Pulmonary hypeension may occur in all of the following conditions except-

Category 1. Pulmonary aerial hypeension (PAH) Key feature: elevation in pulmonary aerial pressure (PAP) with normal pulmonary capillary wedge pressure (pcwp) Includes: Idiopathic (IPAH) * Sporadic * Familial Exposure to drugs or toxins * Persistent pulmonary hypeension of the newborn * Pulmonary capillary hemangiomatosis (PCH) Associated with other active conditions * Collagen vascular disease * Congenital systemic-to-pulmonary shunts * Poal hypeension * HIV infection Category 2. Pulmonary venous hypeension Key feature: elevation in PAP with elevation in pcwp Includes: * Left-sided atrial or ventricular hea disease * Left-sided valvular hea disease * Pulmonary venous obstruction * Pulmonary venoocclusive disease (PVOD) Category 3. Pulmonary hypeension associated with hypoxemic lung disease Key feature: chronic hypoxia with mild elevation of PAP Includes: * Chronic obstructive lung disease * Interstitial lung disease * Sleep-disordered breathing * Alveolar hypoventilation disorders * Chronic exposure to high altitude * Developmental abnormalities Category 4. Pulmonary hypeension due to chronic thromboembolic disease Key feature: elevation of PA pressure with documentation of pulmonary aerial obstruction for >3 months Includes: * Chronic pulmonary thromboembolism * Nonthrombotic pulmonary embolism (tumor, foreign material) Category 5. Miscellaneous Key feature: elevation in PAP in association with a systemic disease where a causal relationship is not clearly understood. Includes: * Sarcoidosis * Chronic anemias * Histiocytosis X * Lymphangiomatosis* Schistosomiasis ref:Harrison&;s principles of internal medicine,ed 18,pg no 2078