Intussusception

Question 1

The most common type of intussusception is:

a. ileoileal
b. colocolic
c. ileocolic
d. ileo-ileocolic

Answer 1

c. ileocolic

Question 2

Contraindications for non-surgical reduction of an intussusception include all of the following except:

a. symptoms for longer than 24 hours
b. shock
c. intestinal perforation
d. peritonitis

Answer 2

a. symptoms for longer than 24 hours

Question 3

Which is the most common pathological lead point found with intussusception?

a. neoplasm
b. appendicitis
c. polyps
d. intestinal duplication
e. Meckel’s diverticulum

Answer 3

e. Meckel’s diverticulum

Question 4

A pathologic lead point can be identified in approximately what percentage of patients with intussusception?

a. 1%
b. 5%
c. 10%
d. 15%
e. 25%

Answer 4

c. 10%

Question 5

The “classical triad” of symptoms of intussusception include:

a. diarrhea
b. vomiting
c. fever
d. bloody stools
e. abdominal pain

Answer 5

vomiting, bloody stools, abdominal pain

Question 6

Which element of the “classical triad” for intussusception usually appears first?

a. diarrhea
b. vomiting
c. fever
d. bloody stools
e. abdominal pain

Answer 6

e. abdominal pain

Question 7

All three of the “classical triad” of symptoms is found in what percentage of patients with intussusception?

a. 9%
b. 21%
c. 50%
d. 70%
e. 90%

Answer 7

b. 21%

Question 8

True/False: A normal abdominal series rules-out intussusception.

Answer 8

False

Question 9

If a mass is palpable on physical examination, it is most often found in the:

a. right upper quadrant
b. right lower quadrant
c. left upper quadrant
d. left lower quadrant

Answer 9

a. right upper quadrant

Question 10

A 13-month-old male presents to the emergency room with 13 h of colicky abdominal pain, emesis, a palpable sausagelike abdominal mass, and blood-tinged stools. Which test is most appropriate to determine the diagnosis?

A. Plain radiograph

B. MRI

C. Upper GI

D. Ultrasound

E. Complete blood count with differential

Answer 10

ANSWER: D

COMMENTS: Intussusception most commonly presents in children aged 2 years or younger.

Ultrasound will demonstrate a 3- to 5-cm diameter mass with the typical target or doughnut sign.

Most pediatric intussusceptions occur at the ileocolic junction; therefore it is common for the mass to be found in the right lower quadrant.

Ultrasound has been described to have as high as 100% accuracy with experienced sonographers.

It is often the first-line imaging study due to its portable nature, high accuracy, and lack of radiation.

Plain abdominal radiograph generally does not provide enough information to exclude or confirm the diagnosis of intussusception and is therefore not used.

An upper GI would be helpful if malrotation were high on the differential; however, given the combination of symptoms, the most likely diagnosis is intussusception.

There is no role for MRI.

Question 11

Select the true statement regarding the operative management of intussusception.

A. After successful reduction by barium enema, exploration is indicated to rule out the associated pathologic processes.

B. After successful reduction by barium enema in a 1-year-old child, delayed surgery should be performed because of the risk for recurrence.

C. If barium enema reduction is not successful, a resection should be performed without an attempt at intraoperative manual reduction, whether or not the bowel appears to be viable.

D. If resection is necessary, a primary ileocolic anastomosis may be performed.

E. Appendectomy should never be performed after successful operative manual reduction since this introduces an additional risk.

Answer 11

ANSWER:

D

COMMENTS: See Question 48. Most pediatric intussusceptions occur at the ileocolic junction.

Unlike in adults, there is rarely a lead point causing the intussusception.

Reduction with a hydrostatic or barium enema is often successful.

If this fails, surgical reduction is warranted.

Incidental appendectomy has a very low complication rate, and in the future clinicians may assume that an appendectomy was performed when there is a laparotomy scar.

Question 12

Contraindications to attempted reduction of an i tion with a hydrostatic or barium enema in a child include which of the following?

A. Pneumoperitoneum

B. Presentation after 48 h of symptoms

C. Recurrence after prior hydrostatic reduction

D. Age older than 5 years

E. Recurrent symptoms in the immediate postreduction period

Answer 12

ANSWER: A

COMMENTS: Ileocolic intussusception should be strongly suspected in a child between the ages of 3 and 18 months with colicky abdominal pain and guaiac-positive stools.

A barium, hydrostatic, or air enema should be performed for an attempted nonoperative reduction of the intussusception via hydrostatic or pneumatic pressure.

In approximately 80% of children, a successful radiologic reduction is the only therapy needed.

An attempt at nonoperative reduction is contraindicated in children with perforation or peritonitis.

In such cases, prompt surgery is required.

When nonviable bowel is encountered at the time of exploration, resection is carried out without an attempt at reduction.

Otherwise, reduction by gentle digital pressure on the intussusceptum is attempted.

Resection is performed if the intussusception is not manually reducible.

Primary anastomosis may be performed.

After a successful operative manual reduction, an appendectomy is usually performed.

Recurrence is not considered to be an absolute indication for surgery, and a second and third attempt may be successful.

A 1-year-old child most likely has “idiopathic” intussusception with no anatomic leading point.

Children older than 5 years are more likely to have surgical lead points such as an intestinal polyp, Meckel’s diverticulum, or tumor such as lymphoma.

If these are encountered, they should be resected.

Further workup and appropriate surgery to prevent recurrences are needed.

Intussusception recurs in 5%–10% of patients regardless of whether the intussusception has been reduced radiographically or operatively.

Treatment involves repeated barium, hydrostatic, or air enema, which is successful in most cases.

Question 13

Discuss intussusception.

Answer 13

Intussusception is a “telescoping” of the intestine, resulting in obstruction and bowel wall edema that can cause ischemia.

It is most frequently seen in children under the age of three years.

The most common type is ileocolic.

Usual presentation includes vomiting and colicky abdominal pain.

Patients are evaluated with ultrasound, which frequently shows a target sign.

However, the gold standard for diagnosis is a contrast enema, which is also usually therapeutic.

In stable patients with ileocolic intussusception, reduction can be attempted with an air contrast enema (up to 120 mmHg) or with an ultrasound-guided saline enema (up to 88 mmHg).

If reduction is successful, the patient can be observed for several hours and then sent home.

If reduction is unsuccessful, it can be repeated for a total of three times.

If all three attempts are unsuccessful, or if the patient is unstable, surgery with manual reduction is necessary.

Surgery can be attempted laparoscopically, but there should be a low threshold to convert to a laparotomy.

The key to successful reduction is milking the intussusceptum out from its distal extent, rather than pulling proximally.

Bowel resection is not needed unless there is perforation or necrosis, or if reduction is not possible.

Question 14

What is intussusception?

Answer 14

Intussusception is a full-thickness telescoping of the bowel where a proximal segment invaginates and is propelled forward by peristalsis into a distal segment.

This telescoping results in obstruction and bowel wall edema that can eventually cause ischemia.

Question 15

What is an intussusceptum?

Answer 15

An intussusceptum is the proximal segment of bowel that constitutes the internal
component of an intussusception.

Question 16

What is an intussuscipiens?

Answer 16

An intussuscipiens is the distal segment of bowel that constitutes the outer layer in an intussusception.

Quick tip: Remember it as the recipient.

Question 17

What is the most common site for intussusception?

Answer 17

Due to the abrupt change in lumen size between the terminal ileum and the cecum,
the most common site of intussusception is at the ileocecal valve.

Question 18

What are features of small bowel intussusception?

Answer 18

Small bowel intussusception, in which both the intussusceptum and intussuscipiens are segments of the small intestine, occurs in up to 25% of cases [1].

It typically occurs in the central abdomen, involves a short length of bowel, and is usually self-resolving [2].

Question 19

What is the most common cause of ileocolic intussusception?

Answer 19

In most cases (90%), the etiology is idiopathic.

It is thought that lymphoid hyperplasia of Peyer’s patches, which occurs after a viral illness, acts as a lead point that is then propelled forward by peristalsis [3].

In the remaining 10% of cases, a pathologic lead point causes the intussusception.

Question 20

What is a pathologic lead point?

Answer 20

This is any recognizable intraperitoneal condition that tethers or obstructs the bowel, initiating the process of intussusception.

Examples include Meckel’s diverticulum, intestinal polyps, intestinal lymphoma, and hemangiomas [4].

Indwelling tubes, like a gastrojejunal feeding tube, can also act as lead points for cases of small bowel-small bowel intussusception.

Question 21

What patient population is most commonly affected by ileocolic intussusception?

Answer 21

Children under the age of three years are most commonly affected, representing 90% of cases [5].

Question 22

What risk factors suggest a pathologic lead point?

Answer 22

Intussusception in a patient over 3 years old is suspicious for pathology.

These patients are more likely to have a Meckel’s’ diverticulum act as a lead point (14% vs. 2%), but not more likely to have a tumor act as a lead point (6% vs. 5%) [5].

Question 23

What is the usual presentation?

Answer 23

Symptoms include vomiting (78%), colicky abdominal pain (69%), and lethsargy/ irritability (67%).

A sausage-shaped mass identified by palpation may be associated with intussusception, but is often hard to appreciate in a distressed child and is only found in 50% of patients [4].

Question 24

What are currant jelly stools?

Answer 24

Edema, lymphatic obstruction, local venous hypertension, and vascular stasis cause mucosal sloughing.

These tissue fragments, combined with blood and intra- luminal fluid, create the currant jelly appearance.

“Currant jelly stools,” classically taught as being pathognomonic in intussusception, occur late in the disease process and are only found in 35% of patients.

Question 25

How is the diagnosis confirmed?

Answer 25

Ultrasound is most frequently used and first line to evaluate for intussusception.

Question 26

What findings on ultrasound are consistent with ileocolic intussusception?

Answer 26

Ultrasound showing a target sign is pathognomonic for intussusception (see Fig. 29.1).

Ultrasound can also show the intussuscipiens and intussusceptum in the longitudinal view and can reveal a pathologic lead point if one is present.

Question 27

What are the most common findings on abdominal plain film?

Answer 27

Common findings include intestinal obstruction (54%), presence of an intracolonic mass or target sign (29%), and paucity of air in the right lower quadrant (10%).

Plain films are normal in 24% of patients [6].

Question 28

How should ileocolic intussusception be managed initially?

Answer 28

If a patient is hemodynamically unstable or has peritonitis or pneumoperitoneum, they should be managed surgically.

Otherwise, initial management should involve fluid resuscitation, attempts at enema reduction, and a surgical consult.

Question 29

How should small bowel intussusception be managed?

Answer 29

Since small bowel intussusception self-reduces in the vast majority of cases, most of these patients will not require any intervention.

However, if the length of intussusception seen on imaging is greater than 3.5 cm, the patient will likely require an operation [7].

Additionally, if symptoms do not resolve and radiographic evidence of small bowel intussusception persists, operative intervention is necessary.

Question 30

Which enema reduction method is most effective for ileocolic intussusception?

Answer 30

The two most commonly used methods of reduction are pneumatic (air-contrast enema) or hydrostatic (ultrasound-guided saline enema).

A randomized con- trolled trial showed that saline enema is the more successful of the two (97% vs. 84%), while also utilizing lower intraluminal pressure (74–88 mmHg vs. 80–120 mmHg) [8].

Question 31

How frequently does intussusception recur after enema reduction?

Answer 31

Intussusception recurs in approximately 7.5% of patients reduced hydrostatically
and 8.5% of patients reduced pneumatically [9].

Question 32

How many times can a successful enema reduction be completed for recurrence?

Answer 32

As long as the intussusception is successfully reduced, enema reduction can be repeated indefinitely.

Clinical practice varies by clinician and health system.

Question 33

How should a patient with successful reduction be managed?

Answer 33

Historically, practice often involved observing the patient post-reduction for at least 24 hours.

Most recent evidence supports safely discharging the patient after four hours of observation in the Emergency Department.

While under observation, they are given clear liquids after 3 hours.

If they have no recurrence of symptoms, they can be discharged home.

If symptoms return, a repeat ultrasound is recommended, with repeat reduction if intussusception is seen [10].

Question 34

How many unsuccessful attempts should be made at enema reduction before proceeding with an operation?

Answer 34

If initial reduction is not successful, attempts can be repeated twice.

If, after three times, reduction is still not successful, that patient should be taken to the operating room for manual reduction [10].

Question 35

How should operative reduction of intussusception be performed?

Answer 35

Operative reduction can be performed laparoscopically.

The key principle of reduction is milking the intussusceptum out from its most distal point (similar to squeezing out toothpaste), rather than pulling on the proximal bowel.

Due to technical limitations of laparoscopy, the reduction is usually completed with controlled tension from the proximal edge.

Bowel resection is only needed in cases of perforation or necrosis, or if the reduction is not possible.

Patients must be evaluated for a pathologic lead point, which should be resected if present.

Question 36

Should the appendix be removed at the time of reduction?

Answer 36

Some surgeons advocate for performing an appendectomy if the patient requires an operative reduction of intussusception, as it removes appendicitis as a differential diagnosis for future episodes of abdominal pain and prevents the appendix from acting as a potential pathologic lead point for recurrence.

However, this upstages the wound classification in cases where no bowel resection is needed.

A database study showed that performing an appendectomy slightly increased the length of stay and total cost, with no difference in the risk for recurrence, suggesting that routine appendectomy is not beneficial [11].

Question 37

Gender predilection in intussusception?

Answer 37

M > F

2:1 or 3:2 ratio

Question 38

Age predilection in intussusception?

Answer 38

75%: Within first 2 years of life
90%: within 3 years of age
>40%: 3-9 months of age

Question 39

Pathologic anatomy of intussusception?

Answer 39

Each intussusception has the following pathologic anatomy: as the intussusception develops with its prograde bowel peristalsis, the proximal invaginated bowel (intussusceptum) carries its mesentery into the distal recipient bowel (intussuscipiens).

The mesenteric vessels are angulated, squeezed, and compressed between the layers of the intussusceptum. This causes intense local edema of the intussusceptum, which in turn produces venous compression, congestion, and stasis leading to an outpouring of mucus and blood from the engorged intussusceptum, the classic red currant jelly stool (Fig. 85-4).

If this process continues unabated, bowel congestion and pressure increase and ultimately produce ischemic changes leading to bowel necrosis in the intussusceptum.

In his classic experiments about intussusception, Ravitch already noted in 1959 that the outermost layer of bowel containing the intussusceptum becomes devitalized first, the innermost layer of the intussusceptum becomes gangrenous much later, and the outer layer of the intussuscipiens rarely, if ever, loses its viability.

In most cases, ischemic necrosis needs more than 72 hours to develop.

Karnak and colleagues 47 noticed a weakened longitudinal whitish line in resected intussusception bowel segments.

Microscopically the authors found mucosal necrosis, disruption of the muscularis mucosa, and loss of some of its muscular tissue. This location on the antimesenteric border and under the taenia libera can be explained by local vascular compromise as a result of the distribution of the terminal arteries of the colon.

After manual reduction, this area should be checked carefully for a longitudinal weakened pressure line. Recognition of such a potentially dangerous weak line on the bowel wall may be an indication for resection.

If the ischemic process goes undiagnosed, bowel obstruction, perforation, or sepsis leads to death within 5 days.

In rare cases, the intussusceptum can become gangrenous, and slough andthe bowel may fuse. No free perforation occurs,and the separated necrotic intussusceptum may pass out of the rectum.

Question 40

General types of intussusception?

Answer 40

1) Permanent (fixed): 80%
- 85% Symptomatic
- All require treatment.

2) Transient (spontaneous reduction): 20%
- Mostly incidentally seen on WAB CT, or UTZ done for other reasons.
- May be seen with gastroenteritis.
- 86% involve only the small bowel, noted in the central and left abdominal regions.
- Mostly asymptomatic.
- Most asymptomatic cases require only clinical observation. No additional imaging necessary.
- Only 6% of symptomatic children have GI pathology as a lead point.

Question 41

Specific types of intussusception?

Answer 41

1) Idiopathic: 95%
- Thickened bowel wall lymphoid tissue (Peyer patches, usually in anti mesenteric area)
- Viral infections (adenovirus, rotavirus)

2) Pathologic lead point: 4%
3) Postoperative: 1%

Question 42

Anatomic types of intussusception?

Answer 42

1) Ileocolic: 85%
2) Ileoileocolic: 10%
3) Appendicocolic, cecocolic, or colocolic: 2.5%
4) Jejunojejunal, ileoileal: 2.5% (including those around indwelling tubes)
5) Other (5% recurrent, 0.3% neonatal)

Question 43

A six-month-old male child presents with sudden onset of excessive cry, vomiting, and bleeding per rectum. Examination shows abdominal distension and vague mass in right-lower abdomen. Stool shows redcurrant jelly appearance. Which is the most likely diagnosis?

A. Volvulus.

B. Intussusception.

C. Duplication cyst.

D. Meckel’s diverticulum.

E. Mesenteric cyst.

Answer 43

B

The A, C, and D are possible, but most likely diagnosis is intussusception.

Question 44

Regarding intussusception management, which of the following is false?

A. In pneumatic reduction, 160–200 mm pressure is delivered.

B. Initial reduction by pneumatic or contrast is slow, but the later part is rapid.

C. The benchmark of successful reduction is reflux of contrast or air in the colon.

D. Ultrasound shows target sign on longitudinal images.

E. All the above.

Answer 44

E

Pressure required is 80-150mmHg. Initial part reduces rapidly. Quite often, intussusception lodges in caecum for that sustained pressure of for 3-4 minutes is required. Benchmark of reduction is reflux of contrast or gas in different loops of ileum. Ultrasound shows target sign on transverse image and pseudo kidney sign on longitudinal image.

Question 45

Regarding surgical management of intussusception, which one of the following is not true?

A. Reduction is achieved by squeezing the bowel from distal to the apex.

B. Resection may be necessary if intussusception is not reduced.

C. Resection is not necessary if the bowel is necrotic.

D. Resection may be necessary if lead point, such as Meckel’s diverticulum or duplication.

E. Resection may be necessary if there is small bowel perforation.

Answer 45

C. Resection is necessary if necrotic bowel

Question 46

Recurrence rate after pneumatic reduction is:

A. 3 percent.

B. 10 percent.

C. 20 percent.

D. 40 percent.

E. 50 percent.

Answer 46

B. About 10% recurrence rate noted after pneumatic reduction.

Question 47

Regarding aetiology of intussusception which one is false?

A. Aetiology is unclear in most cases.

B. Appendix may be the lead point.

C. Cystic fibrosis is present.

D. All of the above are true.

E. None of the above is true.

Answer 47

E. All statements A, B, and C are true. Other suspected causes may include change in diet, misappropriate size between ileum and ileocolic valve, Meckel’s diverticulum, polyp, neurofibroma, hemangioma, hypertrophied lymphoid patch, submucosal haematoma, lymphoma, abdominal trauma and various surgical procedures.

Question 48

In a child with intussusception, réduction with air enema should be attempted how many times?

A. Only once then proceed with surgery
B. 2 to 3 times
C. No limit as long as there is/are no clinical signs of peritonitis

Answer 48

B. 2 to 3 times

Question 49

How do you differentiate Intussusception clinically from rectal prolapse?

Answer 49

Prolapse of the intussusceptum through the anus is a grave sign, particularly when the intussusceptum is ischemic.

The greatest danger in a case of prolapsed intussusceptum is that the examiner will misdiagnose the condition as a rectal prolapse and attempt reduction.

Careful physical examination is mandatory and can be done by inserting a lubricated tongue blade along the side of the protruding mass before reduction.

If the blade can be inserted more than 1–2 cm into the anus along the side of the mass, the diagnosis of intussusception should be considered.

Question 50

What is the maximum safe air pressure used for pneumatic reduction?

Answer 50

80mmHg for younger infants
110-120mmHg for older infants

Question 51

How do you manage recurrent Intussusception?

Answer 51

Recurrent intussusception has been described in association with nonoperative intervention in approximately 10% of cases, with about one-third occurring within 24 hours and the majority within 6 months of the initial episode.

Recurrences are less likely to occur after operative reduction or resection.

After laparoscopic reduction, a recurrence rate as high as 10% has been reported, although a recent systematic review showed it to be much lower at 4%.

When this occurs, it is reasonable to attempt pneumatic reduction again.

Patients with recurrent intussusception tend to be seen earlier in their course because their parents are more aware of how to recognize the signs and symptoms.

Success rates with enema reduction after one recurrence are comparable to those with the first episode and are better if the child did not previously require operative reduction.

This finding has led to a nonoperative approach for initial management of recurrence in most patients as long as they are not toxic or show signs of peritonitis or hemodynamic instability.

A concern in recurrent intussusception is occult malignancy. Unfortunately, the clinical findings or pattern of recurrence do not predict the presence of a malignant lead point and radiographic reduction with follow-up US is recommended to look for an occult pathology.

There is limited guidance on follow-up imaging, but it should be delayed until the expected swelling and potential reactive lymphadenopathy associated with the intussusception has resolved.

Question 52

What is postoperative intussusception?

Answer 52

Postoperative intussusception is a rare clinical entity that has been described after ileocolic intussusception reduction and resection, retroperitoneal dissections, long intra-abdominal procedures, a Ladd procedure, or extraabdominal operations.

It accounts for 3–10% of cases of postoperative bowel obstruction and most often occurs in the initial 10 days following a procedure.

Ileus and adhesive obstruction are more frequently encountered as a cause for intestinal obstruction in the postoperative patient.

Thus, an index of suspicion is needed, and US is a useful diagnostic tool.

Most postoperative intussusceptions are ileoileal and respond to operative reduction without resection.

Question 53

A 9-month-old male from Central America is brought to the emergency department with a 6-hour history of intermittent, inconsolable crying and hugging his knees to his abdomen. He has had two bloody stools and vomiting. The infant is irritable with a temperature of 38.5 C. The abdomen seems tender, and the child continues crying. What is the best initial diagnostic test?

Choices:
1. Stool for giardia antigen, ova, and parasites
2. Air contrast enema with a baseline scout decubitus view
3. Abdominal ultrasound
4. Plain radiograph of the abdomen

Answer 53

Answer: 3 - Abdominal ultrasound

Explanations:
•The patient, being between the ages of 6 months and 4 years, most likely has ileocolic intussusception.
•The history is consistent with this diagnosis, and occasionally a sausage-shaped mass can be palpated in the right upper quadrant. Plain radiographs may be helpful to exclude perforation or when ultrasound is not immediately available and can show characteristic bowel obstruction. The “target sign,” consisting of two concentric radiolucent circles superimposed on the right kidney, represents peritoneal fat surrounding and within the intussuscep-tion. The “crescent sign” is a soft tissue density representing the intussusceptum projecting into the gas of the large bowel, obscured liver margin, or lack of air in the cecum.
• Air, saline, or barium enema can reduce the intussusception or make the diagnosis but are not usually the first study ordered because there is a risk of bowel rupture. Prior to the enema, the patient must be cleared for surgery. There is no preparation required for an abdominal ultrasound.
• Bowel perforation must be excluded prior to radiologic intervention. Air has the least incidence of perforation.

StatPearls

Question 54

A 1-year-old female presents with episodic abdominal pain for 1 day, anorexia, and loose stools. She has no fever or upper respiratory symptoms. On physical exam, her abdomen is soft and non-tender but her stools are bloody and the hemoccult test is positive. Of the following, which radiologic study would be best used to confirm the suspected diagnosis?

Choices:
1. CT with contrast of the abdomen
2. Ultrasound
3. X-ray
4. MRI of the abdomen, with and without contrast

Answer 54

Answer: 2 - Ultrasound

Explanations:
• This patient has suspected intussusception given the episodic abdominal pain and heme-positive stools.
• Though CT, MRI, or x-ray could either identify or help identify intussusception, ultrasound is a much easier, less invasive, and less expensive modality. The sensitivity and specificity reach nearly 100% in institutions with well-trained ultrasonographers.
•Some surgeons will elect to go with a contrast enema when the suspicion of intussusception is high. The technique is both diagnostic and therapeutic.
•Contrast enema usually is not recommended for children older than
3 years, as most of these children have a surgical lead point.

StatPearls

Question 55

A 1-year-old girl presents with episodic abdominal pain, drawing the legs up to the abdomen and kicking the legs in the air for 1 day, anorexia, and loose stools. She has no fever or upper respiratory symptoms. On physical exam, her abdominal exam is soft and non-tender, but her stools are stool guaiac test positive. Of the following, which radiologic study would be recommended for screening?

Choices:
1. CT with contrast of the abdomen
2. Ultrasound
3. Air enema
4. MRI of the abdomen with and without contrast

Answer 55

Answer: 2 - Ultrasound
Explanations:
• This patient has suspected intussusception given the episodic abdominal pain and heme-positive stool.
•Though CT, MRI, or plain film could either identify or help identify intussusception, ultrasound is a much easier, less invasive, and less expensive modality. The sensitivity and specificity reach nearly 100% in institutions with well-trained ultrasonographers.
• Air enema can be used to diagnose intussusception. It often successfully treats the condition. There is a risk of perforation with this procedure, and the patient must be cleared for surgery and surgical backup available before performing. Ultrasound is non-inva-sive and does not require preoperative evaluation.
• Ultrasound can identify both small and large bowel intussusception.

StatPearls

Question 56

A 2-year-old male is taken to the emergency department due to repeated bouts of crouching down and crying, followed by his normal behavior for the past two days. The parents report that he has had multiple stools over the past couple days, some of which have contained red mucus (currant jelly). Physical exam reveals a child playing with his older sibling. Vital signs are unremarkable. Abdominal examination is unremarkable. As the parents are about to leave, the patient curls up and starts crying. Ultrasound reveals target appearing bowel in the right lower quadrant. Which artery is most likely affected by this condition?
Choices:
1. Ileocolic artery
2. Inferior mesenteric artery
3. Right colic artery
4. Superior mesenteric artery

Answer 56

Answer: 1 - Ileocolic artery
Explanations:
• The ileocolic artery can be occluded in ileocecal intussusception or intussusception secondary to Meckel diverticulum.
•Even if not occluded, the ischemia resulting from this condition is in the distribution of the ileocolic artery.
• The ileocolic artery divides into two branches, the superior vascu-larizes the cecum and ascending colon. The inferior vascularizes the cecum and terminal ileum.
The lymphatics associated with the organs in the distribution of the ileocolic artery are generally found within the mesenteries.

Question 57

A 3-year-old male is brought in by his parents with complaints of abdominal pain and blood in the stool. He also has a fever and has had two episodes of bilious vomiting today. The child is lying in discomfort with the knee-chest position. On examination, the temperature is 38.3 C (101 F), the pulse is 92 beats per minute, and the respiratory rate is 28 breaths per minute. Abdominal examination reveals a distended abdomen with a sausage-shaped mass and tenderness in the right upper quadrant. His stool guaiac test is positive. His complete blood count with differential shows leukocytosis but is otherwise nor-mal. Ultrasound of the abdomen shows a target sign. The child is treated with an air enema. What is the next step in the patient’s management?
Choices:
1. Discharge on oral antibiotics to treat any micro-perforations
2. Observe for six to eight hours and discharge to home if tolerating oral feeding
3. Admit for laparoscopic right hemicolectomy
4. Admit for laparoscopic fixation of the cecum

Answer 57

Answer: 2 - Observe for six to eight hours and discharge to home if tolerating oral feeding

Explanations:
•This patient has a classic presentation of intussusception.
• 10% of patients successfully treated may have a recurrence. Some authorities feel all patients should be admitted, but the trend is to observe the patients, and if they are tolerating oral hydration, they can be discharged after six to eight hours.
• Surgery is reserved for patients who are not successfully treated with an air enema or for patients with recurrent episodes after non-operative reduction.
• Repeat air reduction is acceptable for the recurrence, but if there are multiple recurrences, consider contrast enema to define a lead point. Cases that cannot be reduced non-surgically require surgical reduction.

StatPearls

Question 58

Regarding intussusception, which of the following statements is true?

A The most common age at presentation for children with idiopathic intussusception is more than 2 years.

B The most common age at presentation for children with secondary intussusception is 3–6 months.

C Adenovirus is a common aetiological factor in primary intussusception.

D The classic features of vomiting, abdominal pain, redcurrant jelly stool and an abdominal mass on presentation, are seen in 30%–40% of children with intussusception.

E The term ‘intussuscipiens’ refers to the proximal invaginating intestine.

Answer 58

C

Intussusception is one of the most frequent causes of bowel obstruction in infants and toddlers.

It occurs in 1 in 2000 infants and children. male-to-female ratio ranges from 2 : 1 to 3 : 2.

It was first described in 1674 by Paul Barbette and was subsequently described by Treves in 1899.

The classic definition of intussusception is ‘full thickness invagination of the proximal bowel (intussusceptum) into the distal contiguous intestine (intussuscipiens)’.

John Hutchinson reported the first successful operation for intussusception in 1873, and Harald Hirschsprung later described hydrostatic reduction with an associated significant decrease in mortality.

Typically intussusception occurs in well-nourished healthy infants and over two-thirds of patients are male.

Intussusception can be divided into primary (idiopathic) and secondary.

Primary intussusception (no pathological lead point) is the most common type of intussusception, commonly occurring soon after an upper respiratory tract infection or episode of gastroenteritis when the lead point is thought to be hypertrophied Peyer’s patches in the ileal wall.

Adenovirus and rotavirus have been implicated in around 50% of cases.

most cases of primary intussusception occur between the ages of 6 months and 3 years, when children are particularly susceptible to viral illnesses.

There have been case reports of intussusception occurring in the premature neonate.

Secondary intussusception occurs in a slightly older age group, when an identifiable lead point is found. The incidence of definite anatomical lead point ranges from 1.5% to 12%. These anatomical lead points tend to present after 2 years of age, and commonly include meckel’s diverticulum, duplications of the bowel and polyps. other benign lead points include the appendix, foreign bodies, hamartomas associated with Peutz–Jeghers’s syndrome and lipomas. malignant lead points do occur and are seen in lymphomas, lymphosarcomas and melanomas, and the incidence of these increases with increasing age. Small-bowel intussusception associated with indwelling feeding tubes has also been described.

The ‘classic’ history, as found in many textbooks, is that of an infant presenting with intermittent cramping abdominal pain, vomiting, redcurrant jelly stools and a palpable mass on abdominal examination. less than 25% of patients will present with all features.

The abdominal pain tends to be sudden in onset; there may be drawing of the knees to the chest, hyperextension and breath holding followed by vomiting. The pain may then subside quickly, with the child falling asleep. After repeated episodes the child becomes lethargic, may develop abdominal distension and bilious vomiting.

The passage of blood per rectum is a late feature indicating bowel ischaemia and necrosis, placing the child at risk of overwhelming sepsis.

SPSE 1

Question 59

Which segment of bowel is most frequently associated with intussusception?

A ileoileal
B colocolic
C ileocolic
D caecocolic
E jejunojejunal

Answer 59

C

The most common site for intussusception is ileocolic, with the ileum invaginating into the caecum or right ascending colon.

The right lower quadrant may appear empty on examination (Dance’s sign) because of the intussuscepted mass being pulled upwards.

The second most common type is ileoileocolic, and has two anatomical components: first is ileoileal, which then invaginates into the caecum and colon and becomes ileoileocolic.

Although this type can occasionally occur in the idiopathic group, 40% have a pathological lead point. other rarer forms like appendicocolic, caecocolic, colocolic, jejunojejunal and ileoileal are usually associated with a pathological lead point.

SPSE 1

Question 60

Regarding rectal prolapse and intussusception, which of the following is false?

A In rectal prolapse, a lubricated tongue blade can be passed along the side of protruding mass.

B Rectal prolapse can be differentiated from intussusception, based on clinical symptoms.

C Prolapse of intussusceptum through the anus is a grave sign.

D Prolapse of intussusception exhibit signs of systemic illness.

E All of the above.

Answer 60

A

Prolapse of the intussusceptum through the anus is a grave sign, particularly when the intussusceptum is ischaemic.

Such patients exhibit signs of systemic illness.

on digital rectal examination it is often possible to ascertain whether this is a rectal prolapse or a prolapsed rectal intussusception.

In rectal prolapse it is not possible to advance a tongue blade along the side wall of the prolapsed bowel, whereas in intussusception the blade can be advanced.

Rectal prolapse, although it can present with discomfort, is not generally accompanied by vomiting or signs of sepsis. Hence, based on a good clinical history and examination, one can differentiate between the two and prompt management can be instituted.

The greatest danger is the misdiagnosis of a prolapse of the intussusceptum and attempt to reduce what is thought to be a rectal prolapse.

SPSE 1

Question 61

Which of the following is true of investigations in a case of suspected intussusception?

A Abdominal radiograph is a first-line investigation to confirm the diagnosis of intussusception.

B At ultrasonography, a pseudokidney sign on transverse section is diagnostic.

C At ultrasonography, a doughnut sign on longitudinal section is diagnostic.

D Ultrasonography can predict irreducibility of intussusception using pneumatic reduction.

E All of the above are true.

Answer 61

D

The diagnosis of intussusception can be suspected on plain abdominal radiographs.

Features suggestive of intussusception include an abdominal mass, abnormal distribution of gas and faecal contents, sparse large-bowel gas, and air–fluid levels in the presence of bowel obstruction.

The ‘meniscus’ sign is a crescent-shaped lucency in the colon outlining the distal end of the intussusception.

Although these features are suggestive of intussusception, plain films have limited value in confirming the diagnosis and cannot be used as the sole diagnostic test.

A very high accuracy rate has been reported for the use of ultrasonography in the diagnosis of intussusception. A transverse sonographic image of the bowel consisting of alternating rings of low and high echogenicity, representing the bowel wall and mesenteric fat within the intussusceptum, is diagnostic (target or doughnut sign).

The ‘pseudokidney’ sign seen on longitudinal section appears as superimposed hypoechoic and hyperechoic layers.

other features predict the reducibility of the intussusception by enema and the presence of bowel necrosis; for example, a thick peripheral hypoechoic rim of intussusception, free intraperitoneal fluid, fluid trapped within the intussusceptum, enlarged lymph nodes dragged with the mesentery into the intussusception, a pathological lead point and absence of blood flow in the intussusception on Doppler study.

Although the presence of any of the above features may alert one to the possibility of irreducibility or necrosis, or both, it should not preclude attempting reduction by enema.

SPSE 1

Question 62

Which of the following statements is true with regard to non-operative reduction of intussusception?

A The maximum pressure recommended for pneumatic reduction is 180 mmHg.

B The risk of perforation in pneumatic reduction is 3.5%–6.3%.

C If the child develops a pneumoperitoneum following pneumatic reduction, the child should be taken immediately to the operating theatre.

D Hydrostatic reduction should always be performed under fluoroscopic control or ultrasonographic guidance.

E Children with significant abdominal tenderness should receive opiate analgesia prior to attempts at pneumatic and hydrostatic reduction.

Answer 62

D

Prior to any attempts at non-operative/operative reduction, the infant must be adequately resuscitated with intravenous fluids and a nasogastric tube should be passed to decompress the stomach.

The child should have secure intravenous access and be started on appropriate antibiotics.

Persistent hypotension, peritonitis and bowel perforation are absolute contraindications to hydrostatic and pneumatic reduction.

Hydrostatic reduction involves placing a large catheter per rectum and attempts are made to form a seal by strapping the buttocks together.

under fluoroscopic/ ultrasonographic control the contrast is instilled until contrast medium is seen to flow freely beyond the area of obstruction.

Pneumatic reduction uses a similar technique. Here, air is instilled to a maximum pressure of 80 mmHg for younger infants and 120 mmHg for older children, once again under fluoroscopic control.

The perforation rate associated with pneumatic reduction is reported as 0.4%–2.5%.

If the infant develops a tension pneumoperitoneum, a large-gauge cannula is placed immediately into the right iliac fossa to decompress the abdomen before transferring to theatre.

SPSE 1

Question 63

Which of the following is not an indication for operative management of intussusception?

A clinical evidence to suggest a pathological lead-point

B recurrence within 24 hours following non-operative management

C documentation of imaging confirming presence of a pathological lead point

D postoperative intussusception occurring 2 days post bowel resection and primary anastomosis

E persistence of symptoms after a successful reduction enema

Answer 63

B

Treatment of intussusception has changed over the last 50 years, with a move towards non-operative management.

Non-operative reduction is performed by radiologists with pneumatic or hydrostatic pressure under fluoroscopic or sonographic visualisation and is successful in 85% of cases.

Non-operative reduction of intussusception has been shown to reduce the length of hospital stay, shorten recovery, decrease hospital costs and decrease the complications associated with abdominal surgery.

False-positive reductions do occur because of poor visualisation of the intussusception and reduction process.

Somme et al. (2006) reviewed the factors determining the need for operative reduction in children with intussusception. They reviewed 961 children aged less than 6 years, with intussusception, over an 8-year period. They had an operative rate of 25.4%. They identified that risk factors for operative management were the presence of a meckel’s diverticulum and being transferred from one institution to another over 24 hours after admission.

The French Study Group for Paediatric laparoscopy reviewed 69 patients (48 males and 21 females) with intussusception, who were managed initially with attempted hydrostatic reduction but required operative management.

In total 31.9% required an open procedure, 11 patients because of failure of laparoscopic reduction.

The risk for conversion to open surgery was found to be directly linked to the length of time between the onset of symptoms and diagnosis, peritonitis at presentation (did not undergo attempts at non-operative management) and the presence of a pathological lead point.

They concluded that children with a history less than 36 hours with no signs of peritonitis were the best candidates for laparoscopic reduction.

Indications for operative reduction include:

● irreducible recurrence

● clinical evidence to suggest a pathological lead point

● documentation of a pathological lead point by an imaging procedure

● persistence of symptoms after completion of the reduction enema.

Pathological lead points can be identified in about 6% of cases.

Naturally, general manifestations of underlying disease indicate the specific cause of the intussusception for example perioral pigmentation in Peutz–Jeghers’s syndrome and the classic rash of Henoch–Schönlein’s purpura seen over the buttocks and extensor aspects of the arms and legs.

Pathological lead points are identified in the majority of children over the age of 5 years and the percentages with respect to age range are shown in Table 39.1.

In a review of 3468 patients with intussusception, the most common lesions acting as a lead point were, in order, meckel’s diverticulum, lymphoma/lymphosarcoma, Peutz–Jeghers’s, duplication cysts with an overall percentage of 6.5%.

SPSE 1

Question 64

Regarding recurrent intussusception, which of the following statements is false?

A Recurrence of intussusception occurs on average in 5% of patients.

B Recurrent intussusception (within 2 weeks of initial presentation) is less likely to reduce with non-operative methods.

C Thirty-three per cent of recurrences occur within 24 hours.

D Intussusception accounts for 3%–10% of postoperative bowel obstruction.

E Recurrent intussusception tends to present earlier.

Answer 64

B

The recurrence rate for intussusception is quoted as occurring in 2%–20% of cases, with the average being 5%.

A third of recurrences occur within the first 24 hours and the vast majority occur within the first 6 months of the initial episode.

Recurrences do not usually have any defined lead point and they are less likely to occur after surgical reduction/resection.

Success rates with enema reduction after one recurrence are comparable with those after the first episode, but less successful after an initial surgical reduction.

This may be due to the parents presenting earlier because of early recognition of worrying symptoms.

SPSE 1

Question 65

Which of the following statements with regard to postoperative intussusception is false?

A Most postoperative intussusceptions are ileocolic.

B Postoperative intussusception is a recognised complication of Wilms’s tumour resection.

C Postoperative intussusception presents at a similar time to those with adhesive obstruction.

D Postoperative intussusception occurs in 0.08% of all paediatric laparotomies.

E Most postoperative intussusceptions have a latent period of 6–8 weeks following surgery.

Answer 65

C

Postoperative intussusception is a rare but well-recognised clinical entity. The reported incidence ranges from 0.5% to 16% of all cases of intussusception and 0.08% of all paediatric laparotomies.

most cases occur after major abdominal surgery, especially in those where there has been extensive retroperitoneal dissection, such as nephrectomy for Wilms’s tumour.

Postoperative intussusception accounts for 3%–10% of cases of postoperative bowel obstruction during childhood.

In contrast to adhesions, which tend to occur within 2 years of laparotomy, postoperative intussusception occurs in 90% of all cases within less than 14 days (64% within the first 7 days) post laparotomy.

only 25% of patients with postoperative intussusception are infants. In postoperative intussusception the lead point tends to be proximal, involving the jejunum or proximal ileum.

The aetiology of postoperative intussusception is varied; presumed causes include a lead point from a suture line or appendiceal stump, disordered intestinal motility secondary to extensive retroperitoneal dissection, postoperative oedema, bowel handling, electrolyte disturbances, radiation and chemotherapy.

SPSE 1

Question 66

Regarding the occurrence of necrotising enterocolitis (NEC), which of the following is true?

A There is no association between birthweight or gestational age and NEC.

B Almost all patients diagnosed with NEC require surgical intervention.

C The mortality rate for NEC is the same for patients managed medi-

cally or surgically and is approximately 50%.

D Over 90% of patients diagnosed with NEC were previously

enterally fed and breast milk can be considered protective when

compared with formula.

e NEC is much more common in male than female newborn babies.