What is intussusception and what are its classic signs?

Intussusception is a medical emergency where one segment of intestine telescopes into an adjacent segment, causing obstruction, inflammation, and potential necrosis. It is the most common cause of intestinal obstruction in children aged 3 months to 6 years. Classic signs include sudden intermittent episodes of severe colicky abdominal pain causing the child to draw up the knees and cry inconsolably, followed by periods of calm. "Currant jelly" stools containing blood and mucus are a late sign. A sausage-shaped abdominal mass may be palpable. Diagnosis is confirmed by ultrasound. ---