Lung abscess: update on microbiology and management.

A lung abscess is a circumscribed collection of pus in the lung as a result of a microbial infection, which leads to cavity formation and often a radiographic finding of an air fluid level. Patients with lung abscesses commonly present to their primary care physician or to the emergency department with "nonresolving pneumonia." Although, the incidence of lung abscess has declined since the introduction of antibiotic treatment, it still carries a mortality of up to 10%-20%. This article discusses in detail the up-to-date microbiology and the management of lung abscesses.

An algorithmic approach to chronic dyspnea.

QUESTION: The objective of the study was to prospectively evaluate an algorithmic approach to the cause(s) of chronic dyspnea. MATERIALS/PATIENTS/METHODS: Prospective observational study. The study group consisted of 123 patients with a chief complaint of dyspnea of unknown cause present for >8 weeks. Dyspnea severity scores were documented at entry and after therapy. Patients underwent an algorithmic approach to dyspnea. Therapy could be instituted at any time that data supported a treatable diagnosis. Whenever possible, accuracy of diagnosis was confirmed with an improvement in dyspnea after therapy. Tests required, spectrum and frequency of diagnoses, and the values of individual tests were determined. RESULTS: Cause(s) was(were) diagnosed in 122/123 patients (99%); 97 patients had one diagnosis and 25 two diagnoses. Fifty-three percent of diagnoses were respiratory and 47% were non-respiratory. Following therapy, dyspnea improved in 63% of patients. CONCLUSIONS: The prospective algorithmic approach led to diagnoses in 99% of cases. A third of patients were diagnosed with each tier of the algorithm, thus minimizing the need for invasive testing. Specific diagnoses led to improvement in dyspnea in the majority of cases. Based on the results of this study, the algorithm can be revised to further minimize unnecessary tests without loss of diagnostic accuracy.

Clinical approach to acute cough.

Acute cough is among the most common symptoms for which patients seek medical attention. It accounts for millions of days lost from school and work and billions of dollars spent on medical care. Acute cough is defined as cough present for 3 weeks or less. It most often is caused by a viral infection of the upper respiratory tract ("common cold") or lower respiratory tract (i.e., "acute bronchitis"). The most effective treatment for cough due to the common cold is a combination first-generation antihistamine plus decongestant. Antibiotics are not indicated for most cases of acute cough. Occasionally, acute cough can be a symptom of a life-threatening condition.

Cough and asthma.

PURPOSE OF REVIEW: The intention of this article is to discuss and place into perspective recent articles on cough and asthma. RECENT FINDINGS: Asthma continues to be a major diagnosis in most studies of cough. The first prospective study of sub-acute cough demonstrated an asthma incidence lower than that for chronic cough, a logical finding; upper airway cough syndrome often causes cough in the postinfectious state. The first prospective study of cough in infants suggested asthma to be a minor cause of cough in infants, but methodological flaws make the conclusions uncertain. Efforts to separate cough-variant asthma from classic asthma continue. One group has demonstrated that the maximal bronchoconstrictor response in cough-variant asthma is blunted when compared with classic asthma, a possible explanation for the absence of wheeze and dyspnea in cough-variant asthma. Another look at airway resistance showed a less rapid rate of rise in resistance in cough-variant asthma with increasing methacholine dosing than in classic asthma. On the biochemical front, a group has demonstrated differences in vascular endothelial growth factor, which may be the underpinnings of differences between cough-variant asthma and classic asthma. SUMMARY: Recent data suggest that cough-variant asthma is part of a continuum in the expression of asthma symptoms and in the asthmatic inflammatory response.

Overview of common causes of chronic cough: ACCP evidence-based clinical practice guidelines.

OBJECTIVE: To review the literature on the most common causes of chronic cough. METHODS: MEDLINE was searched (through May 2004) for studies published in the English language since 1980 on human subjects using the medical subject heading terms "cough," "causes of cough," and "etiology of cough." Case series and prospective descriptive clinical trials were selected for review. Also obtained were any references from these studies that were pertinent to the topic RESULTS: Upper airway cough syndrome (UACS) due to a variety of rhinosinus conditions, previously referred to as postnasal drip syndrome, asthma, nonasthmatic eosinophilic bronchitis (NAEB), and gastroesophageal reflux disease (GERD) are the most common causes of chronic cough. Each of these diagnoses may be present alone or in combination and may be clinically silent apart from the cough itself. CONCLUSION: In the absence of evidence for the presence of another disorder, an approach focused on detecting the presence of UACS, asthma, NAEB, or GERD, alone or in combination, is likely to have a far higher yield than routinely searching for relatively uncommon or obscure diagnoses.

Chronic upper airway cough syndrome secondary to rhinosinus diseases (previously referred to as postnasal drip syndrome): ACCP evidence-based clinical practice guidelines.

OBJECTIVE: To review the literature on postnasal drip syndrome (PNDS)-induced cough and the various causes of PNDS. Hereafter, PNDS will be referred to as upper airway cough syndrome (UACS). METHODS: MEDLINE search (through May 2004) for studies published in the English language since 1980 on human subjects using the medical subject heading terms "cough," "causes of cough," "etiology of cough," "postnasal drip," "allergic rhinitis," "vasomotor rhinitis," and "chronic sinusitis." Case series and prospective descriptive clinical trials were selected for review. Also, any references from these studies that were pertinent to the topic were obtained. RESULTS: In multiple prospective, descriptive studies of adults, PNDS due to a variety of upper respiratory conditions has been shown either singly or in combination with other conditions, to be the most common cause of chronic cough. The symptoms and signs of PNDS are nonspecific, and a definitive diagnosis of PND-induced cough cannot be made from the medical history and physical examination findings alone. Furthermore, the absence of any of the usual clinical findings does not rule out a response to treatment that is usually effective for PND-induced cough. The differential diagnosis of PNDS-induced cough includes allergic rhinitis, perennial nonallergic rhinitis, postinfectious rhinitis, bacterial sinusitis, allergic fungal sinusitis, rhinitis due to anatomic abnormalities, rhinitis due to physical or chemical irritants, occupational rhinitis, rhinitis medicamentosa, and rhinitis of pregnancy. Because of a high prevalence of upper respiratory symptoms associated with gastroesophageal reflux disease (GERD), GERD may occasionally mimic PNDS. A crucial unanswered question is whether the conditions listed above actually produce cough through a final common pathway of PND or whether, in fact, in some circumstances they cause irritation or inflammation of upper airway structures that directly stimulate cough receptors and produce cough independently of or in addition to any associated PND. CONCLUSION: PNDS (ie, UACS) secondary to a variety of rhinosinus conditions is the most common cause of chronic cough. Because it is unclear whether the mechanisms of cough are the PND itself or the direct irritation or inflammation of the cough receptors located in the upper airway, the guideline committee has decided that, pending further data that address this difficult question, the committee unanimously recommends that the term upper airway cough syndrome be used in preference to postnasal drip syndrome when discussing cough associated with upper airway conditions.

Cough and the common cold: ACCP evidence-based clinical practice guidelines.

OBJECTIVE: To review the literature on cough and the common cold. METHODS: MEDLINE was searched through May 2004 for studies published in the English language since 1980 on human subjects using the medical subject heading terms "cough" and "common cold." Selected case series and prospective descriptive clinical trials were reviewed. Additional references from these studies that were pertinent to the topic were also reviewed. RESULTS: Based on extrapolation from epidemiologic data, the common cold is believed to be the single most common cause of acute cough. The most likely mechanism is the direct irritation of upper airway structures. It is also clear that viral infections of the upper respiratory tract that produce the common cold syndrome frequently produce a rhinosinusitis. In the setting of a cold, the presence of abnormalities seen on sinus roentgenograms or sinus CT scans are frequently due to the viral infection and are not diagnostic of bacterial sinus infection. CONCLUSION: Cough due to the common cold is probably the most common cause of acute cough. In a significant subset of patients with "postinfectious" cough, the etiology is probably an inflammatory response triggered by a viral upper respiratory infection (ie, the common cold). The resultant subacute or chronic cough can be considered to be due to an upper airway cough syndrome, previously referred to as postnasal drip syndrome. This process can be self-perpetuating unless interrupted with active treatment.

Unexplained (idiopathic) cough: ACCP evidence-based clinical practice guidelines.

OBJECTIVE: To review the literature on unexplained cough, previously referred to as idiopathic cough. METHODS: Search of MEDLINE (through May 2004) for studies published in the English language since 1980 on human subjects using the medical subject heading terms "cough," "unexplained cough," and "idiopathic cough." We selected case series and prospective descriptive clinical trials. We also obtained any references from these studies that were pertinent to the topic. RESULTS: The diagnosis of unexplained (idiopathic) cough should only be considered after a thorough diagnostic and treatment approach for the most common causes of cough has been completed and uncommon causes have been adequately evaluated Unless this is done, it is likely that many patients with a definable cause of cough will be misdiagnosed as having "unexplained cough." CONCLUSION: The diagnosis of unexplained cough is probably made too often based on an inadequate diagnostic workup or treatment course to determine the specific cause of cough. Nevertheless, there may be a group of patients in whom none of the usual explanations for cough may be present. For this group, the committee unanimously recommends using the diagnostic term unexplained cough, rather than idiopathic cough.

An empiric integrative approach to the management of cough: ACCP evidence-based clinical practice guidelines.

OBJECTIVE: Review the literature to provide a comprehensive approach, including algorithms for the clinician to follow in evaluating and treating the patient with acute, subacute, and chronic cough. METHODS: We searched MEDLINE (through May 2004) for studies published in the English language since 1980 on human subjects using the medical subject heading terms "cough," "treatment of cough," and "empiric treatment of cough." We selected case series and prospective descriptive clinical trials. We also obtained any references from these studies that were pertinent to the topic. RESULTS: The relative frequency of the disorders (alone and in combination) that can cause cough as well as the sensitivity and specificity of many but not all diagnostic tests in predicting the cause of cough are known. An effective approach to successfully manage chronic cough is to sequentially evaluate and treat for the common causes of cough using a combination of selected diagnostic tests and empiric therapy. Sequential and additive therapy is often crucial because more than one cause of cough is frequently present. CONCLUSION: Algorithms that provide a "road map" that the clinician can follow are useful and are presented for acute, subacute, and chronic cough.