Armando Hasudungan
Biology and Medicine videos


Cough is a common presenting symptom in primary care. Cough is a defensive reflex mechanism that clears secretions from the upper airways of the respiratory tract; it is triggered by the stimulation of a complex reflex arc. Chronic cough can be associated with significant distress and impairment in quality of life.

Overview Cough is initiated as a series of respiratory maneuvers that leads to a sudden expulsion of air creating a characteristic cough sound. Cough is a symptom that has been experienced by every human and is an essential innate protective mechanism that ensures the removal of mucus, noxious substances, and infections from the larynx, trachea, and large bronchi. Cough also minimizes the inhalation of toxic material. Because cough is a normal defensive mechanism, it is a symptom experienced by healthy individuals.

Acute and Chronic Cough An acute cough due to an upper respiratory virus infection generally lasts for no more than 3 weeks, although some postviral coughs may persist for many weeks or months. Thus, a chronic cough is considered to be one that persists longer than 3 weeks.

Acute cough: present up to 14 days/2 weeks
Prolonged acute cough: lasting 2 – 3 weeks
Chronic cough: present > 3 weeks


Think Many cigarette smokers have a chronic cough but rarely seek medical advice regarding their cough because they expect that the irritant effect of cigarette smoke is the cause of their cough. However, a change in character “out of the ordinary” or with haemoptysis may force a smoker to seek medical attention.


Acute Cough Chronic Cough
Common Cold (~48 resolves) Postnasal drip
Viral URTI Asthma
Acute infection
 Can be viral or bacterial. Usually accompanied by dyspnea and fever
  • Pertussis
Whooping character of cough, associated with vomiting. Caused by bordetella pertussis
  • Bronchitis
Inflammation of the mucous membrane in the bronchial tubes. It typically causes bronchospasm and coughing.
Chronic infection
 Overproduction of airway secretions together with a reduced clearance, often within a vicious circle of recurrent bacterial infections. Usually, the patient produces 30 mL or more of mucoid or mucopurulent sputum per day, sometimes accompanied by fever, hemoptysis, and weight loss.
The major cause of chronic debilitating pulmonary disease and pancreatic exocrine deficiency in the first three decades of life. It is characterized by the triad of chronic obstructive pulmonary disease, pancreatic exocrine deficiency, and abnormally high sweat electrolyte concentrations. Characteristic pancreatic changes give the disease its name.
  • Tuberculosis
TB is a disease caused by bacteria called Mycobacterium tuberculosis. TB spreads through the air but it is not easy to catch. In 70% of cases TB affects the lungs. But it can also affect other parts of the body, such as the lymph glands, brain, kidneys, or spine.
Airway disease

Asthma may present predominantly with cough, often nocturnal, and the diagnosis is supported by the presence of reversible airflow limitation and bronchial hyper-responsiveness.

A serious, progressive and disabling condition that limits airflow in the lungs. It includes emphysema and chronic bronchitis. Strongly associated with smoking
  • Chronic postnasal drip
 Cough: Tickly, often with nasal blockage.
Lung parencymal disease
Unable to fully fill the lungs with air. Their lungs are restricted from fully expanding.
  • COPD
A serious, progressive and disabling condition that limits airflow in the lungs. It includes emphysema and chronic bronchitis. Strongly associated with smoking
Foreign body Aspiration 
Cardiovascular Disease
The aortic artery has enlarged to greater than 1.5 times the expected diameter.
  • LVF (heart failure leading to pulmonary oedema)
Cough: Clear sputum, worse when lying flat

GERD, the movement of acid and other components of gastric contents from the esophagus into the larynx and trachea, is one of the most commonly associated causes of chronic cough in all age groups. GERD may lead to symptoms such as heartburn, chest pain, a sour taste, regurgitation, and a chronic persistent cough.

Drugs (ACE inhibitors)

ACE inhibitors are often prescribed for the treatment of hypertension and heart failure -> causes a classic dry cough


Cough with sputum production usually points toward conditions such as chronic bronchitis and bronchiectasis or other causes of bronchorrhea.

Remember Smokers have a chronic cough in the mornings – usually associated with grey sputum production
Classical characteristics of sputum
White/Grey Smoking
Green/yellow Bronchitis, bronchiectasis
Green and offensive Bronchiectasis, abscess
Frothy, pink Congestive heart failure
Very sticky and often yellow Asthma
Redish (blood) Tumour, bronchitis
Remember Haemoptysis most common cause is bronchitis, 90% of massive haemoptysis is from bronchial arteries (massive = >500ml/24hours)
Cough Physiology

Physiology of Coughing

Watch physiology of coughing 


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