A57-year-old woman was referred for assessment of progressive dyspnoea, decreasing exercise tolerance and worsening bluish facial discolouration. She had congenital cirrhosis complicated by portal hypertension aged 4 years, for which she underwent a portacaval shunt. She was an exsmoker of 30 years. On examination, she was centrally cyanosed and clubbed. Her jugular venous pressure was not elevated, cardiac examination was normal and there were no focal chest signs. Spider naevi were noted, but no palpable organomegaly or ascites. Her oxygen saturation, however, was 88% breathing room air, which did not alter when recumbent or supine.
A chest radiograph showed normal lung fields and vasculature, and no effusions. Renal and liver profile blood tests and international normalized ratio were normal. Arterial blood gas analysis revealed: pH 7.43 (normal 7.35–7.45), Pa∘2 7.21 kPa (normal >10.6 kPa), PaC∘2 3.96 kPa (normal 4.6–6.0 kPa) breathing room air. Her AaPa∘2 was 7.8 kPa (predicted agecorrected AaPa∘2 2.10 kPa). Pa∘2 increased to 69.8 kPa breathing 100% inspired oxygen delivered using continuous positive airway pressure. Her calculated intrapulmonary shunt fraction was 7% (normal <5%). Pulmonary function tests showed normal spirometry and preserved lung volumes, however, carbon monoxide diffusing capacity was only 38% predicted, adjusted for haemoglobin 17.8 g/dl.
Transthoracic echocardiography demonstrated normal structure and function of all cardiac chambers. Contrast echocardiography established the presence of intrapulmonary shunting (Figure 1) and confirmed the diagnosis of hepatopulmonary syndrome. She was established on long-term oxygen therapy and is currently under consideration for a liver transplant.
Publication information
¨Cannon J, Usmani OS, Chambers J, Thompson RP, Twort CH. Intrapulmonary shunting and hepatopulmonary syndrome. Hosp Med. 66:312-313, 2005.