Non-obstructive Chronic Bronchitis (NCB)

Introduction

Chronic bronchitis denotes chronic or
recurrent bronchial mucus hyper secretion resulting in Chronic expectoration of sputum.
For clinical or epidemiological purposes,
the term is applied to patients who have
coughed up sputum on most days during
at least three consecutive months in two
successive years.

Non-obstructive Chronic bronchitis (NCB)

In this condition, there is a chronic or
recurrent mucoid hyper secretion
sufficient to cause expectoration but there is no air flow obstruction.

  • Between 10 -25% of adult population are affected by NCB.
  • It tends to be common in men.
  • It is not well understood why some of these persons progress to chronic
    obstructive airway disease and some do not.
  • NCB has a generally good prognosis.
  • With smoking cessation and vigorous treatment early in the disease process the disease may be reversed.
  • The exact cause of the illness is not known
  • More common in urban or industrial areas.
  • Some inhaled irritants play a role in
    persistence and aggravation of
    symptoms and pathology. These include, inhaled tobacco smoke, air pollutant, dusts, powder and noxious fumes.
  • Viral or bacterial infection may precipitate or aggravate disease.
  • Although history of heavy smoking is common, disease may be observed in non smokers.
  • Pathologically, there is hypertrophy and hyperplasia of mucus secreting glands relative to wall thickness.
  • There are diffuse inflammatory changes of bronchial epithelium with ulceration, neutrophil infiltration, loss of cilia, bacterial invasion & area of squamous metaplasia. These changes interfere with muco-ciliary function.

Clinical features:

History

  • Most striking features are impressive history of cough with sputum production for many years.
  • Initially, cough present during cold
    seasons, especially in the morning.
  • Over the years cough increases in
    frequency, severity and duration until cough is present all year round.
  • Sputum is usually scanty, mucoid and more in the mornings and occasionally blood stained.

Physical signs

  • Patient may be overweight
  • Patient may not be in respiratory distress and respiratory rate may be normal.
  • Palpation of chest may reveal local tenderness over recently fractured rib.
  • Percussion note resonant over the lungs.
  • Liver dullness and cardiac dullness normally preserved.
  • Breath sound is vesicular
  • Positive signs are almost all referable to bronchial secretions.
  • Transient basal rales may be noted on inspiration. This may clear completely with cough.
  • Finger clubbing is not commonly observed in pure chronic bronchitis.

Differential diagnosis

  • Asthma
  • Bronchiectasis Pulmonary TB
  • Bronchogenic Carcinoma

Complications

  • Muco-purulent relapses due to secondary bacterial infection.
  • Progression to chronic obstructive airway disease.

Relevant investigations

  • Spirometry may reveal no abnormality in lung function, since there is no airflow obstruction.
  • Chest Xray does not show any characteristic abnormality in simple chronic bronchitis.
  • Bronchography may reveal irregular narrowed or distorted bronchi. There is however, no need for routine bronchography in chronic bronchitis.
  • Sputum examination; In early stages, sputum may be mucoid.
  • Sputum M/C/S may be necessary to detect bacterial infection.
  • Arterial blood gas studies may be
    unnecessary in straightforward
    uncomplicated NCB.

Management

1. Reduction of bronchial irritation

  • Smoking cessation
  • Avoidance of dusty and smoke laden environment.

2. Treatment of respiratory infections

  • Purulent sputum should be treated with amoxicillin 500mg 8hourly for seven days.
  • In the absence of response, a sputum culture and sensitivity is done and antibiotics changed to sensitive ones.

3. Mucolytics

  • Mucolytic expectorant appear to improve quality of life & decreases cough.
  • Iodinated glyceryl at a dose of 60mg four times daily for 1 to 8 weeks can be used.

4. Bronchodilators and steriods

These may not be necessary in simple chronic bronchitis since there is no airway obstruction.

5. Physiotherapy

Postural drainage may be of value in patients with increased sputum production.

Adverse drug reaction

  • Maculopapular reactions may occur in patients taking amoxicillin.