Bedside ultrasound for diagnosis of appendicitis in preterm infants

Objective To investigate the sonographic features of appendicitis in preterm infants. Methods A total of 28 cases of premature infants with acute appendicitis diagnosed by bedside abdominal ultrasound in the First Hospital of Jilin University from November 2012 to January 2019 were recruited. Basic clinical information, abdominal ultrasound images, surgical results, management and outcomes were collected and analyzed. Descriptive statistical methods were used for data analysis. Results Among the 28 cases, 21 (75.0%) were males and seven (25.0%) were females. All of them were diagnosed as having acute appendicitis with perforation according to the bedside ultrasound. Five (17.8%) presented direct signs of appendicitis, i.e. partial structure of the appendix and perforation site. The other 23 (82.2%) showed indirect signs, including heterogeneous echotexture or hypoechoic patterns between the liver and right kidney in six cases, heterogeneously hypoechoic areas between the bowels in the right lower abdomen in seven cases, and dissociative effusion between the bowels in the right lower abdomen with poor sound transmission and disorder of surrounding intestinal structure in ten cases. Twenty-one out of the 28 cases (75.0%) exhibited bowel wall thickening at right lower abdomen, absence of intestinal peristalsis and effusion echoes between the intestines with poor sound transmission. Emergent surgeries were performed and diagnoses of appendicitis with perforation were confirmed. All the 21 cases were discharged after full recovery. Seven cases (25.0%) showed confined cystic images and received conservative treatment. One of them developed adhesive intestinal obstruction during follow-ups and underwent surgical treatment, during which local formations of wrapping after appendiceal perforation and obstruction due to surrounding intestinal adhesion were observed. The other six cases recovered after conservative management with gradually reduced peritoneal effusion, normal omental echo patterns and improved inflammatory indicators and abdominal symptoms, and no ileus occurred during follow-ups after discharge. Conclusions Symptoms of appendicitis in preterm infants are non-specific, and perforation is more likely to be seen. Bedside ultrasonography mainly shows indirect signs of appendicitis, and direct signs in some infants. Bedside ultrasound can be an essential tool for the diagnosis of these conditions with high accuracy. Key words: Appendicitis; Point-of-care testing; Ultrasonography; Infant, premature