Emergency shortness of breath

Medical Emergency - This page is about emergency shortness of breath. If you're after the more bog-standard symptom go to: shortness of breath.

Differential Diagnosis

There are loads:

Lungs - pneumonia, pneumothorax, pleural effusion, hyperventilation, pulmonary embolism
Lower airways- acute asthma, acute exacerbation of COPD, bronchiectasis, fibrosis, anaphylaxis, foreign body in airway
Upper airways - anaphylaxis, epiglottitis, foreign body in airway, lung cancer, airway trauma
Cardiac - acute heart failure, myocardial infarction, cardiac tamponade
Systemic - drugs e.g. salicylate overdose, shock (causes 'air hunger'), metabolic acidosis (specifically DKA)

In a emergency situation, you basically need a quick way to be able to differentiate between the different causes of shortness of breath.

Acute asthma - breathless, hyperventilating, wheezing, history of asthma.
- Severe - peak flow 33-50%; RR>25; HR<110; inability to complete sentences
- Life-threatening - peak flow <33%; Sats<92%; P_aO₂<8kPa; silent chest; cyanosis; poor respiratory effort; bradycardia; hypotension; confusion; coma
Acute exacerbation of COPD - breathless; increasing cough; wheeze; decreased exercise capacity; home oxygen, smoking, exercise capacity all help in deciding management
Anaphylaxis - breathlessness, oedema (larynx, lids, lips, tongues), cyanosis, wheeze, urticaria
Acute heart failure (severe pulmonary oedema) - breathless, orthopnoea (PND), pink frothy sputum, pale, sweaty, tachycardia, tachypnoea, pulsus alternans (alternating weak and strong pulse), raised JVP, fine crackles, gallop rhythm, wheeze

If it's a foreign body, hopefully, that'll be in the history.
Epiglottitis - if suspected, do not examine the throat. Call an anaesthetist and get airway access immediately. The child will be quiet and not moving in order to maintain the airway.
Anaphylaxis - see above
Airway trauma will hopefully be evident with a history of trauma.

Acute heart failure - see above
Pneumonia - breathless, crackles, fever, productive cough, confusion, tachypnoea, haemoptysis, malaise, rigors, pleuritic chest pain
Bronchiectasis and fibrosis. Don't really know anything about these.

Pneumothorax: hyperesonant - respiratory:shortness of breath, pleuritic chest pain, diminished breath sounds, reduced chest expansion; cardiac: tachycardia, hypotension; neck: deviated trachea, distended neck veins
Pleural effusion: "stony dull" - breathless, dull chest pain, tracheal deviation (away from effusion), reduced chest expansion on affected side, reduced vocal fremitus, absent/reduced breath sounds,

Now you've ruled out a large proportion of respiratory causes, you go on to what can in this description be called "the rest".

Pulmonary embolism - breathless, tachynpnoea, tachycardia, pleuritic chest pain, haemoptysis, syncope, hypotension, gallop rhythm, raised JVP, right ventricular heave, pleural rub. Risk factors: cancer, recent surgery, immobility, the Pill, DVT, previous thromboembolism, thrombophilia
Hyperventilation syndrome - due to panic attack. Acute anxiety, chest tightness, paraesthaesia in fingers, numbness
DKA - breathlessness; history of diabetes; coma; vomiting; dehydration; abdominal pain; shock; drowsiness; tachycardia
Metabolic acidosis - depends on cause
Anaemia, shock and certain drugs (aspirin) can cause dyspnoea too.