Acute appendicitis in neonates: complication or morbus sui generis?

Abstract

Neonatal appendicitis (NA) is very rare and is associated with a very high perforation rate. Three cases treated at our hospital since 1969 are presented. All of them had a perforated appendix; two represented a complication of an underlying disease, i.e., Hirschsprung's disease and cystic fibrosis, respectively. These diseases should always be ruled out actively in cases of NA. If an underlying disease is not found, NA might be an isolated form of necrotizing enterocolitis limited to the appendix. Histology cannot distinguish between a simple appendicitis and a localized form of NEC, so NA must be regarded as a complication of an underlying disease as well as a morbus sui generis.

Neonatal Perforated Appendicitis Attributed to Localized Necrotizing Enterocolitis of the Appendix: A Review

“…The rarity of neonatal appendicitis has been attributed to various protective features of the neonatal caecal appendage including a funnel-shaped anatomy, infrequency of lymphadenitis-causing infections, as well as soft diet, and recumbent posture [4,5,7]. These characteristics are thought to render REVIEW ARTICLE the neonatal appendix less prone to intraluminal obstruction than their older counterparts [4,5,7].…”

“…These characteristics are thought to render REVIEW ARTICLE the neonatal appendix less prone to intraluminal obstruction than their older counterparts [4,5,7]. Three etiological theories of neonatal appendicitis exist and are supported by the incidence of associated conditions [4]: impaired immunity such as prematurity (arguing it as a variant of NEC) [7,9,[10][11][12]; vascular insufficiency and hypoxemia (cases associated with cardiorespiratory failure) [9,13]; and finally, intestinal obstruction such as Hirschsprung's disease or strangulated Amyand's hernia [7,14,15]. Interestingly, cases attributed to inguinal hernia have better outcomes due to discrete physical findings and early surgical exploration [2,5,14].…”

“…Predisposing factors include respiratory distress, congenital heart disease, low birth weight, IUGR, formula feeding, and intestinal dysbiosis, among others [10,16]. While fulminant NEC usually involves the colon and/or small bowel globally, perforated appendicitis may be the result of NEC confined, at least initially, to the appendix [7,[9][10][11][12]. This NEC appendicopathy may be either a local pathology or part of a more diffuse disease process [6,17].…”

“…This condition is fatal in approximately a quarter of cases, which can be attributed to its predilection in preterm infants, diagnostic delay, high rate of appendicular perforation, and associated comorbidities [2][3][4]. The causative etiology remains uncertain, and may not be related to intraluminal obstruction as in older patients [4][5][6][7]. NEC is a commonly encountered gastrointestinal emergency in the neonatal intensive care unit (NICU) with a reported incidence of 1-7.7% admissions [8].…”

“…NEC is a commonly encountered gastrointestinal emergency in the neonatal intensive care unit (NICU) with a reported incidence of 1-7.7% admissions [8]. Neonatal perforated appendicitis (NPA) is uncommon and increasingly being recognized as a localized form of NEC involving the appendix [4,7,9,10]. Notably, NEC is the most common preoperative misdiagnosis for NPA confirmed intra-operatively [8].…”