pulmonary arterial hypertension
Summary
Mean pulmonary artery pressure >20 mmHg at rest with elevated pulmonary vascular resistance and normal wedge pressure (≤15). Leads to RV hypertrophy and cor pulmonale; classic histology shows plexiform lesions and medial hypertrophy.
Detail
WHO Group 1 PAH includes idiopathic, heritable (BMPR2 mutation, AD with incomplete penetrance), drug-induced (fen-phen, methamphetamine), connective tissue disease (scleroderma/CREST), HIV, portal hypertension, and congenital heart disease (Eisenmenger). Pathology shows medial hypertrophy, intimal fibrosis, and plexiform lesions of small pulmonary arteries. Presents with exertional dyspnea, fatigue, syncope, loud P2, and signs of right heart failure (JVD, edema, hepatomegaly). Diagnosis requires right heart catheterization. Treatments target three pathways: endothelin antagonists (bosentan, ambrisentan), PDE5 inhibitors (sildenafil), and prostacyclin analogs (epoprostenol). Without treatment, prognosis is poor (~3 year median survival in idiopathic PAH).
Sources
- First Aid for USMLE Step 1 2024
- Robbins Basic Pathology 10th ed
- Pathoma
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