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E
C R
H. Randolph Bailey, Michael J. Snyder, and Colin P. Bird
INTRODUCTION
Endometriosis is a disease characterized by the presence of endometrial glands and stroma outside the uterine cavity. A chronic
inammatory reaction induces scar tissue and adhesion formation
that may distort a woman’s pelvic anatomy and cause disabling pelvic pain and intractable infertility. Although the cause of this disease
is unknown, the most likely explanation involves the implantation
of viable endometrial cells from retrograde menstruation through
the fallopian tubes. Endometriosis has been estimated to aect up
to 15% of all women of reproductive age. Twenty percent of women
with endometriosis will have intestinal involvement, and the majority of these cases involve the rectosigmoid region. Colon and rectal
surgeons most commonly become involved in the management of
patients with intestinal endometriosis as a combined procedure with
a gynecologist treating the other pelvic implants, or in the management of an endometrioma masquerading as a neoplastic or inammatory lesion.
PAIN
Pain, the most common symptom of endometriosis, aects up to 80%
of patients who are subsequently diagnosed with the disease. Dysmenorrhea is the most common gynecologic symptom. Intestinal
symptoms of patients with deep inltrating endometriosis are pelvic pain upon defecation (which can be cyclical), dyspareunia, and
rectal bleeding. In women undergoing laparoscopy for pelvic pain,
endometriosis is discovered in 30% to 50% of cases. Although the
total lesion volume oen equates to the degree of pain, some women
with extensive endometriosis experience little or no pain. Symptoms
appear to be related to the depth of penetration, the type of lesion,
and its location. Implants involving the uterosacral ligaments and
rectovaginal septum are most oen implicated in patients with pelvic
pain. is pain is typically most intense just prior to the onset of menstruation. It is oen associated with back pain, dyschezia, and levator
muscle spasm and is more severe with advanced stages of endometriosis. e presence of dyspareunia is oen seen with xation of the
pelvic organs, especially in the cul-de-sac of Douglas, the uterosacral
ligaments, and the rectovaginal septum.
INFERTILITY
e exact causal relationship between endometriosis and infertility
is also unclear, but the correlation is well established. In women with
known endometriosis, the infertility rate is 30% to 50%, and conversely, in infertile women, the incidence of endometriosis is 25%
to 50%. Fecundity in normal couples ranges from 0.15 to 0.20 per
month and decreases with age, whereas women with endometriosis
tend to have a lower monthly fecundity of about 0.02 to 0.1. ere
is little disagreement that moderate to severe disease with mechani-
cal distortion of the fallopian tubes, ovaries, and peritoneum can
potentiate infertility. Pelvic endometriosis and the resulting inam-
matory response can produce dense, brotic adhesions that may
signicantly interfere with both the oocyte release from the ovary
and the ability of the fallopian tube to pick up and transmit the
oocyte to the uterus. In moderate or severe endometriosis, the preg-
nancy rates aer surgical removal of the endometrial implants are
50% and 40%, respectively, compared with only 7% when expect-
ant management is practiced. Treatment of infertile patients with
mild endometriosis is more problematic. Infertile women with mild
endometriosis did not have any improvement in fertility with either
medical or surgical therapy compared with expectant management.
Other studies have demonstrated a lower pregnancy per cycle rate
in patients with mild endometriosis compared with those who are
free of the disease.
DIAGNOSIS
Physical Examination
Mild cases of endometriosis may not be demonstrable on physi-
cal examination. e diagnosis may not be made unless the patient
undergoes laparoscopy. Bimanual and rectal examination may reveal
nodularity or induration in the utero-sacral ligaments or the cul-de-
sac of Douglas. Fixed tender retroversion of the uterus in a patient
without previous pelvic surgery raises suspicion for endometriosis.
Cyclical pelvic and abdominal pain or bleeding from any location
should be investigated for endometriosis. e inguinal canal, previ-
ous incisions, umbilicus, and lungs can all potentially harbor endo-
metrial implants.
Endoscopy
Endoscopic evaluation of the large bowel is oen normal except
in severe disease with inltrating nodular endometrial implants.
Colonoscopy is most useful in excluding colon cancer from the dif-
ferential diagnosis, especially in older patients presenting with a rec-
tosigmoid mass while undergoing hormone replacement therapy.
Because the typical lesions in endometriosis begin as serosal nodules,
colonoscopic evaluation will generally demonstrate grossly normal
appearance of the mucosa. Occasionally, however, signicant luminal
narrowing may be identied, a result of inltration of the submucosa,
which produces nodularity and distortion of the overlying mucosa.
ese areas of distorted bowel may produce pain, suggesting the
diagnosis of endometriosis.
Rigid proctoscopy is very helpful in predicting the depth of rec-
tosigmoid involvement in patients with severe endometriosis of the
341
EndomEtriosis of thE Colon and rECtum342
cul-de-sac of Douglas. e mucosa is oen xed over areas of submucosal or deep muscular involvement with tethering or puckering
and loss of the normal mucosal mobility. In our experience, these
mucosal ndings have correlated with signicant intestinal wall invasion by the endometrial implant and oen signal a need for intestinal resection. Our experience has demonstrated that this physical
examination nding has a 70% positive predictive value for segmental colonic resection.
Imaging
Ultrasonography, barium enema, computerized tomography (CT),
magnetic resonance imaging (MRI), and immunoscintigraphy have
all been used to help diagnose endometriosis. Oen these tests are
obtained during the evaluation and workup of chronic pelvic pain
and/or bleeding from the reproductive tract or colon. Varying utility
and sensitivity can be attributed to each modality, and their value is
ultimately judged against the diagnostic gold standard, laparoscopy.
Laparoscopy, however, can be inconclusive in assessing deep inltrating disease and cul-de-sac involvement and in correctly predicting
intestinal resection. As such, each imaging modality may have a role
in future operative planning.
Transvaginal ultrasound provides specicity greater than 90% for
ovarian endometriosis. In contrast, pelvic ultrasound is not very sensitive in detecting focal nonovarian endometrial implants. Although
the procedure itself can be quite painful to the patient, if it can be
tolerated, endorectal ultrasound will detect rectal wall invasion of
endometrial implants in the cul-de-sac. Sensitivity and specicity of
endorectal ultrasound for preoperative staging of rectal wall involvement by endometriosis have been reported to be as high as 97%, but
its usefulness is limited by pain.
CT is the imaging technique used most frequently for the evaluation of abdominal and pelvic pain, mainly because of the availability
of CT rather than its utility or sensitivity for this diagnosis. ere is no
standard CT appearance for a mass caused by endometriosis to clearly
dierentiate it from pelvic masses due to other causes. CT colonography may change this limitation because it is able to identify luminal
alterations of the rectosigmoid colon and obliteration of the cul-de-sac,
with sensitivity and specicity approaching 96% and 80%, respectively.
MRI continues to gain an increasing role in the diagnostic workup
of endometriosis. Multiplanar capabilities and superior so tissue
contrast are extremely useful in the detection of deeply inltrating
endometriotic implants, even in the setting of an intense desmoplastic response that may result in complete obliteration of the posterior
cul-de-sac and xed retroversion of the uterus. Colorectal involvement is strongly suspected when disappearance of the fat plane
between the rectum and the vagina is noted, when the hypointense
signal of the anterior bowel wall is lost on T2-weighted images, and
when a contrast-enhanced mass involving the bowel wall is noted
on T1-weighted images. e sensitivity and specicity of MRI for
detecting and adequately evaluating colorectal endometriosis is
approximately 78% and 98%, respectively. e ability of 1.5-T MRI
to characterize the extent of cul-de-sac obliteration by endometriosis
fell short, but the recent introduction of 3-T MRI oers a better space
and contrast resolution, which may translate to better detection of
cul-de-sac implants and associated bowel involvement.
SURGICAL MANAGEMENT
e major goal of surgery in the management of endometriosis is
to completely excise or ablate all endometrial implants. Secondary
goals include the preservation of ovarian function and minimizing
postoperative adhesion formation. When the rectum is involved, several approaches are to be considered, including shaving the disease
o the rectal wall, a formal full-thickness disk excision of the anterior
rectal wall, or a segmental excision of the rectum. Mobilization of the
rectum is an important part of treatment, even when the rectum is not
directly invaded by endometriosis, to allow safe excision of the pelvic
disease without injury to the rectum. e most eective treatment of
pelvic pain still consists of surgical castration along with resection
of the endometrial implants. However, many young patients have a
strong desire to maintain their options for pregnancy. erefore, we
approach these patients in concert with gynecologists experienced in
treating pelvic endometriosis to completely remove all gross disease,
restore normal anatomy, and optimize fertility.
e obliterative nature of endometriosis results in distortion of
normal tissue planes, an environment that frequently is further complicated by adhesions from previous operations. Our goal is safe,
meticulous removal of all endometriosis implants with minimal morbidity. As a result, we elect to perform most of these cases via an open
laparotomy through a Pfannenstiel incision. All patients undergoing
surgery for advanced endometriosis undergo a full mechanical bowel
preparation. We place the patient in the low-lithotomy position to
permit access to both the vagina and rectum for instrumentation.
We frequently place ureteral stents, especially for reoperative cases.
Intraoperative instrumentation of the vagina, proctoscopic evaluation of the rectum, and easy identication of the ureters all aid in
both avoiding iatrogenic injury to these structures and identifying
the endometriosis.
Within the cul-de-sac of Douglas, endometriosis implants are
oen deep brotic nodules extending from the posterior vagina and
anterior rectum to the uterosacral ligaments. ey frequently invade
both the vagina and rectum. Although we routinely employ gonadotropin-releasing hormone therapy preoperatively, a brotic reaction
around the endometriosis tissue results in scarring in the bowel muscularis, leading not only to persistence of the patient’s symptoms but
also mandating surgical resection for cure. It is vital to note that this
“scar” can oen be quiescent endometriosis that grows when hormonal suppression is stopped. Hormonal therapy is most eective
in eradicating peritoneal disease and works poorly on ovarian and
bowel implants. As a result, removal of these implants can require
either resection of a portion of the rectal wall or segmental rectal
resection.
Dissection of the lesion from the vagina isolates the lesion to
the rectal wall and permits en bloc removal. Frequently no discernible plane exists between the endometrial nodules and the walls
of the rectum or vagina. In women desiring eventual pregnancy,
it is vital to completely remove the lesion. Care should be taken to
avoid penetration of the vaginal wall and injury to the cervix; however, should the mucosa be damaged, the key is recognizing that
an injury has occurred and subsequently making the appropriate
repair. Proceeding with the posterior and lateral dissection rst to
adequately dene the lesion, in concert with blunt dissection of the
rectovaginal plane below the area of involvement, can help clarify
the distorted anatomy and avoid inadvertent entry into the bowel
lumen or vagina.
Disk excision of the anterior rectal wall, by either laparoscopic or
open technique, is performed for single lesions that are usually less
than 2 cm in diameter (Fig. 68-1). When performing disk excision,
the lesion is marked circumferentially with electrocautery followed
by the placement of stay sutures. To minimize thermal spread, we use
cutting current to perform a full-thickness excision. A rim of normal
bowel is removed with the endometriosis to ensure complete removal
of the lesion. Transverse closure by interrupted, absorbable suture
(our preference is 2-0 or 3-0 Vicryl) is then used to close the defect.
Segmental resection of the rectosigmoid is reserved for larger
lesions. High ligation of the sigmoid vessels is unnecessary, and the
anastomosis may be either hand sewn or stapled. Our goal is to achieve
margins with grossly normal bowel, and unless multiple lesions exist,
an extensive colonic resection is not required. Although resection is
amenable to laparoscopic techniques, we believe that poorly discernable tissue planes, the intimate association of the rectum and vagina,
the very rare occurrence of distal inltration of endometriosis down
to the mid to lower rectum, and the tactile feedback aorded by an
FIGURE 68-1 Endometriosis disk excision from the anterior rectal
wall.
open technique permits a more complete resection, better long-term
results, and minimal morbidity.
Removal of small intestine lesions requires sharp excision or
vaporization with electrocautery and/or the CO
laser. Both tech-
2
niques have the potential for iatrogenic injury to the intestinal or urinary tracts. Recognizing when a lesion is completely ablated is highly
dependent on surgical technique and the expertise of the surgeon.
Techniques that minimize injury to the surrounding tissue, such as
a cutting current to outline lesions to be removed by electrocautery
and high-power density settings with the CO
laser, are utilized. Aer
2
the lesion is removed, the bowel wall is carefully assessed. Because
most of these supercial lesions can be removed without entering the
mucosa, the defects usually can be reinforced with interrupted longitudinally placed Lembert stitches.
Results after Surgical Therapy
Because of the wide variability in the operative approach to endometriosis and the obvious need for postoperative laparoscopy to
document asymptomatic failure of therapy, recurrence of endometriosis aer surgical excision is dicult to determine. Studies suggest a rate of recurrent endometriosis ranging from 7% to 26%; no
conclusive data indicate that a hysterectomy further reduces this
percentage.
Evaluating the resolution of preoperative pelvic pain or infertility
is an easier metric by which to judge surgical therapy. In the largest
series of intestinal resections for advanced intestinal endometriosis,
with a median follow-up of 5 years, it was found that 86% of patients
had complete or near complete relief of their preoperative pelvic pain,
as well as a 50% crude pregnancy rate, with minimal morbidity, no
anastomotic leaks, and no documented instance of recurrent colorectal endometriosis. Currently, in patients with at least one ovary and a
uterus, in-vitro fertilization can yield a much higher pregnancy rate
than 50%.
In contrast, evaluation of full-thickness disk excision of bowel
implants showed that approximately 40% were incomplete. A review
of other large series reveals morbidity from segmental resection ranging up to 20%. Laparoscopic series of intestinal resections performed
for extensive endometriosis have reported similar results, and more
COLON 343
recent series have demonstrated robotic feasibility. However, it is our
group’s practice to perform these cases via open laparotomy through a
Pfannenstiel incision. We believe the role of tactile feedback in assessing surgical margins and complete removal of deep pelvic lesions is
crucial to removing all foci of disease and minimizing recurrence. In
our experience, this practice has helped obviate the need for “ultra
low” resections and intestinal diversion. It should be noted, however,
that for severe disease, laparoscopic ablation, when possible, had
similar crude pregnancy rates in comparison with laparotomy, and
both techniques were clearly superior to medical management alone.
Combined Medical and Surgical Therapy
In isolation, both medical and surgical therapy for endometriosis may
not be successful in eradicating the disease. Medical therapy aects
endometrial implants variably, and the recurrence rate aer cessation of therapy is high. Surgery alone may not remove microscopic
disease, and postsurgical adhesions may contribute to postoperative
pelvic pain and infertility. As a result, combination therapy, before
and/or aer surgery, has been used for several years. e rationale
for preoperative medical therapy conducted over a period of 3 to 6
months is to decrease the inammation, the vascularity, and possibly
the size of the endometrial implants, thereby allowing easier excision
with diminished formation of adhesions. In addition, 6 months of
hormonal suppression given preoperatively with all stages of endometriosis has demonstrated an improvement in pregnancy rates.
Although the optimal length of therapy is still unclear, our current
philosophy is to administer a gonadotropin-releasing hormone agonist for 3 months prior to denitive surgery. Recent prospective studies have further validated the role of hormone therapy in conjunction
with surgical care, demonstrating that those patients had the lowest
recurrence and highest cure rate.
CONCLUSION
Patients with endometriosis involving the intestines, particularly
the rectosigmoid junction, commonly report pelvic pain, dyspareunia, and rectal bleeding and oen have diculty with fertility. ese
symptoms can be related to the depth of penetration and location of
the lesion and may be cyclical in nature. Endometriosis can frequently
be diagnosed upon physical examination. Imaging studies such as
MRI and CT may be ordered to conrm the diagnosis, but frequently
they do not adequately illustrate the degree or depth of involvement
of these lesions, particularly in the rectosigmoid junction. As a result,
the extent of intervention from the colorectal surgeon, be it local
excision, segmental excision, or none at all, is commonly decided in
the operating room. Augmenting surgical therapy with medical management has been shown to further improve these outcomes, both in
reducing recurrence rates and improving fecundity.
S u g g e S t e d R e a d i n g
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Bailey HR, Ott MT, Hartendorp P. Aggressive surgical management for ad-
vanced colorectal endometriosis. Dis Colon Rectum. 1994;37:747–753.
Bazot M, Darai E, Hourani R, etal. Deep pelvic endometriosis: MR imag-
ing for diagnosis and prediction of extension of disease. Radiology.
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Buttram VC, Reiter RC, Ward SM. Treatment of endometriosis with Danazol:
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Chapron C, et al. Operative management of deep endometriosis inltrating
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Doniec JM, Kahlke V, Peetz F, etal. Rectal endometriosis: high sensitivity
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management. Dis Colon Rectum. 2003;46:1667–1673.
EndomEtriosis of thE Colon and rECtum344
Doyle JO, Missmer SA, Laufer MR. e eect of combined surgical-medical
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Garcia CR, David SS. Pelvic endometriosis: infertility and pelvic pain. Am J
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Inoue M, Kobayshi Y, Honda I, et al. e impact of endometriosis on
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Jansen RPS. Minimal endometriosis and reduced fecundability: prospective
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Jeong SY, Chung DJ, Myung Yeo D, etal. e usefulness of computed tomo-
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Olive DL, Lee KL. Analysis of sequential treatment protocols for endometrio-
sis-associated infertility. Am J Obstet Gynecol. 1986;154:613.
Schwartz D, Mayaux MJ. Female fecundity as a function of age: results of
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husbands. CECOS. N Engl J Med. 1982;306(7):404–406.
P C
I
Susan Galandiuk, Jonathan Rice, Peter G. Deveaux, and Russell Farmer
INTRODUCTION
Pneumatosis cystoides intestinalis (PCI) is a condition in which
multiple gas-lled cysts occur under the serosa or mucosa of the
gastrointestinal tract. PCI is uncommon but increasingly is being
recognized and reported. PCI was described by Du Vernoi in 1730
during cadaver dissection, and it has long been noted in animals.
PCI occurs in two clinical settings: fulminant, which usually requires
immediate surgery, and benign, an incidental nding at colonoscopy
or laparotomy.
ETIOLOGY
PCI has several possible causes, the most notable of which are
mechanical and bacterial. e mechanical theory suggests that gas
is forced into the bowel wall by one or more mechanisms: (1) pulmonary action, (2) trauma, (3) mucosal injury, (4) anastomoses,
(5) obstruction, (6) increased pressure, or (7) increased peristalsis.
Chronic obstructive pulmonary disease may be associated with PCI.
Because coughing, articial insuation of the lungs, straining, and
alveolar ectasia lead to alveolar rupture, air is thought to dissect into
the mediastinum, along the great vessels to the retroperitoneum, and
along the perivascular space, through the mesentery, to the bowel
serosa. Experiments in the early 1960s showed that injection of air
into a catheter inserted into the mediastinum of animals resulted
in subserosal PCI of the colon and sigmoid. e distribution of PCI
is related to the bowel vascular pattern and has been reported aer
such procedures as sigmoidoscopy, colonoscopy, and mucosal biopsy.
Breaks in mucosal integrity, such as ulcerations, also may permit entry
of intraluminal gas into the bowel wall. PCI has been reported aer
end-to-end anastomosis and with increased frequency in patients
who have undergone a jejunoileal bypass. In these patients, the condition aects the bypassed small bowel—usually the midjejunum.
Some investigators believe that the ileosigmoid anastomosis permits
large bowel ora to enter the ileum, with subsequent increased gas
production and cyst formation. Other researchers believe that the
absence of bile may increase bacterial growth, leading to increased
hydrogen production and cyst formation.
A bacterial origin of PCI is supported by several analyses of cyst
gas. Normal luminal gas is approximately 15% hydrogen, compared
with 50% hydrogen found in PCI cysts. Common species in the gut
microbiome are known hydrogen producers. e bacterial cause
of PCI is also supported by breath-hydrogen analyses of aected
patients. Many patients with PCI have increased breath hydrogen levels, leading some investigators to postulate that the high amount of
hydrogen produced by bacteria may be responsible for the persistence
of cysts. Several investigators have injected organisms such as Esch-
erichia coli, Enterobacter aerogenes, and Clostridium perfringens into
intestinal submucosa in animals during experiments and were able to
induce PCI. It is thought that a functional break in the mucosa, with
penetration of bacteria into the submucosa or subserosa or both, may
be involved in this formation of intestinal gas cysts. Interestingly, the
phenomenon of PCI persists independent of the bacteria undergoing
translocation. Decreased intestinal mucosal resistance to infection or
ulceration also may lead to severe fulminant PCI, which occasionally
is seen in adults.
CLASSIFICATION
PCI is still a relatively uncommon nding. It can be classied as either
adult or infantile and can be benign or fulminant. Infantile PCI is
usually submucosal and fulminant, as acute necrotizing enterocolitis,
with edema of the bowel wall and dilatation of lymphatics. In adults,
PCI is usually benign. However, fulminant PCI can occur with a high
mortality rate despite surgery. e benign form can be divided into
primary (idiopathic) and secondary forms. e cysts are submucosal,
subserosal, or both, and are usually found incidentally. e secondary form of the disease accounts for approximately 85% of cases. PCI
aecting the small bowel and ascending colon is thought to be secondary, whereas that aecting the descending colon is idiopathic or
primary. Secondary PCI can be associated with a proximal gastrointestinal lesion such as pyloric stenosis or with chronic obstructive
pulmonary disease. Box 69-1 illustrates some conditions associated
with secondary PCI.
HISTOLOGY AND GROSS PATHOLOGY
e histologic changes observed in PCI can be replicated by injecting air into subcutaneous tissue. Aer several days a foreign body
reaction occurs with inammation, development of a histiocytic
lining, and pericyst brosis. e intestinal gas cysts of PCI are also
surrounded by foreign body giant cells and macrophages (Fig. 69-1).
Serosal cysts usually occur near the mesenteric border, with only a
few on the antimesenteric margin. Cysts are frequently located on
loops of dilated bowel and range in size from a few millimeters to
several centimeters. ey can occur singly or in clusters, occasionally
appearing like soap bubbles on the serosa (Fig. 69-2). Submucosal
cysts, although not visible, give the bowel a spongy consistency; cyst
gas is under pressure and “hisses” when the cysts are punctured.
SYMPTOMS
Symptoms associated with PCI are nonspecic and may include diarrhea and distention. Lesions in the terminal ileum or colon may occur
in the context of a patient with constipation, rectal bleeding, passage
of mucus per rectum, abdominal pain, vague abdominal discomfort,
weight loss, malabsorption, and excessive atus. Hemorrhage associated with PCI is presumed to be due to congested mucosa overlying
345
Pneumatosis Cystoides intestinalis346
BOX 69-1: Conditions Associated With Secondary
Pneumatosis Cystoides Intestinalis
Gastrointestinal
Necrotizing enterocolitis
Pseudomembranous colitis
Ulcerative colitis
Crohn disease
Diverticulitis
Appendicitis
Cholelithiasis
Volvulus
Intestinal obstruction or strangulation
Intestinal anastomosis
Tuberculous enteritis
Refractory celiac sprue
Mucosal trauma
Idiopathic megacolon
Neurogenic bowel dysfunction
Esophageal stricture
Peptic ulcer disease, including pyloric channel lesion
Pyloric stenosis
Nongastrointestinal
Chronic obstructive pulmonary disease, including emphysema
and asthma
Cystic brosis
Collagen vascular diseases
Systemic sclerosis
Dermatomyositis
Exposure to alkyl halides, including chloral hydrate and trichlo-
roethylene
Steroid therapy
Cancer chemotherapy
Transplant-related immunosuppression
Kidney
Heart
Liver
Gra-versus-host disease
Lactulose treatment
Cytomegalovirus infection
Acquired immune deciency syndrome
Leukemia
Lymphoma
From Wong SL, Galandiuk S. Pneumatosis cystoides intestinalis. In: Zuidema GD, Yeo CJ,
eds. Surgery of the Alimentary Tract. 5th ed. Vol. 5. Philadelphia: Saunders; 2002:
461-466.
FIGURE 69-1 High-magnification photomicrograph of pneumatosis
cystoides intestinalis illustrating a gas cyst (arrow), lined in part by
multinucleated giant cells.
FIGURE 69-2 Benign pneumatosis cystoides intestinalis with subserosal
cysts on the mesenteric margin of the ileum distal to a small bowel
stenosis.
the cysts. If partial small bowel obstruction occurs as a result of the
cysts, the patient may experience symptoms of vomiting and abdominal distention. Diarrhea and abdominal distention are the most frequent presenting symptoms in patients with jejunoileal bypass and
PCI. Increased or abnormal peristalsis due to the presence of cysts
may lead to volvulus. Spontaneous pneumoperitoneum is seen
more frequently with the small bowel variant. Complications that
can occur in this condition include volvulus, pneumoperitoneum,
intussusception, intestinal obstruction, tension pneumoperitoneum,
intestinal perforation, and hemorrhage. Cysts also may lead to extrinsic compression of the bowel and cause obstructing adhesions. Lack
of symptoms is common, although only for the benign form of PCI.
Fulminant PCI, as in necrotizing enterocolitis, may cause pneumoperitoneum, diarrhea, abdominal pain, bleeding per rectum, and
ultimately leukocytosis with overt signs of peritonitis and sepsis.
DIAGNOSIS
In fulminant cases, a plain lm of the abdomen may show gas in the
bowel wall and pneumoperitoneum (Fig. 69-3). Crepitance may be a
nding on rectal examination. Ischemic or hemorrhagic necrosis of the
bowel with mesenteric thrombosis is oen present at the time of the
operation or may be seen on preoperative computed tomography (CT)
or CT angiography scans. CT scans may show air in the bowel wall or
tracking along the mesenteric vessels to the liver (Figs. 69-4 and 69-5).
In infantile PCI, concentric rings of gas in the small bowel are pathognomonic. Gas-lled cysts may protrude into the lumen, and streaks of
air may separate loops of bowel. Gas also may be seen in the portal and
mesenteric veins, which is usually a very ominous sign.
e benign forms of PCI may present with free air under the
diaphragm or retroperitoneal gas outlining the kidneys, indicating
spontaneous perforation with pneumoperitoneum or pneumoretroperitoneum. PCI can result in prolonged recurring idiopathic and
asymptomatic pneumoperitoneum without peritonitis. e small
bowel is usually involved in these cases. Persistent pneumoperitoneum implies that gas enters the peritoneum at a rate equal to its
absorption. Some investigators have suggested that subserosal cysts
rupture, followed by repair of rupture sites and relling of cysts.
Repeated rupture occurs, with brosis and obliteration of older
cysts. In the absence of pneumoperitoneum, this curious disease
of the small bowel cannot be diagnosed on abdominal plain lms.
Cysts are dicult to dierentiate from the small bowel gas pattern.
PCI of the colon may have a polypoid appearance upon a barium
enema and colonoscopy. Cysts can be dierentiated from growths
and intramural hematomas, because the entire cyst outline is visible.
Unlike polyps, cyst size changes with distention of the colon, with
attening of the base, and the radiolucency extends into the bowel
wall. In some cases, PCI can be diagnosed by sigmoidoscopy.
COLON 347
FIGURE 69-3 A flat film of the abdomen revealing pneumoperitoneum
and air in the bowel wall (dark arrows in right lower quadrant).
FIGURE 69-4 Computed tomography showing a patient with pneuma-
tosis cystoides intestinalis of the gastric wall (right arrow) and hepatic
portal venous gas (left arrow).
Dierential diagnosis is rarely a problem; the condition is usually an incidental nding at laparotomy. Enterogenous intestinal
cysts may be confused with PCI. ese cysts are usually single and
intramural, most frequently seen in the terminal ileum, lined by
intestinal mucosa, and occur in young adults and children. Diuse
tissue emphysema is usually secondary to a gas-producing infection
and quite dierent from PCI, because gas is distributed in all tissue
FIGURE 69-5 Computed tomography showing a patient with small
bowel pneumatosis cystoides intestinalis (arrow) and air tracking along
mesenteric vessels.
spaces. In emphysematous gastritis, gas is present in the stomach wall.
Unlike PCI, this condition is characterized by hematemesis, pain, and
leukocytosis. Lymphangioma of the peritoneum is an extremely rare
entity that may resemble PCI. In lymphangioma of the peritoneum,
however, cysts contain lymph rather than gas and are not lined by
giant cells. In sclerosing lipogranulomatosis, which usually occurs in
fat tissue, cystic spaces are lined by macrophages and giant cells, but
these spaces are lled with fat rather than gas. Lymph nodes aected
by Whipple disease appear similar to those in pneumatosis but are
associated with intestinal lipodystrophy, whereas those in pneumatosis are not associated with intestinal lipodystrophy.
TREATMENT
Benign PCI noted as an incidental nding at a laparotomy for another
indication may not require any treatment but may warrant an intraoperative consultation. If a segment of bowel aected by subserosal
cysts is found during the course of a laparotomy or laparoscopy, an
eort should be made to ensure that no obstruction is present and
that there is no loss of integrity of the bowel wall itself. If an obstruction is found, it should be treated with resection or strictureplasty
(Fig. 69-6). Strictureplasty, for example, is used in the treatment of
short brotic strictures in patients with Crohn disease. If nonviable
areas of bowel are found, the aected segments must be resected.
e most important goal prior to therapy is to recognize the entity
for what it is. In some patients, colectomy has been performed for
PCI that appeared to be multiple polyps on a barium enema study.
In addition, abdominoperineal resections have been performed for
lesions that were thought to be malignant but were actually PCI cysts.
If the patient has no symptoms and the aected bowel shows no vascular compromise, no therapy is indicated.
In the rare cases of symptomatic but benign PCI, several treatment
options are available. Recurrence aer treatment is very high. PCI has
been successfully treated with high-ow oxygen breathing or hyperbaric
oxygen therapy, which is based on the fact that gas cysts are lled mostly
Pneumatosis Cystoides intestinalis348
Benign PCI
Benign PCI identified on imaging study
(e.g., pneumoperitoneum on plain film)
Assess patient for risk factors: COPD, history of
jejunoileal bypass, immunosuppressive therapy,
collagen vascular diseases, cystic fibrosis, others
Exclude ulcer disease, Crohn disease,
Negative –
no treatment
EGD, colonoscopy
other mucosal disease
Small bowel capsule
Enteroscopy
Hydrogen breath test
Positive–oral neomycin or
metronidazole, 250 mg qid
FIGURE 69-6 Treatment algorithm for benign pneumatosis cystoides intestinalis (PCI). COPD, Chronic
obstructive pulmonary disease; EGD, esophagogastroduodenoscopy; qid, four times a day.
Benign PCI identified as incidental finding
during laparotomy for other indication
Assess affected bowel for obstruction due to
No obstruction Bowel obstruction due to PCI
No treatment of PCI Short fibrotic stricture
PCI
Long segment
Strictureplasty
Resection
with gases other than oxygen at a pressure above atmospheric pressure.
Increasing the concentration of inhaled oxygen results in a higher partial
pressure of oxygen and a lower partial pressure of nitrogen. Most of the
oxygen is metabolized as it passes through tissue and the end capillary
gas pressure decreases, resulting in a pressure gradient with diusion of
cyst gas into the blood. Several physicians have used inhalation of 70%
oxygen via non-rebreather mask or a head tent, resulting in a partial oxygen pressure of approximately 250 mm Hg for a few days, which may
result in partial or complete radiologic and colonoscopic resolution of
PCI and associated symptoms. Only hyperemic and edematous mucosa
are visible on follow-up colonoscopy. To lessen pulmonary and central
nervous system toxicity, hyperbaric oxygen treatment at 2.5 atm for
2.5 hours for 2 to 3 consecutive days has been recommended. Recurrence has been reported as early as 1 year later and occasionally may
occur immediately. Another therapeutic option for patients with
symptomatic benign PCI is a 2-week elemental diet. High fasting
hydrogen breath levels decrease aer this diet, and gas production is
decreased, because the elemental diet does not reach the colon and less
hydrogen is formed by bacteria. Recurrence rates are high aer this
form of treatment, and cysts have been reported to occur as early as 4
months aer resuming a regular diet. Another alternative treatment is
chronic oral antibiotic therapy with agents such as neomycin or metronidazole, but the recurrence rate is also high with this treatment.
In patients with PCI, treatment is determined by the patient’s clinical condition. Benign PCI is usually asymptomatic, and no treatment
is required. Fulminant PCI seen on CT or a plain abdominal radiograph with associated pneumoperitoneum, increasing leukocytosis,
fever, and a deteriorating clinical course suggests hemorrhagic or
ischemic necrosis of the bowel, and the patient’s condition is usually
poor. Resection of the involved segment with exteriorization of the
ends of the bowel is the safest way to proceed. Failure to operate may
lead to bowel necrosis, perforation, sepsis, and death. Depending on
the timing of the operation, the mortality rate is very high.
S u g g e S t e d R e a d i n g S
Coriat R, Ropert S, Mir O, et al. Pneumatosis intestinalis associated with
treatment of cancer patients with the vascular growth factor receptor
tyrosine kinase inhibitors, sorafenib and sunitinib. Invest New Drugs.
2011;29:1090–1093.
DuBose JJ, Lissauer M, Maung AA, etal. Pneumatosis intestinalis: predic-
tive evaluation study (PIPES): a multicenter epidemiologic study of the
Eastern Association for the Surgery of Trauma. J Trauma Acute Care Surg.
2013;75:15–23.
Duron VP, Rutigliano S, Machan JT, etal. Computed tomographic diagnosis
of pneumatosis intestinalis: clinical measures predictive of the need for
surgical intervention. Arch Surg. 2011;146:506–510.
Galandiuk S, Fazio VW. Pneumatosis cystoides intestinalis: a review of the
literature. Dis Colon Rectum. 1986;29:358–363.
Kernagis LY, Levine MS, Jacobs JE. Pneumatosis intestinalis in patients with
ischemia: correlation of CT ndings with viability of the bowel. AJR.
2003;180:733–736.
Lee KS, Hwang S, Rua SMH, etal. Distinguishing benign and life-threatening
pneumatosis intestinalis in patients with cancer by CT imaging features.
AJR. 2013;200:1042–1047.
Morris MS, Gee AC, Cho SD, etal. Management and outcome of pneumatosis
intestinalis. Am J Surg. 2008;195:679–682.
St. Peter SD, Abbas MA, Kelly KA. e spectrum of pneumatosis intestinalis.
Arch Surg. 2003;138:68–75.
ornton E, Howard SA, Jagannathan J, etal. Imaging features of bowel toxici-
ties in the setting of molecular targeted therapies in cancer patients. Br J
Radiol. 2012;85:1420–1426.
Way ne E, Ough M, Wu A, Liao J, etal. Management algorithm for pneuma-
tosis intestinalis and portal venous gas: treatment and outcome of 88 consecutive cases. J Gastrointest Surg. 2010;14:437–448.
C
Evie Carchman and Massarat Zutshi
INTRODUCTION
Constipation is the most common bowel complaint in the United
States, with an estimated prevalence of 2% to 27%. e wide range is
attributed to the variety of denitions of constipation used by patients
and physicians. e Rome Criteria, which were developed to provide
a standardized denition, require two or more of the following conditions for at least 3 months: straining more than 25% of the time,
hard stools for more than 25% of the time, incomplete evacuation
more than 25% of the time, and/or two or fewer bowel movements
per week. Using these criteria, the estimated prevalence of constipation is 15%, and half the persons aected have obstructed defecation
syndrome. Other standardized denitions exist, such as the one by
Cleveland Clinic Florida.
Women are two to three more times likely to have constipation
than are men. e National Health and Nutrition Examination Survey reported a 10.2% prevalence of constipation in women and a
4.0% prevalence in men. Constipated patients reported eating fewer
fruits and vegetables and drinking more coee or tea. e incidence
of constipation increases with age.
CAUSES
Causes of constipation may be mechanical, functional, or a combination of both. Nonmechanical causes with a normal caliber colon
can include reduced peristalsis as a result of immobility, use of drugs,
increasing age, metabolic disorders, endocrine disorders, neurologic
disease, dietary deciencies, physical or sexual abuse, or just slow
transit. When constipation is associated with a dilated colon, causes
include Hirschsprung disease, Chagas disease, and Ogilvie syndrome.
Anatomic factors aecting defecation include rectal inertia, anismus,
and paradoxical internal sphincter contraction. Rectal prolapse,
descending perineum syndrome, and rectocele are related ndings.
Sometimes an episode of gastroenteritis will result in continued
bowel symptoms long aer the oending bacteria or virus has been
eliminated. e cause of constipation in these patients is unknown,
but up to 25% of cases of irritable bowel syndrome (IBS) may be due
to this problem. Chronic treatment with opioids is a specic and
common cause of colonic inertia due to activation of central μ-opioid
receptors in the gastrointestinal tract. Opioid-induced constipation
is associated with increased use of health care dollars and decreased
quality of life. Laxatives alone are usually insucient to treat this condition because they do not target the underlying cause of the constipation (μ-opioid receptor activation). Methylnaltrexone bromide is a
peripherally acting μ-opioid receptor antagonist, and data support its
use for opioid-induced constipation with a favorable tolerance prole. Rare cases of chronic pseudo-obstruction, an unusual disorder
of the gastrointestinal tract characterized by impaired peristalsis that
can lead to constipation or diarrhea, also have been reported. Patients
present with symptoms of bowel obstruction, but no mechanical
cause is identied. Subgroups of this rare disorder include neuropathy, myopathy, or mesenchymopathy, with neuropathy the most
prevalent. Forty percent of cases are primary and 60% are secondary.
is disease is normally progressive. Treatment includes ruling out
obstruction, evaluating for myopathy or neuropathy, and providing
nutritional support.
CLASSIFYING CONSTIPATION
Clinically, patients with constipation are classied into several
categories:
1. Slow transit (colonic inertia)
2. Irritable bowel syndrome—constipation predominant (IBS-C)
3. Pelvic oor dysfunction (obstructed defecation syndrome)
4. Mixed slow transit/pelvic oor disorder
Colonic inertia is frequently associated with symptoms since
childhood and laxative dependency. IBS-C is usually accompanied by
abdominal pain (which is oen relieved by defecation) and irregular
bowel habits. Pelvic oor dysfunction or obstructed defecation syndrome refers to a symptom complex of prolonged straining, the sensation of incomplete evacuation, and the need for digital manipulation.
ASSESSMENT
History
History is the key to the diagnosis of constipation, and taking time to
develop a full picture of the patient’s symptoms in the setting of his
or her overall health and lifestyle is worthwhile. Obtaining a detailed
account of what constipation means to each individual patient is very
important. Information should be obtained about stool frequency,
consistency, size, and the presence of urgency/straining/incomplete
evacuation. e Bristol Stool Form Scale (BSFS) can provide a visual
and numeric reference as a rough estimate of colonic transit. Lower
scale numbers on the BSFS mean slower transit. e BSFS is scored
between 1 and 7 as follows:
1. Small hard lumps, like nuts
2. Sausagelike but lumpy
3. Sausagelike or snakelike with a cracked surface
4. Sausagelike or snakelike, smooth and so
5. So blobs with clear-cut edges
6. Fluy pieces with ragged edges (a mushy stool)
7. Watery stool
e age at which symptoms began should be documented. Constipation from infancy raises the possibility of Hirschsprung disease.
One should ask about typical dietary choices, focusing on ber content
349
Constipation350
and supplementation, and review the eect of ber supplementation
on constipation. Some but not all patients nd ber supplementation
helpful. e patient should be asked about other symptoms such as
abdominal pain/discomfort/bloating and the eect of defecation on
these symptoms, which may be suggestive of other disease or IBSC. e following histories should be obtained and critically assessed:
detailed medical (including diabetes, hypothyroidism, hypercalcemia, connective tissue disorder, and neurologic disease), family,
dietary, psychiatric, surgical, obstetric, and drug (including opiates,
iron, antiparkinsonian drugs, anticholinergic drugs, calcium channel
blockers, and antidepressants). Urinary symptoms and sexual dysfunction may be important because multicompartment pelvic oor
disease is common. A history of sexual/physical abuse, eating disorders, or psychiatric illnesses may be an important factor in the onset
and chronicity of the constipation.
Several validated constipation questionnaires dierentiate constipated patients from healthy volunteers. e constipation severity
instrument is one example. It provides a short, self-reported assessment of constipation severity and identies subtypes of constipation.
e total scale ranges from 0 to 73, with higher scores associated with
more severe symptoms.
Physical Examination
A thorough physical examination includes a generalized assessment,
with particular emphasis on abdominal, neurologic, anorectal, perineal, and vaginal examinations. Some important points of anal and
pelvic examinations are as follows:
n On anorectal examination, the status of the rectum should be
noted—capacious, empty, or full of stool. e sphincter muscle
tone is documented. A patulous anus may indicate neurologic
injury or injury as a consequence of mechanical factors, such
as long-standing rectal prolapse. An unusually tight anus (anismus) may be a cause of incomplete defecation and anal pain.
Sphincter coordination is examined when patients are asked to
squeeze, relax, and then push. With paradoxical puborectalis
contraction, the pelvic oor muscle contracts instead of relaxing when the patient strains down or attempts to defecate.
n Rectal prolapse can cause constipation but also fecal inconti-
nence. When rectal prolapse is suspected but not seen on examination, the patient should be asked to bear down or sit on
the toilet to simulate defecation.
n A rectocele is dened as a herniation of the anterior rectal wall
into the vagina. Rectocele severity can be expressed as stages I
to IV and depends on the maximal protrusion inferiorly with
reference to the hymeneal ring. A rectocele sometimes develops
secondarily to obstructed defecation, and pelvic oor assessment for paradox is important. A large rectocele sometimes can
be seen just by inspecting the perineum, with the anterior wall
of the rectum protruding through the posterior wall of the vagina. One can see a size increase when the patient bears down.
n Rectoanal intussusception, also called internal intussuscep-
tion, internal prolapse of the rectum, and occult rectal prolapse, is a funnel-shaped infolding of the rectum that can occur with Valsalva maneuvers. It is thought to be the start of
rectal prolapse. Descent of the perineum beyond the level of
the ischial tuberosities is suggestive of perineal descent.
n Anoscopy can identify mucosal abnormalities and rectoanal
intussusception. When the patient is asked to bear down as the
anoscope is removed, the redundant rectal mucosa can be seen
impacting into the anus.
n Gynecologic examination focuses on an examination of the
posterior vaginal wall. Prolapse should be noted and staged
based on the Pelvic Organ Prolapse Quantication System.
e physical examination for patients with IBS-C and motility
disorders is frequently normal.
INVESTIGATIONS
With regard to blood work, an evaluation for electrolyte abnormalities (calcium), diabetes, and thyroid function tests is basic, especially
if obstructed defecation has been ruled out.
A colonoscopy should always be performed to exclude mechanical causes of obstruction such as a stricture, cancer, or diverticular
disease. Sigmoid colon adhesions aer pelvic surgery in women can
produce signicant obstruction, with symptoms that are oen misdiagnosed as IBS. During colonoscopy, insertion through the sigmoid is dicult and reproduces the pain and bloating with which the
patient has presented. A sigmoid colectomy should be considered.
Anal manometry provides information on resting and squeeze
anal sphincter pressures, the presence of rectoanal inhibitory reex
(RAIR), rectal sensation, rectal compliance, and balloon expulsion.
Assessment of rectal sensation is performed by determining the lowest volume that evokes a sensation of rectal lling and the maximum
tolerable volume. is assessment is important in patients with fecal
incontinence but also in patients with rectal hyposensitivity. Constipated patients may demonstrate internal sphincter hypertonia.
e presence of a RAIR excludes Hirschsprung disease (although
its absence is not proof of Hirschsprung disease; other conditions,
such as megarectum, can account for the absence of a RAIR). Balloon
expulsion assesses the ability to evacuate and can reliably diagnose
pelvic oor outlet obstruction (i.e., the inability to expel a 50- to 100mL balloon in less than 1 minute).
Electromyography aids in the diagnosis of paradoxical or nonrelaxing puborectalis muscle by demonstrating activation of the
puborectalis during defecation.
Transit marker studies or nuclear medicine transit studies identify
colonic dysmotility. With the sitz marker test, the patient ingests one or
two capsules containing 24 small plastic markers each (rings and panels).
Transit time is estimated based on the rate at which these markers are
eliminated. We instruct patients to take one capsule early Sunday morning. e patient then undergoes serial abdominal radiographs, with one
on Monday morning, the next on Wednesday, and the nal on Friday.
Dierent institutions use dierent practices, therefore the radiologist
should verify and report how many and when the capsules were taken.
Patients are told to eat two servings of over-the-counter high-ber products daily in addition to their usual diet (30 g ber total) and not to use
laxatives. Colonic transit is normal if 80% (38 of 48) of the rings have
been eliminated by day 5. e distribution of the markers throughout the
colon is also important. If the markers tend to accumulate in the rectum,
then outlet obstruction is likely. If the markers remain scattered throughout the colon and more than 20% of the markers remain on the h day,
then colonic inertia is the diagnosis (Fig. 70-1).
Scintigraphic evaluation is not as widely available but is useful
in terms of assessing transit of the proximal small bowel in addition
to the colon. Scintigraphic evaluation utilizes a radiolabeled meal
as the marker of transit. Small bowel and gastric emptying can be
determined and is useful in patients who have received a diagnosis of
slow-transit constipation, because patients with generalized motility
disorders have less favorable results aer surgical intervention.
Video defecography demonstrates the mechanism of defecation,
providing information on the anatomic relationships of the anus,
rectum, sigmoid, vagina, and pelvic oor during defecation. ickened barium paste is introduced into the rectum until the patient
experiences the urge to defecate. e vagina is then opacied with
Gastrogran. Pictures are taken at rest and at maximal squeeze prior
to starting video recording. Patients are asked to squeeze, relax, and
defecate. At the end of the study, three reference lines are drawn—
anorectal angle, puborectalis length, and extent of perineal descent.
A study with normal ndings will demonstrate relaxation of the
puborectalis during defecation (an increase in the anorectal angle,
lengthening of puborectalis, and blunting of the puborectalis notch).
Defecography can also identify intussusception, rectal prolapse,
enterocele, sigmoidocele, rectocele, and perineal descent (Fig. 70-2,
A and B).