CRA30 PULMONARY ARTERIOVENOUS MALFORMATION(PAVM): A RARE CAUSE OF HYPOXAEMIA INDUCED ERYTHROCYTOSIS

Nurul Izzati Zakaria, Kezreen Kaur Dhaliwal, Noor Hidayah Yahya
Internal Medicine, Hospital Enche’ Besar Hajjah Khalsom, Kluang, Johor, Malaysia

Introduction:

Most Pulmonary Arteriovenous Malformations(PAVMs) (80-90%) are associated with hereditary hemorrhagic telangiectasia(HHT). PAVMs in general population occur more commonly in females and in the lower lobes(50-70%). We present a case of a male patient, referred to us for further investigations of polycytheamia, who was detected to have non-HHT PAVM in the right upper lobe.

Objective:

To highlight the importance of considering PAVM as an etiology of hypoxaemia-induced erythrocytosis.

Methodology:

66 years old Indian gentleman, non-smoker, with underlying hypertension, was referred to us for further investigation of polycythaemia(haemoglobin:19.6g/dL, haematocrit: 57%). He was asymptomatic. He never lived at high altitude area. Clinically, he had clubbing of his hands and toes, but no cyanosis. Respiratory, cardiovascular and abdominal examinations were normal. Other cell lines; TWBC:9.46X109/L, platelet: 264X109/L were normal. 

Results:

Full Blood Picture(FBP) revealed polycythaemia to exclude secondary cause. JAK -2 and calreticulin were negative. Echocardiogram was also normal. Arterial blood gas(ABG) under room air showed mild hypoxaemia (pH:7.42, pO2:72mmHg, pCO2:32mmHg, SaO2:95.1%). Hence, we proceeded with HRCT Thorax to look for chronic lung disease, which, instead revealed a lobulated lesion at the apical segment of right upper lobe measuring 2.8 x 2.3 x2.1 cm. CTPA confirmed that the lesion avidly enhanced in arterial phase and is supplied by segmental branch of right upper lobe pulmonary artery and draining into the right upper lobe pulmonary vein, representing a right PAVM. Retrospectively, HHT was ruled out according to the Curacao criteria. The cardio-thoracic team was consulted, but since patient was asymptomatic and the size of the lesion was small, there was no role of surgical intervention. 

Conclusion:

Although rare, clinicians should be aware of PAVM as a cause of hypoxaemia-induced erythrocytosis.