Intussusception is a medical condition in which a part of the intestine folds into the section immediately ahead of it. It typically involves the small bowel and less commonly the large bowel. Symptoms include abdominal pain which may come and go, vomiting, abdominal bloating, and bloody stool. It often results in a small bowel obstruction. Other complications may include peritonitis or bowel perforation.
The cause in children is typically unknown; in adults a lead point is sometimes present. Risk factors in children include certain infections, diseases like cystic fibrosis, and intestinal polyps. Risk factors in adults include endometriosis, bowel adhesions, and intestinal tumors. Diagnosis is often supported by medical imaging. In children, ultrasound is preferred while in adults a CT scan is preferred.
Intussusception is an emergency requiring rapid treatment. Treatment in children is typically by an enema with surgery used if this is not successful. Dexamethasone may decrease the risk of another episode. In adults, surgical removal of part of the bowel is more often required. Intussusception occurs more commonly in children than adults. In children, males are more often affected than females. The usual age of occurrence is six to eighteen months old.
Signs and symptoms
Early symptoms can include periodic abdominal pain, nausea, vomiting (sometimes green in color from bile), pulling legs to the chest area, and intermittent moderate to severe cramping abdominal pain. Pain is intermittent—not because the intussusception temporarily resolves, but because the intussuscepted bowel segment transiently stops contracting. Later signs include rectal bleeding, often with "red currant jelly" stool (stool mixed with blood and mucus), and lethargy. Physical examination may reveal a "sausage-shaped" mass, felt upon palpating the abdomen. Children, or those unable to communicate symptoms verbally, may cry, draw their knees up to their chest, or experience dyspnea (difficult or painful breathing) with paroxysms of pain. In neonates it may present with bilious vomiting and blood stained stools
Fever is not a symptom of intussusception. However, intussusception can cause a loop of bowel to become necrotic, secondary to ischemia due to compression to arterial blood supply. This leads to perforation and sepsis, which causes fever.
In rare cases, intussusception may be a complication of Henoch–Schönlein purpura, an immune-mediated vasculitis disease in children. Such patients who develop intussusception often present with severe abdominal pain in addition to the classic signs and symptoms of HSP.
Cause
Causes of intussusception are not clearly established or understood. About 90% of cases of intussusception in children arise from an unknown cause. They can include infections, anatomical factors, and altered motility. Meckel's diverticulum Polyp Duplication Appendix Hyperplasia of Peyer's patches Idiopathic
While an earlier version of the rotavirus vaccine was linked to intussusception, the current versions are not.
Pathophysiology
In the most frequent type of intussusception, the ileum enters the cecum. However, other types occur, such as when a part of the ileum or jejunum prolapses into itself.
The part that prolapses into the other is called the intussusceptum, and the part that receives it is called the intussuscipiens. Almost all intussusceptions occur with the intussusceptum having been located proximally to the intussuscipiens. This is because peristaltic action of the intestine pulls the proximal segment into the distal segment. There are, however, rare reports of the opposite being true.
An anatomic lead point (that is, a piece of intestinal tissue that protrudes into the bowel lumen) is present in approximately 10% of intussusceptions. The lead point (best exemplified by a polyp) serves as a focal area of traction, which the peristaltic action pulls into the distal bowel, thus invaginating the attached bowel segment.
The trapped section of bowel may have its blood supply cut off, which causes ischemia (lack of oxygen in the tissues). The mucosa (gut lining) is very sensitive to ischemia, and responds by sloughing off into the gut. This creates the classically described "red currant jelly" stool, which is a mixture of sloughed mucosa, blood, and mucus. A study reported that in actuality, only a minority of children with intussusception had stools that could be described as "red currant jelly", and hence intussusception should be considered in the differential diagnosis of children passing any type of bloody stool.