内镜对嗜酸细胞性食管炎的诊断价值不足

北卡罗来纳大学食管疾病与吞咽中心的Hannah P. Kim及其同事在9月刊《临床胃肠病学与肝病学》杂志上发表文章称，仅凭内镜检查中的发现既不足以诊断嗜酸细胞性食管炎(EoE)，也不能断定是否应进行活检(Clin. Gastroenterol. Hepatol. 2012 [doi:10.1016/j.cgh.2012.04.019])。

Kim等人对PubMed 、EMBASE和消化会议中的80篇文章和20篇摘要进行了Meta分析，共涉及4,678例EoE患者和2,742名非EoE的对照者。所有入选的研究均纳入至少10例EoE患者，并且能提供相关内镜检查结果的信息。各项研究受试者的平均年龄为6~55岁不等。

作者在分析中发现，总体样本中的食管环流行率为44%，食管狭窄流行率为21%，线状沟流行率为48%。观察发现食管内径狭窄的汇总流行率仅为9%，食管白斑或渗出的流行率为27%。41%的患者在内镜下肉眼观察到苍白或血管减少，17%观察到侵蚀性食管炎。“17%的病例内镜检查结果正常。”

作者还发现，上述内镜下表现的流行情况因患者年龄而不同。例如，食管环和食管狭窄在成人中比在儿童中更多见(分别为57% vs. 11%和25% vs. 8%；均P＜0.05)。而白斑和苍白/血管减少在儿童中比在成人中更常见(分别为36% vs. 19%和58% vs. 18%；均P＜0.05)。

作者还评估了每种内镜下表现的总体敏感性、特异性、汇总阳性预测值(PPV)和阴性预测值(NPV)。结果显示，食管环的这4项指标分别为48%、91%、64%和84%；食管狭窄分别为15%、95%、51%和76%；“线状沟的操作特征略好一些”，分别为40%、95%、73%和83%；苍白和(或)血管减少分别为43%、90%、65%和79%。与单项内镜下表现敏感性低不同的是，如果有1项以上的内镜下异常发现，敏感性增至87%，特异性为47，PPV和NPV分别为42%和89%。

 “尽管食管环、线状沟、白斑或渗出等内镜下表现被认为是EoE的典型特征，但内镜医师并不是总能识别出这些表现。而且尽管上消化道内镜检查在绝大多数EoE患者中都能有所发现，但单项表现的敏感性较低，即使特异性较高，最后得到的预测值仍不足以达到诊断目的。因此，不论内镜下有无特殊发现，凡是有EoE症状的患者均应接受食管活检。”

作者称该研究获得了国立卫生研究院和Doris Duke慈善基金会的资金支持。作者自己无利益冲突披露。

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By: DENISE NAPOLI, Internal Medicine News Digital Network

Endoscopic findings alone are not sufficient to diagnose eosinophilic esophagitis and instead, biopsies are needed, reported Ms. Hannah P. Kim and her colleagues in the September issue of Clinical Gastroenterology and Hepatology.

Indeed, while findings like rings, strictures, and linear furrows ought to raise suspicion, a meta-analysis of more than 4,600 patients confirms that "low sensitivity and variable predictive values make them inadequate both for the diagnosis of EoE [eosinophilic esophagitis] and for the decision of whether or not to obtain biopsies."

Ms. Kim of the Center for Esophageal Diseases and Swallowing at the University of North Carolina, Chapel Hill, and her colleagues analyzed data from 80 articles and 20 abstracts that included a total of 4,678 patients with EoE and 2,742 patients without, who served as controls.

The studies were culled from PubMed, EMBASE, and gastroenterology meetings. All studies included in the analysis had more than 10 patients with EoE and provided information on the associated endoscopic findings. The mean age of participants ranged from 6 years to 55 years in the different studies.

In an analysis, the authors found that the overall pooled prevalence of esophageal rings in the sample was 44%. For strictures, the prevalence was 21%, and for linear furrows, 48% (Clin. Gastroenterol. Hepatol. 2012 [doi:10.1016/j.cgh.2012.04.019]).

Narrow-caliber esophagus findings had a pooled prevalence of only 9% of the total sample, while the presence of white plaques or exudates was 27%. Visible pallor or decreased vasculature on endoscopy was seen in 41% of patients, and erosive esophagitis in 17%.

"The endoscopic examination was normal in 17% of cases," added the authors.

They also found a difference in prevalence according to age of patients. For example, rings and strictures were more prevalent in adults (57% and 25%, respectively) than in children (11% and 8%; P less than .05 for each).

"On the other hand, white plaques and pallor or decreased vasculature were more prevalent in children (36% and 58%) than in adults (19% and 18%; P less than .05 for each)."

Finally, Ms. Kim and her associates assessed the overall sensitivity, specificity, pooled positive predictive value (PPV), and pooled negative predictive value (NPV) for each of the assessed endoscopic characteristics.

For rings, the overall sensitivity was 48%, the specificity was 91%, the PPV was 64%, and NPV was 84%. Strictures had an overall sensitivity of 15%, specificity of 95%, PPV of 51%, and NPV of 76%.

"The operating characteristics were slightly higher for linear furrows, with a sensitivity of 40%, specificity 95%, PPV 73%, and NPV 83%," wrote the authors.

And for the endoscopic finding of pallor and/or decreased vasculature, sensitivity was 43%, specificity 90%, PPV 65%, and NPV 79%.

"In contrast to the low sensitivity of individual endoscopic findings, when examining the presence of at least one endoscopic finding, an abnormal endoscopy had a sensitivity of 87%, specificity of 47%, PPV of 42%, and NPV of 89%," the authors added.

"Although endoscopic features of EoE such as esophageal rings, linear furrows, and white plaques or exudates are often considered to be typical features of EoE, these are not always identified by endoscopists," wrote the researchers.

And while most patients with EoE have abnormal findings on upper endoscopy examinations, "the sensitivity values of individual endoscopic findings were modest, and although the specificity values were higher, the predictive values were inadequate for diagnostic purposes."

"Esophageal biopsies should be obtained from all patients who present with symptoms of EoE, regardless of the endoscopic appearance of the esophagus."

The authors stated that the study was supported by grants from the National Institutes of Health and the Doris Duke Charitable Foundation. They stated that they had no individual disclosures.