Pediatric case of the day.

Abstract

A previously healthy 5-year-old girl had marked dyspnea and fatigue, which had developed oven the course of a week. A chest radiograph showed an enlarged heart, large central pulmonary arteries, diffuse interstitial lung markings, thickened interlobulan septal lines, bilateral pleural effusions, and bibasilan consolidative lung infiltrates (Fig. 1A). Echocandiography showed enlargement of the night side of the heart, dilated pulmonary arteries, and severe pulmonary arterial hypertension. No evidence of shunting on congenital heart defect was seen. Further studies were undertaken to find the cause of the pulmonary hypertension. Fast CT revealed no evidence of pulmonary emboli or cardiac defect. The central pulmonary veins were normal in appearance (Figs. 1 B-i 0). Pulmonary angiography again showed night-sided heart enlargement and dilated pulmonary arteries (Fig. 1 E). Instead of the normally seen smooth homogeneous panenchymal blush, inhomogeneous enhancement was seen in the pulmonary parenchymal phase (Fig. 1 F). The pulmonary veins and left atrium were normal in appearance (Fig. 1G). The pulmonary artery wedge pressure was normal. Open lung biopsy was diagnostic of pulmonary venoocclusive disease. The intenlobular septa were thickened and fibrotic. Obstructive changes were present in the small to medium-sized veins in the intenlobulan septa. The veins displayed eccentric medial smooth muscle proliferation with associated intimal proliferation, thrombosis, and necanalization. Hemosidenin-laden macnophages were present in the alveoli. Pulmonary venoocclusive disease is a rare cause of pulmonary hypertension that generally affects children and young adults [1 -3]. It was described in the 1930s and was rarely reported before 1 960. It is either increasing in prevalence or being recognized more frequently, as the number of reported cases has increased significantly in the past two decades [1].Pathologically,infiltration a d thickening of the intima of the small pulmonary veins and venules resultsin intimalfibrosis.Medium and large pulmonary veins may on may not be affected. Pulmonary arterial hypertension, dilated congested lymphatics, and thickened intralobular septa develop in response to the obstructed pulmonary venous flow. Hemosidenin-laden macnophages due to episodes of pulmonary hemorrhage also can be found. Pulmonary venoocclusive disease is of uncertain cause. Rather than being a single disease, it may be the final common pathway of multiple disorders [1-3]. There appear to be a number of predisposing causal factors, including viral infections, environmental toxins, autoimmune diseases, heredity, and chemotherapy [3]. Patients typically present with progressive dyspnea, orthopnea, fatigue, and syncope [1 , 2, 4]. No known treatment is adequate, although steroids and anticoagulation have been tried. Lung transplantation has been suggested as a possible alternative. After a nelatively short course, pulmonary venoocclusive disease is usuallyfatal[1, 2, 4]. The radiographic hallmarks are enlargement of the right side of the heart, large central pulmonary arteries, interstitial pulmonary edema, and thickened septal or Kerley’s B lines [1 , 5]. The combination of findings of pulmonary arterial hypertension and pulmonary edema with lack of involvement of the left atrium and mid-sized to large pulmonary veins implicates a vascular problem at the capillary level [1 , 6]. These findings should suggest the diagnosis of pulmonary venoocclusive disease. Primary pulmonary arterial hypertension should not result in pulmonary edema. Left-sided heart lesions such as valvulan disease should result in left atrial enlargement on engorgement of the pulmonary veins [1 , 5, 7]. Pulmonary angiognaphic findings are variable. Pulmonary circulation time may be prolonged, with a phase of inhomogeneous patchy parenchymal enhancement [5, 7]. The visible pulmonary veins are usually normal in appearance. The pulmonary artery wedge pressure is most often normal [1 , 4, 6, 7]. Pulmonary artery wedge pressure classically measunes the pressure in the larger pulmonary veins, which are not affected in pulmonary venoocclusive disease, and is not truly a “capillary” wedge pressure [6]. Diagnosis can be suggested by the radiologic findings but is usually made by lung biopsy on at autopsy.