Master Respiratory Medicine
for MRCP Part 1

Core Concepts

Respiratory medicine focuses on conditions affecting the airways, lungs, pleura, and respiratory muscles, crucial for gas exchange (O2 uptake, CO2 excretion). Key physiological principles include ventilation (airflow), perfusion (blood flow), and the ventilation-perfusion (V/Q) ratio; V/Q mismatch is central to many respiratory pathologies. Spirometry assesses lung function, distinguishing obstructive patterns (reduced FEV1/FVC, e.g., asthma, COPD) from restrictive patterns (reduced FVC with normal or increased FEV1/FVC, e.g., ILD, chest wall disease). Respiratory failure is broadly classified into Type I (hypoxaemic, normal CO2) and Type II (hypoxaemic and hypercapnic). Understanding basic lung anatomy (trachea, bronchi, bronchioles, alveoli, pulmonary vasculature, pleura, diaphragm) is fundamental.

Clinical Presentation

• Cough: Acute (<3 weeks), subacute (3-8 weeks), chronic (>8 weeks). Productive (sputum colour/consistency) vs. non-productive. Causes: infection, asthma, COPD, GORD, ACE inhibitors, malignancy.
• Dyspnoea: Shortness of breath. Onset (sudden vs. gradual), severity, associated features (wheeze, chest pain), orthopnoea (cardiac failure), paroxysmal nocturnal dyspnoea (PND).
• Chest Pain: Pleuritic (sharp, worse on inspiration/cough, localised) suggests pleural irritation (pneumonia, PE, pneumothorax). Non-pleuritic (angina, musculoskeletal, GORD, anxiety).
• Wheeze/Stridor: Wheeze (expiratory, musical) indicates lower airway narrowing (asthma, COPD, bronchiectasis). Stridor (inspiratory, harsh) indicates upper airway obstruction (epiglottitis, foreign body, laryngeal tumour).
• Haemoptysis: Coughing up blood (streaks vs. frank blood). Causes: infection (bronchiectasis, TB), malignancy, PE, vasculitis.
• Systemic Symptoms: Fever, night sweats, weight loss (infection, malignancy), fatigue.
• Signs: Cyanosis, clubbing, lymphadenopathy. Tachypnoea, accessory muscle use, tracheal deviation, percussion (dullness - effusion/consolidation, hyper-resonance - pneumothorax/emphysema). Auscultation (crackles - fibrosis/oedema/consolidation, wheeze, rhonchi, pleural rub, absent breath sounds).

Diagnosis (Gold Standard)

Initial assessment often includes chest X-ray (CXR) for gross pathology (pneumonia, effusion, pneumothorax, tumour). Computed Tomography (CT) Thorax provides detailed anatomical information for masses, interstitial lung disease (ILD), bronchiectasis, and pulmonary embolism (PE, via CTPA). Spirometry (with reversibility) is the gold standard for diagnosing and monitoring obstructive airway diseases (Asthma, COPD) and restrictive patterns. Arterial Blood Gas (ABG) assesses oxygenation, ventilation, and acid-base status, critical for respiratory failure. Bronchoscopy with bronchoalveolar lavage (BAL) or biopsy is used for specific infections, malignancies, or ILD. Sleep studies (polysomnography) diagnose sleep apnoea. Pleural fluid analysis (differentiating exudate vs. transudate via Light's criteria) guides management of effusions. Tuberculin skin test (Mantoux) or Interferon-gamma release assay (IGRA) for TB screening, with sputum smears (AFB) and culture for active disease. ECG and echocardiogram are crucial to rule out cardiac causes of respiratory symptoms.

Management (First Line)

Asthma: Short-acting beta-agonists (SABA) for relief. Inhaled corticosteroids (ICS) as first-line maintenance, stepped up with long-acting beta-agonists (LABA) and/or long-acting muscarinic antagonists (LAMA) if uncontrolled. Oral corticosteroids for exacerbations. COPD: SABA/SAMA for relief, LAMA/LABA as maintenance. Oxygen therapy for chronic hypoxaemia. Smoking cessation is paramount. Pneumonia: Empirical antibiotics (e.g., Amoxicillin, Macrolide, Doxycycline) guided by CURB-65 score and local resistance patterns, refined with culture results. Pulmonary Embolism (PE): Anticoagulation (LMWH then DOAC/Warfarin) for most. Thrombolysis or surgical embolectomy for massive PE. Pneumothorax: Small, asymptomatic managed conservatively. Large or symptomatic requires needle aspiration or chest drain insertion. Pleural Effusion: Treat underlying cause. Therapeutic aspiration for symptomatic relief. Interstitial Lung Disease (ILD): Management is specific to the subtype (e.g., antifibrotics like Pirfenidone/Nintedanib for IPF, immunosuppression for CTD-ILD). Tuberculosis (TB): Multi-drug regimen (e.g., RIPE: Rifampicin, Isoniazid, Pyrazinamide, Ethambutol) for at least 6 months. Obstructive Sleep Apnoea (OSA): Continuous Positive Airway Pressure (CPAP).

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