Pulmonary Veno-occlusive Disease: a Probably Underdiagnosed Cause of Pulmonary Hypertension in Systemic Sclerosis

Pulmonary hypertension is a serious complication of systemic sclerosis and remains one of the leading causes of mortality. Pulmonary veno-occlusive disease (PVOD), recently reclassified as pulmonary arterial hypertension (PAH) with overt features of venous/capillaries involvement, is a subgroup of group 1 pulmonary hypertension, which has been rarely reported in systemic sclerosis patients. It is symptomatically indistinguishable from idiopathic pulmonary arterial hypertension and should be suspected in those with manifestations of pulmonary arterial hypertension who have evidence of pulmonary venous congestion in the absence of left-sided heart disease. Thoracic high-resolution computed tomography can give important hints for the diagnosis, such as ground-glass opacities/nodules, mediastinal lymph node enlargement and interlobular septal thickening. Patients with PVOD usually have a poor prognosis and might experience acute pulmonary oedema after introduction of pulmonary vasodilators. Due to clinical similarities between scleroderma-related PAH and PVOD, some patients are misdiagnosed and this could explain, in part, the worse prognosis associated with this clinical condition, when compared with idiopathic PAH. We report the case of a 72-year-old woman with limited systemic sclerosis, who was initially diagnosed with systemic sclerosis-related pulmonary arterial hypertension. However, after introduction of sildenafil and bosentan, the patient developed acute pulmonary oedema, and findings from complementary exams were suggestive of PVOD.