Intussusception is telescoping of one portion of the intestine (intussusceptum) into an adjacent segment (intussuscipiens), causing intestinal obstruction and sometimes intestinal ischemia.
Intussusception generally occurs between ages 3 months and 3 years, with 65% of cases occurring before age 1. It is the most common cause of intestinal obstruction in this age group. Most cases are idiopathic. In older children, there may be a lead point (ie, a mass or other intestinal abnormality that triggers the telescoping). Examples include polyps, lymphoma, Meckel’s diverticulum and Henoch-Schönlein purpura. Cystic fibrosis is also a risk factor.
The telescoping segment obstructs the intestine and ultimately impairs blood flow, causing ischemia, gangrene and perforation.
Symptoms: The initial symptoms are recurrent colicky abdominal pain that occurs every 15 to 20 min, often with vomiting. The child appears relatively well between episodes. Later, as intestinal ischemia develops, pain becomes steady, the child becomes lethargic, and mucosal hemorrhage causes heme-positive stool on rectal examination and sometimes spontaneous passage of a currant-jelly stool (stool mixed with blood and mucus). The latter, however, is a late occurrence, and physicians should not wait for this symptom to occur to suspect intussusception. A palpable abdominal mass, described as sausage-shaped, is sometimes present. Perforation results in signs of peritonitis, with significant tenderness, guarding, and rigidity. Pallor, tachycardia, and diaphoresis indicate shock.
Diagnosis: Ultrasound of abdomen
Studies and intervention must be done urgently, because survival and likelihood of nonoperative reduction decrease significantly with time. Approach depends on clinical findings.
Barium enema was once the preferred initial study because it revealed the classic “coiled spring” appearance around the intussusceptum. In addition to being diagnostic, barium enema was also usually therapeutic; the pressure of the barium often reduced the telescoped segments. However, barium occasionally enters the peritoneum through a clinically unsuspected perforation and causes significant peritonitis. Currently, ultrasonography is the preferred means of diagnosis; it is easily done, relatively inexpensive, and safe.
Treatment: If intussusception is confirmed, an air enema is used for reduction, which lessens the likelihood and consequences of perforation. The intussusceptum can be successfully reduced in 75 to 90% of children. Children are observed overnight after reduction to rule out occult perforation. If reduction is unsuccessful, immediate surgery is required. Without surgery, the recurrence rate is 5 to 10%.
Clinical Vignettes
A 3 year old boy is brought to the emergency department by his parents because of a 24-hour history of intermittent, generalized abdominal pain. The parents tell you that he complains of the pain for 10-minute episodes and during these times he refuses to walk, but then he spontaneously returns to his normal activities. This occurred 8-9 times yesterday. Today the symptoms occurred more frequently and were associated with 3 episodes of non-bloody, non-billous emesis so the parents brought him into the hospital. There is no history of fever, constipation, or soiling. On examination the patient appears tired and has mild diffuse abdominal pain. He has guaiac-positive stool. His pulse is 125/min. The study most likely to provide a diagnosis is
A. an abdominal x-ray
B. a barium enema
C. a CBC with differential
D. a CT scan of the abdomen
E. a lumbar puncture
The correct answer is B. This patient presents with a very common complaint in the pediatric population, abdominal pain. The key to this case is the quality and frequency of this abdominal pain. The pain was described as being diffuse and intermittent with periods of resolution of the symptoms. This type of pain pattern, along with emesis, the lethargy seen in the emergency department, and the guaiac-positive stools should raise red flags for the diagnosis of intussusception. In intussusception a segment of bowel (most commonly the distal ileum into the cecum) telescopes into an adjacent segment causing obstruction. This obstruction tends to resolve and recur causing the intermittent abdominal pain. The barium enema is diagnostic and in many cases a curative procedure as well and is therefore the study of choice in this case.
A 2-year-old boy is brought to the ED by his parents. Reportedly, he has been ill with a “viral syndrome” for the past 2 days with fever, anorexia, and rhinorrhea. However, during the past 6 to 8 hours, he has become ex- tremely lethargic, and he has started to vomit and com- plain of diffuse abdominal pain. His father is sure his son has appendicitis and requests that a surgeon attend to him immediately. On physical examination, a firm mass in the right upper quadrant is palpable. Your next step should be to
A. call a surgeon immediately
B. obtain a CBC, blood chemistries, and liver enzymes
C. obtain a plain film of the abdomen
D. obtain a CT of the abdomen
E. obtain an ultrasound of the abdomen
Which of the following procedures is indicated in the care of this child?
A. Appendectomy
B. Barium enema
C. Intravenous antibiotics
D. Lumbar puncture
E. Colonoscopy
The answers are: C, B. This patient presents with an intussusception, which occurs when there is invagination of one part of the intestine into another, resulting in abdominal pain, obstruction, and vomiting. It most commonly occurs before the age of 2 years, and the recurrence rate may be as high as 15%. Specific lead points for invagination, which include Meckel diverticulum, lymphoma, foreign bodies, and polyps, are found in only 5% of children. In many children, hypertrophy of Peyer patches secondary to a viral infection may ultimately serve as a lead point.
An intussusception may be serious if it is not rapidly identified; impaired arterial inflow and ve- nous outflow to the involved bowel occur as a result, and necrosis and perforation may develop. An abdominal mass is felt in approximately 50% of cases and, with the proper clinical history, can point to the diagnosis.
It is important to obtain plain films first. Abdominal radiographs demonstrate a paucity of gas downstream from the obstruction and signs of obstruction proximally. Although ultrasound and CT would also be diagnostic, a plain radiograph is easier to obtain and results in a more rapid diagnosis.
If these films indicate obstruction, a barium enema is then warranted. In 75% of cases, this procedure is both diagnostic and therapeutic. The hydrostatic pressure reduces the obstruction. An appendectomy is inappropriate unless there is inflammation of the appendix, which is not present in this case.
A 4-month-old infant is brought to the ED with a history of several hours of irritability, crying, and vomiting. The parents state that the infant had been doing well up until yesterday when he developed periodic episodes of col- icky abdominal pain and some loose stools. In the last hour, he has passed a red stool with a “jelly-like” consistency. On physical examination, a vertically oriented mass is present in the right abdomen. There is only mild abdominal tenderness. The infant is afebrile. Which of the following is the most likely diagnosis?
A. Meckel’s diverticulum
B. Acute appendicitis
C. Intra-abdominal adhesions
D. Intussusception
E. Pyloric stenosis
Which of the following would be the next therapeutic step in the care of this infant?
A. Contrast enema
B. CT
C. Emergent surgery
D. Observation with intravenous hydration
E. Narcotic analgesia and intravenous antibiotics
The answers are: D, A. This child presents with the classic triad of colicky abdominal pain, vomiting, and currant jelly stools, which signify intussusception. Most cases are idiopathic and occur in children younger than 3 years of age. There is often inflammation of the mucosal tissue of the intestines that serves as a lead point for the telescoping or prolapse of one portion of the bowel into an immediately adjacent segment. Some other predisposing conditions include Meckel diverticulum, intestinal lymphoma, and polyps. The finding of an abdominal mass is also indicative of this condition. All of the other answers for this question would be much less likely in this situation. Ultrasound can be used to diagnose the condition, but a contrast enema is both diagnostic and therapeutic in this case. It is important to have surgical consultation be- fore the performance of this study. In over 95% of cases, the contrast enema is diagnostic, and in 75% of cases, it is therapeutic.