Idiopathic pulmonary arterial hypertension in a patient with pyruvate kinase deficiency and paravertebral extramedullary hematopoiesis

Abstract

Dear Editor, Pulmonary arterial hypertension (PAH) is defined as a sustained elevation of pulmonary arterial pressure to more than 25 mmHg at rest or to more than 30 mmHg during exercise, with a mean pulmonary–capillary wedge pressure and left ventricular end-diastolic pressure of less than 15 mmHg, leading to right ventricular dysfunction, congestive heart failure, and death [1]. PAH is a well-known complication in patients with hemoglobinopathies such as sickle cell disease and thalassemia. PAH is closely related to the hemolytic anemia. Nonhepatosplenic extramedullary hematopoiesis has been described in association with a wide variety of myeloproliferative diseases and hemoglobinopathies such as sickle cell disease and thalassemia [2]. It is due to increased renal excretion of erythropoietin secondary to anemia or hypoxia and can involve any organs and tissues, including the mediastinum, pleura, lungs, and heart. In most cases, the diagnosis is fortuitous, and rarely, the lesions are symptomatic, displaying neurological signs, pleural effusion, cardiac tamponade, and dyspnea [2]. Pyruvate kinase (PK) deficiency is the most common cause of hereditary nonspherocytic hemolytic anemia, transmitted as an autosomal recessive condition, with classical features ranging from mild anemia to a transfusion-dependant disease [3]. We report in this paper a case of dyspnea indicating idiopathic PAH associated with paravertebral hematopoiesis in a patient with PK deficiency. A 47-year-old man, current smoker, with PK deficiency diagnosed at birth requiring splenectomy at age 5 years and who denied any drug intake, was hospitalized in July 2007 for dyspnea on exertion [New York Heart Association (NYHA) class III] present for 1 month. On examination, he appeared healthy. A grade 3/6 systolic murmur was heard best in the pulmonary area. Mucocutaneous jaundice was found. The findings on laboratory testing of renal function, liver test function, and C-reactive protein, search for antinuclear antibodies and anti-extractable nuclear antibodies, and HIV testing were normal or negative. Hepatitis B virus serology was consistent with past immunization, and hepatitis C virus serology was positive, with a negative viral load. Other laboratory test results are indicated in Table 1. Arterial blood gas analysis showed pO2 73 mmHg, pCO2 34 mmHg, pH 7.43, SaO2 93% while breathing ambient air. Chest X-ray (Fig. 1) and computed tomography (CT) scan demonstrated paravertebral soft tissue masses extending from T1 to T10, with heterogeneous enhancement after contrast administration and main pulmonary artery enlargement at 43 mm without signs of thrombotic or embolic disease concordant with the ventilation-perfusion lung scan. Magnetic resonance imaging (MRI) displayed the paravertebral masses isointense on T1-weighted sequences, Ann Hematol (2009) 88:603–605 DOI 10.1007/s00277-008-0644-z