Hypoxaemia During Pregnancy: Pulmonary Arteriovenous Dilatation As A Likely Cause

To the Editor: Pregnancy induces marked physiological changes in the respiratory and cardiovascular systems that can be accompanied by “physiological dyspnoea”, but not by any significant modification of haematosis [1]. Herein, we report the case of a 34-year-old pregnant female at 22 weeks gestation of spontaneous dichorionic diamniotic twins, who was referred to the emergency room for increasing dyspnoea. She had a smoking history of 15 pack-years. She had had a caesarean delivery for her first pregnancy 5 years earlier, but had not suffered any dyspnoea. She had no personal or family history of either thromboembolic disease or epistaxis. Dyspnoea had started at the beginning of the current pregnancy and had recently increased (grade 2 of the modified Medical Research Council scale). The patient had no fever, cough or chest pain. At examination, she had palmar erythema and telangiectasia on the chest, which had appeared 3 months earlier. She had no signs of heart failure or thrombophlebitis of the legs. Cardiopulmonary auscultation was normal. Leukocyte count, haemoglobin level and brain natriuretic peptide were normal. D-dimers were elevated (1158 ng·mL−1; n<500). Arterial blood gas at rest in the supine position and in ambient air showed an increased alveolar–arterial oxygen tension difference ( P A–aO2), since arterial carbon dioxide tension ( P aCO2) was 26 mmHg and arterial oxygen tension ( P aO2) was 72 mmHg. The ECG was normal but in sinus tachycardia (96 beats·min−1). Clinical probability of pulmonary embolism was considered moderate. Doppler ultrasound of the legs, computed tomography (CT) scan, ventilation/perfusion lung scan …