+++
SURGICAL AND GENITOURINARY*
++++
*The authors acknowledge the special contributions of Jennifer H. Chao, MD, and Andrea Marmor, MD, to the prior edition.
++
Intussusception occurs when the proximal portion of the intestine invaginates into the distal portion, causing abdominal pain, bowel injury, and eventually bowel obstruction. Early in the process, lymphatic return is impeded; then, as the edema and pressure increase, venous followed by arterial flow becomes compromised, leading to infarction of the entrapped bowel segment. Intussusception usually occurs between the ages of 3 months to 3 years, with a peak in infants <1 year old. In children <3 years old, it is generally idiopathic and possibly due to prominent lymphoid tissue in the intestine serving as a lead point. The majority of intussusceptions are ileocolic, although they may present anywhere along the lower gastrointestinal (GI) tract. In older patients, lead points include Meckel diverticula, polyps, tumors (lymphomas or hemangiomas) or intramural edema, and hematomas from Henoch-Schönlein purpura. Sites other than ileocolic are also associated with underlying pathology.
++++++++
Patients typically present with a sudden onset of severe, colicky abdominal pain at regular intervals, vomiting (initially nonbilious, but may progress to bilious), and bloody stool (“currant jelly”—with mucus and gross or occult blood). Patients often curl up to guard ...