Department of Pediatrics and Nuclear Medicine, Cairo University, Cairo, Egypt.
Eur J Gastroenterol Hepatol. 2010 Aug;22(8):1006-12. doi: 10.1097/MEG.0b013e328336562e.
The hepatopulmonary syndrome (HPS) is a triad of advanced chronic liver disease (CLD), arterial hypoxemia and intrapulmonary arteriovenous shunting in the absence of a primary cardiopulmonary disease. HPS has been more frequently reported in adults than in children with no data on its prevalence in children with CLD. The aim of this study was to detect the prevalence of the HPS in a cohort of children with CLD because of chronic hepatitis B and/or C virus infection, schistosomiasis as well as inborn metabolic errors. We also aimed to evaluate the role of Technetium labeled macroaggregated albumin (Tc--MAA) perfusion lung scan versus contrast enhanced echocardiography (CEE) with intravenous injection of agitated saline in the diagnosis and quantification of intrapulmonary shunts and their relationship to important clinical and laboratory findings.
Forty Egyptian children (22 males) were investigated. Their ages ranged from 5 to 12 years (with a mean of 9.5 years). Twenty individuals proved to have cirrhosis.
Blood gas determination revealed more significant arterial hypoxemia in cirrhotics than noncirrhotics both under room air and after breathing 100% oxygen for 15 mins. CEE showed comparable cardiac measurements in cirrhotic and noncirrhotic patients, and diagnosed intrapulmonary shunts in three hypoxemic cirrhotic patients; whereas Tc--MAAperfusion lung scan diagnosed shunts in seven patients (five of them cirrhotic). The presence of shunts was significantly correlated with the duration of CLD, clinical findings, presence of cirrhosis and porto-systemic collaterals. We calculated for each patient a shunt index (SI) by the formula: (activity outside thorax/activity outside plus inside thorax) 100; and an SI value of 0.278 was found to be a cutoff value for shunt detection. All patients with SI above this value had shunting associated with hypoxemia and all patients with SI below this value had no hypoxemia (specificity 100%).
Arterial hypoxemia and intrapulmonary shunts were diagnosed in 17.5% of this cohort of children with cirrhotic or noncirrhotic CLD representing the classic HPS. Tc--MAA perfusion lung scan was more sensitive than CEE in detection of intrapulmonary shunts. SI cutoff value of 0.278 was found to be highly specific for shunt detection and we recommend its validation in further studies.
肝肺综合征（HPS）是一种在没有原发性心肺疾病的情况下，由慢性肝脏疾病（CLD）、动脉低氧血症和肺内动静脉分流组成的三联征。HPS 在成人中比在儿童中更为常见，但在患有慢性乙型肝炎和/或丙型肝炎病毒感染、血吸虫病以及先天性代谢错误的儿童中，尚无其患病率的数据。本研究的目的是检测因慢性乙型肝炎和/或丙型肝炎病毒感染、血吸虫病以及先天性代谢错误而导致 CLD 的患儿中 HPS 的患病率。我们还旨在评估锝标记的巨聚合白蛋白（Tc--MAA）灌注肺扫描与静脉注射搅动盐水的对比增强超声心动图（CEE）在诊断和量化肺内分流及其与重要临床和实验室发现的关系方面的作用。
共调查了 40 名埃及儿童（22 名男性）。他们的年龄在 5 至 12 岁之间（平均年龄为 9.5 岁）。20 名患儿被证实患有肝硬化。
血气测定显示，在吸入空气和 15 分钟 100%氧气后，肝硬化患儿的动脉低氧血症比非肝硬化患儿更为显著。CEE 显示肝硬化和非肝硬化患者的心脏测量值相当，并在 3 名低氧血症性肝硬化患儿中诊断出肺内分流；而 Tc--MAA 灌注肺扫描在 7 名患者（其中 5 名肝硬化）中诊断出分流。分流的存在与 CLD 的持续时间、临床发现、肝硬化和门体侧支循环的存在显著相关。我们通过公式为每位患者计算分流指数（SI）：（胸腔外的活性/胸腔外加胸腔内的活性）100；发现 SI 值为 0.278 是分流检测的截断值。所有 SI 值高于该值的患者均有与低氧血症相关的分流，所有 SI 值低于该值的患者均无低氧血症（特异性 100%）。
在患有肝硬化或非肝硬化 CLD 的患儿中，有 17.5%的患儿出现动脉低氧血症和肺内分流，这代表了经典的 HPS。Tc--MAA 灌注肺扫描在检测肺内分流方面比 CEE 更敏感。SI 截断值为 0.278 对分流检测具有高度特异性，我们建议在进一步的研究中验证该值。
