Pulmonary Embolism (PE)

Clinical features

•    Sudden-onset dyspnoea, pleuritic chest pain

•    Haemoptysis (pulmonary infarction)

•    Tachycardia, tachypnoea

•    Possible hypotension (massive PE)

•    Possible signs of DVT

Investigations

•    Wells score to assess probability:

o    4 → "PE likely" → CTPA

o    ≤4 → "PE unlikely" → D-dimer (if positive, proceed to CTPA)

•    ABG: may show hypoxaemia, hypocapnia (due to hyperventilation)

•    ECG: sinus tachycardia, S1Q3T3 pattern (rare)

•    CXR: usually normal; possible wedge-shaped infarct (Hampton’s hump)

Management

•    Anticoagulation:

o    DOACs first line (e.g., apixaban, rivaroxaban)

o    LMWH bridging to warfarin in certain cases (e.g., antiphospholipid syndrome)

•    Thrombolysis for massive PE with haemodynamic instability

Pulmonary Hypertension (PH)

Signs

•    Loud P2 (pulmonary component of second heart sound)

•    Parasternal heave (right ventricular hypertrophy)

•    Right heart failure signs (elevated JVP, hepatomegaly, peripheral oedema)

Causes (WHO classification)

1.    Pulmonary arterial hypertension (PAH) (idiopathic, CTD-related, HIV, portal HTN)

2.    Left heart disease (mitral stenosis, LV dysfunction)

3.    Lung disease or hypoxia (COPD, ILD)

4.    Chronic thromboembolic PH (CTEPH)

5.    Miscellaneous (sarcoidosis, haematological)

Investigations

•    Echocardiogram (screening tool): estimates pulmonary artery systolic pressure

•    Right heart catheterisation: definitive diagnosis

Management

•    Treat underlying cause

•    PAH-specific therapy: endothelin receptor antagonists (bosentan), PDE-5 inhibitors (sildenafil), prostacyclin analogues

Granulomatosis with Polyangiitis (GPA, Wegener’s)

Features

•    Upper respiratory tract: sinusitis, nasal crusting, saddle-nose deformity

•    Lower respiratory tract: nodules (may cavitate), haemoptysis

•    Renal: rapidly progressive GN (haematuria, red cell casts)

Investigations

•    cANCA (PR3) positive (high specificity)

•    Biopsy: necrotising granulomatous inflammation

Management

•    Induction: cyclophosphamide + high-dose steroids

•    Maintenance: azathioprine, methotrexate

Eosinophilic Granulomatosis with Polyangiitis (EGPA, Churg–Strauss)

Features

•    Asthma (almost universal)

•    Peripheral eosinophilia

•    Mononeuritis multiplex

•    Pulmonary infiltrates (transient)

•    Skin purpura

Investigations

•    pANCA (MPO) positive (≈40%)

Management

•    Steroids ± cyclophosphamide if severe

Polyarteritis Nodosa (PAN) & Henoch–Schönlein Purpura (HSP)

PAN

•    Medium-vessel vasculitis

•    Multisystem: renal infarcts (no GN), mesenteric ischaemia, neuropathy

•    HBV association

HSP (IgA vasculitis)

•    Small-vessel vasculitis

•    Classic tetrad:

o    Palpable purpura (legs/buttocks)

o    Arthralgia

o    Abdominal pain

o    Renal involvement (IgA nephropathy)

•    Rare pulmonary involvement: alveolar haemorrhage

Connective Tissue Disease Lung Involvement

•    Rheumatoid arthritis:

o    ILD (UIP pattern most common)

o    Pleural effusions

o    Nodules

•    Systemic sclerosis:

o    ILD (NSIP pattern common)

o    Pulmonary hypertension

•    SLE:

o    Pleural effusions (common)

o    Shrinking lung syndrome

o    Diffuse alveolar haemorrhage

Pulmonary Eosinophilia

Causes

•    Parasitic infections (e.g., Ascaris, Strongyloides)

•    Drugs: nitrofurantoin, NSAIDs, antibiotics

•    ABPA

•    Idiopathic (e.g., simple pulmonary eosinophilia — Loeffler’s)

Clinical features

•    Cough, dyspnoea

•    Peripheral eosinophilia

Management

•    Remove cause

•    Steroids if severe

Extra Revision Pearls

•    Wells score ≥4 → straight to CTPA

•    Saddle-nose deformity clue → GPA

•    Asthma + eosinophilia → think EGPA

•    Loud P2 → classic clue for PH on exam

•    HBV link → think PAN

•    RA + lower lobe fibrosis → consider UIP pattern

•    Pleuritic chest pain + dyspnoea + normal CXR → suspect PE

•    Alveolar haemorrhage clues → GPA, SLE, HSP