Pulmonary hypertension (PH) is defined as an increase in mean pulmonary arterial pressure ≥ 25 mmHg at rest as assessed invasively by right heart catheterisation. It can affect patients at any age and presents with non-specific symptoms. Accurate diagnosis is important as while PH is a potentially lethal disease it is treatable. Identification of the cause of PH is crucial to ensure that the patient receives appropriate management.