User Tools

Site Tools


acute dyspnoea / shortness of breath (SOB)


  • A 2017-published international trial (Australia, NZ, Singapore, Malaysia,Hong Kong) of 3,044 people found: Patients with dyspnoea made up 5.2% of ED presentations, 11.4% of ward admissions, and 19.9% of intensive care unit (ICU) admissions. The most common diagnoses were lower respiratory tract infection (20.2%), heart failure (14.9%), chronic obstructive pulmonary disease (13.6%), and asthma (12.7%). Hospital ward admission was required for 64% of patients with 3.3% requiring ICU admission. In-hospital mortality was 6%.
  • In the ED a general approach to diagnosis starts with the common differentials.

Common Causes

Differential Diagnosis

Therapeutic Options

  • Oxygen (+ if the diagnosis is anaphylaxis: 10mcg/kg of IM adrenaline (adult dose 0.5mg))
  • Pleural drainage
  • Antibiotics
  • Venodilators (eg GTN infusion or topical)
  • Steroids (Prednisolone po or hydrocortisone IV)
  • Beta-2 agonists (eg salbutamol)
  • Magnesium (usually as MgSO4 infusion)
  • Thrombolysis (in selected patients with intermediate or high risk PE, see thrombolysis in Mx of PE)
  • Anticoagulation (in all PE patients without a major contra-indication)
  • IM (Intra-Muscular) adrenaline is the specific treatment for anaphylaxis
  • Intubation and mechanical ventilation may be required in particular circumstances, for the critically ill.
  • Ketamine is the drug of choice for safer intubation of sick respiratory patients (see rapid sequence induction (RSI) for emergency intubation)

Rarer Causes

Differential Diagnosis Continued

Useful tests

  • CXR - will usually diagnose 3 of the 6 common causes
  • UEC - check the bicarbonate to rule out metabolic acidosis
  • FBE - lymphopenia, neutrophilia
  • D-dimer - interpreted in context; useful in selected patients with low pre-test probability of PE
  • VBG - sometimes helpful to monitor response to therapy
  • 12 lead ECG - especially if tachycardic / bradycardic
  • CRP - greater than 60 is meaningful
  • CTPA or VQ scan are the two main options in patients with suspected PE
  • Bedside echo may be useful to look for pericardial problems or ventricular dysfunction
  • very limited role for BNP, blood cultures, mast cell tryptase
acute_dyspnoea.txt · Last modified: 2019/10/09 18:46 (external edit)