Episode Transcript
Hi, my name is Gail Shibata. I am a clinical professor at UCSF Benioff’s Children Hospital. Today I will be discussing intussusception in the pediatric patient. I will go through perioperative considerations and anesthetic management. At the end of this podcast, you should be able to identify key presenting features of intussusception, describe perioperative considerations in managing pediatric patients with intussusception and formulate an appropriate anesthetic plan for a pediatric patient undergoing surgery for a non-reducible intussusception.
Intussusception occurs when a proximal segment of bowel slides or telescopes into its distal lumen causing bowel obstruction. It is the most common cause of bowel obstruction in children between 3 months and 2 years of age. Intussusception is a medical emergency, and a high index of suspicion is needed to make an early diagnosis. A delay in diagnosis may lead to bowel ischemia, perforation or death.
Intussusception can occur anywhere in the gastrointestinal tract, but 90% are located at the ileocecal junction. This is where the terminal ileum invaginates through the ileo-cecal valve into the colon. The remaining 10% are ileo-ileal and colo-colic intussusceptions.
Most episodes of intussusception occur in otherwise healthy children who are
younger than 2 years of age. It occurs less commonly before 3 months and after 6 years. Males are affected twice as often as females. Although intussusception is most common among infants and toddlers, it is important to consider the diagnosis of intussusception in children outside of this age range.
Intussusceptions can either be idiopathic or caused by a lead point (I will discuss lead points in a moment). The majority (90%) of intussusception cases are idiopathic with no clear disease trigger. Some evidence suggests that viral factors may play an important role in these cases. For example, up to 30% of patients experience some kind of viral illness such as upper respiratory tract infection, flu-like symptoms, otitis media or viral gastroenteritis before the onset of intussusception. It is thought that these lead to lymphoid tissue hypertrophy, particularly within Peyer’s patches in the terminal ileum which then act as a point for intussusception. In 10% of intussusception cases, there is a pathologic lead point.
Lead point intussusceptions more commonly occur in children younger than 3 months or older than 5 years. A lead point is where a lesion or variation in the intestine becomes trapped by peristalsis and is dragged into a distal segment of the intestine. The most common pathologic lead point is from a Meckel’s diverticulum. Other examples of lead points are polyps, duplication cysts, tumors, hematomas or vascular malformations .
Whether the intussusception is idiopathic or caused by a lead point, the pathophysiologic process is similar. The invagination of bowel causes a variable degree of venous occlusion that results in edema and eventually arterial compromise. Ischemia of the bowel causes loss of mucosal integrity with resultant oozing of blood and mucus from the bowel lumen. Progressive edema can result in ischemic necrosis, perforation, peritonitis and death.
The diagnosis of intussusception can be challenging because of the many ways it can present. The presenting symptoms can be nonspecific, such as vomiting, crying and irritability. The classic triad of abdominal pain, a palpable sausage-shaped abdominal mass and currant jelly stool is seen in less than 15% of cases. A more typical presentation is a previously healthy infant or toddler who presents with sudden onset of crampy abdominal pain and vomiting. The pain comes in intermittent waves and is progressive in nature. In between episodes of pain, the child may behave normally, and this can lead to a delay in diagnosis. In less than 50% of cases, a mass or fullness may be palpable in the abdomen, especially in the right upper quadrant. Blood-streaked stools are often absent in cases less than 48 hours duration. 20% of children are pain
free at initial presentation. 30% present with diarrhea which may be confused with
gastroenteritis. Some infants can present with lethargy, altered consciousness or shock. They may not have abdominal pain, rectal bleeding or other symptoms that suggest an
intraabdominal process. Often the first thought is sepsis or a neurologic syndrome such as an acute infection of the CNS.
The diagnosis is made by assessment of presenting symptoms, physical exam and diagnostic imaging. Ultrasound is the method of choice to detect intussusception. The sensitivity and specificity are 100%. The diagnostic sign on ultrasound is a target sign or the “bull’s” eye representing layers of the intestine within the intestine. If the clinical findings are confusing and symptoms vague, plain radiography as the initial diagnostic procedure is reasonable to screen for other causes of abdominal symptoms and to rule out perforation. Sensitivity to diagnose intussusception is less than 48% for plain radiography.
The initial treatment of intussusception favors non-operative reduction if the child is stable and has an ileocolic or colo-colonic intussusception. This can be done using either pneumatic or hydrostatic enema techniques under fluoroscopic or ultrasound guidance. These techniques are dependent on the expertise and comfort level of the radiologist at your institution. The non-operative reduction technique does not require anesthesia and is successful 80-95% of the time. Both pneumatic and hydrostatic reduction carry a less than 1 percent risk of perforation, most commonly occurring on the distal side of the intussusception. Indications for surgery are a child who is hemodynamically unstable due to peritonitis, evidence of a mass or lead point, when the non-operative reduction is either incomplete or unsuccessful, or if the intussusception is noted to be jejun-jejunal, ileo-ilea or jejunal-ileal which are more likely due to a mass.
Laparoscopic reduction has been proven to be both safe and effective in several studies. Alternatively, a small incision is made on the right side of the abdomen and the intestine is pushed back into its normal position. If the intussusception cannot be reduced, then the surgeon will surgically remove the involved segment of the bowel.
Preoperative anesthetic management
Preoperatively, infants and children with intussusception should be assessed for signs and symptoms of dehydration, such as dry mucosal membranes, sunken fontanelles, sunken eyes, and minimal urine output. A basic metabolic panel of electrolytes, glucose, BUN, creatinine, CBC with differential should be ordered preoperatively. Electrolyte findings in intussusception will vary depending on duration of the intussusception. Minimal dehydration and normal electrolyte values would not be surprising in the infant who has been ill for only several hours. Infants who have prolonged vomiting may demonstrate hypo-chloremic metabolic alkalosis, much like those with pyloric stenosis, while infants who are in shock will demonstrate metabolic acidosis. The goals of pre-operative fluid management are to restore vascular and interstitial volumes and to correct electrolyte and acid-base imbalances prior to the induction of anesthesia. Discussion with the surgery team will determine the urgency and how long the surgery can be delayed for preoperative optimization (rehydration
and correction of electrolyte abnormalities). All cases will need some degree of fluid
resuscitation to restore the circulating volume and produce adequate urine output. Preoperative correction of electrolyte abnormalities and dehydration to obtain an adequate urine output for at least 4 hours prior to surgery has been shown to decrease mortality and morbidity in such cases. The presence of hypovolemic shock is a medical emergency that necessitates fluid resuscitation prior to surgery.
Intraoperative/Postoperative Anesthetic Management:
Standard monitoring includes ECG, noninvasive blood pressure, pulse oximetry and
temperature. An additional large gauge peripheral intravenous catheter should be placed if there is a possibility of significant fluid resuscitation and transfusion of blood products. Consider an A-line for pediatric patients who are hemodynamically unstable due to sepsis or in anticipation of equal or greater estimated blood volume loss during the surgery.
Infants and children with intussusception have intestinal obstruction and should be treated as a “full stomach” even if they are appropriately NPO. The patient should have a rapid sequence intravenous induction or a modified rapid sequence with cricoid pressure and a muscle relaxant of choice(either succinylcholine or rocuronium) to facilitate tracheal intubation and reduce the risk of aspiration of gastric contents. Maintenance of anesthesia is accomplished with sevoflurane or an opioid based anesthetic in critically ill patients.
Laparoscopic reduction is often the preferred approach especially for ileocolic intussusceptions. Local anesthetic at the port sites combined with a multimodality pain approach of opioids and nonopioids such as acetaminophen and ketorolac (ask the surgeon first) are commonly used for intraoperative and post-operative pain management. If the operation is via laparotomy, consider neuraxial techniques such as a caudal or lumbar or thoracic epidural(depending on the location of the incision), which can be utilized to improve post-operative pain management and decrease post-operative opioid use. Neuraxial techniques should not be performed in patients with hypovolemia or sepsis. An alternative technique that some institutions perform are bilateral TAP blocks under general anesthesia.
Continual aggressive fluid management will be required during and after surgery with urine output greater than 0.5-1 ml/kg/hr to guide circulating volume status.
The required level of postoperative care will be influenced by the patient’s general condition. For most patients recovering from an uncomplicated intussusception surgery, disposition to a general patient care unit is acceptable. Infants with severe or unstable co-existing conditions especially if patient presented with shock or had significant fluid and blood resuscitation, recovery in the intensive care unit or intermediate unit may be warranted.
