Differentials

Asthma

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Onset of asthma is usually in early life. A personal or family history of allergy, rhinitis, and eczema is often present. There is daily variability in symptoms, and patients have overt wheezing that usually rapidly responds to bronchodilators. Cough variant asthma mimics many features of COPD.

INVESTIGATIONS

Pulmonary function tests (PFTs) show reversibility with bronchodilators and no decrease in diffusing capacity of the lung for carbon monoxide (DLCO). Sputum or blood eosinophilia is suggestive of asthma.

Congestive heart failure

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Usually a history of cardiovascular diseases is present. Patients report symptoms of orthopnoea, and fine bibasilar inspiratory crackles may be heard on auscultation.

INVESTIGATIONS

B-type natriuretic peptide levels are usually elevated, and CXR reveals increased pulmonary vascular congestion. Echocardiogram may confirm the diagnosis.

Bronchiectasis

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

There may be a history of recurrent infection in childhood. Large volume of purulent sputum is usually present. Coarse crackles may be heard on auscultation. History of pertussis or tuberculosis is a clue to diagnosis.

INVESTIGATIONS

Chest CT reveals bronchial dilation and bronchial wall thickening.

Tuberculosis

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

A history of fever, night sweats, weight loss, and chronic productive cough is usually present. Tuberculosis is more common in immigrants to non-endemic countries, and in people living in endemic countries.

INVESTIGATIONS

The diagnosis requires microbiological confirmation. Infiltrates, fibrosis, or granuloma seen on CXR or chest CT may suggest tuberculosis. Patients usually have positive skin test for tuberculosis.

Bronchiolitis

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Bronchiolitis may affect patients at younger ages. The patient may have a history of connective tissue disorders, especially rheumatoid arthritis, or fume exposure. Some cases are post-infectious.

INVESTIGATIONS

PFTs in bronchiolitis can present with obstructive, restrictive, or mixed pattern. CXR shows hyperinflation. High-resolution chest CT may show diffuse, small, centrilobular nodular opacities, but is rarely done in children due to radiation risk.

Upper airway dysfunction

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Can affect patients of any age. History of prior trauma or intubation is very helpful. Lung examination is usually normal, but signs of upper airway restriction, such as wheezing and stridor, may be present. Patients may have voice hoarseness if vocal cords are involved.

INVESTIGATIONS

The flow-volume curve in pulmonary function testing may reveal a characteristic expiratory or inspiratory plateau, or both. Diagnosis is confirmed by direct visualisation of the affected airway by endoscopy.

Chronic sinusitis/postnasal drip

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Chronic sinusitis/rhinitis is a very common cause of chronic cough. Patients may complain of sinus pressure, rhinorrhoea, non-productive cough, and/or headache.

INVESTIGATIONS

CT of sinuses and/or empirical trial of antihistamines is commonly utilised to aid in diagnosis.

Gastro-oesophageal reflux disease (GORD)

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Patients with GORD often have dyspepsia and frequent belching, and can have a chronic cough that worsens at night when supine.

INVESTIGATIONS

Diagnosis is usually based on response to empirical therapy with proton-pump inhibitors.

ACE inhibitor

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

ACE inhibitors can cause chronic cough; however, the cough is usually non-productive.

INVESTIGATIONS

Diagnosis is usually based on improvement of symptoms after empirical cessation of ACE inhibitor.

Lung cancer

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Patients may have weight loss, night sweats, haemoptysis, and/or chest or back pain.

People with COPD are also at increased risk of lung cancer.

INVESTIGATIONS

Radiography is important in the assessment for lung cancer. Bronchoscopy may be necessary to evaluate for endobronchial cancer if suspicion is high.

Use of this content is subject to our disclaimer