Breathlessness u/e
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breathlessness dyspnea causes evaluation clinical approach
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acute breathlessness differential diagnosis emergency management
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Here is a structured overview of Breathlessness (Dyspnea) — Undergraduate-level (U/E) Review:
Breathlessness (Dyspnea)
Definition
Dyspnea is the subjective sensation of uncomfortable or difficult breathing. It is a symptom, not a diagnosis, arising from complex interactions between cardiovascular, respiratory, and musculoskeletal neural feedback mechanisms.
Causes — Major Categories
Respiratory
| Condition | Key Features |
|---|---|
| Asthma / Exercise-induced bronchospasm | Wheeze, chest tightness, reversible |
| COPD | Chronic smoker, barrel chest, pursed-lip breathing |
| Pneumonia | Fever, cough, consolidation on CXR |
| Pulmonary Embolism (PE) | Pleuritic chest pain, risk factors (immobility, DVT), tachycardia |
| Pneumothorax | Sudden onset, unilateral reduced breath sounds |
| Pleural effusion | Stony dull percussion, reduced BS at base |
| Paradoxical vocal fold movement (PVFM) | Inspiratory stridor, young athletes |
Cardiovascular
| Condition | Key Features |
|---|---|
| Acute LVF / Pulmonary oedema | Orthopnoea, PND, S3, bibasal creps |
| STEMI | May present as sudden breathlessness alone — especially in elderly and diabetics (Harrison's, p. 7567) |
| Aortic dissection | Tearing chest/back pain, pulse differential |
| Cardiac tamponade | Beck's triad (hypotension, raised JVP, muffled heart sounds) |
| Arrhythmias | Palpitations + breathlessness |
Other
- Anaemia — exertional dyspnea, pallor, fatigue
- Anxiety / Hyperventilation — perioral tingling, no hypoxia
- Metabolic acidosis — Kussmaul breathing (DKA, renal failure)
- Obesity / deconditioning — exertional only, appropriate for effort
- Neuromuscular disease — bilateral diaphragm weakness, orthopnoea
History — Key Questions
- Onset: Sudden (PE, pneumothorax, acute LVF) vs. gradual (COPD, anaemia)
- Timing: Exertional only, constant, nocturnal (PND = cardiac), positional (orthopnoea = cardiac; platypnoea = hepatopulmonary syndrome)
- Associated symptoms: Wheeze, stridor, chest pain, palpitations, ankle swelling, haemoptysis, cough, fever
- Context: New vs. change from baseline; change in exercise tolerance; recent illness, immobility, surgery (PE risk)
- Past history: Smoking, known cardiac/lung disease, DVT, malignancy
- Medications: ACE inhibitors (cough/angioedema), beta-blockers (bronchospasm), amiodarone (pulmonary toxicity)
Examination
| Finding | Suggests |
|---|---|
| Tachycardia + hypoxia | PE, acute LVF, pneumonia |
| Wheeze | Asthma, COPD, acute LVF ("cardiac asthma") |
| Stridor | Upper airway obstruction, PVFM |
| Stony dull percussion | Pleural effusion |
| Hyperresonance + absent BS | Pneumothorax |
| Bibasal fine creps | LVF, pulmonary fibrosis |
| Raised JVP + oedema | Right heart failure, cardiac tamponade |
| Cyanosis | Severe hypoxia |
Investigations
First-line (bedside/urgent):
- Oxygen saturations (SpO₂)
- ECG — AF, STEMI, RBBB (PE), LVH
- CXR — consolidation, effusion, cardiomegaly, pneumothorax
Blood tests:
- ABG — hypoxia, hypercapnia, type I vs. II respiratory failure, metabolic acidosis
- FBC — anaemia, infection
- BNP/NT-proBNP — heart failure marker
- D-dimer — if PE suspected (low pre-test probability)
- Troponin — acute coronary syndrome
Specialist:
- CTPA — gold standard for PE
- Echo — LV function, effusion, valvular disease
- Spirometry — obstructive vs. restrictive pattern
- CPET — objective exercise capacity assessment
Acute Management Framework (ABC)
- Airway — ensure patent; consider high-flow O₂
- Breathing — target SpO₂ 94–98% (88–92% in known COPD)
- Circulation — IV access, monitor, 12-lead ECG
- Treat the underlying cause:
- Acute LVF: furosemide IV, GTN, sit upright
- Asthma/COPD exacerbation: bronchodilators, steroids
- PE: anticoagulation ± thrombolysis if haemodynamically unstable
- Pneumothorax: aspiration or chest drain (if large/tension)
- Pneumonia: antibiotics
Red Flags (Urgent Assessment Required)
- SpO₂ < 94% at rest
- RR > 30/min
- Use of accessory muscles / inability to complete sentences
- Haemodynamic instability
- New-onset dyspnoea in elderly/diabetic patient (consider silent MI)
- Sudden onset at rest (PE, pneumothorax, acute LVF)
Key exam pearl: In the elderly and in diabetics, STEMI can present solely as sudden-onset breathlessness without chest pain — always have a low threshold for an ECG (Harrison's, p. 7567).
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