European Journal of Cardiovascular Medicine

Bronchiectasis is a persistent respiratory disorder initially characterized by Laënnec in 1819 [1]. High-resolution computed tomography (HRCT) is regarded as the definitive standard for diagnosis [2,3]. Numerous clinical conditions can precipitate this chronic debilitating disorder: post-infectious states, allergic bronchopulmonary aspergillosis (ABPA), immunodeficiency syndromes, connective tissue diseases (CTD), cystic fibrosis (CF), chronic respiratory ailments such as asthma, chronic obstructive pulmonary disease (COPD), primary ciliary dyskinesia (PCD), and instances of unknown etiology, i.e., idiopathic [4,5]. Because these conditions vary in their management and prognosis, identifying the underlying etiology is necessary.

Non-cystic fibrosis bronchiectasis (NCFB) has been thought of as an orphan lung disease for a long time [6], even though CF-associated bronchiectasis has been studied a lot. People are becoming more interested in this disease that has been ignored for a long time, even though it causes a lot of illness and death around the world [4].

Clinical features and etiologies of bronchiectasis exhibit geographic variation [7]. Previous studies indicated that the cause of bronchiectasis was often unclear for most patients; however, a study conducted in the United States identified immune dysregulation as the primary cause of bronchiectasis [8]. Conversely, post-infectious bronchiectasis emerged as the primary underlying etiology in recent data published from India and a study conducted in China [9,10].

Cole’s “vicious cycle model” illustrates that bronchiectasis is linked to the microbiological colonization of the airways, which results in recurrent infections and chronic inflammation. This process ultimately leads to impaired mucociliary clearance and progressive lung damage [11]. Infections significantly contribute to the progression of bronchiectasis, leading to considerable morbidity and mortality. While Haemophilus influenzae, Pseudomonas aeruginosa, Moraxella catarrhalis, Staphylococcus aureus, and Enterobacteriaceae are frequently identified pathogens in bronchiectatic airways, the microbiological colonization by certain organisms has been shown to result in poorer outcomes compared to others [12]. Based on our understanding of CF patients, colonization with Pseudomonas is linked to a decline in lung function, frequent exacerbations, and increased mortality [13]. This phenomenon arises from its propensity to create biofilms and its capacity to acquire antibiotic resistance. Data from 21 observational studies demonstrated comparable results involving patients with both CF and NCFB [14]. The US bronchiectasis registry indicated that nontuberculous mycobacteria (NTM) were more frequently identified in women, with bronchiectasis being diagnosed at a later age and gastroesophageal reflux disease (GERD) recognized as the primary underlying condition [15]. Faverio et al. conducted a study revealing that patients with bronchiectasis who tested positive for NTM in respiratory samples exhibited milder disease and improved pulmonary functions compared to those with Pseudomonas [16]. The outcomes of bronchiectasis are influenced by the specific microorganism that is isolated. Because of the heterogeneous nature of this chronic debilitating condition, with evidence of geographic variation in etiologies and other clinical features and since sparse data is available from developing countries especially from South East Asia, we found it imperative to collect our data. The aim of the study was to study the microbiological profile and radiological pattern in the subjects.

Study Design and Setting

This cross-sectional study will be conducted in the Department of Pulmonary and Critical Care Medicine, King George's Medical University (KGMU), Lucknow, from May 2024 to November 2024.

Study Population

The study will include patients diagnosed with bronchiectasis who attend the outpatient department (OPD) or are admitted under the Pulmonary and Critical Care Medicine Department at KGMU, Lucknow.

Sample Size Calculation

The sample size was calculated using OpenEpi, version 3, an open-source calculator. The calculation was based on the following parameters:

• Population size (N) = 70
• Hypothesized frequency of the outcome factor in the population = 65.9% ± 5
• Confidence limit = 10%
• Design effect (DEFF) = 1.5
• Z (95% confidence level) = 1.96
• Margin of error (d) = 5%

Based on these parameters, the calculated total sample size is 59 patients.

Inclusion Criteria

• Patients aged >18 years of both genders diagnosed with bronchiectasis.
• Patients who have given informed consent to participate in the study.

Exclusion Criteria

• Patients unwilling to participate in the study.
• Patients aged <18 years.
• Pregnant women.

Methodology

1. Clinical Evaluation

Each enrolled patient will undergo a detailed history-taking and physical examination, including assessment of symptoms, duration of illness, previous infections, and history of antibiotic use.

2. Radiological Assessment

• All patients will undergo high-resolution computed tomography (HRCT) of the thorax to confirm the diagnosis of bronchiectasis.
• The radiological pattern will be classified based on HRCT findings, including bronchial dilatation, peribronchial thickening, mucus plugging, and associated lung pathology.

3. Microbiological and Drug Sensitivity Profile

• Sputum and bronchoalveolar lavage (BAL) samples will be collected from each patient for microbiological evaluation.
• Samples will be cultured for bacterial, fungal, and mycobacterial growth.
• Antimicrobial susceptibility testing will be performed for isolated pathogens using standard drug sensitivity assays.

Statistical Analysis

All collected data will be tabulated and analyzed using appropriate statistical methods. Descriptive statistics will be used to summarize demographic, microbiological, and radiological data. Categorical variables will be presented as frequencies and percentages, while continuous variables will be expressed as mean ± standard deviation (SD). A p-value <0.05 will be considered statistically significant.

Ethical Considerations

The study will be conducted following the ethical guidelines set by the Institutional Ethics Committee of KGMU, and informed consent will be obtained from all participants before enrollment.

Table 1: Demographic and Clinical Characteristics of Study Subjects

Table 1 presents the demographic and clinical characteristics of the study subjects. Among the 70 enrolled patients, 39 (55.7%) were female, while 31 (44.3%) were male. The majority of patients (51.2%) were in the 61–70 years age group, with a smaller proportion (7.3%) aged ≤50 years.

Regarding allergy history, only 5 patients (7.3%) reported a history of allergy, while 92.7% had no such history. Smoking status analysis revealed that 65.9% were non-smokers, 26.8% were ex-smokers, and 7.3% were current smokers.

In terms of prior diagnoses, 34.1% of the patients had a past history of tuberculosis, 24.4% had no definite etiology, 22% had a history of COPD, 14.6% had past pneumonia, and 4.9% had a history of childhood fever.

Comorbidities were prevalent, with diabetes mellitus observed in 31.7%, hypertension in 22%, dyslipidemia in 12.2%, coronary artery disease in 24.4%, and chronic kidney disease (CKD) in 4.9%. Notably, 48.8% of the patients had no comorbidities.

Among the chief complaints, cough was the most commonly reported symptom (73.2%), followed by sputum production (70.7%), dyspnea (60.9%), hemoptysis (15%), and fever (9.8%). Sputum characteristics showed that 62% had mucopurulent sputum, 27.5% had mucoid expectoration, and 10% had purulent expectoration.

The Modified Medical Research Council (mMRC) dyspnea grading indicated that most patients (76%) had Grade 3 dyspnea, while 16% had Grade 4 and 8% had Grade 2. Clinical signs included crepitations in 73.1%, clubbing in 61%, and rhonchi in 7.3% of patients.

Table 2 : Radiological Findings of Study Patients (N = 70)

Table 2 presents the radiological findings of the study subjects. Among the 70 patients, bilateral lung involvement was observed in 65.9% of cases, whereas right-side involvement was seen in 26.8%, and left-side involvement in only 7.3%.On high-resolution computed tomography (HRCT), the cystic pattern was the most common radiological presentation, observed in 46.3% of patients. The cylindrical pattern was present in 39%, while a mixed pattern (varicose and cystic) was noted in 14.6% of cases.Regarding lobe involvement, the lower lobes were affected in 63.4% of patients, while upper lobe involvement was seen in 61% and middle lobe involvement in 48.8%.The number of lobes involved varied among patients: 19.5% had a single lobe affected, 39% had two lobes involved, 26.8% had three lobes affected, and 14.6% had five lobes involved.

Table 3: Comparison of Radiological Patterns with Sputum Culture Results

Among patients with bilateral lung involvement, 71% had Pseudomonas aeruginosa, 63% had Klebsiella pneumoniae, 75% had other bacteria (Acinetobacter & E. coli), and 53% had no bacterial growth. Right-side involvement was noted in 19% of Pseudomonas cases, 21% of Klebsiella cases, 25% of other bacteria cases, and 47% of no-growth cases. Left-side involvement was observed less frequently, with no cases among patients with no bacterial growth.Regarding CT patterns, the cystic pattern was most common among Pseudomonas aeruginosa (58%) and Klebsiella pneumoniae (47%), whereas the cylindrical pattern was predominant in the no-growth group (59%). The mixed pattern (varicose/cystic) was seen in smaller proportions across all groups.For lobe involvement, lower lobe involvement was most common, especially among Klebsiella pneumoniae (74%) and other bacteria (75%) cases. Upper lobe involvement was evenly distributed across bacterial groups, while middle lobe involvement was highest in the no-growth group (65%).When analyzing the number of lobes involved, single-lobe involvement was more frequent in no-growth cases (29%), while multiple lobe involvement was more prevalent in cases with Pseudomonas aeruginosa and Klebsiella pneumoniae. Notably, 42% of Pseudomonas cases had involvement of two lobes, and 29% had three lobes affected. In contrast, five-lobe involvement was seen in 13% of Pseudomonas aeruginosa cases and 24% of no-growth cases.

These findings indicate that Pseudomonas aeruginosa and Klebsiella pneumoniae infections are associated with greater radiological severity, particularly in terms of cystic patterns and multilobar involvement

The study's findings on bronchiectasis presentation and its clinical-radiological-microbiological correlations offer valuable insights into the disease's complexity. The demographic profile, with a predominance of elderly patients (51.2% in the 61-70 years age group) and a slight female preponderance (55.7%), aligns with the chronic nature of bronchiectasis and the challenges associated with age-related complications[17,18]. The low prevalence of current smokers (7.3%) suggests that smoking may not be a primary contributing factor in this cohort, which is consistent with other studies highlighting diverse etiologies for bronchiectasis[19,20].

A notable finding is the high prevalence of previous tuberculosis (34.1%) among the study population, indicating post-TB bronchiectasis as a significant etiology in this context[18]. This is supported by studies that emphasize the role of infectious processes in bronchiectasis developmesnt[21]. The substantial presence of comorbidities, particularly diabetes mellitus (31.7%), underscores the complexity of disease management and the need for a comprehensive treatment approach[18,22].

The clinical presentation, dominated by productive cough (73.2%) and sputum production (70.7%), with a high prevalence of grade 3 mMRC dyspnea (76%), is consistent with the typical clinical syndrome of bronchiectasis[19,21]. Physical examination findings of widespread crepitations (73.1%) and clubbing (61%) correlate with the chronic nature and severity of the disease[21]. These manifestations align with radiological findings showing bilateral involvement (65.9%) and lower lobe predilection (63.4%), which are common in bronchiectasi[23].

The radiological patterns, with cystic bronchiectasis being the most common (46.3%) on HRCT, and multiple lobe involvement in 80.5% of cases, suggest extensive disease[23,24]. The strong correlation between Pseudomonas aeruginosa colonization and more severe radiological findings, including bilateral involvement (71%) and cystic bronchiectasis (58%), highlights the importance of targeted antimicrobial strategies[18,25]. This aligns with studies emphasizing the role of specific bacterial pathogens in disease severity and progression[26, 27].

The study's findings have significant implications for clinical practice, emphasizing early detection and management of underlying conditions, regular microbiological monitoring, and targeted therapy based on radiological patterns[18, 22]. The presence of extensive disease and significant comorbidities underscores the need for a holistic management approach[22, 28].

Future research should focus on long-term follow-up studies to understand disease progression and outcomes better. Investigating preventive strategies, particularly in post-TB cases, and evaluating targeted therapeutic approaches based on radiological-microbiological correlations would be valuable[29,18]. Additionally, studies on the impact of comorbidity management on disease outcomes could provide important insights for improving patient care[22,28].

In conclusion, this study provides comprehensive insights into the radiological, and microbiological characteristics of bronchiectasis, highlighting the complexity and variability of the disease. The findings emphasize the predominance of elderly patients, significant comorbidities, and a high prevalence of previous tuberculosis as an etiological factor. The clinical presentation is marked by chronic respiratory symptoms and extensive radiological involvement, often associated with Pseudomonas aeruginosa colonization. These correlations underscore the importance of targeted antimicrobial strategies and comprehensive management approaches that address both the disease itself and its associated comorbidities.

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