Keywords
intussusception - intestinal obstruction - colonic
Intussusception represents a rare form of bowel obstruction in adults and is an uncommon
cause of abdominal pain, accounting for only 1 to 5% of intestinal obstructions and
5% of all intussusceptions.[1]
[2] Almost 90% of the cases of intussusception in adults are secondary to a pathologic
condition that serves as the lead point, such as carcinoma, polyp, Meckel's diverticulum,
colonic diverticulum, stricture, or benign neoplasm, usually discovered intraoperatively.
It is extremely rare to see intussusception involving descending colon. Two-thirds
of the colonic intussusceptions are associated with primary carcinoma of the colon.
Left-sided colon resection and anastomosis are usually done with proximal covering
ileostomy unlike right-sided resections. The preferred treatment in such cases is
resection of intussusception without initial surgical reduction, to minimize the operative
manipulation of potential malignancy.
Case Report
A 46-year-old man presented to the emergency room with complaints of multiple episodes
of loose stools (15–20 episodes/day) mixed with blood and nonprojectile bilious vomiting
(10–15 episodes/day) for 2 days. He reports acute-onset severe colicky abdominal pain,
associated with abdominal distention during this time period. On general physical
examination, a positive finding of pallor was noted. His recorded vitals at presentation
were: pulse rate 110 beats/min, blood pressure 110/70 mm Hg, respiratory rate 20 breaths/min,
oxygen saturation 98% on room air, and body temperature 98.6°F, and examination of
the respiratory, cardiovascular, and central nervous systems revealed no obvious abnormality.
His abdominal examination showed gross distension with apparent peristalsis and was
diffusely tender with evidence of guarding on palpation. Examination of the external
genitalia, hernial orifices, and back revealed no abnormality. On digital rectal examination,
rectum was collapsed and the finger was stained with mucus.
Blood investigations, that included a complete blood count with liver and kidney function
tests, revealed values within normal range. A plain roentgenogram of the chest and
the abdomen showed grossly dilated large bowel loops, multiple air–fluid levels, absence
of any free intraperitoneal air, and a crescent-shaped soft tissue density projecting
into the gas of the large bowel ([Fig. 1]). Ultrasound of the abdomen revealed an intraluminal echogenic content telescoping
into distal lumen giving “target appearance” with mild proximal upstream dilatation.
Hence, a provisional diagnosis of acute intestinal obstruction secondary to intussusception
was made.
Fig. 1 Abdominal radiograph showing (A) crescent-shaped soft tissue density in an air–fluid level in erect view and (B) grossly dilated large bowel loops with absent rectal gas shadow in a supine film.
Initial resuscitation that preceded emergency surgery included oxygen supplementation,
nasogastric decompression, intravenous fluids, and antibiotics. A note of dilated
large bowel loops due to colocolic intussusception, present from distal transverse
colon till sigmoid colon, was made on exploration of the abdomen. On gentle palpation,
tight constriction at the splenic flexure due to telescoping of distal transverse
colon and adjoining greater omentum into the descending colon could be appreciated.
The healthy condition of the involved large bowel segment warranted a left hemicolectomy
with resection from mid-transverse to the sigmoid colon followed by a primary end-to-end
colocolic anastomosis ([Fig. 2]). The patient was allowed orally on the fourth postoperative day on return of bowel
function and went home with a healthy wound and no abdominal complaints. The resected
mass sent for histopathological examination showed gray–white areas with hemorrhage.
Finally, the microscopic report was suggestive of a well-differentiated adenocarcinoma
(PT2N0M0) arising in a tubular adenoma polyp, with no lymph vascular invasion or perineural
invasion ([Fig. 3]). Hence, the final diagnosis was acute intestinal obstruction secondary to malignant
left-sided colocolic intussusception.
Fig. 2 Intraoperative photograph depicting (A) constriction at splenic flexure with dilated adjacent distal colon and (B) resected specimen of the large bowel.
Fig. 3 Histopathological examination after hematoxylin and eosin stain demonstrating (A) well-differentiated adenocarcinoma (×40), (B) tumor cells infiltrating into the muscularis propria (×100), and (C) tumor cells arranged in a glandular pattern with a moderate degree of nuclear pleomorphism
(×400).
Discussion
Intussusception could be described as an “introversion” of the proximal bowel with
its mesenteric fold within the lumen of the adjacent distal bowel as a result of overzealous
or impaired peristalsis, further obstructing the free passage of intestinal contents
and, more severely, compromising the mesenteric vascular flow of the intussuscepted
segment. Adult intussusception is uncommon; it accounts for only 5% of all cases of
intussusception. The clinical presentation of intussusception varies from acute, subacute,
to chronic nonspecific symptoms.[3] Adults usually present with nonspecific and often long-standing complaints. The
classic triad of abdominal mass, hemoglobin-positive stools, and tenderness of intussusception
are rarely found in adults.[3] Literature states that only ∼1 to 5% of intestinal obstructions are due to intussusception.[4] Vomiting, gastrointestinal bleeding, and change in bowel habits are some of the
nonspecific symptoms of intussusception that were the presenting complaints of our
patient.
Intussusception can be broadly classified into enteric (jejunojejunal, ileoileal),
ileocecal, ileocolic, and colonic based on the location. Ileocolic intussusception
is the most common type, accounting for 80% of cases in children. Left-sided adult
colon intussusception is a rare entity.[5] The patient, described herein, had colocolic intussusception (transverse colon prolapsing
into the descending colon). Intussusception can also be classified according to the
etiology (benign, malignant, and idiopathic). Small bowel intussusceptions are usually
benign unlike large bowel, which are mostly malignant. A sessile polypoid mass measuring
6 × 5 cm was found, as the lead point at the level of mid-transverse colon, postresection
in our patient.
Only 8 to 10% of adult intussusceptions are idiopathic, unlike in children which are
90%. In adult patients, intussusception lead points are typically pathological in
90% of cases, 65% of which are neoplastic in nature.[6] Colonic intussusception usually has a malignant pathology and needs high suspicion.
Adenocarcinoma is the most common etiology of malignant colonic cases. In subjects
presenting with enteric malignant intussusception, metastatic melanomas are the commonest.
In benign causes, Meckel's diverticulum and lipoma rank first in enteric and colonic
intussusception, respectively.[7]
[8]
The diagnosis of intussusception is rarely made preoperatively. Abdominal radiographs,
though not sensitive or specific, are the first diagnostic tool in emergency and may
help in identifying the site of obstruction. An ultrasound of the abdomen may be less
useful in adults, as often cannot identify the pathologic lead point but quite handy
in the setting of a palpable abdominal mass. Barium scan, diagnostic and therapeutic
modality in the children, has been replaced by an abdominal computed tomography (CT)
scan in adults because it has been proved to be more informative and most sensitive.
Stacked coin, coil-spring appearance, or cup-shaped filling defect is characteristically
demonstrated in barium studies.[9] CT scan helps in revealing the site and cause of intussusception (underlying pathology)
apart from the diagnosis itself. It has a diagnostic accuracy of 58 to 100%. Tomography
may be helpful in judging the degree of vascular compromise if walls of the intussusceptum
demonstrate any fluid or gas collection.[10] The presentation of acute intestinal obstruction with peritonism and visualization
of “target sign” on ultrasonography led to the decision of upfront surgery in the
described patient.
Most surgeons agree on the fact that laparotomy is required. The current treatment
strategy is to go for resection without reduction to avoid the risk of seeding and
dissemination of tumor cells.[11] On the contrary, various case reports have shown limited resection of bowel after
reduction preoperatively. So, if a benign etiology is diagnosed preoperatively by
colonoscopy, it is suggested that we can attempt the reduction of intussusception.
Colonoscopy, a very efficient and safe method of treatment for intussusceptions in
children, has limited therapeutic role in adults.[12] It has been reported that left-sided or rectosigmoid colon resection is performed
with construction of proximal stoma specially in cases of emergency surgery. Our patient
could be successfully managed with a primary anastomosis without stoma due to the
absence of intraperitoneal contamination and the involved bowel segment being nongangrenous.
The laparoscopic approach could be feasible in selected cases only because when a
bowel obstruction occurs, bowel edema is developed, and little space is left in the
abdominal cavity.[13]
Conclusion
Although rare, left-sided colocolic intussusception in adults requires the surgeon
to understand the epidemiology and various treatment options. Preoperative radiology
facilitates diagnosis. En bloc resection is the preferred surgical treatment for large
bowel intussusception due to underlying pathologic lead point. In cases with benign
etiology, unnecessary resections are avoided to prevent short bowel syndrome. A covering
ileostomy may be avoided in healthy bowel or minimal peritoneal contamination.
