reference 1

TWO types of cough.

1. Productive cough with expectoration
(useful cough, wet cough)
expels secretions, exudates, etc. from the respiratory tract.
should be encouraged (cough stimulants).

2. Unproductive cough without expectoration
(useless cough, dry cough).
irritating, has to be suppressed (cough suppressants

Sound of Cough
prolonged wheezy coughing severe asthma or COPD
feeble non-explosive 'bovine' cough with hoarseness lung cancer, neuromuscular disorders
harsh, barking or painful cough and associated with hoarseness & stridor laryngeal inflammation, infection and tumour
moist cough with secretions bronchial infection and bronchiectasis.
persistent moist 'smoker's cough' first thing in the morning chronic bronchitis ( any change > indicate lung cancer)
dry, centrally painful / non-productive tracheitis and pneumonia
chronic dry cough nterstitial lung disease, e.g. idiopathic pulmonary fibrosis	,
nocturnal cough disrupting sleep asthma
daytime cough GORD and chronic sinus disease with associated postnasal drip
coughing during and after swallowing liquids neuromuscular disease of the oropharynx
a dry cough, particularly in women using ACEI

sputum charactor

Clear or 'mucoid‘ - COPD without active infection.

Yellowish sputum - acute lower respiratory tract infection (live neutrophils) and also in asthma (eosinophils).

Green sputum (dead neutrophils) indicates chronic infection as in exacerbations of COPD, bronchiectasis, etc. Purulent sputum is usually green because of the presence of lysed neutrophils and their breakdown products, specifically the green-pigmented enzyme verdoperoxidase.

The first sputum produced in the morning by a patient with COPD may be green because of nocturnal stagnation of neutrophils.

In the early stages of pneumococcal pneumonia sputum may be a characteristic rusty red colour as pneumonic inflammation passes through the red hepatization phase.

In coal miners with pneumoconiosis the rupture of necrotic areas of pulmonary fibrosis can result in the expectoration of black sputum (melanoptysis).