Other nonneoplastic disease

Pulmonary hypertension

Last author update: 1 December 2011
Last staff update: 24 August 2020

Copyright: 2003-2023,, Inc.

PubMed search: pulmonary hypertension [title] lung

Elliot Weisenberg, M.D.
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Cite this page: Weisenberg E. Pulmonary hypertension. website. Accessed September 21st, 2023.
Clinical features
  • Defined clinically as mean resting pulmonary artery pressure > 25 mm Hg or systolic > 30 mm Hg, usually not symptomatic until 60 mm Hg
  • Also defined as 25% or more of systemic pressure (normal is 10%)
  • Classified based on consensus conference (J Am Coll Cardiol 2009;54:43)

Pulmonary arterial hypertension (PAH):
  • Idiopathic
  • Familial
  • Associated with:
    • Collagen vascular disease
    • Congenital systemic to pulmonary shunts
    • Portal hypertension
    • HIV infection
    • Drugs and toxins (historically diet drug fenfluramine and phentermine fen-phen)
    • Other
  • Associated with significant venous or capillary involvement:
    • a) Pulmonary venous occlusive disease
    • b) Pulmonary capillary hemangiomatosis

Pulmonary venous hypertension:
  • Left sided atrial or ventricular heart disease
  • Left sided valvular heart disease

Pulmonary hypertension associated with hypoxemia:
  • COPD
  • Interstitial lung disease
  • Sleep-disordered breathing
  • Alveolar-hypoventilation disorders
  • Chronic exposure to high altitudes

Pulmonary hypertension due to chronic thrombotic or embolic disease:
  • Thromboembolic obstruction of proximal pulmonary arteries
  • Thromboembolic obstruction of distal pulmonary arteries
  • Nonthrombotic pulmonary embolism (tumor, parasites and foreign material)
  • Miscellaneous (sarcoidosis, Langerhan cell histiocytosis and compression of pulmonary vessels)

  • In secondary forms, endothelial cell dysfunction initiates the disorder; causes decreased production of nitric oxide and prostacyclin and increased levels of endothelin, leading to endothelial cell activation, constriction and thrombogenesis; usually women ages 20 - 40 years; some patients have vasospastic element

  • Sporadic, requires exclusion of other known causes
  • Usually women 20 - 40 years old
  • Sometimes children are initially asymptomatic, then shortness of breath, fatigue, angina, progressing to right ventricular hypertrophy, cor pulmonale, pulmonary emboli or pneumonia

  • Rare, autosomal dominant with incomplete penetrance
  • Mutations in bone morphogenic protein receptor 2 signalling pathway (BMPR2)
  • Vasodilators, calcium channel blockers, nitric oxide, antithrombotic medications, prostacyclin analogues, endothelial cell receptor antgonists, phosphodiesterase-5 inhibitors and lung transplant in selective patients
  • Disease reversible if arterial lesions restricted to medial hypertrophy, intimal thickening of longitudinal smooth muscle or cellular intimal proliferation
Gross images

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Microscopic (histologic) description
  • Organizing thrombi (suggests recurrent pulmonary emboli)
  • Interstitial fibrosis if hypoxia
  • Changes in major vessels / branches are similar to systemic atherosclerosis
  • Small vessels have medial hypertrophy and intimal fibrosis, which may narrow lumina to pinpoint
  • Plexogenic arteriopathy: tuft of capillaries spanning lumina of arteries, changes can be quantified using Reid index
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