Pulmonary arterial hypertension strains the right side of theheart, which leads to hypertrophy and dilation of the right ventricle. This may result in cor pulmonale, a condition in which right-sided heart failure leads to hepatic congestion, fluid retention, and tricuspid insufficiency. In severe cor pulmonale, theventricular septum may be displaced toward the left ventricle,hindering left ventricular function. The most common causesof cor pulmonale in children are chronic lung diseases, especially severe bronchopulmonary dysplasia and scleroderma, andsevere untreated obstructive sleep apnea (with chronic hypoxia).
Pulmonary arterial hypertension should be suspected wheneverthere is prolonged hypoxemia or hemodynamically significantleft-to-right cardiac shunting. In addition to the other physicalfindings associated with pulmonary and cardiac diseases, anaccentuated pulmonary component of the second heart soundmay be heard. Definitive diagnosis is made by cardiac catheterization, but echocardiography may confirm the presence ofright ventricular hypertrophy, ventricular dysfunction, inter-ventricular septal flattening, and tricuspid insufficiency, whichcan be used to estimate the pulmonary artery pressures.
For those with pulmonary hypertension in groups 2 through 5, treatment should focus on the underlying condition. In all conditions of PH and PAH, the relief of hypoxemia with supplemental O2 therapy is essential. Heart failure may require treatment with diuretics and restrictions of salt and fluid intake. Vasodilator therapy (sildenafil) is helpful in some patients, and inhaled nitric oxide can be used short term. Continuous infusions of prostacyclin may be helpful both acutely and chronically and is available in inhaled, subcutaneous, and intravenous forms. Endothelium antagonists may be beneficial. Unfortunately, many patients with the idiopathic form of PAH have progressive courses, and lung or heart-lung transplantation may be the only treatment option.
Pulmonary hemorrhage is a rare but potentially life-threatening condition in children. It can be due to bleeding fromthe airways (hemangiomas, bronchial vessel bleeds) or fromdiffuse capillary bleeding (alveolar hemorrhage). Alveolarhemorrhage is usually due to diffuse capillary disruption/inflammation caused by autoimmune disorders and after bonemarrow transplantation. Airway bleeding can be due to airway hemangiomas, pulmonary arteriovenous malformations(as with hereditary hemorrhagic telangiectasia), and bronchial artery collaterals, which develop in some patients withchronic lung infections, especially cystic fibrosis. Idiopathic pulmonary hemosiderosis is a rare disorder characterized byrecurrent alveolar bleeding, iron deficiency anemia, and hemosiderin-laden macrophages in the lung, which can be identifiedmicroscopically with the use of special iron-staining techniquesin bronchoalveolar lavage or lung biopsy specimens. Althoughthe term hemosiderosis is sometimes used interchangeablywith pulmonary hemorrhage, it is a pathologic finding thatresults from bleeding anywhere in the lung, airway, pharynx,nasopharynx, or mouth leading to hemosiderin accumulationin the lung. Pulmonary hemorrhage is a preferable term for bleeding from an intrathoracic source.
Available @ StudentConsult.com