Intussusception. A case that suggests a new cardinal symptom--lethargy.

Intussusception is an uncommon condition, but it is the most frequent cause of bowel obstruction in infants and children aged 3 months to 5 years. If undiagnosed, it can result in bowel necrosis, perforation, and even death. Four cardinal signs and symptoms (abdominal pain, rectal bleeding, vomiting, and abdominal mass) are described in patients with intussusception, but these manifestations are not always present and their absence may lead to misdiagnosis. Lethargy might be considered a fifth cardinal symptom. As demonstrated in this case, lethargy may be a significant presenting feature in an infant with no history of abdominal pain, and in association with the other cardinal symptoms, it may be an early indication of a significant illness such as intussusception. Awareness of this association may result in an earlier diagnosis and an improved outcome in patients with intussusception.