratory Testing
While laboratory testing is not required to diagnose pneumonia, some studies may be helpful in determining the severity of disease and assessing prognosis. The complete blood count (CBC) may show leukocytosis, although this finding is absent in 40% of patients.19,21 Both high and low white blood cell (WBC) counts have been associated with more severe disease, although this was not shown to be a predictor of mortality in a recent, large study. (See following sections on Disposition and Prognostic Scoring.) A low hematocrit has been associated with more severe disease.5
Chemistry panels (electrolytes, blood urea nitrogen [BUN], creatinine, and glucose) may be helpful in assessing patients with pneumonia. Findings associated with higher mortality include elevated blood glucose, elevated BUN, and decreased sodium.5
Microbial Testing
Microbial testing is performed to determine the etiology of pneumonia, so that therapy may be directed at the individual pathogen. The value of this testing in patients with pneumonia is a matter of some debate. The Infectious Disease Society of America (IDSA) recommends that microbial testing be performed to determine the etiologic diagnosis for patients admitted with CAP.13 Their reasoning in favor of testing includes the ability to select antibiotics active against the specific pathogen, limiting the consequences of antibiotic overuse (cost, resistance, and adverse drug reactions), and the low cost of microbial studies (< 1% of hospital costs for patients with pneumonia).13
Guidelines from the American Thoracic Society (ATS) agree that early etiologic diagnosis is optimal, but note that the pathogen is not identified in up to 50% of patients. The role of the sputum gram stain and cultures is not emphasized.12
Studies of the benefit of diagnostic testing have had varying results. One recent study reports no outcome benefit in adults with CAP,28 but others found that obtaining blood cultures within the first 24 hours in elderly patients with pneumonia was associated with lower 30-day mortality.29 No well designed prospective studies have tested the hypothesis that obtaining microbiologic studies improves outcomes in patients with pneumonia.
Sputum Gram Stain and Culture. The yield of a sputum gram stain is approximately 30-40%, and is primarily limited by the fact that most patients are unable to produce acceptable sputum samples.13 For example, sensitivity for detecting S. pneumoniae as the etiologic agent is approximately 50-60%, although specificity is somewhat greater (> 80%).13 A sputum sample for microbiologic tests should be a grossly purulent, deep-cough specimen obtained in the presence of the physician or nurse. The specimen should be examined within 1-2 hours by an experienced observer. Specimens with less than 10 squamous epithelial cells and greater than 25 PMNs per low-powered field are considered acceptable. The sputum should be obtained before antibiotic therapy if possible, as prior antibiotic therapy may decrease the sensitivity and specificity of the test. However, the treatment of acutely ill patients should not be delayed due to difficulty in obtaining sputum specimens.13,30
Although not routinely performed, sputum also may be induced or obtained by transtracheal or transthoracic aspiration, or bronchoscopy. In the intubated patient, sputum may be obtained from suctioning pulmonary secretions. If an adequate sputum specimen is obtained, and a predominant organism is identified on gram stain, directed antimicrobial therapy may be appropriate.13,30,31
Sputum cultures are generally ordered in conjunction with the gram stain,21 although contamination and overgrowth limit the sensitivity and specificity of standard culture techniques determining the etiology of pneumonia.13,30
Blood Cultures. Blood cultures have a low yield for etiologic agents in pneumonia (4-18%).30 However, they are recommended by both the ATS and IDSA guidelines in patients admitted to the hospital with pneumonia. They cite the low cost, ease of obtaining blood cultures, the specificity in identifying the causative organism, and the ability to test for antimicrobial sensitivity. Antimicrobial therapy may be altered in up to 50% of patients with positive blood cultures.32 Obtaining blood cultures within 24 hours of admission in patients with CAP also has been associated with lower mortality.29 Consequently, this has been used as a quality care indicator for patients with CAP.33 As the yield of blood cultures is lowered by prior antibiotic therapy, they should ideally be obtained before antibiotic therapy is instituted.34
Other Microbial Tests. Other diagnostic tests that may be useful in determining the etiology of pneumonia include antigen detection tests, serologies, and nucleic acid detection by DNA probes or polymerase chain reaction (PCR).13,30 Since these results are not readily available to emergency physicians and are not affected by prior antibiotic therapy, they need not be obtained in the ED.
Differential Diagnosis
The differential diagnosis of pneumonia is broad and depends upon presenting symptoms. Patients with respiratory symptoms (cough, dyspnea) may have an upper respiratory tract infection, acute or chronic bronchitis, congestive heart failure, pulmonary embolism, malignancy, or a pleural effusion as the cause of their symptoms. Elderly patients who present primarily with non-respiratory symptoms, such as confusion, fever, falls, or functional decline, also must be evaluated for other infections (urinary tract infection, meningitis, endocarditis, bacteremia) and non-infectious causes (electrolyte abnormalities, acute stroke, subdural hematoma, encephalopathy).
Management
Non-Pharmacologic Management. Prompt, aggressive, and adequate supportive care must be provided to geriatric patients who present to the hospital with pneumonia. As with other aspects of emergency care, this frequently must be performed in conjunction with history, examination, and diagnostic testing. Most important are the assessment and treatment of inadequate breathing (oxygenation and ventilation) and perfusion.
Oxygenation should be rapidly assessed using pulse-oximetry. Patients with arterial oxygen saturations of less than 90% should receive supplemental oxygen. Arterial blood gases may be helpful when hypercarbia is suspected. This may include patients with COPD, decreased mental status, and fatigue. Patients who have hypoxia that does not respond to supplemental oxygen and those with hypercarbia may be candidates for mechanical ventilation. This may be done with intubation and mechanical ventilation or non-invasive ventilation (bilevel positive pressure ventilation [BiPAP]). Recent studies have shown BiPAP to be successful in treating patients with respiratory failure due to pneumonia.35 When readily available to the emergency physician, this may avert the need for endotracheal intubation and its potential complications. Patients with evidence of bronchospasm on exam or a history of obstructive airways disease (asthma or COPD) may benefit from inhaled bronchodilator therapy.
Evidence of inadequate perfusion may range from mild dehydration with tachycardia to life-threatening hypotension due to septic shock. Patients with septic shock have evidence of decreased tissue perfusion, such as confusion and oliguria, but have a hyperdynamic circulation. In either case, initial therapy consists of intravenous (IV) fluids (normal saline or lactated Ringer’s solution) administered through a large bore IV. In elderly patients, fluid overload is a potential complication, and it is wise to administer IV fluids in bolus doses, with frequent assessment of response. Patients who do not respond to crystalloid infusion may require treatment with vasopressors.
Disposition. Determining whether to admit or discharge patients with pneumonia is the most costly decision emergency physicians make.1 For this reason, there have been increasing efforts to treat patients with CAP as outpatients.36-39 The disposition decision for geriatric patients with pneumonia should take into account the severity of the pneumonia, as well as other medical and psychosocial factors.5,40,41
Prognostic Scoring. Although there have been many efforts to assess severity and risk of death in patients with pneumonia,40,42-45 the study by Fine and colleagues has received much recent attention. This study developed a prediction rule, the Pneumonia Severity Index, for 30-day mortality in patients with CAP.5 The rule was derived and validated with data on more than 52,000 inpatients, and then validated with a second cohort of 2287 inpatients and outpatients as part of the Pneumonia PORT study. Subsequent evaluation and validation has been performed with other cohorts, including geriatric patients and nursing home residents.46,47 Patients are assigned to one of 5 risk classes (1 is lowest risk, 5 is highest risk) based upon a point system that considers age, co-existing disease, abnormal physical findings, and abnormal laboratory findings. Elderly patients cannot be assigned to Class 1, as a requirement is age younger than 50 years. Table 3 shows the point scoring system for assignment to Classes 2-5, associated mortality rates, and recommended disposition.5
|
Table 3. Pneumonia Severity Score for Elderly Patients5 |
|||
| CHARACTERISTIC |
POINTS |
||
| Historical Findings |
Age (years) |
||
|
Age Men Women Nursing home resident Coexisting disease Neoplastic disease Liver disease Congestive heart failure Cerebrovascular disease Renal disease |
|
||
| Physical examination findings | |||
| Altered mental status (acute) |
20 |
||
| Respiratory rate > 30 |
20 |
||
| Systolic BP < 90 mmHg | 20 | ||
| Temperature < 35°C or > 40°C | 15 | ||
| Pulse > 125/min | 10 | ||
| Diagnostic testing findings | |||
| Arterial pH < 7.35 | 30 | ||
| BUN > 30 mg/dL | 20 | ||
| Sodium < 130 mmol/L | 20 | ||
| Glucose > 250 mg/dL | 10 | ||
| Hematocrit < 30% | 10 | ||
| PaO2 < 60 mmHg (or SaO2 < 90%) | 10 | ||
| Pleural effusion | 10 | ||
| Risk class | Point score | Mortality (%) | Disposition |
| 2 3 4 5 |
> 70 71-90 91-130 > 130 |
0.6 2.8 8.2 29.2 |
Outpatient Brief inpatient Inpatient Inpatient |
In older patients, age contributes the most points to the overall score. Males older than 70 years and females older than 80 years would be assigned to Class 3 on the basis of age alone, without any other risk factor. In the study by Fine et al, patients assigned to Class 1 and 2 were typically younger patients (median ages, 35-59 years) and patients in Class 3-5 were older (median ages, 72-75 years).5
Outpatient management is suggested for Classes 1 and 2, brief inpatient observation for Class 3, and traditional hospitalization for Classes 4 and 5.5,13,40 For a geriatric patient to qualify for outpatient treatment based on these recommendations, they would have to be younger than age 70 for males or younger than 80 years of age for a females, and have no additional risk factors. Inpatient observation or traditional hospitalization would be recommended for all other patients based on this rule. Other studies have suggested outpatient management for Class 3 patients.37,48
Geriatric patients considered for management as outpatients also must be able to take oral fluids and antibiotics, comply with outpatient care, and carry out activities of daily living (ADLs) or have adequate home support to assist in ADLs.5,40,41 Table 4 presents a simplified method of admission decision making for elderly patients with CAP based on the Pneumonia Severity Index as well as the additional medical and psychosocial concerns.
|
Table 4. Outpatient Treatment |
| • Age < 70 for males, < 80 for females |
| • No significant comorbidity* |
| • Normal mental status |
| • No significant vital sign abnormality |
| • No significant diagnostic test abnormality |
| • Able to take PO fluids and medications |
| • Compliant with outpatient care |
| • Able to carry out ADLs, or have adequate home support |
|
* CHF, neoplastic, liver, cerebrovascular, or renal disease. RR > 30, systolic BP < 90 mmHg, temperature < 35°C or ³ 40°C, HR > 125/min. Arterial pH < 7.35, BUN ³ 30 mg/dL, sodium <130 mmol/L, glucose > 250 mg/dL, hematocrit < 30%, PO2 < 60 mmHg (or SaO2 < 90%), pleural effusion. |
Other factors previously noted to increase the risk of morbidity or mortality from pneumonia were not found to be significant in the Pneumonia Severity Index. These include other comorbid illnesses (diabetes mellitus, COPD, post-splenectomy state), altered mental status, suspicion of aspiration, chronic alcohol abuse or malnutrition, and evidence of extrapulmonary disease.12 Additional laboratory studies that may suggest increased severity of illness include white blood cell count less than 4 or greater than 30, absolute neutrophil count less than 1, elevated prothrombin time or partial thromboplastin time, decreased platelet count, or radiographic evidence of multilobar involvement, cavitation, and rapid spreading.12
Severe pneumonia may require intensive care unit (ICU) admission. In the study by Fine et al, 6% of patients in Class 3, 11% of patients in Class 4, and 17% of patients Class 5 required ICU admission.5 The ATS guidelines define severe pneumonia as the presence of at least one of the following: respiratory rate greater than 30, severe respiratory failure (PaO2/FIO2 < 250), mechanical ventilation, bilateral infiltrates or multilobar infiltrates, shock, vasopressor requirement, or oliguria (urine output < 20 cc/hr). The presence of at least one of these is highly sensitive (98%), but not very specific (32%), for the need for ICU management.49
It is emphasized that the above guidelines for admission should not supersede clinical judgment of the need to hospitalize patients.5,12,13,40
Antibiotic Treatment
Ideally, antibiotic treatment of pneumonia would consist of narrow-spectrum, etiology-specific antibiotics. Because of the inability to determine the etiology of pneumonia based on history, physical examination, or radiographic features, and the limited usefulness of microbial studies, the initial antibiotic treatment of pneumonia usually is empiric. Empiric antibiotic regimens should be directed against likely pathogens. Most guidelines and consensus panels recommend antibiotic coverage against S. pneumoniae, H. influenzae, M. catarrhalis, and the atypical pathogens Mycoplasma, Legionella, and C. pneumoniae. Empiric antibiotic decisions also are affected by such factors as the setting in which the pneumonia is obtained (community-acquired vs nursing home setting); the age of the patient; the severity of illness; suspicion for an aspiration pneumonia (with gram-negative and anaerobic pathogens) in patients with histories of altered mental status, seizures, and swallowing difficulties; comorbidity, including chronic alcoholism (increased risk for K. pneumoniae); and the likelihood of drug-resistant organisms (based on community studies or treatment failure).
Antibiotics should be administered as soon as possible in the ED, and should not be excessively delayed to obtain microbial studies or left to the admitting physician. Studies have shown that delayed antibiotic administration is associated with increased mortality in patients with pneumonia.13,29 Development of clinical pathways for the treatment of pneumonia in the ED may reduce delays in antibiotic treatment.50
In the past, combination therapy was necessary to cover the likely pathogens for pneumonia. Newer antibiotics, such as azithromycin and levofloxacin make monotherapy possible. Two recent, randomized studies involving selected patients with CAP have found azithromycin to be as efficacious as cefuroxime plus erythromycin.51,52 Importantly, patients with aspiration or evidence of gram-negative infections were excluded from these studies, as well as nursing home residents. Comparative trials also have shown levofloxacin to be efficacious when used alone.53 Advantages to monotherapy include cost savings and ease of administration, as well as the opportunity to transition to oral therapy with the same antibiotic. Although monotherapy may be effective in straight-forward cases of CAP, it is not appropriate for patients who need ICU admission or have a high likelihood of infection with gram-negative organisms. Additional concern has been expressed regarding increasing antibiotic resistance when extended spectrum quinolones (such as levofloxacin or gatifloxacin) are used as first-line therapy for CAP. Accordingly, a recent report from the CDC Drug-Resistant Streptococcus pneumoniae Therapeutic Working Group recommends that a suitable empirical antimicrobial regimen includes a parenteral beta-lactam (such as cefuroxime, cefotaxime, ceftriaxone, or ampicillin-sulbactam) plus a macrolide (such as erythromycin, clarithromycin, or azithromycin).54
With the above caveats in mind, a brief discussion of specific antibiotics for the treatment of pneumonia, follows. Recommended treatment regimens for CAP, based on IDSA treatment guidelines, are shown in Table 5.
|
Table 5. Antibiotic Treatment of Elderly Patients with Pneumonia13 |
||
| SETTING | PREFERRED | ALTERNATIVES |
| Outpatients | Macrolide* or fluoroquinolone | Doxycycline Amoxicillin/clavulanate or 2nd generation cephalosporin |
| Suspected PRSP | Fluoroquinolone | |
| Suspected aspiration | Amoxicillin/clavulanate | |
| Inpatients General medical ward |
b-lactam# ±
macrolide* or fluoroquinolone (alone) |
Cefuroxime + macrolide* or azithromycin (alone) |
| Intensive care unit | b-lactam# plus either macrolide* or fluoroquinolone | |
| Modifying factors | ||
| Structural lung disease | Anti-pseudomonal penicillin§,
carbapenem, or cefepime plus either a macrolide* or a fluoroquinolone, plus an aminoglycoside |
|
| Penicillin allergy | Fluoroquinolone ± clindamycin | |
| Suspected aspiration | Fluoroquinolone plus either clindamycin or metronidazole or b-lactam/b-lactamase inhibitor (alone) |
|
| *Azithromycin,
clarithromycin, or erythromycin. Levofloxacin, gatifloxacin, moxifloxacin, sparfloxacin, or other fluoroquinolone with enhanced activity against S. pneumoniae. Cefuroxime, cefpodoxime, or cefprozil. # Cefotaxime, ceftriaxone, or a b-lactam/b-lactamase inhibitor. § Ticarcillin or piperacillin. |
||
Extended Spectrum Fluoroquinolones
Newer members of the class, including levofloxacin, sparfloxacin, grepafloxacin, gatifloxacin, moxifloxacin, and trovafloxacin, provide increased coverage of S. pneumoniae compared to ciprofloxacin and ofloxacin.13,55 Penicillin-resistant S. pneumoniae (PRSP) also are susceptible to these "enhanced spectrum" fluoroquinolones. Their coverage includes gram-negative bacilli, H. influenzae, M. catarrhalis, Legionella, M. pneumoniae, and C. pneumoniae, making them excellent choices for single-drug treatment of pneumonia.13,55
Of the fluoroquinolones with enhanced activity against S. pneumoniae, levofloxacin and gatifloxacin have the advantage of being available for both IV and oral use. The recommended dose for lower respiratory infections is 500 mg qd IV or orally for levofloxacin and 400 mg qd IV or orally for gatifloxacin. Both should be continued for 7-14 days. Oral and IV dosing are interchangeable. Other advantages include once-daily dosing, and a low incidence of side effects.56
Grepafloxacin recently has been withdrawn from the market in the United States. Trovafloxacin use has been significantly restricted by the FDA due to severe and sometimes fatal hepatotoxicity. Sparfloxacin is not available for IV use, causes more photosensitivity, and can prolong the QT interval on ECG.57,58 Moxifloxacin is not available for IV use.
Although these newer quinolones are efficacious in combination or as monotherapy, concerns about increasing drug resistance have led to recommendations that limit their use. The CDC Report from the Drug-Resistant Streptococcus pneumoniae Therapeutic Working Group recommends that they be limited to adults who: 1) have failed first-line treatment (cephalosporin plus macrolide); 2) are allergic to alternative agents; or 3) have a documented infection with highly drug-resistant pneumococci (e.g., penicillin MIC > 4 mcg/mL).54
Macrolides. Macrolides provide excellent coverage of atypical bacterial infections, including M. pneumoniae, C. pneumoniae, and Legionella. S. pneumoniae is increasingly resistant to macrolides (10-20%). The rate of resistance is much higher in PRSP.13
Erythromycin has multiple disadvantages for the treatment of pneumonia in elders, including qid dosing and increased gastrointestinal side effects. Erythromycin also is relatively ineffective against H. influenzae, a more common pathogen in the elderly, especially in smokers and those with chronic bronchitis.13
Better choices for pneumonia treatment in this group are azithromycin and clarithromycin. Azithromycin is more active against H. influenzae, Legionella, and M. pneumoniae, whereas clarithromycin provides better coverage of S. pneumoniae and C. pneumoniae.13,58 Significant advantages to azithromycin include a simplified dosing schedule of once daily for five days, and the availability of an IV preparation. Outpatient oral therapy consists of an initial 500 mg dose, followed by 250 mg once a day for four days. Inpatient dosing is 500 mg once daily for 2-5 days, followed by oral azithromycin (500 mg qd) for a total of 7-10 days of treatment.
Doxycycline. Doxycycline is one of the recommended antibiotics in the IDSA guidelines for the outpatient treatment of CAP, and is a reasonable alternative to the macrolides. Twice-daily dosing and low cost are its main advantages. Coverage is excellent for the atypical organisms; however, there are concerns over increasing resistance to S. pneumoniae (5-8%) and H. influenzae.13 Because of better coverage and convenience, the newer macrolides have generally supplanted use of this tetracycline.
Beta-Lactams. Although penicillin remains the drug of choice for the treatment of susceptible strains of S. pneumoniae (which account for approximately 70% of pneumonia due to this organism),13 beta-lactam/beta-lactamase inhibitors are the members of this group recommended for empiric treatment of pneumonia. The only oral agent available is amoxicillin/clavulanate. Intravenous preparations include ticarcillin/clavulanate, ampicillin/sulbactam, and piperacillin/tazobactam. These drugs provide activity against H. influenzae, anaerobes, M. catarrhalis, S. pneumoniae, and S. aureus.13 Atypical organisms are not covered. Ticarcillin and piperacillin offer the best coverage of Pseudomonas.13
Cephalosporins. Many cephalosporins have been studied for the treatment of pneumonia. Second generation oral cephalosporins, including cefuroxime, cefpodoxime, or cefprozil, are considered alternatives for the outpatient treatment of CAP.13 However, their use alone would leave atypical pathogens uncovered. For this reason, the newer macrolides (clarithromycin or azithromycin) or quinolones have generally replaced the cephalosporins as monotherapy. For inpatient use, cefotaxime and ceftriaxone have the best in vitro activity against S. pneumoniae.13 Cefepime is recommended for those with underlying structural lung disease due to its enhanced activity against Pseudomonas.13 The addition of a macrolide to cover atypical organisms is warranted.
Other Antimicrobials. Trimethoprim-sulfamethoxazole is recommended in the ATS guidelines for CAP,12 but not the IDSA guidelines.13 Increasing resistance to S. pneumoniae (15-25%) and H. influenzae is noted, and atypical organisms are not adequately covered.13
Aminoglycosides (gentamycin, tobramycin, amikacin) should be added if Pseudomonas infection is suspected. This includes patients with structural lung disease, those on ventilators, and corticosteroid-dependent nursing home patients.8,13,58 Carbapenems (imipenem, meropenem) also may be used in patients with severe pneumonia and underlying structural lung disease. Antimicrobials indicated in suspected anaerobic infections include clindamycin and metronidazole.13
Risk factors for infection with PRSP include the use of beta-lactams in the past three months, immunosuppression, hospitalization within six months, and nosocomial pneumonia.58 PRSP also is demonstrating increased resistance to macrolides.13 Fluoroquinolones with enhanced activity against S. pneumoniae should be used in patients with these risk factors and in patients with comorbid illnesses or in communities with high resistance to S. pneumoniae.58
Recommended duration of antibiotic therapy varies. For S. pneumoniae, treatment should be continued for 7-14 days, or until the patient is afebrile for 72 hours. Atypical pathogens should be treated for 10-21 days.13 Given these recommendations, for the empiric outpatient treatment of CAP in elder adults, treatment for 10-14 days would be appropriate. Table 5 presents the recommended treatment for CAP based on IDSA treatment guidelines.
Special Considerations
Prevention. Given the morbidity, mortality, and economic cost of pneumonia in elder adults, prevention of this disease is desirable. Immunization against influenza and S. pneumoniae is recommended for all patients ages 65 years and older. These immunizations have been shown to be effective at reducing hospitalizations for pneumonia and death by as much as 63% and 81%, respectively.59 Low-risk elders benefit more from immunization than high-risk elders.60
Sixty-five percent of patients older than age 65 are immunized for influenza, and 45% are immunized for S. pneumoniae. Persons ages 65-74 years are less likely than older persons to be immunized, as are non-whites and persons with lower educational levels.61 Studies in one urban ED showed that only 3% of high-risk patients reported immunization against S. pneumoniae, and 28% reported immunization against influenza.62
The American College of Emergency Physicians has recently published a policy that "supports the immunization of high-risk patients against influenza and pneumococcal disease in the ED."63 Prior ED studies have shown that ED-based immunization programs are feasible and beneficial. Length of stay was not affected, as the median time needed for all immunization related activities was only 4 minutes.62,64 Other studies have estimated significant cost savings for such programs.65 Based on these studies, ED based immunizations of elders against influenza and S. pneumoniae should be strongly considered.
Nursing Home-Acquired Pneumonia. Risk factors for the development of pneumonia in nursing home patients include increasing age, male gender, swallowing difficulty, and inability to take oral medications. Influenza vaccination appears to be protective against nursing home-acquired pneumonia.66 The most common cause of pneumonia acquired in a nursing home is gram-negative bacilli as a group, which causes 30-40% of pneumonias in this setting. However, S. pneumoniae remains the most common individual bacterial cause (20-30% of cases). H. influenzae causes 10-20% of nursing home-acquired pneumonias, and S. aureus pneumonia also occurs with greater frequency (5-12%) in this population. Atypical organisms and viruses may cause outbreaks of pneumonia in nursing homes.8-10
Nursing home patients were included in the derivation of the Pneumonia Severity Index,5 which has been subsequently validated in this population.47 An additional risk factor for mortality in nursing home patients with pneumonia is severe ADL dependence.67
Nearly all elderly nursing home patients with pneumonia would require admission based on the recommendations of the Pneumonia Severity Index. However, other studies have shown that the mortality rate for nursing home patients may not be improved by hospitalization. One study showed no difference in mortality between two nursing homes (mean mortality rate, 24.8%), despite a doubling of the admission rate in one nursing home.68 One randomized trial of selected patients with nursing home-acquired pneumonia demonstrated the efficacy and safety of intramuscular ceftriaxone and cefoperazone in the nursing home setting. Clinical cure was seen in greater than 90% of patients, and overall mortality was 4.5%.69 The abilities of nursing homes to provide hydration, IV antibiotics, oxygen, and other skilled nursing care varies, and the decision to admit these patients should be made in conjunction with the nursing home physician.
Treatment of nursing home-acquired pneumonia should include coverage of the above-mentioned organisms. Options include an enhanced spectrum fluoroquinolone alone, or the combination of a beta-lactam/beta-lactamase inhibitor or cephalosporin with azithromycin or doxycycline.
Tuberculosis. In the United States, persons older than age 65 have a higher prevalence of tuberculosis (TB) than any other age group, with 12.8 cases per 100,000 population in 1998.70 The risk is higher in nursing home patients than in community-dwelling elders.71 Active TB can occur either from reactivation of previously inactive disease or by new infection.
Typical symptoms of active TB include fatigue, weight loss, low-grade fever, night sweats, and cough, which may last for months. Again, elderly patients less commonly have a typical presentation. Weight loss is more common but fever, night sweats, and hemoptysis occur less often.71 The classic chest x-ray finding in patients with TB is an apical infiltrate. The elderly more frequently have middle or lower lobe infiltrates or miliary disease.71
TB skin tests, sputum smears for acid-fast bacilli, and chest x-rays in combination with classic symptoms can provide presumptive evidence of infection. The diagnosis of TB requires culture, although 4-6 weeks are required for growth.
Drug therapy consists of a combination of isoniazid, rifampin, pyrazinamide, ethambutol, or streptomycin. The duration of therapy is 6-9 months.71
Conclusion
Increasingly, emergency physicians will be called upon to manage elderly patients with pneumonia. Although a common and serious illness, the assessment and diagnosis of pneumonia in this population may be especially difficult. The emergency physician who understands the etiologies of pneumonia in this population and can assess the severity of illness can make appropriate decisions regarding disposition and antibiotic treatment.
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