Category Archives: Pulmonary Function

Structural Changes in Airway Diseases: Structural Alterations in Occupational Asthma

Structural Changes in Airway Diseases: Structural Alterations in Occupational AsthmaStructural airway changes such as epithelial damage and subepithelial fibrosis seem to be prominent in asthma from occupational origin. Initial report suggested that changes in airway structure were more prominent in occupational asthma than in other types of asthma such as seasonal asthma. This was particularly true in the condition initially called reactive airways dysfunction syndrome. Inhalation of toxic products or high concentrations of a variety of chemical substances with irritant properties can induce airway obstruction and hyperresponsiveness. RADS was originally described as the onset of respiratory symptoms in the minutes or hours attributable to a single accidental inhalation of high concentrations of irritant gas, aerosol, or particles, followed by asthma-like symptoms and persistent AHR. there Continue reading

Structural Changes in Airway Diseases: Study

Furthermore, airway cartilage is an important determinant of wall stiffness and integrity. Decreased cartilage volume and increased cartilage proteoglycan degradation are seen in asthmatic air-ways. Reduced cartilage integrity may result in a more powerful bronchoconstriction from ASM load reduction.
Changes in the airway wall microvasculature can contribute to airway wall edema and result from angiogenesis. Increased airway vascularity is seen in asthma in association with a greater expression of the vascular endothelial growth factor.
Continue reading

Structural Changes in Airway Diseases: Definition

Structural Changes in Airway Diseases: DefinitionEpithelial cells of asthmatic patients show an increased expression of epidermal growth-factor receptor and CD44 proportional to disease severity, potentially playing a role in bronchial epithelial repair., These observations therefore suggest that epithelial damage is not only an artifact of sampling.
The layer of epithelial cells lies on a basement membrane that appears thickened in histologic studies. This apparent thickening of the basement membrane results from subepithelial fibrosis at the level of the lamina reticularis, the lower part of the basement membrane area, and this fibrosis may extend into the submucosal layer. Since it was first observed in 1922 (reviewed by Redington and Howarth) in fatal asthma, subepithelial fibrosis has been found in asthma of all severities, in atopic rhinitic patients, and even in young children with difficult-to-treat asthma. This fibrosis results from an increased deposition of collagens I, III, and V, fibronectin, tenascin, lumican, and biglycan.

Continue reading

Structural Changes in Airway Diseases: Structural Alterations in Asthma

Morphometric measurements of airways are commonly used to describe structural alterations. These measurements are done after standard or specific staining. Transbronchial biopsies have also allowed to evaluate the remodeling process in the small airways. Other tools such as induced sputum or BAL have been used to assess indirectly some aspects of airway remodeling and surrogate markers evaluated. However, analysis of human tissues is still the best way to assess structural changes.
Continue reading

Structural Changes in Airway Diseases

Structural Changes in Airway DiseasesAsthma and COPD are the most prevalent airway obstructive conditions. Both are complex diseases in which inflammatory and remodeling processes have been depicted. Less is known about remodeling features of other airway diseases, such as reactive airways dysfunction syndrome (RADS), cystic fibrosis (CF), and bronchiectasis. In this review, we will describe briefly the main airway remodeling features observed in obstructive diseases—tentatively defined as a change in the nature, content, and distribution of structural airway elements—their potential functional consequences and clinical relevance, as well as current evidence of pharmacologic modulation of these features in airway diseases,

Continue reading

Chronic Cough Due to Chronic Interstitial Pulmonary Diseases: Summary of Recommendations

Chronic Cough Due to Chronic Interstitial Pulmonary Diseases: Summary of Recommendations1.    In patients with chronic cough, before diagnosing ILD as the sole cause, common etiologies such as upper airway cough syndrome (UACS), which was previously referred to as postnasal drip syndrome, asthma, and GERD should be considered. As these common causes may also share clinical features with specific ILDs, a diagnosis of ILD as the cause of cough should be considered a diagnosis of exclusion. Level of evidence, expert opinion; benefit, substantial; grade of recommendation, E/A
2.    In patients with cough secondary to an ILD, because of the prognostic implications, primary treatment should be dictated by the specific disorder. Level of evidence, low; benefit, substantial; grade of recommendation, B
Continue reading

Chronic Cough Due to Chronic Interstitial Pulmonary Diseases: Treatment

The pathogenesis of cough in HP is unknown. Pathologically, the small airways are affected by cellular granulomatous inflammatory change (a bronchiolitis), and physiologic airflow limitation, either with or without reversibility, is frequently iden-tified. This suggests that in at least a portion of patients, the mechanism may be similar to that of asthma. In the chronic or fibrotic form of the disease, airflow limitation is much less common; however, cough is at least as frequent, suggesting that additional mechanisms are also operative.
The diagnosis of HP requires a comprehensive evaluation, as noted above. Often strongly suggestive historical evidence of exposure will be present. The appropriate history combined with typical radiographic, physiologic, and serologic precipitin features with a lymphocytic BAL sample and/or trans-bronchial lung biopsy findings of bronchiolocentric granulomatous inflammation are often adequate for diagnosis. However, in order to attribute the cough solely or primarily to HP requires that cough go away with successful treatment for HP.

Continue reading

Chronic Cough Due to Chronic Interstitial Pulmonary Diseases: HP

Chronic Cough Due to Chronic Interstitial Pulmonary Diseases: HPHP, or extrinsic allergic alveolitis, is a diffuse parenchymal lung disease that is characterized by an immunologic reaction to the repeated inhalation of a finely dispersed allergen. The immunologic mechanism appears to be primarily a type IV (T-cell-mediated) delayed type hypersensitivity reactions. Histopathologically, this is generally identified by bronchiolocentric granulomatous inflammation. From a clinical perspective, HP is not one disease but a complex group of syndromes that can be classified by the following characteristics: the temporal relationship between exposure and symptoms; occupation; or the type of antigen. While the types of allergens that can cause HP are vast and growing, they can be classified by type, as follows: organic particles (eg, mammalian and avian proteins, fungi, and thermophilic bacteria) make up the vast majority of clinically important antigens, and the inhalation of certain small molecular weight volatile and nonvolatile chemicals by a susceptible individual can cause the same syndrome.

Continue reading

Chronic Cough Due to Chronic Interstitial Pulmonary Diseases: Recommendations

Despite a number of prospectively performed, randomized, controlled trials, the role of corticosteroid therapy in the treatment of sarcoidosis remains a subject of considerable debate. Differences in the stage and duration of disease, baseline symptoms, and level of physiologic impairment may account for some of the conflicting data. Based on an analysis of seven randomized controlled trials, a Cochrane Database review concluded that the use of therapy with oral corticosteroids was associated with an improvement in symptoms (including cough), spirometry findings, and chest radiographic abnormalities over a period of 6 to 24 months. A randomized controlled trial of inhaled corticosteroids after initial therapy with oral corticosteroids showed a nonstatistically significant improvement in cough. Given that cough is but one feature of this systemic disease, that corticosteroids can be associated with significant side effects, and that there are few data beyond 2 years of therapy to indicate a beneficial effect on long-term disease progression, the use of corticosteroids requires an individualized analysis of the overall benefit and risk.

Continue reading

Chronic Cough Due to Chronic Interstitial Pulmonary Diseases: Definition

Chronic Cough Due to Chronic Interstitial Pulmonary Diseases: DefinitionWhile the cause of sarcoidosis is unknown, essentially identical clinical and pathologic features can be seen in berylliosis and aluminosis, disorders with known etiologies, and these three should be considered as one for the purposes of this discussion. The systemic granulomatous disease that complicates common variable immunodeficiency, while superficially similar, appears to be a distinct clinical disorder.
All races, ages, and both sexes are affected. Prevalence rates range widely from < 10 to > 80 per 100,000 population, depending on the age, gender, ethnicity, geographic location, and method of diag-nosis. When a diagnosis is made by radiographic screening, > 50% of patients will be asymptomatic. Of those patients with symptoms, cough, with or without scant amounts of mucoid sputum, is seen in 40 to 80%. review

Continue reading