Bronchiectasis

Etiology and pathogenetic cascade

The pathology is polyetiological. The formation of bronchiectasis requires a combination of a basic prerequisite (congenital morphological inferiority of the wall) and the impact of inflammatory triggers. There are three groups of causes:

1. Congenital anomalies: underdevelopment or absence of the cartilaginous framework, muscular or elastic tissue (Williams-Campbell and Mounier-Kuhn syndromes).
2. Genetic defects and immunodeficiencies: cystic fibrosis, primary ciliary dyskinesia, $\alpha_1$-antitrypsin deficiency, Bruton disease.
3. Infectious factors: recurrent bronchitis and pneumonia, past tuberculosis, pertussis, and measles.

A significant role is played by obstrucion (bronchial obstruction) due to foreign body aspiration or external compression by lymph nodes. It disrupts patency, leads to the development of atelectasis and the addition of secondary infection.

Pathogenesis occurs in stages. Impaired drainage causes inflammation of the mucosa (endobronchitis), which then spreads to all layers of the wall (panbronchitis) and the pulmonary parenchyma. Normal ciliated epithelium dies, being replaced by stratified squamous or cuboidal epithelium. The bronchi become deformed, lose connection with bronchioles, and end blindly. The affected area is completely excluded from ventilation and gas exchange, turning into a destructive-purulent focus.

Classification and morphological changes

According to the anatomical shape of the pathological bronchial dilation, three main types are distinguished:

• Cylindrical: uniform dilation of the lumen with focal destruction of the elastic framework.
• Fusiform and mixed: uneven dilation alternating with narrowing.
• Saccular: the most severe form with the formation of rounded cavities and deep damage to the muscular layer and cartilage plates.

According to prevalence, the process can be localized or diffuse (involving an entire lung or more than 9 segments in bilateral lesions).

Histological paradox: at the microscopic level, due to total purulent tissue lysis, it is practically impossible to distinguish congenital bronchiectasis from acquired. At the level of subsegmental bronchi, arteries become inflamed (endarteritis) and pathological anastomoses form between the bronchial and pulmonary vascular beds.

Clinical presentation and physical examination data

The disease runs a chronic, undulating course with gradual progression. In children of the first years of life, exacerbations can be continuous and recurrent (on average up to 3–4 times a year).

The main complaint is a persistent wet cough. The maximum volume of sputum is discharged in the morning hours. During exacerbations, dyspnea and oral crepitation join. Hemoptysis is rare in modern pediatric practice, remaining the prerogative of adult patients.

Objective examination reveals characteristic changes:

• Chest: asymmetric deformation (flattening or retraction on the affected side).
• Musculoskeletal system: against the background of hypoxia, Pierre Marie–Bamberger syndrome (hypertrophic osteoarthropathy) develops — clubbing of the nail phalanges ("drumstick fingers").
• Auscultation: stable, clearly localized moist rales of various calibers. Over large saccular cavities, amphoric breathing may be heard.

Diagnostic methods

The basis for verifying the diagnosis is imaging and endoscopic methods, since the changes are predominantly localized in the lower lobes (especially on the left):

• Computed tomography (CT): the modern gold standard, which has completely replaced classical bronchography (where a specific "leafless tree" sign was previously sought).
• Bronchoscopy: visualizes the severity of endobronchitis (catarrhal-purulent or purulent inflammation).
• PFT and angiopulmonography: spirometry reveals mixed (obstructive-restrictive) disorders, and angiograms in the affected areas show "silent" zones with impoverished blood flow. Additionally, radioisotope diagnostics is used to assess the functions of specific segments.

Treatment strategy

Absolute priority is given to conservative therapy aimed at suppressing infection and restoring drainage:

1. Antibacterial therapy: the basis of treatment for exacerbations. Ideally, it is selected based on antibiotic susceptibility testing. Empirically, penicillins, second- and third-generation cephalosporins, and macrolides are used. It is optimal to combine systemic and inhalation administration.
2. Basic therapy: mucolytics (ambroxol, acetylcysteine), bronchodilators (salbutamol), kinesitherapy (postural drainage, vibratory massage).
3. Inhaled GCS (budesonide, fluticasone) are prescribed for bronchial hyperreactivity — they suppress local inflammation by reducing the activity of T-lymphocytes.

Surgical intervention (organ-sparing resection) is indicated only for unilateral refractory forms or life-threatening complications (hemorrhage). It is important to remember: radical removal does not guarantee recovery — in approximately 50% of patients, relapses occur in the long-term period, since structural tissue changes are irreversible and maintain chronic inflammation for life.

Class and exam questions

What else to study on this topic

• Differential diagnosis with lung cysts and intralobar sequestration
• The role of inhaled glucocorticosteroids (ICS) in suppressing the activity of interleukin-8 (IL-8)
• Technique of postural drainage and kinesitherapy in infants and young children
• Features of radioisotope diagnostics of regional lung functions
• Prognostic criteria of the postoperative period

Other topics in "Chapter 4. Respiratory Diseases"

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.