tolerance Individual variation exists such that some children with an appendiceal abscess will appear to have minimal pain, whereas other children with a functional etiology of their abdominal pain will appear quite distressed A number of illnesses that present with abdominal pain including conditions such as tonsillitis with high fever, viral syndromes, and streptococcal pharyngitis cannot be readily explained neurophysiologically as the triggers of abdominal pain Despite the appearance of localized abdominal pain, clinicians need to perform a thorough physical examination that should include the assessment of the oropharynx, lung, skin, and genitourinary system The principal causes of abdominal pain in children and adolescents are summarized in Table 53.1 Table 53.2 highlights the life-threatening disorders DIFFERENTIAL DIAGNOSIS Intra-abdominal injuries can be life-threatening (such as hemorrhage from solid organ laceration or fluid loss and infection from perforated hollow viscus) and rarely may occur after minor trauma An accurate history may not always be provided and, thus, clinicians must specifically inquire about a history of trauma in a child presenting with acute abdominal pain Typical mechanisms include motor vehicle crashes, falls, and child abuse (see Chapter 103 Abdominal Trauma ) Bowel obstruction may occur as a result of adhesions in a child with previous abdominal surgery Malrotation with volvulus, and necrotizing enterocolitis, should be considered in neonates with bilious emesis Intussusception typically occurs among children months to years of age Colicky abdominal pain is a typical feature of intussusception The presence of blood in the stool, or “currant jelly stool,” is a relatively late finding among children with intussusception Among children of all ages, appendicitis can cause peritoneal irritation and focal tenderness It occurs most commonly in children older than years The classic history of diffuse abdominal pain that later migrates to the right lower abdomen is not always elicited The diagnosis of appendicitis in younger children can be more difficult and is often made later in the course of disease; as such, the rate of perforation in younger children is higher (see Chapter 116 Abdominal Emergencies for further information) Primary bacterial peritonitis is an uncommon cause of abdominal pain among children, but should be considered among children with nephrotic syndrome or liver failure Common conditions that are associated with acute abdominal pain include viral gastroenteritis, systemic viral illness, streptococcal pharyngitis, lobar pneumonia, and UTIs Frequent causes of chronic or recurrent abdominal pain include colic