A type of pulmonary hypertension with a prevalence 0.1-0.2 cases per million population.
Many cases are unrecognized and the cause is unknown.
Some cases, have mutations in the gene encoding bone morphogenetic protein receptor2 (BMPR2)(Montani D).
May be associated with scleroderma (Johnson SR).
CT thorax poisonings include interlobular septal thickening, centilobular ground-glass opacities, pleural effusions, enlarged pulmonary arteries, small or normal size pulmonary and adenopathy.
The tunica media of the the venules and veins may become thickened with an increased number of elastic fibers, and smooth muscle.
Treatment with vasodilators may precipitate clinical worsening.
Characterized by intimal proliferation and fibrosis of the intrapulmonary veins and venules.
The lumen occlusion may be solid or partial with attempts at re-canalization of occlusive thrombI.
Lung biopsy is necessary for the diagnosis, but it is associated with significant risks and the clinical diagnosis is most common.
Prognosis is worse than for pulmonary arterial hypertension, as there is no effective treatments available.
Median time between diagnosis and death or transplantation is 22 months.
Only definitive treatment is lung transplantation.