ORIGINAL RESEARCH
Sonographic Distinction Between Acute Suppurative Appendicitis and Viral Appendiceal Lymphoid Hyperplasia (‘‘Pink Appendix’’) With Pathological Correlation Alison D. Sheridan, MD,* Lauren Ehrlich, MD,* Raffaella A. Morotti, MD,Þ and T. Robin Goodman, MD* Abstract: The viral etiology of mesenteric lymphadenitis may also affect the lymphoid tissue of the appendix in children giving rise to symptomatic appendiceal lymphoid hyperplasia, the so-called ‘‘pink appendix.’’ The present study used ultrasound (US) to determine if certain sonographic features correlated with appendiceal pathological findings. Our results indicate that a fluid-filled appendix always correlates with a suppurative or mixed pathological appearance that likely merits surgery. A lymphoid predominant pathological appearance occurred only in cases where appendiceal wall thickening alone was seen on US. This pilot project therefore shows that US has the potential to stratify acute appendix patients into different treatment regimens, given that lymphoid hyperplasia could be treated conservatively. Further studies correlating other clinicoradiological parameters with this sonographic appearance are warranted. Key Words: appendix, ultrasound, lymphoid hyperplasia (Ultrasound Quarterly 2015;31:95Y98)
A
cute appendicitis (AA) is a common problem worldwide, and approximately 60,000 to 80,000 pediatric cases are diagnosed every year in the United States.1 Classically, patients present with early periumbilical pain that migrates to the right lower quadrant, accompanied by nausea, vomiting, and signs of peritoneal irritation.2 Laboratory values can aid in the clinical diagnosis, including leukocytosis with neutrophilia and elevated inflammatory markers.3 Unfortunately, the classic clinical pattern is neither sensitive nor specific and may be absent in up to half of children.2,4 Diagnosis of AA is increasingly being established on the basis of ultrasound (US) findings, with cross-sectional imaging used particularly in patients with equivocal physical examination and laboratory findings. While cross-sectional imaging allows for relative operator independence and potentially higher accuracy,5,6 the major advantages of US include lack of ionizing radiation exposure, decreased need for sedation, portability, and lower cost.7,8 Given the increasing awareness of computed tomography as a source for ionizing radiation exposure in
children,9 US-based findings need to provide as much diagnostic information as possible in the pediatric population. The pathophysiology of acute suppurative appendicitis is thought to be the result of secondary bacterial infection after luminal obstruction, most commonly secondary to local lymphoid hyperplasia or a fecalith that results in vascular compromise and ischemia.10 However, another frequently encountered cause of right lower quadrant pain in children is mesenteric lymphadenitis where inflammation of lymphoid tissue within the mesentery takes place. Although mesenteric lymphadenitis has been described with a variety of pathogens, in pediatric practice an adenoviral etiology is the commonest explanation.11 Sonographic findings in mesenteric adenitis are nonspecific but include multiple lymph nodes containing enlarged lymphoid tissue.12 We postulate that this virally induced lymphoid hyperplasia may also affect the lymphoid tissue within the wall of the appendix (the so-called ‘‘pink appendix’’), and as such, a distinct sonographic appearance can be recognized. This appearance would include hypertrophy of the prominent lymphoid tissue within the appendiceal wall, giving rise to an appendix that is enlarged secondary to wall thickening (WT) rather than luminal obstruction. In these cases, the mucosal stripe would be intact. Other sonographic appendiceal inflammatory features (eg, compressibility, vascularity, and periappendiceal inflammation) would be unaffected. As such, in this study, we describe 2 distinct morphologic appearances on graded compression US in cases that presented with AA: (1) an appendix with an intact mucosal stripe and WT and (2) an appendix with a fluid-filled lumen (FFL). We hypothesize that patients presenting with WT represent lymphoid hyperplasia (pink appendix), whereas patients with an FFL represent cases of suppurative appendicitis. To this end, 2 cohorts of surgical appendectomy cases that had representative imaging findings of either FFL or WT were selected to assess for potential clinical, laboratory, and pathological differences.
MATERIALS AND METHODS Received for publication November 11, 2014; accepted January 19, 2015. Departments of *Radiology and †Pathology, Yale University School of Medicine, New Haven, CT. The authors declare no conflict of interest. Reprints: T. Robin Goodman, MD, Department of Diagnostic Radiology, PO Box 208042, New Haven, CT 06520 (e
Sonographic Distinction Between Acute Suppurative Appendicitis and Viral Appendiceal Lymphoid Hyperplasia (‘‘Pink Appendix’’) With Pathological Correlation Alison D. Sheridan, MD,* Lauren Ehrlich, MD,* Raffaella A. Morotti, MD,Þ and T. Robin Goodman, MD* Abstract: The viral etiology of mesenteric lymphadenitis may also affect the lymphoid tissue of the appendix in children giving rise to symptomatic appendiceal lymphoid hyperplasia, the so-called ‘‘pink appendix.’’ The present study used ultrasound (US) to determine if certain sonographic features correlated with appendiceal pathological findings. Our results indicate that a fluid-filled appendix always correlates with a suppurative or mixed pathological appearance that likely merits surgery. A lymphoid predominant pathological appearance occurred only in cases where appendiceal wall thickening alone was seen on US. This pilot project therefore shows that US has the potential to stratify acute appendix patients into different treatment regimens, given that lymphoid hyperplasia could be treated conservatively. Further studies correlating other clinicoradiological parameters with this sonographic appearance are warranted. Key Words: appendix, ultrasound, lymphoid hyperplasia (Ultrasound Quarterly 2015;31:95Y98)
A
cute appendicitis (AA) is a common problem worldwide, and approximately 60,000 to 80,000 pediatric cases are diagnosed every year in the United States.1 Classically, patients present with early periumbilical pain that migrates to the right lower quadrant, accompanied by nausea, vomiting, and signs of peritoneal irritation.2 Laboratory values can aid in the clinical diagnosis, including leukocytosis with neutrophilia and elevated inflammatory markers.3 Unfortunately, the classic clinical pattern is neither sensitive nor specific and may be absent in up to half of children.2,4 Diagnosis of AA is increasingly being established on the basis of ultrasound (US) findings, with cross-sectional imaging used particularly in patients with equivocal physical examination and laboratory findings. While cross-sectional imaging allows for relative operator independence and potentially higher accuracy,5,6 the major advantages of US include lack of ionizing radiation exposure, decreased need for sedation, portability, and lower cost.7,8 Given the increasing awareness of computed tomography as a source for ionizing radiation exposure in
children,9 US-based findings need to provide as much diagnostic information as possible in the pediatric population. The pathophysiology of acute suppurative appendicitis is thought to be the result of secondary bacterial infection after luminal obstruction, most commonly secondary to local lymphoid hyperplasia or a fecalith that results in vascular compromise and ischemia.10 However, another frequently encountered cause of right lower quadrant pain in children is mesenteric lymphadenitis where inflammation of lymphoid tissue within the mesentery takes place. Although mesenteric lymphadenitis has been described with a variety of pathogens, in pediatric practice an adenoviral etiology is the commonest explanation.11 Sonographic findings in mesenteric adenitis are nonspecific but include multiple lymph nodes containing enlarged lymphoid tissue.12 We postulate that this virally induced lymphoid hyperplasia may also affect the lymphoid tissue within the wall of the appendix (the so-called ‘‘pink appendix’’), and as such, a distinct sonographic appearance can be recognized. This appearance would include hypertrophy of the prominent lymphoid tissue within the appendiceal wall, giving rise to an appendix that is enlarged secondary to wall thickening (WT) rather than luminal obstruction. In these cases, the mucosal stripe would be intact. Other sonographic appendiceal inflammatory features (eg, compressibility, vascularity, and periappendiceal inflammation) would be unaffected. As such, in this study, we describe 2 distinct morphologic appearances on graded compression US in cases that presented with AA: (1) an appendix with an intact mucosal stripe and WT and (2) an appendix with a fluid-filled lumen (FFL). We hypothesize that patients presenting with WT represent lymphoid hyperplasia (pink appendix), whereas patients with an FFL represent cases of suppurative appendicitis. To this end, 2 cohorts of surgical appendectomy cases that had representative imaging findings of either FFL or WT were selected to assess for potential clinical, laboratory, and pathological differences.
MATERIALS AND METHODS Received for publication November 11, 2014; accepted January 19, 2015. Departments of *Radiology and †Pathology, Yale University School of Medicine, New Haven, CT. The authors declare no conflict of interest. Reprints: T. Robin Goodman, MD, Department of Diagnostic Radiology, PO Box 208042, New Haven, CT 06520 (e
