Chronic abdominal pain in children is defined as any type of pain localized to the abdomen of at least 2 months’ duration that limits normal activity.1 It is one of the most common presenting complaints to pediatricians. Up to 24% of elementary and middle school students and 17% of high school students experience persistent weekly abdominal pain.1,2 Chronic abdominal pain accounts for approximately 4% of pediatric office visits.1 Most children with chronic abdominal pain have functional abdominal pain disorders, characterized by pain with or without other gastrointestinal symptoms that is not attributable to another medical condition. Of remaining patients with an identifiable medical condition, their pain is likely the result of inflammation with or without infection, anatomic problem (e.g., choledochal cyst, recurrent volvulus), gastrointestinal motility disorder, metabolic disorder, late effect of trauma, or a neoplastic process involving a lower thoracic or abdominal organ. This chapter focuses on identifying, evaluating and treating conditions causing chronic abdominal pain, with emphasis on those causes related to infectious diseases.
Although the differential diagnosis of chronic abdominal pain is broad, localization and associated additional symptoms offer a framework for approaching the diagnosis. Because pain fibers that innervate the peritoneum, diaphragm, and abdominal wall travel in spinal nerves, pain signals from those areas, including those caused by inflammation of those structures due to adjacent-organ inflammation, often localize to isolated areas of the abdomen. However, pain afferents from the esophagus, stomach, and intestine converge via perivascular, sympathetic, and parasympathetic nerve plexi and the vagus nerve, resulting in less focused localization with some overlap. Visceral pain arising from intra-abdominal organs is also more likely to be associated with autonomic symptoms (e.g., pallor, sweating) and strong affective symptoms.3 Therefore, localization of pain can hone the differential to disorders arising from structures in the vicinity of the pain, and alternatively to disorders associated with poor localization. Functional abdominal pain disorders most frequently localize poorly with generalized or periumbilical pain. Functional dyspepsia pain is typically epigastric or localizes to the right upper quadrant, and irritable bowel syndrome frequently localizes to the lower abdomen. Once localization has narrowed the focus, other symptoms such as vomiting, diarrhea, hematochezia, fever, jaundice can guide evaluation to identify infectious and noninfectious causes.
Pain emanating from the right upper quadrant (RUQ) usually originates from the liver and/or biliary tree. Occasionally, RUQ pain is caused by diseases of the stomach, duodenum, or colon (Figure 11-1). Phrenic pain may also present as right upper quadrant pain.
Differential diagnosis of chronic abdominal pain. Letters W, J, and F refer to accompanying symptoms.
Pain originating from the liver occurs when the liver capsule is stretched, since the capsule is the only ...