Editorial Comment on: D. Schreiber-Dietrich, M. Pohl, X.W. Cui, B. Braden, C.F. Dietrich, L. Chiorean Perihepatic lymphadenopathy in children with chronic viral hepatitis

Abstract

The article entitled Perihepatic lymphadenopathy in children with chronic viral hepatitis(1) is an original paper of high clinical relevance – viral hepatitis B and C are the main causes of chronic hepatitis and liver cirrhosis in children. Based on ultrasound findings, the authors assessed the presence of the perihepatic lymph nodes and their morphology in 49 children with chronic viral hepatitis B and C (38 and 11 children, respectively). The authors hoped that this investigation would help establish a new, non-invasive marker enabling screening examinations to be conducted in children with chronic viral hepatitis. In adults, a correlation was found between the activity of hepatitis and the morphology of the lymph nodes in a US examination, but such a correlation has, until now, not been reported in children(2–4). The results of the study have a clinically significant aspect – the loops of the hepatoduodenal ligament are relatively readily available in a transabdominal examination, and ultrasonography is an inexpensive and safe method to be conducted in children. The authors assumed that the lymph nodes with the size of over 14 mm in the long axis were pathologically enlarged. In a US examination, such nodes were visualized in 70% of children with viral hepatitis and in 11% of healthy children. Based on the studies conducted, it was concluded that the general volume of the perihepatic lymph nodes is greater in children with chronic hepatitis in a statistically significant way (p < 0.05), compared to healthy children: 1.0 ± 1.2 mL (0.1–5.4 mL) vs 0.1 ± 0.1 mL (0.0–0.4 mL). Ultrasonography demonstrated a moderate level of sensitivity (70%) and NPV (75%), and considerable specificity (89%) and PPV (86%) in detecting enlarged perihepatic lymph nodes in children with chronic viral hepatitis. Enlarged lymph nodes of the hepatoduodenal ligament were present in patients with both chronic hepatitis B and C. There were no significant differences in the sensitivity and specificity levels of ultrasonography between the two types of hepatitis (hepatitis B: sensitivity 69%, specificity 89%; hepatitis C: sensitivity 70%, specificity 89%), but the method was characterized by superior accuracy in confirming hepatitis B (PPV 83%) compared to hepatitis C (PPV merely 58%). However, ruling out chronic viral hepatitis based on US findings was much more accurate in children with hepatitis C than in children with hepatitis B (NPV 93% vs 79%). The article summarized above is a very good example of research methodology, particularly for young scientists. The design is exemplary: the study is prospective, randomized; the inclusion and exclusion criteria are clearly specified. The methods involve the principles of so-called good clinical practice. The accurate assessment of the repeatability of size and volume measurements in a US examination must be emphasized. The evidence for a high repeatability of the measurements is an additional argument for including the perihepatic lymph node assessment into everyday clinical practice involving the treatment of children with chronic viral hepatitis B and C. In the Discussion, the authors prove how innovative their results are and indicate the path for further research – the possibility of monitoring the therapy of chronic viral hepatitis using size measurements of the perihepatic lymph nodes. Moreover, the authors also mention other methods enabling perihepatic lymph node imaging, such as CT and MRI. However, the argument concerning limited possibilities of the lymph node reconstruction in the age of multi-slice CT seems unconvincing. Furthermore, the methods of conducting US examinations applied by the authors seem lacking: the authors used a 3.5 MHz transducer in all patients irrespective of their age (1–17). Yet our experience and literature guidelines suggest that probes of higher frequency should be used for the assessment of visceral lymph nodes in younger children. The results of the measurements of the size and volume of the perihepatic lymph nodes in children with chronic viral hepatitis also raise questions regarding their accurate assessment (configuration of the hilum, blood supply and direction of flow) as well as a possible relationship of these features with the activity of the disease. Further investigations should continue the issues started in this article.