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Biomedical subjects

R S Irwin

Publications and source records attributed to R S Irwin.

At least 19 recordsLinked to original sources
PubMed1998

Chronic obstructive pulmonary disease.

Acute exacerbations of underlying COPD are a common cause of respiratory deterioration. Developments have been made in preventive measures, but admission to hospital for acute exacerbations can be expected to remain common. Several expert consensus guidelines have been published to define the appropriate management of COPD patients. These consensus guidelines generally agree, but all acknowledge a lack of large well-controlled clinical studies, especially studies focusing on the management of acute exacerbations. Consequently, many potential controversies exist about the details of managing patients with acute exacerbations. Although studies of many fundamental aspects of management are still needed, the results of controlled clinical trials are sufficient to emphasise the importance of a careful clinical assessment, supplemental oxygen, inhaled bronchodilators to partially improve airway obstruction, corticosteroids to decrease the likelihood of treatment failures and to speed recovery, antibiotics, especially in severe patients, and non-invasive positive-pressure ventilation for treatment of acute ventilatory failure in selected patients.

Acute Disease↗
PubMed1998

From a prospective study of chronic cough: diagnostic and therapeutic aspects in older adults.

BACKGROUND: Cough is the most common complaint for which adults see a physician in the ambulatory setting in the United States. An anatomical diagnostic protocol has been used since 1981 to evaluate patients with chronic cough. It has been shown to be effective in diagnosing the cause of cough and leading to specific treatment in a variety of adult populations but has never been evaluated specifically in a population of older adults. OBJECTIVES: To question whether the spectrum and frequency of causes of chronic cough and the response to therapy would be different in older adults. METHODS: Thirty patients at least 64 years of age with a history of cough lasting at least 3 weeks were prospectively evaluated with a protocol designed to detect diseases that stimulate the afferent limb of the cough reflex. The final diagnosis of the cause of chronic cough required fulfillment of pretreatment criteria and having cough disappear with specific therapy. When more than one disease fulfilled pretreatment diagnostic criteria, therapy was instituted in the order that these were fulfilled. Probability statistics were used to describe the testing characteristics of individual components of the diagnostic protocol in terms of sensitivity, specificity, positive predictive value, and negative predictive value as they applied to chronic cough. RESULTS: Forty causes of chronic cough were identified in all 30 patients. Postnasal drip syndrome, gastroesophageal reflux disease, and asthma were the most common causes of chronic cough, accounting for 85% of all causes found. Among patients with normal chest radiograph findings who were not cigarette smokers and not taking an angiotensin-converting enzyme inhibitor, postnasal drip syndrome, gastroesophageal reflux disease, and asthma accounted for 100% of all causes found. Specific therapy was successful in eliminating chronic cough in 100% of the patients studied. Except for barium esophagography, all laboratory tests for which information was available had sensitivities and negative predictive values of 100%. CONCLUSIONS: Postnasal drip syndrome, gastroesophageal reflux disease, and asthma accounted for 85% of all causes of chronic cough in older adults. Chronic cough caused substantial physical and emotional morbidity among older patients. The major value of performing objective testing in evaluating chronic cough is its ability to rule out specific diseases as a diagnostic possibility. The following clinical profile consistently predicts patients with cough attributable to gastroesophageal reflux disease: the patient has cough that has been persistently troublesome for at least 3 weeks; does not smoke cigarettes; does not take an angiotensin-converting enzyme inhibitor; does not have or has not responded to therapy for postnasal drip syndrome and asthma; and has normal or nearly normal findings and stable chest radiograph. The differences between what we observed regarding chronic cough in older adults and observations by ourselves and others regarding chronic cough in general are minor.

Aged↗
PubMed1998

Perforation of the right ventricle: a complication of blind placement of a chest tube into the postpneumonectomy space.

We were asked to review a case from an outside hospital in which there was inadvertent perforation of the right ventricle during the percutaneous placement of a chest tube. We present the case in the hopes that by doing so, others will avoid such a complication in the future. After reviewing the case, it appeared that the complication occurred because the physician was not knowledgeable about the anatomy of the postpneumonectomy space and the physician failed to use the safest procedure in placing the tube.

Bronchiectasis↗
PubMed1997

Interpretation of positive results of a methacholine inhalation challenge and 1 week of inhaled bronchodilator use in diagnosing and treating cough-variant asthma.

BACKGROUND: In diagnosing cough due to asthma, methacholine chloride inhalation challenge (MIC) interpreted in a traditional fashion has been shown to have positive predictive values from 60% to 82%. OBJECTIVE: To determine whether any features of positive results of an MIC or the results of a 1-week trial of inhaled beta-agonist therapy were helpful in predicting when the cough was due to asthma. METHODS: The study design was a prospective, randomized, double-blind, placebo-controlled, crossover format performed in adult, nonsmoking subjects, who were referred for diagnosis and treatment of chronic cough. The subjects had no other respiratory complaints or medical conditions for which they were taking medications, the results of baseline spirometry and chest roentgenograms were normal, and the results of MIC were positive. After obtaining baseline data, including MICs on 2 separate days, objective cough counting, and self-assessment of cough severity using a visual analog scale, subjects were randomized to receive 2 inhalations (1.3 mg) of metaproterenol sulfate or placebo by metered dose inhaler attached to a spacer device every 4 hours while awake. At 1 week, data identical to baseline were collected, and subjects received the other metered dose inhaler for 7 days. At 1 week, data identical to baseline were collected. After completion of the protocol, subjects were followed up in the clinic to observe the final response of the cough to specific therapy. RESULTS: Based on the disappearance of the cough with specific therapy, the cough was due to asthma in 9 of 15 subjects and nonasthma in 6 of 15 subjects. Baseline data were similar between groups. With respect to MICs, there were no significant differences between groups in the cumulative dose of methacholine that provoked a 20% decrease in forced expiratory volume in 1 second from the postsaline baseline value (PD20 values), slopes of dose-response curves, and maximal-response plateaus. Cough severity significantly improved after 1 week of metaproterenol use compared with the severity of the cough at baseline (P = .03) and with placebo (P = .02) only in subjects with asthma. CONCLUSIONS: No matter how the results are analyzed, positive MIC results, without observing response to therapy, are only consistent with asthma as the cause of the cough. The results are only diagnostic of asthma when they are followed by a favorable response to asthma therapy. After 1 week of inhaled beta-agonist, only the cough due to cough-variant asthma is significantly better.

Administration, Inhalation↗
PubMed1996

Predictive values of the character, timing, and complications of chronic cough in diagnosing its cause.

BACKGROUND: It is not clear whether careful history taking with detailed questioning of the characteristics of cough is diagnostically useful. OBJECTIVE: To determine if the character, timing, or complications of chronic cough were helpful in determining its cause. METHODS: A prospective, descriptive study of consecutive, unselected, immunocompetent patients referred to our university outpatient clinic because of chronic cough. All patients were evaluated by a previously published and validated systematic diagnostic protocol, a self-administered questionnaire, and by observing the character of involuntary and voluntary coughs. The final diagnosis of the cause of cough required fulfillment of pretreatment criteria plus having cough disappear or substantially improve as a complaint with specific therapy. RESULTS: Eighty-eight patients met inclusion criteria and were fully evaluated. The mean +/- SD age was 53.1 +/- 16 years (range, 15-83 years) and 24 were males and 64 were females with a mean +/- SD history of cough for 6.6 +/- 9.8 years (range, 1 month-44 years). The cause of chronic cough was established in 86 (98%) of 88 patients. Eighty-one (92%) of 88 had cough disappear as a complaint. Cough was as a result of a single cause in 39% and multiple causes in 59%. Gastroesophageal reflux disease, postnasal drip syndrome, and asthma were the 3 most common causes of chronic cough and accounted for 90% of diagnoses. Gastroesophageal reflux disease, postnasal drip syndrome, and asthma were again found to be the 3 most common causes of chronic cough irrespective of patient estimated quantity of daily sputum production. These 3 conditions caused chronic cough in 99.4% of patients with the following characteristics: (1) nonsmoker; (2) not receiving an angiotensin-converting enzyme inhibitor drug; and (3) normal or nearly normal and stable chest radiograph. With respect to the spectrum and frequency of diagnoses and their interrelationships with the character, timing, and complications of cough, multiple stepwise linear regression analysis showed that none of the variability of the character, timing, or complications of cough could be explained by any specific diagnosis. CONCLUSIONS: A carefully taken history with detailed questioning of the character, timing, and complications of chronic cough is not likely to be useful in diagnosing the cause of cough. The cause can be determined and successfully treated with specific therapy in the greatest majority of cases. Chronic cough is often caused by multiple, simultaneously contributing causes. Postnasal drip syndrome, asthma, and gastroesophageal reflux disease remain the 3 most common causes of chronic cough and there is a clinical profile that nearly always predicts their presence in immunocompetent patients.

Adolescent↗
PubMed1996

Metastatic papillary thyroid carcinoma to lung diagnosed by bronchoalveolar lavage.

The diagnosis of papillary carcinoma of the thyroid metastatic to the lung frequently requires a battery of noninvasive tests. Occasionally, invasive procedures such as open lung biopsy, transthoracic needle biopsy, and transbronchial lung biopsy are employed to confirm the diagnosis. A 31-yr-old woman with papillary thyroid carcinoma treated previously by a near-total thyroidectomy and 131I ablation presented to our clinic with shortness of breath and a clear chest roentgenogram. A post-131I treatment whole body scan revealed widespread 131I pulmonary uptake, and the presence of papillary thyroid cancer was confirmed by bronchoalveolar lavage. We conclude that bronchoalveolar lavage should be considered when tissue confirmation of metastatic papillary carcinoma to the lung is needed. During the evaluation and follow-up of this patient, we were able to determine that metastatic papillary carcinoma to the lung may cause a methacholine bronchoprovocation test to be falsely positive for asthma.

Adult↗
PubMed1995

Chronic cough with a history of excessive sputum production. The spectrum and frequency of causes, key components of the diagnostic evaluation, and outcome of specific therapy.

STUDY OBJECTIVE: To determine (1) the spectrum and frequency of causes of chronic cough with a history of excessive sputum production (CCS) and (2) the response of these causes to specific therapy. STUDY DESIGN: Prospective study utilizing the anatomic diagnostic protocol originally developed to diagnose chronic cough. PATIENTS: Seventy-one immunocompetent adults who complained of expectoration of greater than 30 mL of sputum per day. LOCATION: University hospital pulmonary outpatient clinic. RESULTS: Patients were seen an average of 4.2 times over 4.6 months before a specific diagnosis was made. The cause of CCS was determined in 97%. It was due to one cause in 38%, 2 in 36%, and three in 26%. Postnasal drip syndrome (PNDS) was a cause 40% of the time, asthma 24%, gastroesophageal reflux disease (GERD) 15%, bronchitis 11%, bronchiectasis 4%, left ventricular failure 3%, and miscellaneous causes 3%. Among patients with a normal chest radiograph who were nonsmokers and not taking an angiotensin converting enzyme inhibitor; CCS was due to PNDS, or asthma, or GERD, or all three in 100% of cases. Chest radiograph, methacholine inhalation challenge, 24-h esophageal pH monitoring, bronchoscopy, and spirometry with bronchodilator each had a sensitivity and negative predictive value of 100%. Chest radiograph and barium swallow had positive predictive values of only 38% and 30%, respectively. CONCLUSIONS: (1) The anatomic diagnostic protocol for cough is also valid for CCS; (2) the major causes of chronic excessive sputum production and chronic cough are so similar that CCS should be considered a form of chronic cough; (3) the evaluation of CCS is more complicated and takes longer than the evaluation of chronic cough; (4) the major strength of the laboratory diagnostic protocol is that it reliably rules out conditions; (5) the outcome of specific therapy is almost always successful; and (6) the term "bronchorrhea" can be misleading if it is applied to excessive sputum production before a specific diagnosis of its source is made since the most common cause of excessive sputum that is expectorated (PNDS) is a disorder of the upper respiratory tract. Therefore, nonspecific therapies theoretically aimed at reducing mucus production in the lower respiratory tract are not likely to be helpful.

Adolescent↗
PubMed1993

Difficult-to-control asthma. Contributing factors and outcome of a systematic management protocol.

To our knowledge, there are no published results of protocols for managing difficult to control asthma (DTCA) or of the spectrum and frequencies of reasons why asthma can be difficult to control (DTC). To assess the usefulness of a systematic management protocol and determine the reason(s) why asthmatics are DTC, we developed a protocol that systematically considered multiple factors that may make asthma worse and prospectively evaluated the outcomes of therapeutic interventions for these factors and of inhaled corticosteroids (ICS) and azathioprine. We studied 42 consecutive and unselected DTCAs (19 men and 23 women) whose age was 48 +/- 15.9 years. They had a diagnosis of asthma for 15.1 +/- 15.8 years, were DTC for 4.8 +/- 7.8 years, and were followed up by us in the study for a total of 3.5 +/- 1.9 years. Initially, the dose of prednisone was 30.2 +/- 22 mg/d. Following utilization of the protocol, 74 percent were no longer DTC. It took 1.8 +/- 1.7 years for them to no longer be DTC; they remained so for 1.8 +/- 1.5 years. In these patients, 2.7 +/- 1.2 factors appeared to be responsible for the DTC state; 80 percent had > or = 2. Improvement was more likely if gastroesophageal reflux (GER) was a factor (p = 0.014); it correlated with the addition of ICS (p = 0.04) and treatment for GER (p = 0.02). Failure to reverse DTCA correlated with the suspicion (p = 0.004) and admission of nonadherence (p = 0.04). In 14 patients given azathioprine, prednisone dose decreased from 45 +/- 25.3 to 13.3 +/- 21.6 mg/d (p = 0.003); 6 of 14 achieved no longer DTC status; and substantial morbidity occurred. The reason(s) for DTCA could be determined in most instances by utilizing a systematic protocol; multiple factors were responsible in the majority of cases; treatment for GER and ICS were the two most helpful interventions; nonadherence was the most likely reason suspected for maintaining DTCA; and azathioprine acted as a corticosteroid-sparing agent that should not be prescribed routinely.

Adolescent↗