Internal Diseases and Therapy · MU Sofia

8. Purulent diseases - bronchiectasis, pulmonary abscess

Covers the suppurative lung diseases, starting with bronchiectasis: its definition, a table of causes grouped by mechanism, the vicious-circle pathogenesis, clinical features, HRCT-based diagnosis and staged treatment. It then addresses cystic fibrosis in outline, and lung abscess, including classification, aspiration-related pathogenesis, a chest X-ray picture, a list of cavity differentials and antibiotic and surgical management.

Inside: 4 sections · 1 labelled picture · 1 table · 15 flashcards · 11 min

Topic 8 of 139 in the MU Sofia syllabus for Internal Diseases and Therapy (Medicine, Years 4 and 5). The free AceMed note covers it in 4 sections, about 1,621 words (11 min of reading), with 15 flashcards.

In this note

  1. Introduction
  2. Bronchiectasis
  3. Cystic fibrosis
  4. Lung abscess

Introduction

The suppurative (purulent) lung diseases are those with chronic or necrotising infection and pus in the airways or lung tissue: bronchiectasis (including cystic fibrosis), lung abscess and, in the pleura, empyema (see pleural effusions).

Bronchiectasis

Definition

Permanent, irreversible dilatation of the bronchi with destruction of their walls, caused by chronic infection and inflammation, presenting with chronic cough, sputum production and recurrent respiratory infections.

Etiology

Pathogenesis

  • "Vicious circle" (Cole): impaired mucociliary clearance → mucus retention → chronic bacterial infection → neutrophilic inflammation (elastase, proteases, cytokines) → destruction of elastin, cartilage and muscle of the bronchial wall → dilatation → even poorer clearance.
  • Diffuse bronchiectasis: a systemic cause (CF, immune defect, PCD) inflames small and medium airways; the wall of larger airways is destroyed; small-airway walls thicken → airflow obstruction on spirometry; fibrosis spreads to the surrounding parenchyma.
  • Focal bronchiectasis: obstruction of one large airway → retained secretions behind it → infection–inflammation cycle. The right middle lobe is most often affected (small, angled bronchus surrounded by lymph nodes).
  • Bronchial arteries enlarge and anastomose with pulmonary arteries → haemoptysis (sometimes massive).
  • Morphological types (Reid): cylindrical (tubular, uniform), varicose (irregular, beaded), cystic/saccular (balloon-like, most severe).
  • Common organisms: Haemophilus influenzae, Pseudomonas aeruginosa (worse prognosis), Moraxella catarrhalis, Staphylococcus aureus, Streptococcus pneumoniae, non-tuberculous mycobacteria, Aspergillus.

Clinical presentation

  • Chronic productive cough with large volumes of purulent sputum, daily, worse in the morning and on changing position; foul smell with anaerobes; sputum may separate into three layers on standing.
  • Haemoptysis (from streaks to massive); dyspnoea, wheeze, pleuritic pain; fatigue, weight loss.
  • Recurrent exacerbations ("chest infections"): more sputum, purulence, fever.
  • Chronic rhinosinusitis (CF, PCD).
  • Examination: coarse inspiratory crackles over the affected area, wheeze; finger clubbing; cyanosis and cor pulmonale in advanced disease.

Diagnosis

  • High-resolution CT (HRCT) — the diagnostic standard: bronchus wider than its accompanying artery (broncho-arterial ratio > 1, "signet ring" sign), lack of tapering towards the periphery, bronchi visible within 1 cm of the pleura, thickened walls, mucus plugs, tree-in-bud, cysts with air-fluid levels.
  • Chest X-ray: often normal; may show "tram-track" lines, ring shadows, cystic spaces with fluid levels.
  • Sputum culture (bacteria, mycobacteria, fungi) at baseline and in exacerbations.
  • Spirometry: usually obstructive.
  • Search for the cause: blood count, serum immunoglobulins (IgG, IgA, IgM) and specific antibody response to vaccines, total IgE and Aspergillus-specific IgE/IgG (ABPA), sweat test and CFTR genetics (CF), nasal NO and ciliary studies (PCD), α1-antitrypsin, rheumatoid factor/anti-CCP, HIV; bronchoscopy for focal disease (foreign body, tumour).

Continue reading free

The whole note, all 4 sections, is free with an AceMed account, with its 15 flashcards. Premium adds flashcard recall, highlights and Ask AI.

Start freeAlready a member? Open the note