Community-acquired pneumonia: development of a bedside predictive model and scoring system to identify the aetiology

Although initial presentation has been commonly used to select empirical therapy in patients with community-acquired pneumonia (CAP), few studies have provided a quantitative estimation of its value. The objective of this study was to analyse whether a combination of basic clinical and laboratory information performed at bedside can accurately predict the aetiology of pneumonia. A prospective study was developed among patients admitted to the Emergency Department University Hospital Arnau de Vilanova, Lleida, Spain, with CAP. Informed consent was obtained from patients in the study. At entry, basic clinical (age, comorbidity, symptoms and physical findings) and laboratory (white blood cell count) information commonly used by clinicians in the management of respiratory infections, was recorded. According to microbiological results, patients were assigned to the following categories: bacterial (Streptococcus pneumoniae and other pyogenic bacteria), virus-like (Mycoplasma pneumoniae, Chlamydia spp and virus) and unknown pneumonia. A scoring system to identify the aetiology was derived from the odds ratio (OR) assigned to independent variables, adjusted by a logistic regression model. The accuracy of the prediction rule was tested by using receiver operating characteristic curves. One hundred and three consecutive patients were classified as having virus-like (48), bacterial (37) and unknown (18) pneumonia, respectively. Independent predictors related to bacterial pneumonia were an acute onset of symptoms (OR 31; 95% CI, 6-150), age greater than 65 or comorbidity (OR 6.9; 95% CI, 2-23), and leukocytosis or leukopenia (OR 2; 95% CI, 0.6-7). The sensitivity and specificity of the scoring system to identify patients with bacterial pneumonia were 89% and 94%, respectively. The prediction rule developed from these three variables classified the aetiology of pneumonia with a ROC curve area of 0.84. Proper use of basic clinical and laboratory information is useful to identify the aetiology of CAP. The prediction rule may help clinicians to choose initial antibiotic therapy.     

Community-acquired pneumonia

This seminar reviews important features and management issues of community-acquired pneumonia (CAP) that are especially relevant to immunocompetent adults in light of new information about cause, clinical course, diagnostic testing, treatment, and prevention. Streptococcus pneumoniae remains the most important pathogen; however, emerging resistance of this organism to antimicrobial agents has affected empirical treatment of CAP. Atypical pathogens have been quite commonly identified in several prospective studies. The clinical significance of these pathogens (with the exception of Legionella spp) is not clear, partly because of the lack of rapid, standardised tests. Diagnostic evaluation of CAP is important for appropriate assessment of severity of illness and for establishment of the causative agent in the disease. Until better rapid diagnostic methods are developed, most patients will be treated empirically. Antimicrobials continue to be the mainstay of treatment, and decisions about specific agents are guided by several considerations that include spectrum of activity, and pharmacokinetic and pharmacodynamic principles. Several factors have been shown to be associated with a beneficial clinical outcome in patients with CAP. These factors include administration of antimicrobials in a timely manner, choice of antibiotic therapy, and the use of a critical pneumonia pathway. The appropriate use of vaccines against pneumococcal disease and influenza should be encouraged. Several guidelines for management of CAP have recently been published, the recommendations of which are reviewed.     

Community-acquired pneumonia

Community-acquired pneumonia (CAP) remains a leading cause of morbidity and mortality worldwide and has significant financial implications for health-care systems. The epidemiology and fundamental biology of the disease has evolved, reflecting the human immunodeficiency virus pandemic, increasing world travel, and, as always, poverty. The promise held out by molecular diagnostic technology has yet to deliver in this arena, and antibiotic resistance continues to drive the quest for new antimicrobial agents. The emergence of multidrug-resistant Streptococcus pneumoniae, the microorganism most often implicated as a cause of CAP, continues to threaten treatment options. The evolution of this organism, the persistently high mortality rate associated with CAP, and increasing health-care costs have prompted the publication of guidelines by various authorities that can be used to assist in the initial assessment of the patient and then guide empirical antimicrobial therapy. It is unclear whether these guidelines will have significant impact on cost and mortality, although the trend toward a rational and evidence-based approach to antimicrobial therapy must be a goal to aspire to.     

Community-acquired pneumonia

Community-acquired pneumonia (CAP) is the most common form of severe infectious disease in developed countries. The mortality is particularly high in elderly patients. For risk stratification simple clinical scores such as the CRB-65 (confusion, respiratory rate, blood pressure, age over 65 years) are recommended. The spectrum of pathogens is characterized by Pneumococcus and Haemophilus influenzae as well as atypical and viral pathogens. Resistance plays a subordinate role in Germany. In addition to the clinical symptoms an X-ray examination is also helpful to confirm the diagnosis and biomarkers can also be useful. Microbiological investigations are not necessary in practice. Particularly in cases of uncharacteristic clinical symptoms and therapy failure there are many differential diagnoses which can be hidden behind the clinical diagnosis of pneumonia. The calculated treatment of CAP should correspond to the current recommendations in national guidelines. The options for prevention by general measures and vaccinations should be applied consistently.     

Community-acquired pneumonia

Community-acquired pneumonia (CAP) remains an important cause of morbidity and mortality. Streptococcus pneumoniae is the most common pathogen and respiratory syncitial virus the most important viral pathogen in children. The role of urinary antigen testing and PCR for the diagnosis forS. pneumoniae infection has been an important adjunct to clinical examination, showing good sensitivity and specificity. Host-related immune responses play an important role in defining the severity of illness. Other than the use of Activated Protein C and immunization, the clinical use of therapies designed to modulate these abnormal responses remains largely experimental. The 7-valent vaccine represents a major advance in the prevention of invasive pneumococcal disease. The importance of effective triage and the deleterious effects of deviation from protocols are underscored. Continuous positive pressure ventilation and noninvasive mechanical ventilation are available as options for respiratory support in cases of severe CAP and require further evaluation.     

Community-acquired pneumonia: An overview

Community-acquired pneumonia (CAP) accounts for a significant number of hospitalizations and outpatient visits, as well as substantial health care expenditures. CAP is particularly common among the elderly who account for more than 90% of deaths due to pneumonia. Streptococcus pneumoniae is believed to be the most common microbial etiology of CAP, but recent studies suggest that the atypical pathogens may be more common than previously thought, particularly among ambulatory patients. Recent studies have provided data regarding risk of mortality and process of care and outcomes. Increasing resistance among strains of S. pneumoniae has impacted the approach to the empiric therapy of CAP. The Infectious Diseases Society of America published guidelines for the evaluation and management of CAP this past year. Pathogen-specific therapy guided by the results of sputum gram stain and culture is emphasized. Despite enthusiasm for practice guidelines and clinical pathways, there remains insufficient published data to determine their impact on quality and cost of care in patients with CAP.     

Community-acquired pneumonia in children

PURPOSE OF REVIEW: This review highlights recent developments in the diagnosis, etiology, therapy, and prevention of community-acquired pneumonia in children. RECENT FINDINGS: Sensitive new diagnostic methods have increased the detection rate of the causative agent up to 94%. Streptococcus pneumoniae is the most prevalent bacterial pathogen in all ages. Polymerase chain reaction is a rapid and sensitive method for the detection of Chlamydia pneumoniae and Mycoplasma pneumoniae, which have gained greater importance in recent years. During the period covered by this review, two new agents causing pneumonia were extensively studied. Human metapneumonovirus detected in young children is a leading cause of respiratory disease during the first years of life. A novel coronavirus was identified as the causative agent of severe respiratory syndrome, a new respiratory illness that affects adults and children. One multicenter trial concluded that nonsevere pneumonia can be treated with a short course of oral amoxicillin and a multicenter international study showed that children with severe pneumonia have similar outcomes whether treated with oral amoxicillin or parenteral penicillin, but more data are needed to demonstrate the safety and efficacy of such regimens. SUMMARY: The continued evolution of bacterial resistance highlights the need for appropriate use of antibacterials. Improved diagnostic techniques will aid the treatment of children with community-acquired pneumonia. Aggressive vaccination with the pneumococcal conjugate vaccine and other available vaccines as well as the development of new vaccines will aid the prevention of respiratory disease in children.     

Community-acquired pneumonia in adults

Efforts to reduce hospitalization or the length of stay are common topics in papers published last year. Chlamydia pneumoniae is now recognized worldwide as a common pathogen in community-acquired pneumonia. A great variation in the frequency of various pathogens is found in different countries, stressing the importance of ascertaining the aetiological and epidemiological situation in each respective country.     

Community-acquired pneumonia in children

The clinical findings and etiologic agents of childhood pneumonia vary, dependent upon the age of the child, with major differences seen in neonates, young infants 1 to 3 months of age, older infants or young children 3 months to 5 years of age, and older children or adolescents. Appropriate medical management and antibiotic therapy of children with pneumonia require consideration of these various age-dependent factors. Commonly the bacterial or viral etiologic agent causing community-acquired childhood pneumonia is not identified and thus antibiotic therapy is based on the probability of the most likely causative organisms. The choice of antibiotic for continuation of therapy is based on the clinical response to empiric therapy.     

Community-acquired pneumonia in very elderly patients: causative organisms,clinical characteristics,and outcomes

We performed an observational analysis of prospectively collected data on 1,474 adult patients who were hospitalized for community-acquired pneumonia; 1,169 patients were under 80 years of age and 305 (21%) patients were over 80 years ("very elderly"). Mean patient ages were 60 years in the former group and 85 years in the latter group. Severely immunosuppressed patients and nursing-home residents were not included. Comorbidities significantly associated with older age were chronic obstructive pulmonary disease, chronic heart disease, and dementia. The most common causative organism was Streptococcus pneumoniae (23% in both groups). Aspiration pneumonia was more frequent in the very elderly (5% in younger patients versus 10% in the very elderly); Legionella pneumophila (8% in younger patients versus 1% in the very elderly) and atypical agents (7% in younger patients versus 1% in the very elderly) were rarely recorded in the very elderly. While very elderly patients complained less frequently of pleuritic chest pain, headache, and myalgias, they were more likely to have absence of fever and altered mental status on admission. No significant differences were observed between groups as regards incidence of classic bacterial pneumonia syndrome (60% versus 59%) in 343 patients with pneumococcal pneumonia. The development of inhospital complications (26% in younger versus 32% in very elderly patients) as well as early mortality (2% in younger versus 7% in very elderly patients) and overall mortality (6% in younger versus 15% very elderly patients) were significantly higher in very elderly patients. Acute respiratory failure and shock/multiorgan failure were the most frequent causes of death, especially of early mortality. Factors independently associated with 30-day mortality in the very elderly were altered mental status on admission (odds ratio, 3.69), shock (odds ratio, 10.69), respiratory failure (odds ratio, 3.50), renal insufficiency (odds ratio, 5.83), and Gram-negative pneumonia (odds ratio, 20.27).     

Community-acquired and nosocomial pneumonia

Mortality of pneumonia is low in the outside setting (1%) but rises up to 20% in hospital admitted patients. Early diagnosis and standardized therapy improve patient's prognosis. For community acquired pneumonia age, comorbidity and the setting of therapy (outside department, normal ward or intensive care unit) are the most important variables to choose an adequate antibiotic treatment. For nosocomial pneumonia risk stratification is according to severity of illness, length of hospital stay and antibiotic pretreatment. In the outpatient setting a 7-day monotherapy is mostly successful. In severe illness the combination of a betalactam antibiotic with a new fluorchinolon seems to be superior to an aminoglycosid therapy. Antibiotic resistance due to mistakes in antibiotic therapy is an increasing problem in the intensive care unit. Therefore, pneumonia preventive measures like influenza and pneumococcal vaccination become more important. Standardized hygienical procedures help to reduce nosocomial, mainly ventilator associated pneumonia.     

Community-acquired pneumonia and sepsis

Sepsis is a frequent and often fatal complication of pneumonia. This article discusses the epidemiology, pathophysiology, and treatment of sepsis in the setting of pneumonia. Particular consideration is given to the role of mechanical ventilation in amplifying organ dysfunction in sepsis and to treatments that have positive effects on sepsis mortality and respiratory dysfunction.     

Community-acquired viral pneumonia

Advanced age often is associated with functional and immunologic decline and chronic cardiopulmonary diseases that predispose to pneumonia when viral infection occurs. Influenza virus remains the primary viral pathogen in the elderly, although the impact of the other respiratory viruses remains to be defined. The clinical syndromes associated with respiratory viruses frequently are indistinguishable from one another or bacterial pathogens; often, viral illness in older adults exacerbates underlying conditions, complicating diagnosis. Antiviral therapy is available for influenza A and B; specific viral diagnosis, particularly with the use of rapid antigen detection, may be useful for clinical management. Treatment for other viruses primarily is supportive.     

Community-acquired pneumonia: the clinical dilemma

Community-acquired pneumonia (CAP) is the sixth most common cause of death in the United States. Despite its frequency and mortality, specific etiologic diagnosis remains a major clinical challenge. The organisms most commonly implicated in CAP are Streptococcus pneumoniae, Mycoplasma pneumoniae, Legionella pneumophila, Haemophilus influenzae, Chlamydia pneumoniae (TWAR), and viruses. Clinical and radiographic criteria have proven to be of little value in determining the etiology of CAP. Laboratory studies, including Gram's stain and culture of sputum, have also been shown to be of severely limited value to the clinician faced with the patient with CAP. Antibiotic therapy must, therefore, generally be empiric. Regimens including erythromycin either as a single agent or coupled with an aminoglycoside or cephalosporin appear to be most efficacious.     

Community-acquired pneumonia in older adults

Community-acquired pneumonia is an important cause of morbidity and mortality in older adults. Residents of long-term care facilities, a distinct subpopulation of elderly people, are at particularly high risk for developing nursing-home acquired pneumonia. In this review, the best evidence for etiology, risk factors, clinical presentation, management and prevention of community acquired pneumonia in persons 65 years and older are summarized. The emphasis is on the clinical characteristics unique to community-acquired pneumonia in the elderly as well as nursing home acquired pneumonia.     

Community-acquired pneumonia in elderly patients

CAP in elderly patients carries a significant economic and clinical burden and will be more commonly encountered in the future as the US population ages. Diagnosis may be obscured by a nonclassic presentation in an elderly patient, and the clinician needs to be especially suspicious of pneumonia whenever the clinical status of an elderly patient deteriorates. The single most important clinical decision is the site of care; this determination is not always based on clinical factors but also on social factors. Severity assessment is key to stratifying appropriate therapy and to predicting outcome. Timely and appropriate empiric therapy enhances the likelihood of a good clinical outcome, although clinical resolution may be more delayed than in younger patients. Newly emerging patterns of antibiotic resistance have altered recent guidelines for CAP treatment; DRSP is now a consideration in elderly patients because an age older than 65 years is a well-described risk factor for infection with this organism. Prevention should always be implemented, with a focus on pneumococcal and influenza vaccination.