Intussusception: Clinical sciences

Intussusception is a type of intestinal obstruction that occurs when one segment of the intestine telescopes inside of another segment of the intestine. This telescoping often occurs around the ileocecal junction, which is where the ileum of the small intestine and cecum of the large intestine meet. Typically, the distal ileum folds into the cecum. If left untreated, it can result in intestinal edema due to venous and lymphatic congestion, and can ultimately lead to ischemia, necrosis, and intestinal perforation. Intussusception is a true emergency and must be treated promptly, either through reduction with an enema, or if unsuccessful, by surgical intervention.

Alright, if a pediatric patient presents with a chief concern suggesting intussusception, your first step is to perform an ABCDE assessment to determine if your patient is unstable or stable. If they’re unstable, initiate acute management by stabilizing the airway, breathing, and circulation. Next, obtain IV access and initiate IV fluids for resuscitation. Make sure to continuously monitor vital signs, including pulse oximetry, blood pressure, and heart rate. Finally, make your patient NPO and consider placing an NG tube for gastric decompression.

Okay, once you’ve acutely managed your patient, your next step is to obtain a focused history and physical exam. Symptoms typically occur in patients who are 4 to 36 months old, consisting of sudden, severe, paroxysmal abdominal pain and cramping; and the child will often draw their knees up toward the chest. The pain is characterized by intermittent severe pain with pain-free periods in between. Additionally, caregivers typically note the child has had bloody stools that are often intermixed with mucus, called “currant jelly” stools; as well as vomiting, which can start out as nonbilious but may become bilious. Additional symptoms may include lethargy and fever.

You will also want to ask about potential risk factors in your patient’s history. These include a recent viral illness or bacterial enteritis, as well as Meckel diverticulum, duplication cysts, vascular malformations, polyps, or lymphoma. These conditions create a lead point, which serves as a spot that the intestinal wall snags on, creating the condition for it to telescope in on itself.

Here’s a high yield fact! The rotavirus vaccine has been associated with intussusception, although this side effect is very rare, and is not a reason to avoid giving this vaccine.

On a physical exam, you may find hypotension and tachycardia, along with an altered mental status. Patients may also have abdominal tenderness, distention, rebound, and guarding, which are concerning for perforation and peritonitis. On palpation, look for a sausage-shaped mass in the right abdomen.

Now, on laboratory analysis, CBC may show leukocytosis, while CMP may show electrolyte derangements. With this presentation, suspect intussusception complicated by perforation or peritonitis, with or without sepsis.

Okay, so the next step is to order an abdominal ultrasound and an abdominal X-ray. On ultrasound, look for evidence of the intestine within the intestine, also known as the "target sign," consisting of multiple concentric rings of bowel wall as one segment of the bowel telescopes into another; as well as a pathological lead point.

Meanwhile, on abdominal X-ray, if you find signs of perforation, such as pneumoperitoneum, you can diagnose intussusception that has been complicated by perforation or peritonitis, with or without associated sepsis.