Segura Rosa M
Hospital Universitari Vall d'Hebron, Barcelona, Spain.
Paediatr Respir Rev. 2004;5 Suppl A:S205-12. doi: 10.1016/s1526-0542(04)90039-5.
In a patient with an undiagnosed pleural effusion, the first question to answer is whether the fluid is an exudate or a transudate. This is usually determined by means of Light's criteria, which differentiate transudative effusions from exudative effusions by measuring the levels of total protein and lactate dehydrogenase in the pleural fluid (PF) and serum. In patients under diuretic treatment, Light's criteria misclassify transudates as exudates, but the serum to pleural fluid albumin gradient usually remains above 12 g/L. When tests are done only in PF, protein concentration >30 g/L performs at least as well as the other individual markers. To diagnose tuberculous pleuritis among exudates, PF adenosine deaminase and PF interferon-g exhibit high diagnostic accuracy. When malignancy is suspected the addition of tumour markers to the results of cytologic analysis increases the rate of detection. Other biochemical markers are useful in specific circumstances involving pleural effusion, such as amylase in effusions due to pancreatitis, or oesophageal rupture, and triglycerides in chylothorax. Several PF markers are associated with complicated parapneumonic effusion - e.g. low PF pH and glucose, and high PF LDH activity -- although PF pH appears to be the best biochemical aid in decisions regarding chest tube drainage. Recent reports suggest that neutrophil-derived enzymes (polymorphonuclear elastase and myeloperoxidase) can be useful as early indicators of the need of chest tube insertion; however these findings must be confirmed in large series. This review discusses the clinical usefulness of biochemical markers in the diagnosis and management of pleural effusions. The vast majority of prospective studies in this field have been conducted in adults and, although the mechanisms of pleural effusion production do not differ in children and adults, the prevalence of each etiologic cause does. Therefore it seems advisable to confirm or recalculate the predictive values of each marker in the paediatric population.
对于患有未确诊胸腔积液的患者，首先要回答的问题是积液是渗出液还是漏出液。这通常通过利氏标准来确定，该标准通过测量胸腔积液（PF）和血清中的总蛋白及乳酸脱氢酶水平，将漏出性胸腔积液与渗出性胸腔积液区分开来。在接受利尿剂治疗的患者中，利氏标准会将漏出液误分类为渗出液，但血清与胸腔积液白蛋白梯度通常仍高于12g/L。当仅对胸腔积液进行检测时，蛋白浓度>30g/L的诊断效果至少与其他单项指标相当。在渗出液中诊断结核性胸膜炎时，胸腔积液腺苷脱氨酶和胸腔积液干扰素-γ具有较高的诊断准确性。当怀疑为恶性肿瘤时，在细胞学分析结果中加入肿瘤标志物可提高检出率。其他生化标志物在涉及胸腔积液的特定情况下有用，例如胰腺炎或食管破裂所致胸腔积液中的淀粉酶，以及乳糜胸中的甘油三酯。几种胸腔积液标志物与复杂性类肺炎性胸腔积液相关——例如低胸腔积液pH值和葡萄糖，以及高胸腔积液乳酸脱氢酶活性——尽管胸腔积液pH值似乎是决定是否进行胸腔置管引流的最佳生化辅助指标。最近的报告表明，中性粒细胞衍生酶（多形核弹性蛋白酶和髓过氧化物酶）可作为胸腔置管需求的早期指标；然而，这些发现必须在大量病例中得到证实。本综述讨论了生化标志物在胸腔积液诊断和管理中的临床应用。该领域的绝大多数前瞻性研究是在成人中进行的，尽管儿童和成人胸腔积液产生的机制并无差异，但每种病因的患病率有所不同。因此，似乎有必要在儿科人群中确认或重新计算每种标志物的预测值。
