WCS03 Respiratory System

Question 1

History taking

Answer 1

1. Chief complaint (+ Duration)
2. History of present illness
3. Personal / Social history, Travel, Occupational history (***TOCC: for all patients with fever + CXR consolidation)
   - Travel: SARS, Avian flu, COVID, MERS
   - Smoking: Cancer, COPD
   - Occupation: Silicosis, Asbestosis, Poultry farmer (Avian flu)
4. Past health
5. Family history
   - TB
   - Asthma
6. Drug history / addiction
   - Aspirin, β-blocker: Worsening of asthma / COPD
   - Corticosteroids: ↑ Infections (e.g. TB)
   - Amiodarone: Lung fibrosis

Question 2

Major pulmonary symptoms

Answer 2

Respiratory symptoms

1. Cough, Sputum
2. Dyspnea
3. Haemoptysis
4. Chest pain

Systemic symptoms

1. Fever
2. Chills, rigors
3. Weight loss
4. Appetite

Symptoms assessment:

1. Onset: acute / chronic
2. Severity
3. Timing of occurrence
4. Associated factors and diseases
5. Other associated symptoms

Question 3

1. Cough and Sputum

Answer 3

Acute (days):

• ***Viral / Bacterial URTI
• ***Acute pneumonia
• Asthma

Subacute (weeks):

• ***TB
• ***Lung cancer
• Asthma

Chronic (years):

• ***COPD
• ***Bronchiectasis
• Asthma

Question 4

Cough

Answer 4

• Productive / Non-productive
• Type / Quantity (e.g. large amount in bronchiectasis)
• Time relations (e.g. at night)
• Provoking factors (e.g. cold air)
• Associated features (e.g. wheeze, fever)

Question 5

TOCC history

Answer 5

For all patients with fever and CXR consolidation

Travel
Occupation
Contact
Cluster

Question 6

2. Dyspnea

Answer 6

Acute:

• Asthma
• Acute exacerbation of COPD
• Pneumothorax (Pain)
• Pneumonia (Pain if pleuritis)
• Acute pulmonary edema (e.g. MI: Pain)
• ***Pulmonary embolism (Pain)

Chronic (days - weeks)

• Pleural effusion
• Pneumonia
• Asthma
• Heart failure

Chronic (months - years)

• COPD
• Bronchiectasis
• Restrictive lung diseases: Pulmonary fibrosis, Silicosis, Kyphosis, Scoliosis, Destroyed lung by TB
• Asthma
• Heart failure

Question 7

3. Haemoptysis

Answer 7

• ***Carcinoma of lung (Pain: if pleura / thoracic cage metastasis)
• ***TB
• ***Bronchiectasis
• ***Pulmonary embolism with infarct (Pain)
• Acute tracheitis / bronchitis / necrotising pneumonia / lung abscess

Question 8

Physical examination

Answer 8

General

1. Respiratory distress
2. Fever
3. Cyanosis
4. Clubbing
5. Tobacco staining
6. JVP
7. Edema of legs
   - **bilateral: Cor pulmonale (RHF due to lung / pulmonary vascular disease)
   - **unilateral: DVT
8. Cervical / Supraclavicular LN

Chest:

1. Inspection
   - chest wall deformity
   - scars
2. Percussion
   - Resonant: Normal
   - **Dull: Collapse, Consolidation
   - Stony dull: Effusion
   - **Hyperresonant: Air (Pneumothorax, Emphysema)
3. Auscultation
   - ***Coarse crackles: Bronchiectasis, Pleural effusion
   - Fine crackles: Fibrosis

Question 9

Finger clubbing

Answer 9

1. Lung cancer
2. Suppurative lung diseases (X TB!!!)
   - Lung abscess
   - Bronchiectasis
   - Empyema
3. Idiopathic lung fibrosis

Question 10

Acute pulmonary thromboembolism with infarct

Answer 10

1. Chest pain
2. Dyspnea
3. Haemoptysis

Question 11

***Clinical features of Bronchiectasis

Answer 11

1. Cough and Sputum
2. Dyspnea
3. Haemoptysis
4. Clubbing
5. Dull
6. Coarse crackles

Question 12

Common respiratory investigations

Answer 12

1. Blood
   - CBC: neutrophilia, eosinophilia
   - Serology: infections (paired samples for Ab in 14 days), autoimmune vasculitis diseases with pulmonary presentations (e.g. SLE, RA): ANF (Anti-nuclear factor), ds-DNA, Rheumatoid factor etc.
2. Sputum
   - Appearance
   - Amount
   - Microscopy
   —> Wright’s stain (WBC)
   —> Gram’s stain (Bacteria)
   —> ZN stain (AFB)
   —> Cytology (malignant cells)
   - Culture
   —> Bacteria (aerobic / anaerobic)
   —> Mycobacteria
   —> Fungi
   - Molecular testing
   —> TB, virus, others
3. Nasopharyngeal aspirate
   - Influenza: molecular test detecting viral RNA
   - SARS / MERS / COVID-19: molecular test detecting viral RNA
4. Pleural fluid (via Thoracentesis / Chest tapping)
   - Appearance —> clear / bloody / purulent / milky
   - Chemistry —> Protein + LDH
   - Cell counts, differential count
   - Cytology
   - Microbiology
5. Imaging (radiology)
   - CXR
   - CT
6. Lung function tests
   - Peak flow rate —> measure Airway
   - Spirometry (FEV1/FVC) —> measure Airway
   - Lung volume (TLC)
   - Diffusing capacity (DLCO) —> measure Alveoli function
   - Arterial blood gases (pH, pO2, pCO2)
   - Oximetry (SaO2) —> define Respiratory failure
7. Arterial blood gases / SaO2 (Invasive)
8. Bronchoscopy
   - Flexible bronchoscopy
   —> Brush for Cytology (↓ bleeding risk)
   —> Forceps for Tissue biopsy
9. Lung FNA / biopsy
   - For ***peripheral lung lesions (transthoracic)
10. Polysomnography
    - record body functions during sleep
    —> electrical activity of brain
    —> respiratory effort
    —> air flow
    —> SaO2
    - diagnose sleep apnea + determine severity
    - stay in sleep lab overnight

Question 13

FEV1/FVC

Answer 13

Normal:

• > 70%
• FEV1 normal
• FVC normal

Restrictive:

• > 70%
• FEV1 low
• FVC even lower

Obstructive:
- <70%

Question 14

DLCO

Answer 14

Measure function of alveoli

Function of respiration is Gaseous exchange (O2, CO2)
—> Respiratory failure is defined by abnormal body O2 / CO2:

**Low SaO2 / PaO2 (Oxygenation failure / type 1) —> **Give Oxygen

**Low PaO2 + High PaCO2 (Ventilation failure / type 2) —> **Give Oxygen + Ventilation

Question 15

SaO2

Answer 15

SaO2 with PaO2 ***13kPa ~97%

SaO2 with PaO2 ***8kpa ~90%

Question 16

Pulse oximetry vs Arterial blood gases

Answer 16

Pulse oximetry:

• SaO2 + Pulse rate
• Non-invasive
• Continuous + Real-time

Arterial blood gases:

• pH, PaO2, PaCO2, HCO3 —> Complete acid-base picture
• Invasive
• Not continuous