Solutions for difficult diagnostic cases of acute exacerbations of chronic bronchitis

Acute exacerbation of chronic bronchitis (AECB) is a very common condition, which presents with deteriorating sputum production and dyspnoea in a patient with pre-existing COPD or chronic bronchitis. As these symptoms are relatively non-specific and also the presenting feature of a wide range of other conditions, the physician should carefully consider the differential diagnosis before deciding on whether or not a patient indeed has AECB. The differential diagnosis can be summarised as pneumonia, pneumothorax, cardiac failure/cor pulmonale, bronchiectasis, asthma, tuberculosis, sinusitis and other forms of upper respiratory tract sepsis, diffuse panbronchiolitis, lung cancer, gastro-oesophageal reflux, the presence of a foreign body in the airway, melioidosis, and lung abscess. This article aims to discuss these conditions, with brief presentation of clinical cases, in the evaluation of differential diagnosis of AECB.     

Severe community-acquired pneumonia

Although several pneumonia severity criteria have been firmly established, the exact definition of severe community-acquired pneumonia (CAP) remains elusive. Mortality from CAP remains high, reaching 50% in some series. The particular role of and spp. in severe CAP has been defined more clearly. Microbial diagnosis in the individual patient remains a difficult task. Despite promising new diagnostic tools, concerns about possible mixed origins preclude a change from the currently advocated broad-spectrum approach of antimicrobial treatment. Although there is some evidence that guidelines may optimize outcomes, their role in limiting the spread of resistance has only recently received attention. Finally, although there are promising data on the use of noninvasive positive pressure ventilation to treat pneumonia in patients without chronic obstructive pulmonary disease, its place in the management of acute respiratory failure remains to be defined in randomized studies.     

Treatment of community-acquired pneumonia

Lower respiratory tract infections are the major cause of death due to infectious disease in the developed and developing world. Despite substantial progress in defining pathogens and in therapeutic options, there continues to be major controversies in the clinical management of these infections. This report reviews the guidelines for community-acquired pneumonia from the Infectious Diseases Society of America (IDSA), updated from the initial publication. Diagnosis should include a chest X-ray to differentiate acute bronchitis from pneumonia. The decision for hospitalization should be based on social factors and evaluation of severity of illness. Identification of an etiological agent for inpatients should include two pretreatment cultures, one pretreatment sputum specimen, with seriously ill patients requiring studies for Legionella spp. Recommendations for empiric treatment of outpatients are doxycycline, a macrolide or a fluoroquinolone. Recommendations for empiric treatment of hospitalized patients are a cephalosporin plus a macrolide, or a fluoroquinolone alone. Recommendations for ICU patients are a beta-lactam combined with either a macrolide or a fluoroquinolone. While concern has arisen about increasing resistance to fluoroquinolones, arguments in favor of these agents include the fact that they have good in vitro activity against nearly all treatable pathogens except some anaerobes. Clinical trials have shown equivalence or superiority compared to other standard agents. They are well tolerated, and can be administered intravenously or orally, once daily. A recent retrospective review has shown superior outcome with fluoroquinolone treatment compared to cephalosporins, including a 36% reduction in mortality.     

Treatment of community-acquired pneumonia

Community-acquired pneumonia is the sixth leading cause of death in the USA. Adherence to the 2007 Infectious Diseases Society of America/American Thoracic Society community-acquired pneumonia guidelines has been associated with improved clinical outcomes. However, choice between guideline-recommended treatments is at the discretion of the prescribing clinician. This review is intended to discuss the characteristics of these treatment options including dosing frequency, dose adjustment for renal/hepatic dysfunction, serious/common adverse events, drug interactions, lung penetration, pharmacokinetic-pharmacodynamic target and effect of obesity to help guide antimicrobial selection. An increasing portion of patients are receiving expanded empiric coverage for methicillin-resistant Staphylococcus aureus as recommended by the American Thoracic Society and Infectious Diseases Society of America for healthcare-associated pneumonia. However, this expanded coverage may not be achieving the desired improvements in clinical outcomes. We expect this increasingly diverse spectrum of patients with pneumonia to eventually result in the merger of these two guidelines to include all patients with pneumonia.     

Levofloxacin for the treatment of community-acquired pneumonia

New respiratory fluoroquinolones (FQs), such as levofloxacin, offer many improved qualities over older agents, such as ciprofloxacin. These include retaining excellent Gram-negative bacilli activity, with improved Gram-positive activity. New FQ-like levofloxacin possesses greater bioavailabilty and a longer serum half-life compared with ciprofloxacin, allowing for once-daily dosing, which may improve patient adherence. The high bioavailability of levofloxacin allows for rapid step-down from intravenous administration to oral therapy, minimizing unnecessary hospitalization, which may decrease costs and improve patient quality of life. Levofloxacin has been evaluated for the treatment of community-acquired pneumonia (CAP) in numerous randomized clinical trials. Most published studies have used the 500 mg dose, although more recent studies have investigated the 750 mg dose once daily. These trials demonstrate that levofloxacin is effective and safe for the treatment of CAP, displaying relatively mild adverse effects that are more or less comparable with ciprofloxacin. Levofloxacin has much to offer in terms of bacterial eradication, including for resistant respiratory pathogens. However, ciprofloxacin-resistant organisms are becoming more prevalent so prudence must be exercised when prescribing this agent.     

Levofloxacin for the treatment of community-acquired pneumonia

New respiratory fluoroquinolones (FQs), such as levofloxacin, offer many improved qualities over older agents, such as ciprofloxacin. These include retaining excellent Gram-negative bacilli activity, with improved Gram-positive activity. New FQ-like levofloxacin possesses greater bioavailabilty and a longer serum half-life compared with ciprofloxacin, allowing for once-daily dosing, which may improve patient adherence. The high bioavailability of levofloxacin allows for rapid step-down from intravenous administration to oral therapy, minimizing unnecessary hospitalization, which may decrease costs and improve patient quality of life. Levofloxacin has been evaluated for the treatment of community-acquired pneumonia (CAP) in numerous randomized clinical trials. Most published studies have used the 500 mg dose, although more recent studies have investigated the 750 mg dose once daily. These trials demonstrate that levofloxacin is effective and safe for the treatment of CAP, displaying relatively mild adverse effects that are more or less comparable with ciprofloxacin. Levofloxacin has much to offer in terms of bacterial eradication, including for resistant respiratory pathogens. However, ciprofloxacin-resistant organisms are becoming more prevalent so prudence must be exercised when prescribing this agent.     

社区获得性肠杆菌肺炎与普通肺炎的比较

目的通过对社区获得性肠杆菌肺炎与普通肺炎的临床对比研究,探讨社区获得性肠杆菌肺炎新的流行病学变化趋势及其特点。方法10例社区获得性肠杆菌肺炎与20例社区获得性普通肺炎进行配对研究,回顾性分析其临床特点、易患因素、病原学检查特点以及抗生素治疗特点。结果(1)社区获得性肠杆菌肺炎的临床症状、生化检查、胸部X线表现等无特殊性,两组病死率比较差异无显著性。(2)患有基础疾病者易发生社区获得性肠杆菌肺炎。(3)不适合抗生素使用时间的过度延长引起一个复杂的疾病过程,而适合抗生素使用的延迟未引起患者病死率的明显增加。结论(1)对因社区获得性肺炎住ICU的患者,如果具备年老,至少有一种基础疾病存在,有既往住院史,有既往抗菌素使用史等特点,应警惕社区获得性肠杆菌肺炎的可能。(2)对疑诊患者早期病原学检查有助于抗生素的合理的选择。     

Optimal therapy for severe pneumococcal community-acquired pneumonia

Streptococcus pneumoniae is responsible for two-thirds of ICU admissions due to community-acquired pneumonia (CAP) and is the leading cause of CAP-related death. Early death is principally due to cardiovascular collapse, whereas late death is associated with hypoxemic respiratory failure. Outcome depends on interactions between non-modifiable factors of predisposition (age, comorbidities, host defences, genetic predisposition) or infection (toxins, virulence, bacterial burden) and modifiable factors (organ-failure support, surgical drainage for empyema, adjuvant therapies and antibiotics). Excess mortality has been reported when initial therapy is discordant, but more than 95% of isolates have minimum inhibitory concentration (MIC) < 4 μg/ml. Therefore, cefotaxime, ceftriaxone and high doses of amoxicillin remain successful for non-meningeal infections. Recent studies suggest that initial combination therapy improves survival in the subset of bacteremic episodes with highest severity, conceivably due to the immunomodulatory effects of macrolides. Prospective, randomized clinical trials of pneumonia patients with a pneumonia severity index score above 90 are warranted to define optimal antibiotic regimens.Supported in part by FISS PI 04/1500     

Risk stratification for patients with community-acquired pneumonia

Community-acquired pneumonia (CAP) is a common medical illness with a prognosis that ranges from rapid complete recovery to severe medical complications and death. Approximately 4 million adults are diagnosed with CAP in the US each year; with more than 600,000 (15%) hospitalised. An estimated $4 billion is expended annually on patients with CAP, with inpatient therapy costing as much as 20 times that of outpatient antimicrobial therapy. Determining severity of illness and using this information to risk-stratify patients with CAP is important from several perspectives. Clinically, understanding prognosis can assist physicians in the initial site of treatment decision (home versus hospital) and can be used to communicate expected outcomes to patients. From a research perspective, risk stratification can be used to select appropriate patient subgroups for clinical trials and to provide severity-adjusted outcomes comparisons. From a policy perspective, severity-adjusted outcomes can be used as a proxy for quality of medical care.     

Guidelines for community-acquired pneumonia in the ICU

Community-acquired pneumonia remains a common and serious condition worldwide. Severe community-acquired pneumonia requiring ICU admission is a distinct entity with different pathogens, outcomes, and management. The mortality rate in severe community-acquired pneumonia can be more than 50%. Over the past decade, some international guidelines for the management of community-acquired pneumonia have been developed in an attempt to optimize patient care. These guidelines have developed prediction tools to direct clinicians in the management of community-acquired pneumonia, including when to admit a patient to the ICU and selecting appropriate investigations and antimicrobial therapy. The individual recommendations of these guidelines and the guidelines as a whole require further studies.     

Changing needs of community-acquired pneumonia

Community-acquired pneumonia (CAP) is a serious condition associated with significant morbidity and potential long-term mortality. Although the majority of patients with CAP are treated as outpatients, the greatest proportion of pneumonia-related mortality and healthcare expenditure occurs among the patients who are hospitalized. There has been considerable interest in determining risk factors and severity criteria assessments to assist with site-of-care decisions. For both inpatients and outpatients, the most common pathogens associated with CAP include Streptococcus pneumoniae, Haemophilus influenzae, group A streptococci and Moraxella catarrhalis. Atypical pathogens, Gram-negative bacilli, methicillin-resistant Staphylococcus aureus (MRSA) and viruses are also recognized aetiological agents of CAP. Despite the availability of antimicrobial therapies, the recent emergence of drug-resistant pneumococcal and staphylococcal isolates has limited the effectiveness of currently available agents. Because early and rapid initiation of empirical antimicrobial treatment is critical for achieving a favourable outcome in CAP, newer agents with activity against drug-resistant strains of S. pneumoniae and MRSA are needed for the management of patients with CAP.     

Fluoroquinolones for the treatment of outpatient community-acquired pneumonia

The increasing prevalence of beta-lactam and macrolide resistance in bacteria that cause respiratory infections has underscored the need for effective antimicrobial agents. The broad spectrum, excellent oral bioavailability, and once-daily dosing of fluoroquinolones contributed to the introduction of several new agents in the past decade. This class is among the world's most used antimicrobial therapies in community and hospital settings. Fluoroquinolones are generally well tolerated, but safety profiles differ widely among agents. Knowledge of in vitro activity, local microbiologic susceptibility and resistance patterns, adverse effects, and potential drug interactions should influence the selection of the best agent for individual patients. This overview of the fluoroquinolones directs particular attention to use in community-acquired pneumonia and safety.