The diagnostic workup of a child with pulmonary arterial hypertension is similar to that of an adult, although other more common causes of pulmonary hypertension in childhood must be excluded. These include congenital heart disease and persistent pulmonary hypertension of the newborn, which has not regressed satisfactorily. Children can be extremely ill at presentation having deteriorated swiftly, but the principals of management are the same in children and adults.
Choice of therapy is based on the findings at cardiac catheterisation and the response to acute vasodilator testing, which includes the study with nitric oxide. Greater reactivity is expected in children, based on both pathological and clinical data.