MUST MBBS 2024-2025 Year 5
Revision Block
Medicine-related topics
陸思聰 Lok Si Chong
Associate Professor
2025/02/17
Respiratory medicine
Cough
• Acute cough (< 3 weeks)
• Infections (URTI, LRTI)
• Acute exacerbations of lung disease
• Inhaled irritant
• Inhaled foreign body
• Chronic cough
• GORD
• Post-nasal drip, upper airway irritation
• Asthma, COPD
• Infections e.g. TB
• Bronchiectasis
• Carcinoma
• Interstitial lung disease
• Drugs: ACE inhibitors
• Heart failure
• Functional
Haemoptysis
• Expectorating (coughing up) blood
• Haemoptysis vs nasopharyngeal bleeding vs haematemesis
• Volume and character
• Streaks mixed in sputum
• Fresh blood or clots
• “Massive” haemoptysis
• Causes
• Infection: bacterial, TB, fungal, lung abscess
• COPD, bronchiectasis
• Carcinoma
• Pulmonary infarction
• Foreign body inhalation
• Autoimmune e.g. GPA, anti-GBM disease
• (Others: e.g. drugs, trauma, post-operative)
Dyspnoea
• Dyspnoea (breathlessness)
• Awareness of increased effort for breathing
• Tachypnoea
• Increased breathing rate
• Hypopnoea / apnoea
• Decreased breathing rate / absent breathing
• Orthopnoea
• Breathless lying flat
• Onset
• Timing
• Duration
• Character
• Severity: modified Medical Research Council (MRC) dyspnoea scale
Dyspnoea quantification
• Modified Medical Research Council (MRC) dyspnoea scale
Score Severity
0 On strenuous exercise
1 When hurrying on flat, when walking up hill
2 Slower than others of same age, stops for breath walking at own pace
3 Stops for breath after 100m or few minutes on flat
4 Too breathless to leave house, breathless when dressing
• New York Heart Association (NYHA) functional classification
Class Symptoms
I No limitation, no symptoms with ordinary physical activity
II Slight limitation, symptoms with ordinary physical activity
III Marked limitation, symptoms with less than ordinary physical activity
IV Severe limitation, symptoms at rest, any physical activity increases discomfort
Dyspnoea
• Causes
• COPD, asthma
• Infection, bronchiectasis
• Interstitial lung disease
• PE
• Foreign body
• Carcinoma: lung, pleura
• Pneumothorax
• Pleural effusion
• Chest wall restriction, neuromuscular diseases
• MI, heart failure, cardiomyopathy, mitral valve disease, pericardial disease
• Acid-base disorders
• Functional
• Physical deconditioning
• Obesity
• Diaphragmatic splinting in pregnancy
Clubbing: causes
• Cardiac • Gastrointestinal
• Cyanotic congenital heart disease • Cirrhosis
• Infective endocarditis • Inflammatory bowel disease
• Atrial myxoma • Coeliac disease
• A-V malformation • Lymphoma
• Respiratory • Endocrine
• Pulmonary fibrosis • Thyrotoxicosis (thyroid acropathy)
• Lung cancer (HPOA) • Secondary hyperparathyroidism
• Pleural tumours
• Bronchiectasis • Pregnancy
• Lung abscess, empyema, TB
• Pulmonary A-V malformation
• Congenital
• (NOT asthma / COPD)
Lung auscultation
• Breath sounds
• Vesicular (normal) vs bronchial (consolidation)
• Reduced: e.g. pleural effusion, pneumothorax
• Added (adventitious) sounds
• Stridor
• Inspiratory sounds: large airways
• Wheeze
• Expiratory musical sounds: small airways; polyphonic (asthma) vs monophonic (tumour)
• Coarse crackles
• Inspiratory: e.g. infection, cardiac failure
• Fine crackles
• End-inspiratory, “Velcro”: pulmonary fibrosis
• Pleural rub
• Inspiratory and expiratory: pleurisy
• Sounds that clear on coughing are insignificant
• Vocal resonance
• Auscultation equivalent of tactile vocal fremitus
Peak expiratory flow rate
• Peak expiratory flow rate (PEFR)
• L/min
• Best of 3 attempts
• Peak flow meter
• Monitoring of asthma
Spirometry
Obstructive Restrictive
FEV1 ↓↓ ↓
FVC ↓ ↓ Obstructive
% ↓ →/↑
Normal Restrictive
aneskey.com
Pleural effusion
• Excessive accumulation of fluid in pleural space
• 300 ml: detectable on X-ray; 500 ml: detectable clinically
• Symptoms and signs
• Breathlessness, chest pain
• ↓ expansion, stony dull percussion, ↓ breath sounds, ↓ vocal resonance
• Signs of underlying disease
• Imaging
• X-ray: blunted costophrenic angle, meniscus
• Ultrasound
• CT with contrast
• Light’s criteria: exudate vs transudate
Exudate if any of
• Fluid protein : serum protein >0.5
• Fluid LDH : serum LDH >0.6
• Fluid LDH >2/3 serum upper limit of normal
Pleural effusion: causes
• Transudate
• Heart failure
• Hypoproteinaemia: Nephrotic syndrome, cirrhosis
• Hypothyroidism
• Ovarian tumour (right effusion: Meigs’ syndrome)
• Exudate
• Infection e.g. bacterial, TB
• Parapneumonic, empyema
• Carcinoma
• Primary pleural: mesothelioma
• Metastatic: lung, others e.g. breast, colon
• PE
• Autoimmune e.g. RA, SLE
• Post MI
• Pancreatitis
• Trauma: haemothorax
• Lymphatic: yellow nail syndrome, chylothorax
• Drugs
Pleural effusion: procedures
• Use ultrasound guidance
• Diagnostic pleural fluid aspiration
• Send for:
• Protein, LDH, glucose
• Microscopy and culture
• pH
• Cytology + immunostaining
• Aspiration (therapeutic) / drainage
• Suspected infection → pH <=7.2 → drain
• Thoracoscopy
• Pleurodesis e.g. talc
Needle above rib
• Chronic indwelling pleural catheter
• E.g. malignant effusions requiring repeated drainage
Radiologykey.com
Lung cancer
• Primary
• Non-small cell lung cancer (NSCLC)
• Adenocarcinoma
• Squamous cell carcinoma
• Large cell carcinoma
• Small cell lung cancer (SCLC)
• Secondary
• Breast, bowel, kidney, testicular, melanoma, bladder
• Causes
• Tobacco smoking (including passive smoking)
• Air pollution
• Radiation: medical imaging, radon
• Asbestos
• Other chemicals e.g. occupational exposure
• Genetic
Lung cancer: clinical features
• Local symptoms and signs
• Breathlessness, wheeze, stridor
• Cough, haemoptysis, chest pain
• Post-obstructive pneumonia
• Hoarse voice: left recurrent laryngeal nerve
• Horner’s, wasting of hand muscles: Pancoast tumour invading brachial plexus
• SVC obstruction
• Lymph node spread
• Mediastinal, cervical, axillary, intra-abdominal
• Metastatic sites
• Pleura: malignant pleural effusion
• Liver
• Bone
• Adrenal glands
• Brain
Talley and O’Connor Ch. 11
Kumar and Clark Ch. 28
Lung cancer: clinical features
• Non-metastatic extrapulmonary manifestations (paraneoplastic)
• General
• Anorexia, cachexia, fever
• Endocrine
• Hypercalcaemia: carcinoma, PTHrP
• Ectopic hormones e.g. SIADH, ectopic ACTH: small cell cancer
• Neurological / MSK / skin
• Clubbing, hypertrophic pulmonary osteoarthropathy
• Peripheral neuropathy
• Eaton-Lambert syndrome
• Subacute cerebellar degeneration
• Polymyositis, dermatomyositis
• Haematological
• Anaemia, thrombocytosis, thrombophlebitis, DIC
• Renal
• Membranous glomerulonephritis
Talley and O’Connor Ch. 11
Kumar and Clark Ch. 28
Lung cancer: investigations
• Bloods
• Hb, liver function, renal function Na+, Ca2+
• Imaging for staging
• CXR
• CT (chest + abdomen + pelvis with contrast)
• PET-CT
• Others e.g. MRI (Pancoast tumour), bone scan
• Tissue sampling
• Primary lesion e.g. bronchoscopy & biopsy, CT-guided lung biopsy
• LN or metastatic lesion e.g. US-guided LN biopsy, US-guided pleural aspiration
• Functional assessment
• Lung function: spirometry, lung volume, gas transfer (DLCO)
• 6-minute walk test
• Cardiopulmonary exercise test (CPET)
• Assess stage
• TNM staging
Lung cancer: management
• Curative treatment often unsuitable
• Late-stage diagnosis, co-morbidities
• Small cell lung cancer treatment different
• Surgery
• Radiotherapy
• Curative or palliative
• Chemotherapy
• Targeted therapy 標靶藥
MHC
• E.g. tyrosine kinase inhibitors (TKIs)
• Immune checkpoint inhibitors TCR
• E.g. PD-1/PD-L1 inhibitors
• Bronchoscopic interventions
• E.g. cryotherapy, stents
• Palliative care
NIH National Cancer Institute cancer.gov
Asthma
• No gold standard definition
• Clinical assessment
• Episodic symptoms: cough, chest tightness, wheeze, breathlessness
• Diurnal variability
• Atopic history
• No symptoms or signs to suggestive alternative diagnosis
• Wheeze on auscultation
• Investigations: options
• Spirometry and reversibility
• PEFR chart
• Challenge tests e.g. methacholine
• Fractional exhaled nitric oxide (FeNO)
• Blood eosinophil count
• Skin-prick test, total and allergen-specific IgE
• Endotypes
• Eosinophilic (Th2), neutrophilic, mixed, paucigranulocytic
BTS / SIGN Guidelines
Asthma: chronic management
BTS / SIGN Guidelines
Asthma attack severity
Severity of acute asthma attack: adults Severity of acute asthma attack: children
BTS / SIGN Guidelines
Asthma: acute management
• ABC
• Maintain SpO2 94-98%
• Assess severity of asthma
• Inhaled short-acting beta2 agonist (salbutamol) via spacer
• Nebulised short-acting beta2 agonist
• Nebulised short-acting anti-muscarinic (ipratropium)
• Steroids: oral prednisolone or IV hydrocortisone
• Reassess
• Consider repeat nebulisers
• Consider IV magnesium
• If no improvement call for senior help
Asthma deaths
Patients at risk of near-fatal
or fatal asthma
BTS / SIGN Guidelines
COPD: causes
• GOLD definition
• “Heterogenous lung condition characterized by chronic respiratory symptoms
(dyspnea, cough, sputum production and/or exacerbations) due to abnormalities
of the airways (bronchitis, bronchiolitis) and/or alveoli (emphysema) that cause
persistent, often progressive, airflow obstruction.”
• Causes
• Tobacco smoking
• Biomass: household fuel burning e.g. wood, coal
• Air pollution
• Occupational exposure
• Genetic: alpha-1 antitrypsin (AAT) deficiency
• AAT: serpin (serine protease inhibitor)
• Genotype: MM = normal, ZZ = AAT deficiency
• Other causes of chronic airflow obstruction
• Chronic asthma
• Chronic respiratory infections The Guardian UK:
• HIV cigarette packaging
Smoking and COPD
• Fletcher and Peto 1977 BMJ
• Smoking → accelerated lung function decline → COPD
• Not all smokers develop COPD
Never smoked /
not susceptible
Susceptible smoker
Stopped aged 45
Disability
Stopped aged 65
Death
Parkes et al. 2008 BMJ (Adapted from Fletcher and Peto 1977)
COPD: diagnosis
• Spirometry
• FEV1 / FVC <0.7: required for diagnosis
• Other investigations
• Lung volumes, gas transfer (DLCO)
• Exercise testing
GOLD assessment: endotypes
• Imaging e.g. CT
• FBC: Hb, eosinophil count
• Sputum culture
• ABG: respiratory failure
• Echo: cor pulmonale
COPD stage FEV1 %predicted
1 ≥ 80%
2 50 – 79%
3 30 – 49%
4 < 30%
GOLD COPD Guidelines
COPD: management
Multidisciplinary
• Smoking cessation
• Pulmonary rehabilitation
• Long-term oxygen therapy
• Vaccinations
• Influenza, pneumococcal, COVID-19
• Education
• Self-management plans
• Inhaler technique
• Pharmacological
• Bronchodilators
• Inhaled corticosteroids (note pneumonia risk)
• Treat exacerbations
• Antibiotics, corticosteroids
• Non-invasive ventilation (also long term)
• Avoid uncontrolled oxygen: chronic hypercapnia and hypoxic respiratory drive
