[Dyspneic bronchiectasis in adults. Diffuse cystic bronchiectasis originating in the collaterals of the axial bronchi].
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Bronchiectasis is defined as acquired and permanent abnormal dilation and destruction of the bronchial walls. Secondary amyloidosis is a disorder characterized by the deposition of amyloid A (AA) in multiple organs and tissues in the body. End-stage renal disease (ESRD) secondary to bronchiectasis-related amyloidosis has only been mentioned in case reports. Little is known about the complications of bronchiectasis-related amyloidosis and the outcomes in patients who develop ESRD due to amyloid deposition in the kidneys. The aim of this study was to identify the clinical characteristics of this patient group, and to report the outcomes of these cases relative to bronchiechtasis type. We assessed the records of 40 patients with AA-type amyloid nephropathy and ESRD who were on hemodialysis (HD) at Baskent University Hospital between 1997 and 2000. The diagnosis of amyloidosis was based on histopathological findings in kidney, rectum, bone marrow, lymph node, thyroid, bladder, liver, and stomach biopsies. Bronchiectasis was diagnosed on the basis of history and findings on physical examination, chest X-ray, and thoracic high-resolution computerized tomography (HRCT). The patients' records were retrospectively evaluated for cause of secondary amyloidosis, and cases with causes other than bronchiectasis were excluded. Secondary amyloidosis due to bronchiectasis and recurrent pulmonary infection was identified in 40% (16 patients) of the 40 patients. For each of these 16 cases, we recorded patient age, duration of bronchiectasis, duration of HD, amount of lung involvement, and biopsy site(s). The means for age, duration of bronchiectasis, and duration of HD in the 16 patients were 50.6 +/- 13.5 years, 22.18 +/- 12.02 years (range, 6-42 years), and 30.81 +/- 36.94 months (range, 4-144 months), respectively. The most common biopsy site was the rectum (n = 8). Thoracic HRCT revealed cystic bronchiectasis in 8 cases (50%). Four of these 8 patients (25% of the group of 16) died from sepsis within 3-year follow-up period. Two of the four patients who died had bilateral cystic bronchiectasis, and the other two had unilateral cystic bronchiectasis. In the other eight patients in the group, thoracic HRCT showed chronic fibrotic changes in the pulmonary parenchyma and minimal traction bronchiectasis. Four of these patients exhibited apical fibrosis and bronchiectasis (25% of the group of 16), and these radiological findings were considered sequelae of previous tuberculosis infections. In conclusion, chronic respiratory infections and associated bronchiectasis remain a serious problem in Turkey due to insufficient prevention, diagnosis, and treatment. It is important that patients with progressive cystic and diffuse bronchiectasis be followed carefully, as they may develop amyloidosis and ESRD in time. Also, the clinical course in patients with cystic bronchiectasis may be worse than that in other types of bronchiectasis due to complicating pulmonary infections.
OBJECTIVE: The purpose of this study was to determine whether the pattern and distribution of bronchiectasis shown on CT scans can be used to discriminate between idiopathic cases and those with an identifiable cause. MATERIALS AND METHODS: The CT scans of 168 patients with chronic purulent sputum production and who were suspected of having bronchiectasis were analyzed (117 patients with idiopathic bronchiectasis, 15 with allergic bronchopulmonary aspergillosis, 15 with hypogammaglobulinemia, 15 with impaired mucociliary clearance, and seven with cystic fibrosis diagnosed in adult life). The scans were analyzed in random order by two observers. The extent, site, type, and lobar distribution of bronchiectasis and the severity of bronchial dilatation and bronchial wall thickening were scored. The frequency of these features in the known-cause groups was compared with that in the idiopathic group to identify any significant differences. RESULTS: Compared with idiopathic bronchiectasis, no significant lobar predominance was seen in any of the known-cause groups, apart from a higher frequency of lower lobe involvement in the patients with syndromes of impaired mucociliary clearance (p < .02). The bronchiectasis of allergic bronchopulmonary aspergillosis and adult cystic fibrosis was more often widespread (five or six lobes involved (p < .001 and p < .01, respectively) than idiopathic bronchiectasis. Central bronchiectasis was more common in allergic bronchopulmonary aspergillosis (p < .005), although the sensitivity when this was used as a diagnostic feature was only 37%. In all groups, cylindrical bronchiectasis was the most common type, with varicose and cystic bronchiectasis occurring more frequently in allergic bronchopulmonary aspergillosis (p < .01). On multiple regression analysis, allergic bronchopulmonary aspergillosis and adult cystic fibrosis showed more extensive disease than idiopathic bronchiectasis (p < .0005 and p < .001, respectively), independent of other CT features. In hypogammaglobulinemia, dilatation of the bronchial lumen was less than in idiopathic bronchiectasis (p < .02) independent of disease extent and bronchial wall thickness. CONCLUSION: Although differences in distribution and morphology of bronchiectasis may be seen on CT scans in groups of patients with bronchiectasis of different causes, CT findings applied to individual patients are of limited value in discriminating between idiopathic bronchiectasis and bronchiectasis of various known causes.
The aim of this study was to evaluate the accuracy of 3-mm-thick reconstructed sections in the diagnosis of bronchiectasis with multislice CT (MSCT). Forty consecutive patients suspected of bronchiectasis (23 females, 17 males; mean age 51 years) underwent MSCT of the entire thorax with a 4x1-mm collimation (120 kV, 0.5 s/rotation, 80 mAs/slice) and a pitch of 1.75. From each data set (mean z-axis coverage: 257 mm; mean duration: 21 s), two series of images were systematically generated: 1-mm (group 1) and 3-mm (group 2)-thick reconstructed scans. Both series of images were obtained at 10-mm intervals and reconstructed with a high-spatial-frequency algorithm. Two observers independently analyzed the presence of bronchiectasis and associated abnormalities in group-1 and group-2 lung images. No significant difference between group 1 and group 2 was found in: (a) the detection of bronchiectasis, identified in 24 patients (60%) in group 1 and in 23 patients (57.5%) in group 2 ( p=0.08); (b) the evaluation of the extent of bronchiectasis, identifying focal bronchiectasis in 10 patients (25%) in group 1 and 7 patients (17.5%) in group 2 ( p=0.39) and multifocal bronchiectasis in 16 patients (40%) in both groups; (c) the characterisation of bronchiectasis (cylindral bronchiectasis: group 1, n=24, 60%; group 2, n=21, 53%, p=0.08); varicose bronchiectasis: group 1, n=5, 12.5%; group 2, n=6, 15%, p=0.56); and cystic bronchiectasis: group 1, n=2, 5%; group 2, n=2, 5%). Apart from the identification of abnormal bronchial wall thickening (group 2, n=35, 87.5%, vs group 1, n=31, 77.5%, p<0.05), recognition of associated bronchopulmonary anomalies did not differ between the two groups. This study demonstrates a comparable accuracy of the 3- and 1-mm-thick reconstructed scans in the detection and characterization of bronchiectasis. These results suggest the potential usefulness of 3-mm-thick scans generated from 4x2.5-mm acquisitions in the screening of bronchiectasis, which would allow a 20% radiation dose reduction compared with the present investigation.
The usefulness of CT with 4-mm-thickness cuts at 5-mm intervals in the diagnosis of bronchiectasis was studied by comparing the results of CT with those of bronchography in 323 segmental bronchi in 20 patients. No bronchiectasis was found on either study in 222 segmental bronchi. Of the 101 segmental bronchi showing bronchiectasis on bronchography, CT correctly identified bronchiectasis in 98 segments (97%). Bronchography showed cystic bronchiectasis in 35 and varicose bronchiectasis in 14 segmental bronchi, all of which were correctly identified on CT. Of the 52 segmental bronchi showing cylindrical bronchiectasis on bronchography, CT correctly identified these changes in 49 segments but failed to detect it in three. The presence of interstitial lung disease with emphysema and very localized mild bronchiectasis in one case each made the identification of cylindrical bronchiectasis difficult and caused the false-negative results. When bronchography is used as the criterion, CT with medium-thickness cuts and medium slice intervals appears to be 100% specific for all types of bronchiectasis, 100% sensitive for cystic and varicose bronchiectasis, and 94% sensitive for cylindrical bronchiectasis.
OBJECTIVE: In a multicenter study, we evaluated the relationships between the extent and severity of bronchiectasis on CT and clinical symptoms, spirometric abnormality, and sputum characteristics. SUBJECTS AND METHODS: The study population included 261 patients with symptomatic, physiologically significant bronchiectasis, who were enrolled in another study evaluating the clinical efficacy of deoxyribonudease in treatment of bronchiectasis. Patients with cystic fibrosis, allergic bronchopulmonary aspergillosis, and fungal or mycobacterial infection were excluded. In addition to high-resolution CT scanning, all patients underwent clinical evaluation, spirometry, and sputum culture. CT features scored by consensus of two observers included the extent of bronchiectasis, type of bronchiectasis (cylindric, varicose, or cystic), extent of mucoid impaction, and degree of bronchial wall thickening. RESULTS: Scores for the severity and extent of bronchiectasis correlated with the forced expiratory volume in 1 sec (FEV1) (r = -.362, p < .0001) and with the forced vital capacity (FVC) (r = -.362, p < .0001). Scores for bronchial wall thickening correlated with the FEV1 (r = -.367, p < .0001) and FVC (r = -.239, p < .001). Patients with cystic bronchiectasis were significantly more likely to grow Pseudomonas from their sputa and to have purulent sputa than were patients with cylindric or varicose bronchiectasis. Patients with cystic bronchiectasis had significantly lower FEV1 and FVC values than did patients with cylindric or varicose bronchiectasis. CONCLUSION: In this patient population, we found weak but significant correlations between the degree of morphologic abnormality on CT and the extent of physiologic impairment. Cystic bronchiectasis was associated with sputum purulence and with the growth of Pseudomonas. CT classification of the type of bronchiectasis may be useful as an index of severity of disease.
BACKGROUND: Bronchiectasis is associated with chronic obstructive pulmonary disease (COPD) in 30% to 50% of patients. This study evaluated whether association with bronchiectasis has any influence on morbidity and mortality in patients with COPD during their intensive care unit (ICU) stay. METHODS: The study was conducted at a respiratory ICU of a university hospital, and 93 mechanically ventilated patients with COPD were studied. Twenty-nine (31%) of 93 patients with COPD also had bronchiectasis. Patients with bronchiectasis had more frequent hospitalizations, more severe airflow limitation, and higher pulmonary artery pressure than patients without bronchiectasis. Duration of ICU (27+/-32 days [median: 14]; 16+/-16 days [median: 9]; P=.01) and hospital stays (44+/-44 days [median: 24.5]; 28+/-26 days (median: 20); P=.046) in patients with bronchiectasis were significantly longer than in patients without bronchiectasis, respectively. Bronchiectasis was an independent predictor for ICU stay longer than 10 days (odds ratio: 5, 95% confidence interval: 1.02-21, P=.043). The development rate of ventilator-associated pneumonia, especially with Pseudomonas aeruginosa, was significantly higher in patients with bronchiectasis (P=.034). Despite these prolonged durations, bronchiectasis did not increase mortality in this study population (P=.865). RESULTS: These results suggest that the coexistence of bronchiectasis in patients with COPD may increase the duration of ICU stay and hospitalization but does not influence the mortality.
BACKGROUND: Non-tuberculous mycobacteria (NTM) are ubiquitous environmental organisms. Patients with pre-existing lung damage are susceptible to NTM, but their prevalence in bronchiectasis is unknown. Distinguishing between lung colonisation and disease can be difficult. METHODS: A prospective study of 100 patients with bronchiectasis was undertaken to evaluate the prevalence of NTM in sputum, and a retrospective analysis of clinical, microbiological, lung function and radiology data of our clinic patients with NTM sputum isolates over 11 years was performed. RESULTS: The prevalence of NTM in this population of patients with bronchiectasis was 2%. Patients in the retrospective study were divided into three groups: bronchiectasis+multiple NTM isolates (n=25), bronchiectasis+single isolates (n=23), and non-bronchiectasis+multiple isolates (n=22). Mycobacterium avium complex (MAC) species predominated in patients with bronchiectasis compared with non-bronchiectasis lung disease (72% v 9%, p<0.0001). Single isolates were also frequently MAC (45.5%). Multiple isolates in bronchiectasis were more often smear positive on first sample than single isolates (p<0.0001). NTM were identified on routine screening samples or because of suggestive radiology. No particular bronchiectasis aetiology was associated with an NTM. Pseudomonas aeruginosa and Staphylococcus aureus were frequently co-cultured. Six (25%) of multiple NTM patients had cavities of which five were due to MAC. Half the patients with multiple isolates were treated, mostly due to progressive radiology. CONCLUSIONS: NTM are uncommon in non-cystic fibrosis bronchiectasis. Routine screening identifies otherwise unsuspected patients. MAC is the most frequent NTM isolated.
BACKGROUND: Bronchiectasis is a chronic suppurative lung disease characterised by irreversible dilation of the bronchi and persistent purulent sputum. The immunopathology of the disease was studied using a quantitative immunostaining technique with particular reference to T lymphocytes, macrophages, and granulocytes. METHODS: Bronchial mucosal biopsy specimens were obtained by fibreoptic bronchoscopy from 12 patients with bronchiectasis (six receiving inhaled steroids) and 11 normal healthy controls. Immunostaining (APAAP method) was performed on frozen cryostat sections with a panel of monoclonal antibodies to total leucocytes (CD45), T lymphocyte phenotypic markers (CD3, CD4, CD8), macrophages (CD68), eosinophils (EG2), and neutrophils (elastase). RESULTS: There was a mononuclear cell infiltrate in both patients with bronchiectasis and normal controls, but an overall increase in total leucocyte cell numbers (CD45+ cells) was identified in those with bronchiectasis (median values 422 cells/mm2 versus 113 cells/mm2 in control tissue, p < 0.001). Intense infiltration of CD3+ T lymphocytes was observed compared with healthy controls (292 cells/mm2 and 40 cells/mm2, respectively, p < 0.001). This comprised predominantly CD4+ T cells (118 cells/mm2) rather than CD8+ T cells (47 cells/mm2). CD3+ cells counts were reduced in those subjects on inhaled steroids compared with those not receiving inhaled steroids (197 cells/mm2 versus 369 cells/mm2, p < 0.05), as were CD4+ cell counts (82 cells/mm2 versus 190 cells/mm2, p < 0.05). Neutrophil and macrophage cell numbers were also increased in patients with bronchiectasis (114 cells/mm2 and 213 cells/mm2, respectively) compared with controls (41 neutrophils/mm2 and 40 macrophages/mm2). EG2+ (activated) eosinophil numbers were much lower than T cells, macrophages, and neutrophils in patients with bronchiectasis but were increased compared with controls (36 cells/mm2 versus 0 cells/mm2, p < 0.001). In view of the markedly increased neutrophil counts in patients with bronchiectasis, biopsy specimens were immunostained for interleukin 8 (IL-8) which was highly significantly increased compared with controls (47 cells/mm2 versus 15 cells/mm2, p < 0.01). IL-8+ cells were less prominent in steroid treated patients than in patients not receiving treatment (30 cells/mm2 versus 60 cells/mm2, p < 0.05). A further characteristic of bronchiectasis was mucous gland hypertrophy. Gland area comprised up to 40% of the tissue in some bronchiectasis sections while no hypertrophy was noted in control biopsy specimens (p < 0.05). CONCLUSION: Airway inflammation in bronchiectasis is characterised by tissue neutrophilia, a mononuclear cell infiltrate composed mainly of CD4+ T cells and CD68+ macrophages, and increased IL-8 expression. Inhaled corticosteroid treatment in patients with bronchiectasis is associated with a less marked infiltration by T cells and IL-8+ cells within the bronchial mucosa, although this finding requires confirmation in a prospective placebo controlled trial.
PURPOSE: To retrospectively establish the prevalence of interlobular septal thickening at thin-section computed tomography (CT) in patients with bronchiectasis and to retrospectively examine the relationship between septal thickening and various CT features of bronchiectasis and functional parameters. MATERIALS AND METHODS: Institutional review board approval or informed consent are not required for such a retrospective study. Thin-section CT scans of 94 patients (29 men, 65 women; age range, 18-82 years) with idiopathic bronchiectasis confirmed at thin-section CT and without any history or condition that causes bronchiectasis were assessed independently by two observers. The presence and signs of bronchiectasis, extent and distribution of septal thickening at global and lobar levels, and presence of emphysema were recorded. Univariate and multiple regression analyses were used to identify relationships between individual parameters of bronchiectasis, the extent of septal thickening, and functional indices. RESULTS: Interlobular septal thickening was present in 56 (60%) of 94 patients with idiopathic bronchiectasis, excluding those with trivial septal thickening (34 of 94, 36%). At a lobar level, 69% (514 of 748) of lobes with bronchiectasis had septal thickening. There was strong correlation between the extent of septal thickening and the extent (r = 0.61, P < .001) and severity (r = 0.54, P < .001) of bronchiectasis. Stepwise regression analysis showed a relationship between the extent of septal thickening and the extent of bronchiectasis (P < .001). Septal thickening was not linked to functional indices of obstruction or restriction. CONCLUSION: At thin-section CT, interlobular septal thickening is a frequent finding in patients with idiopathic bronchiectasis.
OBJECTIVES: There are several reports of the pulmonary findings in children with HIV disease; however, the occurrence of bronchiectasis rarely has been noted. We evaluated occurrence of bronchiectasis in a large group of children referred to us with AIDS pneumopathy. METHODS: From January 1984 to April 1996, 203 children with AIDS and respiratory problems were referred to the pediatric pulmonary division at Children's Medical Center of Brooklyn. Medical records for 164 of these children were available and retrospectively reviewed. RESULTS: Uncomplicated pneumonia was present in 75, 24 had recurrent pneumonia, and 18 had unresolved pneumonia; lymphocytic interstitial pneumonitis (LIP) was diagnosed in 47 patients, worsening with time in all patients. Bronchiectasis was observed in 26 patients (26/164, 15.8%), diagnosed by chest radiograph in 26 (26/26, 100%), confirmed by CT scan of chest in 10 (10/26, 38.4%), and by histology in three (3/26, 11.5%). Median age at time of diagnosis of bronchiectasis was 7.5 years (range, 1 to 16 years). Sixteen children with LIP developed bronchiectasis (16/47, 34.0%). Three patients with recurrent pneumonia (3/24, 12.5%) developed bronchiectasis. Five patients with unresolved pneumonia (5/18, 27.7%) developed bronchiectasis. One infant developed bronchiectasis after Pneumocystis carinii pneumonia; another child developed bronchiectasis after P. carinii and Mycobacterium tuberculosis pneumonia. The CD4+ T-cell counts measured within 6 months of diagnosis of bronchiectasis were available in 23/26 patients and, all were < 100 cells per cubic millimeter. CONCLUSION: We conclude, from our experience, that there is a significant occurrence of bronchiectasis in children with AIDS and pulmonary disease, especially in children developing LIP, recurrent pneumonia and unresolved pneumonia, and CD4+ T-cell counts < 100 cells per cubic millimeter.
OBJECTIVE: The purpose of this study was to compare conventional high-resolution CT (HRCT) with helical 16-MDCT in the detection of bronchiectasis. MATERIALS AND METHODS: We retrospectively evaluated 80 patients including 61 with bronchiectasis (mean age, 64 years; range, 22-87 years) and a control group of 19 patients with normal MDCT of the chest. Two sets of images were blindly, randomly analyzed by two observers: contiguous 1-mm slices (MDCT set) and 1-mm slices every 10 mm (HRCT set) derived from the MDCT set. Images were scored independently for presence, extent, and severity of bronchiectasis, followed by a consensus interpretation. Kappa analysis assessed inter- and intraobserver agreement. MDCT was the radiologic gold standard. RESULTS: Of the 61 patients with bronchiectasis diagnosed with MDCT, 56 (92%) were positive for bronchiectasis on conventional HRCT. Seven patients had positive MDCT scans only, and two patients had positive HRCT scans only. Of 479 lobes, 59 were positive for bronchiectasis on MDCT and negative on HRCT, and 19 lobes were positive for bronchiectasis on HRCT and negative on MDCT (p < 0.0001). MDCT showed 25 more lobes with cylindric, 11 more lobes with varicose, and four more lobes with cystic bronchiectasis than did HRCT. Sensitivity, specificity, and positive and negative predictive values of HRCT in detecting bronchiectasis were 71%, 93%, 88%, and 81%, respectively. Interobserver agreement for presence, extent, and severity of bronchiectasis ranged from moderate to good for MDCT (kappa values, 0.64, 0.5, and 0.48, respectively) and poor to good for HRCT (kappa values, 0.65, 0.46, and 0.25, respectively). CONCLUSION: Contiguous helical 16-MDCT with 1-mm collimation is superior to HRCT at 10-mm intervals in showing the presence and extent of bronchiectasis.
Asthma represents one of the most common chronic medical conditions affecting children. Although complications of asthma are rare, they deserve consideration when treating children with asthma. The aim of this study was report our experience with an 11-year-old boy with asthma that was complicated by bronchiectasis and to review our hospital's 10-year experience with bronchiectasis. We observed clinical and laboratory findings in a young boy with chronic asthma who developed bronchiectasis, reviewed medical records of 53 children with bronchiectasis followed at a university children's hospital to identify etiologies of bronchiectasis, and reviewed articles in the medical literature. Complications of asthma along with their diagnosis, pathogenesis, and treatment options are outlined in the discussion section. We describe the case of an 11-year-old boy with chronic asthma who did not respond to conventional asthma management and was found to have bronchiectasis. A detailed workup undertaken to identify the cause was negative for usual etiologies of bronchiectasis. In this patient, bronchiectasis was felt to be secondary to a long-standing history of asthma. Aggressive treatment of bronchiectasis led to significant improvement of asthma. Among 53 patients admitted for bronchiectasis, only 3 cases (5.6%) of asthma were identified. Cystic fibrosis (50.9%) and infection (13.2%) were the most common etiologies identified in our hospital's experience. No clear etiology was identified in 1.8% of patients. Although rare, bronchiectasis does occur in patients with chronic asthma. It is important that complications be recognized and treated for optimal management of asthma.
In human bronchiectasis, the bronchial wall is the seat of abnormal mononuclear cell infiltration, which suggests the presence of a cell-mediated immune reaction. The histopathology of a recently devised animal model of experimental bronchiectasis resembles that of the human disease. We have investigated its immunohistology to validate the similarity to that of human bronchiectasis in order to provide a model for the study of cellular immune aspects of the pathogenesis of bronchiectasis. The immunohistology of the bronchial wall mononuclear cell population in experimental rat bronchiectasis was compared with that in control and normal rats. The control rats did not develop bronchiectasis, and the composition and distribution of mononuclear cells in the bronchial wall were similar to those of normal animals. In the rats developing bronchiectasis, there was infiltration of T lymphocytes, macrophages, and dendritic cells (as defined by monoclonal antibodies) in all compartments of the lung, particularly in the bronchial wall and around vessels. The bronchus-associated lymphoid tissue was disrupted by heavy infiltration of T cells, and follicular aggregates of T lymphocytes were seen deeper in the lung parenchyma. Expression of Ia antigen increased in the bronchial epithelium and in large numbers of mononuclear cells throughout the lung. These findings suggest that a cell-mediated immune response appears during the development of experimental bronchiectasis in this rat model. This cellular immune response is similar to that described in human bronchiectasis and may enable this animal model to be used in defining the role of cellular immunity in the pathogenesis of bronchiectasis.
OBJECTIVE: To determine clinical, radiographic, and pathologic features of bronchiectasis in cats. DESIGN: Retrospective study. ANIMALS: 12 cats with histologic evidence of bronchiectasis. PROCEDURE: Information on signalment, body weight, clinical signs of respiratory disease, concurrent diseases, method by which lung tissue specimens were obtained (surgical biopsy or necropsy), and histopathologic findings was obtained by reviewing medical records from January 1987 to June 1999 for cats with confirmation of bronchiectasis by histologic examination. Available thoracic radiographs were reviewed by a board-certified radiologist. RESULTS: Bronchiectasis was most commonly identified in older male cats. Clinical signs referable to the lower portion of the respiratory tract were detected in only 5 cats but, when evident, were usually chronic (duration > 1 year). Radiographic pattern of bronchiectasis was cylindrical in 4 cats, and in 1 of these cats, a saccular pattern was also identified. For most cats, bronchiectasis was detected in a single lung lobe. Radiographic evidence of bronchiectasis was not detected in 2 cats. Concurrent respiratory diseases included chronic bronchitis and bronchiolitis, neoplasia, bronchopneumonia, endogenous lipid pneumonia, and emphysema. CONCLUSIONS AND CLINICAL RELEVANCE: Bronchiectasis appears to be an uncommon respiratory tract disorder that predominantly affects older male cats. Thoracic radiography may not be sensitive for the diagnosis of bronchiectasis in cats. Bronchiectasis in cats appears to be a sequela of chronic inflammatory bronchopulmonary diseases, especially chronic bronchitis, neoplasia, and bronchopneumonia.
A prospective study of the prevalence of bronchiectasis in rheumatoid arthritis was conducted over an 18-month period in 46 patients (34 women and 12 men with a mean age of 60.1 years) meeting 1987 American College of Rheumatology criteria for rheumatoid arthritis. All patients underwent high-resolution computed tomography of the chest, whose results were confronted with a number of clinical, laboratory test and lung function testing parameters. Bronchiectasis or bronchiolectasis was found in 23 patients (50%) and was the most common abnormality detected by high-resolution computed tomography. When the four patients with isolated bronchiolectasis were excluded, the prevalence was 41%. Eighteen of the 23 patients had not been diagnosed with bronchiectasis before the study and 13 were free of respiratory symptoms. No significant differences were found between the 23 patients with and the 23 patients without bronchiectasis for age at onset or duration of the rheumatoid arthritis, extraarticular involvement, positive rheumatoid factors, bony erosions, use of corticosteroids or immunosuppressives, respiratory manifestations, smoking, or spirometry parameters. Patients without bronchiectasis were more likely to have impaired diffusion of carbon monoxide across the alveolar-capillary membrane. Among the patients with bronchiectasis, those with respiratory symptoms (n = 10) were more likely to have a history of lung disease and those without respiratory symptoms (n = 13) were more likely to have a diagnosis of bronchiectasis secondary to rheumatoid arthritis; no other differences were found between these two subgroups. Routine use of high-resolution computed tomography, a technique capable of demonstrating silent bronchiectasis, showed that bronchiectasis was the most common lung change in rheumatoid arthritis in our study. At the time of the study, there was no evidence that presence of bronchiectasis was associated with more severe joint or lung symptoms.
BACKGROUND: Bronchiectasis is a chronic airway disease characterized by persistent inflammation and structural damage, with substantial clinical and etiologic heterogeneity. Although previous studies have identified associations between blood cells and bronchiectasis, the causal relationships remain unclear. Moreover, the mechanisms underlying blood cell perturbation responses and their potential mediation by immune cells in disease progression are largely unexplored. METHODS: Two-sample Mendelian randomization (MR) analysis was used to explore genetically predicted associations among immune cell traits, blood cell perturbation response phenotypes, and bronchiectasis, based on genome-wide association study summary data. Mediation MR analysis was further applied to assess whether immune cells mediate these associations. Multiple sensitivity analyses, including tests for heterogeneity and horizontal pleiotropy, were performed to evaluate the validity and robustness. RESULTS: Five blood cell perturbation response phenotypes and twenty-nine immune cell traits showed significant genetically predicted associations with bronchiectasis. Mediation analysis showed that natural killer (NK) cell absolute count partially mediated the causal effect between the eosinophil perturbation response and bronchiectasis, with a mediation proportion of 9.626%. CD38 on transitional B cells mediated the causal effect between the monocyte perturbation response and bronchiectasis, with a mediation proportion of 10.580%. Additionally, CD45 on NK cells played a mediating role in the association between the white blood cell perturbation response and bronchiectasis, with a mediation proportion of 10.651%. CONCLUSION: This study systematically explores genetically predicted associations between blood cell perturbation responses and bronchiectasis and highlights potential immune-mediated pathways. These exploratory findings provide novel genetic insights into the pathogenesis of bronchiectasis and identify potential therapeutic targets for future strategies.
Bronchiectasis among children living in developing regions is associated with respiratory infections during early childhood, but specific risk factors that precede childhood bronchiectasis are not fully characterized. We hypothesized that severe respiratory syncytial viral (RSV) infection in infancy would increase the risk of bronchiectasis among Alaska Native children in rural Alaska. This was a follow-up cohort study of a 1993-1996 case-control study of RSV-hospitalized case patients and their controls. For each 5-8-year-old former case-patient and control subject, we reviewed medical records, interviewed parents, performed physical examinations and spirometry, collected sera, and analyzed all historical chest radiographs. Ten (11%) RSV cases and 10 (9%) controls had radiographic evidence of bronchiectasis. The mean age at radiographic diagnosis of bronchiectasis was 3.3 years (range, 1.2-6.1 years). Children were more likely to develop bronchiectasis if their chest radiographs, when they were < 2 years of age, showed lung parenchymal densities (RR = 3.9, P < 0.013), persistent parenchymal densities > 6 months' duration (RR = 3.0, P = 0.02), or infiltrates on multiple episodes (test for trend, P = 0.003). Radiographic features of hyperinflation and atelectasis among children < 2 years old were not associated with eventual bronchiectasis. A single severe infection with RSV alone did not predispose Alaska Native infants to bronchiectasis. Childhood bronchiectasis was associated with lung and hence airway injury, manifested on radiographs by parenchymal densities or "pneumonia" rather than by hyperinflation or atelectasis.