Clinical syndromes in adults caused by respiratory infection

From monocausality to systems thinking: a complementary and alternative conceptual approach for better understanding the development and prevention of sports injury

The science of sports injury control, including both its cause and prevention, has largely been informed by a biomedical and mechanistic model of health. Traditional scientific practice in sports injury research has routinely involved collapsing the broader socioecological landscape down in order to analyse individual-level determinants of injury - whether biomechanical and/or behavioural. This approach has made key gains for sports injury prevention research and should be further encouraged and allowed to evolve naturally. However, the public health, Applied Human Factors and Ergonomics, and injury epidemiological literature more broadly, has accepted the value of a socioecological paradigm for better understanding disease and injury processes, and sports injury research will fall further behind unless it does the same. A complementary and alternative conceptual approach towards injury control known as systems thinking that builds on socioecological science, both methodologically and analytically, is readily available and fast developing in other research areas. This review outlines the historical progression of causal concepts in the field of epidemiology over the course of the modern scientific era. From here, causal concepts in injury epidemiology, and models of aetiology as found in the context of sports injury research are presented. The paper finishes by proposing a new research agenda that considers the potential for a systems thinking approach to further enhance sports injury aetiological understanding. A complementary systems paradigm, however, will require that sports injury epidemiologists bring their knowledge and skillsets forwards in an attempt to use, adapt, and even refine existing systems-based approaches. Alongside the natural development of conventional scientific methodologies and analyses in sports injury research, progressing forwards to a systems paradigm is now required.

Pulmonary and cardiac infections in athletes

Pulmonary and cardiac infections in the athlete can have a wide range of presentations and complications. These infections may present few problems for the training athlete or become life threatening. The team physician must be able to make an accurate diagnosis, give the appropriate treatment, understand the potential complications, and ensure proper follow-up and return-to-play protocols.

Could single-nucleotide polymorphisms (SNPs) affecting the tumour necrosis factor promoter be considered as part of rheumatoid arthritis evolution?

Tumour necrosis factor (TNF), a cytokine mainly produced by macrophages, is associated with a broad spectrum of biological effects, mainly associated with the host defense against microbes. The TNF gene is located on chromosome six within the major histocompatibility complex (MHC). Rheumatoid arthritis (RA) is a systemic autoimmune disease where TNF plays a central role in its etiology and pathogenesis. Written medical evidence of RA can be traced at least as far back as the 17th century, while human paleopathological studies appear to show the presence of RA prior to this period. The fact that RA has experienced an increment both in severity and mortality could be explained by many causes, particularly the crucial role of the immune system. Single-nucleotide polymorphisms (SNPs) are the most common genetic variations and occur at a frequency of approximately 1 in 1000 bp throughout the genome. The -308 TNF SNP is a mutation that affects the promoter region of the TNF gene. It defines the TNF1 and TNF2 alleles, determining low and high levels of TNF expression, respectively. The presence of the TNF2 allele has also been linked to increased susceptibility to and severity in a variety of autoimmune and inflammatory disorders, including RA, systemic lupus erythematosus, and ankylosing spondylitis. Studies on the functional significance of -308 SNP have detected higher levels of TNF production by cells from TNF2-carrying individuals than cells from TNF1 individuals. This difference does not appear to be due to other genes lying within the MHC region. Since the presence of the TNF2 allele may increase the host's resistance to local infection, by increasing local production of TNF at the infection site, we may suggest that such a mutation has emerged as a selective advantage to carriers of the TNF2 allele. This hypothesis may prove itself by observing the high incidence of tuberculosis and other infectious processes in those patients treated with anti-TNF therapy. Since the human lifespan has increased, the persistence of the TNF2 allele at high frequency in the population now confers what appears to be a marked survival disadvantage. As a result of the disregulation of the immune system, the genetically-predisposed host expresses larger amounts of TNF, leading to chronic inflammatory processes and autoimmune diseases, currently more prevalent. We suggest that RA, a relatively new and increasingly frequent disease, is favored by the presence of the -308 TNF promoter polymorphism, responsible for increased TNF production.

Antibiotic treatment of acute respiratory tract infections in the elderly: effect of a multidimensional educational intervention

OBJECTIVES

: To measure and improve antibiotic use for acute respiratory tract infections (ARIs) in the elderly.

DESIGN

: Prospective, nonrandomized controlled trial.

SETTING

: Ambulatory office practices in Denver metropolitan area (n=4 intervention practices; n=51 control practices).

PARTICIPANTS

: Consecutive patients enrolled in a Medicare managed care program who were diagnosed with ARIs during baseline (winter 2000/2001) and intervention (winter 2001/2002) periods. A total of 4,270 patient visits were analyzed (including 341 patient visits in intervention practices).

INTERVENTION

: Appropriate antibiotic use and antibiotic resistance educational materials were mailed to intervention practice households. Waiting and examination room posters were provided to intervention office practices.

MEASUREMENTS

: Antibiotic prescription rates, based on administrative office visit and pharmacy data, for total and condition-specific ARIs.

RESULTS

: There was wide variation in antibiotic prescription rates for ARIs across unique practices, ranging from 21% to 88% (median=54%). Antibiotic prescription rates varied little by patient age, sex, and underlying chronic lung disease. Prescription rates varied by diagnosis: sinusitis (69%), bronchitis (59%), pharyngitis (50%), and nonspecific upper respiratory tract infection (26%). The educational intervention was not associated with greater reduction in antibiotic prescription rates for total or condition-specific ARIs beyond a modest secular trend (P=.79).

CONCLUSION

: Wide variation in antibiotic prescription rates suggests that quality improvement efforts are needed to optimize antibiotic use in the elderly. In the setting of an ongoing physician intervention, a patient education intervention had little effect. Factors other than patient expectations and demands may play a stronger role in antibiotic treatment decisions in elderly populations.

Principles of appropriate antibiotic use for treatment of uncomplicated acute bronchitis: background

The following principles of appropriate antibiotic use for adults with acute bronchitis apply to immunocompetent adults without complicating comorbid conditions, such as chronic lung or heart disease.1.

The evaluation of adults with an acute cough illness or a presumptive diagnosis of uncomplicated acute bronchitis should focus on ruling out serious illness, particularly pneumonia. In healthy, nonelderly adults, pneumonia is uncommon in the absence of vital sign abnormalities or asymmetrical lung sounds, and chest radiography is usually not indicated. In patients with cough lasting 3 weeks or longer, chest radiography may be warranted in the absence of other known causes.

2.

Routine antibiotic treatment of uncomplicated acute bronchitis is not recommended, regardless of duration of cough. If pertussis infection is suspected (an unusual circumstance), a diagnostic test should be performed and antimicrobial therapy initiated.

3.

Patient satisfaction with care for acute bronchitis depends most on physician–patient communication rather than on antibiotic treatment.

[Gonzales R, Bartlett JG, Besser RE, Cooper RJ, Hickner JM, Hoffman JR, Sande MA. Principles of appropriate antibiotic use for treatment of uncomplicated acute bronchitis: background. Ann Emerg Med. June 2001;37:720-727.]

The relation between purulent manifestations and antibiotic treatment of upper respiratory tract infections

OBJECTIVE

To describe the clinical features of patients diagnosed with upper respiratory tract infections (URIs), and determine which clinical features are associated with antibiotic use.

DESIGN

Prospective cohort study.

SETTING

Three ambulatory care practices at a group-model HMO in the Denver metropolitan area.

PATIENTS

Adults (aged 18 years or older) seeking care for acute respiratory illnesses.

MEASUREMENTS

Clinical features were documented on standardized encounter forms. Clinician type, secondary diagnoses, and antibiotic treatment were extracted from administrative databases. Results are presented as adjusted odds ratios (ORs) with 95% confidence intervals (CIs).

MAIN RESULTS

Antibiotics were prescribed to 33% (95% CI 28%, 38%) of patients diagnosed with URI, after excluding patients with coexisting antibiotic-responsive conditions (e.g., sinusitis, pharyngitis) or a history of cardiopulmonary disease. Multivariate logistic regression analysis identified tobacco use (OR 2.8; 95% CI 1.5, 5.1), history of purulent nasal discharge (OR 2.0; 95% CI 1.1, 3.6) or green phlegm (OR 4.8; 95% CI 2.1, 11.1), and examination findings of purulent nasal discharge (OR 5.2; 95% CI 2.4, 11.2) or tonsillar exudate (OR 3.7; 95% CI 1.1, 12.1) to be independently associated with antibiotic use. The majority of patients treated with antibiotics (82%) had at least one of these factors present.

CONCLUSIONS

Antibiotic treatment of URIs is most common when purulent manifestations are present. Efforts to reduce antibiotic treatment of URIs should educate clinicians about the limited value of purulent manifestations in predicting antibiotic-responsive disease.

Dissent in science: styles of scientific practice and the controversy over the cause of AIDS

In this paper, we use a scientific controversy, and the efforts to legitimize and undermine a theory, to examine the co-production of facts and the rules for verifying facts over time. We discuss these processes in terms of what we call 'styles of scientific practice.' In contrast to the focus of idealist philosophers on theory production and validation as forms of logic or ways of thinking, our styles of practice also include the activities of hands and eyes and the discourses between multiple actors in diverse situations. We discuss aspects of the different styles of practice deployed by opponents in a current controversy surrounding the etiology of AIDS to understand how the same data are interpreted in different ways to support diametrically opposed views. Our study describes and examines rules of confirmation used by supporters of the theory that HIV causes AIDS. For example, we introduce an 'epidemiological' style of practice used by AIDS researchers to synthesize information to understand this disease. Styles of practice stress the historically located collective efforts of scientists, technicians, administrators, institutions, and various 'publics' as they build and sustain ways of knowing. Yet, we also show that the 'history' is also a contested construction, not a given in dusty archives. We describe the different versions of history constructed by various participants in the debate to validate their current constructions and definitions of the disease AIDS. Finally, we discuss the politics behind disease definitions and the consequences of different definitions.

Adult bacterial nasopharyngitis: a clinical entity?

OBJECTIVE

To investigate bacterial nasopharyngitis as a cause of adult upper respiratory infection.

DESIGN

Prospective case series.

SETTING

Walk-in medical clinic of a university hospital.

PATIENTS

507 patients with cold or flu symptoms, sore throat, or recent cough; 21 control subjects without symptoms of upper respiratory infection.

MEASUREMENTS AND MAIN RESULTS

After thorough history and physical examination, the patients underwent nasopharyngeal aspiration and throat culture. Nasopharyngeal specimens were cultured for both bacteria and viruses; antigens for influenza, parainfluenza, and respiratory syncytial virus were sought by enzyme-linked immunosorbent assay (ELISA); serum antibodies to viral respiratory pathogens were determined. Group A beta-hemolytic streptococci grew from the throat specimens of 39 of the 507 patients (8%) or 38 of 334 patients (11%) who had clinical diagnoses of pharyngitis. Thirty-three cases of influenza A, 20 cases of influenza B, and seven cases of parainfluenza infections were diagnosed. Bacteria were cultured from the nasopharyngeal secretions of 284 patients (56%). In contrast to pharyngeal culture, commensal mixed flora were rarely found in nasopharyngeal culture. Nasopharyngeal culture of bacteria usually considered to be respiratory pathogens was significantly associated with the presence of leukocytes. Streptococcus pneumoniae (odds ratio 6.0, 95% confidence interval 2.6-14.2), Moraxella catarrhalis (odds ratio 12.9, 95% confidence interval 3.1-79.5), and Hemophilus influenzae (odds ratio 3.0, 95% confidence interval 1.2-7.4) were all associated with the presence of leukocytes. In contrast, nasopharyngeal culture of coagulase-negative staphylococci, mixed flora, and the documentation of a viral infection were not associated with the presence of leukocytes. For none of 21 control subjects were "pathogenic" bacteria found.

CONCLUSIONS

These data suggest that potentially pathogenic bacteria may have a causal role in adult nasopharyngitis, although further data are needed to confirm this hypothesis.