Pulmonary hypertension in chronic interstitial lung diseases

Abstract

Pulmonary hypertension (PH) is a common complication of interstitial lung diseases (ILDs), particularly in idiopathic pulmonary fibrosis and ILD associated with connective tissue disease. However, other lung diseases, such as combined pulmonary fibrosis and emphysema syndrome, pulmonary Langerhans cell histiocytosis, and lymphangioleiomyomatosis, may also include PH in their clinical manifestations. In all of these diseases, PH is associated with reduced exercise capacity and poor prognosis. The degree of PH in ILDs is typically mild-to-moderate. However, some of these patients may develop a disproportionate increase in PH that cannot be justified solely by hypoxia and parenchymal injury: this condition has been termed "out-of-proportion" PH. The pathogenesis of PH in these diseases is various, incompletely understood and may be multifactorial. The clinical suspicion (i.e. increased dyspnoea, low diffusion capacity) and echocardiographic assessment are the first steps towards proper diagnosis of PH; however, right heart catheterisation remains the current gold standard for diagnosis of PH. At present, no specific therapies have been approved for the treatment of PH in patients with ILDs.

Figure 1.

High-resolution computed tomography image showing a typical pattern of idiopathic pulmonary fibrosis. Main pulmonary artery and right pulmonary artery enlargement are present. The patient was a 73-year-old, male ex-smoker.

Figure 2.

Subpleural intralobular interstitial thickening, reticulation, and traction bronchiectasis and initial honeycombing in a patient with systemic sclerosis. Oesophageal dilatation is present.

Figure 3.

High-resolution computed tomography (HRCT) images from a 75-year-old, male ex-smoker with combined pulmonary fibrosis and emphysema syndrome (CPFE). a) HRCT image shows sub-pleural honeycombing in the middle lung, traction bronchiectasis and emphysema. On the right side a consolidation compatible with lung carcinoma is present, a frequent complication in CPFE syndrome. Echocardiography documented a pulmonary arterial pressure of 75 mmHg. b) Focal lucencies associated with paraseptal emphysema are more evident in the upper lobes in the same patient.

Figure 4.

High-resolution computed tomography from a 63-year-old, female nonsmoker with lymphangioleiomyomatosis showing diffuse thin-walled lung cysts.

Figure 5.

Irregular, thick- and thin-walled cysts and nodules in a patient with pulmonary Langerhans cell histiocytosis.