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A
B
FIGURE 8.46. Differing patterns of growth in colon cancer. Colectomy specimens demonstrate (A)
polypoid carcinoma, more commonly found in the right colon; and (B) napkin-ring carcinoma, more
commonly found in the left colon. (Courtesy of Linda D. Ferrell, MD.)
C linical D isorders and Management .................................................................................................. 299
2. Rectal bleeding usually presents as blood mixed with
or streaking the stool, which often also contains
mucous. More severe bleeding is possible, but profuse
bleeding is rare.
3. Left colon obstruction causes partial obstructive symptoms (i.e., suprapubic colicky pain and constipation)
before complete obstruction develops.
Carcinoma of the Rectum
Presenting symptoms and signs include the following:
1. Rectal bleeding is the most significant symptom.
2. Red blood is passed with stools (hematochezia) and, at
times, bleeding may be severe.
3. A rectal mass is found on digital examination, with or
without blood on the examining finger.
4. Rectal examination can determine the size and fixation
of the tumor.
Investigations
Laboratory Studies
Anemia is a very frequent finding. Liver function tests
should be obtained. Elevated alkaline phosphatase might
suggest the presence of hepatic metastasis. Carcinoembryonic antigen (CEA), a glycoprotein expressed in the embryo
and in cell membranes of many adult tissues, is elevated in
approximately 70% of patients, particularly those with
Duke C or D lesions. CEA levels not only provide diagnostic guidance but serve to determine whether all tumor has
been extirpated by colonic resection. If CEA levels return to
normal postoperatively after complete resection, an elevation of these levels during follow-up usually indicates a
recurrence of tumor. Measurement of susceptibility genes
and telomerase activity in biopsy specimens and other
genetic markers hold promise for earlier and improved
diagnosis and treatments in the future.
Radiologic Studies
Barium enema is the best radiological technique to diagnose colon cancer. Cancers in the right colon appear as
intraluminal masses, while those in the descending colon
typically show as apple core lesions due to annular tumor
growth. All diagnosed or suspected lesions require colonoscopic examination and biopsy. Chest x-ray should always
be obtained. CT scan or MRI are useful, not only in detecting liver metastasis, but also in evaluating extramural extension of tumor and pericolonic lymph node involvement.
Endoscopy
Flexible sigmoidoscopy and biopsy are often the initial
steps. Endoscopic evaluation of the entire colon requires
colonoscopy in every patient. When a distal lesion is seen
on sigmoidoscopy, colonoscopy evaluates for synchronous
lesions. Fully 60% to 70% of colon cancers are beyond the
reach of sigmoidoscopy. Colonoscopy and barium enema
complement one another in examination of the entire
colon.
Endorectal Ultrasonography
This examination is an accurate way to determine depth
of tumor invasion and presence of enlarged pararectal
lymph nodes. In both evaluations, endorectal ultrasound
is more accurate than CT scan.
Surgical Treatment
Surgery provides the only definitive treatment for colorectal cancer. Colectomy is usually contraindicated in
patients with advanced tumor who have bilobar multiple
metastases and peritoneal seeding. Even in these patients,
however, it may be best to perform surgical decompression
of the colon to treat obstruction and palliative colectomy
to control hemorrhage. The type of curative surgical
resection required depends on tumor location. An attempt
must be made to minimize intraoperative spread by:
1. Ligating the tumor-bearing bowel at both ends to
prevent transluminal spread.
2. Ligating the mesenteric vein early to minimize
hematogenous spread during manipulation.
3. Limiting the amount of manipulation of the tumor.
Preoperative Bowel Preparation
Mechanical and bacteriologic preoperative bowel preparation reduces the incidence of anastomotic dehiscence,
intra-abdominal abscesses, and wound infection. Even
after the recommended bacteriological preparation, the
colon is not sterilized, and elective colectomy is considered
a clean-contaminated operation. Mechanical cleansing is
achieved either by mono and dibasic sodium phosphate
purgatives or, more commonly, by whole-gut lavage using
4 L of isotonic solution containing polyethylene glycol
(Golytely®). The solution can be taken orally or instilled
by nasogastric tube over a period of 4 h. Bacteriologic
preparation may be accomplished by using a combination
of poorly absorbed oral antibiotics, typically 1 g of
neomycin and 1g of erythromycin given in three doses
the preceding day, at 19, 18, and 9h prior to operation.
Intravenous, broad-spectrum antibiotic is administered
just before the procedure.
Operative Treatment
Figure 8.47 depicts the various types of resections required
for tumors at different locations.
300 ................................................................................................................ Small and L arge Intestine
A
B
C
D
FIGURE 8.47. (A–D) Extent of colon resection depends on the location of the primary carcinoma.
C linical D isorders and Management .................................................................................................. 301
CARCINOMA OF THE RIGHT COLON Cecal cancer is
treated by right hemicolectomy and ileotransverse colectomy. Resection lines are 6 to 8 inches proximal or distal to
the ileocecal valve and the hepatic flexure of the colon,
respectively. This requires division of both the ileocolic and
right colic arteries and resection of the mesentery to the
origin of these vessels.
Carcinoma of the ascending colon requires extending
the resection distally to the left of the midtransverse
colon and sacrificing the right branch of the middle
colic.
Transverse colon cancer is treated by transverse colectomy and colocolic anastomosis in which the entire middle
colic is sacrificed. In some cases, it may be technically
preferable to remove the entire right colon and perform
ileodescending colostomy.
C
ARCINOMA OF THE LEFT COLON Carcinoma of the
splenic flexure is treated by resection of most of the
descending colon and the left half of the transverse colon
and their mesentery. Descending colon carcinoma requires
resection of most of the sigmoid, the entire ascending colon
and splenic flexure. Sigmoid carcinoma requires removal of
the upper rectum, the sigmoid, and half of the descending
colon. The splenic flexure has to be mobilized completely
so that colorectal anastomosis can be performed without
tension.
C
ARCINOMA OF THE RECTUM The advent of intralu-
minal surgical stapling instruments has allowed the performance of lower and safer anastomosis deep in the pelvis
after rectal resection. Low anterior resection of the rectum
requires: (1) adequate blood supply and absence of tension at the anastomosis, and (2) preservation of adequate
anal sphincter function. Resection of the rectum for
cancer requires division of the inferior mesenteric artery
at its origin and removal of the mesorectum and most
of the pararectal tissue. Resection margins should be
at least 10cm proximally and 2 cm distally. Low anastomoses are often protected with temporary diverting
loop ileostomy.
When a sphincter-saving resection is not feasible, the
treatment of choice is abdominoperineal resection of the
rectum (Mile’s procedure). In this operation, the rectum
is mobilized through the abdomen and perineum and the
entire rectum and anus are removed. An end-sigmoid
colostomy is then constructed in the left lower quadrant
of the abdomen.
Colostomy and ileostomy sites should be marked
preoperatively with ink. This practice is an important
consideration in the surgical management of rectal
cancer.
S
URGICAL RESECTION OF LOW-LYING RECTAL CANCER
The definitive surgical treatment of low-lying rectal cancer
is abdominoperineal resection (Mile’s procedure). If the
anal sphincter can be preserved without compromising
surgical cure, however, more limited resection is desirable.
Sometimes this can be accomplished by performing a low
anterior resection if a distal surgical margin of 2 to 3 cm
can be achieved. Such anastomoses are usually covered with
temporary diverting ileostomy.
Low-lying rectal cancer can also be locally resected
either transacrally (Kraske procedure) or transanally.
Sacral Resection Sacral resection, or the Kraske procedure, is rarely performed today. Using the sacral approach,
the rectum containing the lesion can be resected and
intestinal continuity restored by anastomosis. The procedure is associated with a high rate of anastomotic leakage
and recurrence and has now been supplanted by transanal
excision.
Transanal Excision Lesions less than 4 cm in size,
located within 8 cm of the anal verge, and unassociated
with lymph node metastases may be treated by local excision. The procedure is performed after dilating the rectum
widely. The goal is to accomplish full-thickness excision
with 1 cm normal margins and closure of the defect preferably in two layers.
A preoperative transanal ultrasonography is important
to assess depth of invasion and whether lymph node
metastases are present. When transanal resection is preferred to abdominoperineal resection in patients who are
fit and have small lesions, the following principles must be
observed:
1. The excised specimen must be regarded as total
biopsy and the patient informed that further
decision as to whether abdominoperineal resection
should be done will await the results of pathologic
examination.
2. Abdominoperineal excision should be considered if:
a. Tumor is present at excision margins.
b. Histology shows poorly differentiated, high-grade
carcinoma.
c. Tumor is transmural.
In patients who are poor candidates for abdomino-
perineal resection because of concurrent illness, transanal
excision or transanal destruction of the tumor by electrocautery or radiation therapy may be used.
Transanal Endoscopic Microsurgery Using instruments
similar to those used in laparoscopic surgery and with
appropriate rectal insufflation with carbon dioxide, excision is performed with electrocautery. Full-thickness resection should be undertaken only for lesions that are
extraperitoneal (i.e., 8cm anteriorly or 12 cm posteriorly or
lower).
Endocavitory Radiation This form of primary therapy
is indicated in frail patients considered not suitable for
surgery. It can also be used as postexcision therapy.
302 ................................................................................................................ Small and L arge Intestine
Staging and Prognosis
The TNM classification for colorectal cancer is given in
Table 8.14. Although Dukes’ classification is most widely
used, the TNM classification provides more pathological
detail. Table 8.15 compares Dukes’ classification to TNM
stages and provides 5-year survival rates. These figures
make it clear that earlier diagnosis is the most important
strategy to improve survival. Surveillance for colorectal
cancer in individuals over the age of 50 has improved
survival in the past 25 years. Important tests include
periodic fecal occult blood evaluation, sigmoidoscopy and
colonoscopy, and more careful follow-up in high-risk individuals (e.g., polyps, CUC, CD). The exploding knowledge
of the genetics of colorectal cancer is providing additional
tools, which will become more precise and in the future
help us to detect colorectal cancer early.
The prognosis is adversely affected by the following
circumstances:
1. Poor histological differentiation and vascular and
perineural invasion.
2. Presence of obstruction or perforation.
3. Aneuploid tumor cells.
4. Mucin-producing and signet cell tumors (intracytoplasmic mucin).
5. Elevated CEA levels.
Furthermore, younger patients appear to have a worse
prognosis than older ones, and preoperative blood transfusion may have an adverse effect.
Adjuvant Chemotherapy
Colorectal cancer is relatively resistant to chemotherapy.
Nevertheless, it appears to be more effective when the
burden of carcinoma is lowest and when cell division is
maximal.
Large clinical trials have now shown that the combination of levamisole and 5-fluorouracil (5-FU), given after
curative resection, improves disease-free survival rate and
overall survival rates after surgery in Stage III (Dukes’ C)
cancer.
30
Recurrence rate was reduced by 39%, cancerrelated deaths by 32%, and overall death rate by 31% in
patients receiving the combination therapy postoperatively compared with those who underwent resection but
received no chemotherapy. No survival advantage was seen
in Stage II cancer.
Adjuvant chemotherapy does not appear as effective in
rectal cancer as it does in colon cancer. Even then, some
randomized prospective trials have shown that there may
be modest gain in the use of levamisole and 5-FU in Stage
II and Stage III rectal cancer in combination with
radiation.
31
ANORECTAL DISORDERS
Anorectal disorders are a common human affliction. They
include hemorrhoids, anorectal abscesses and fistulae,
fissure-in-ano, pruritus ani, condylomata, and malignant
neoplasms of the anus. In this section, we also consider
rectal prolapse and pilonidal disease.
Hemorrhoid
Hemorrhoidal plexus of veins occur above and below the
dentate line. Those above the dentate are internal and are
covered by rectal mucosa. Those below are external and are
covered by the anoderm of the anal canal. Engorgement
and enlargement of the internal hemorrhoids can be
symptomatic. The main clinical significance of external
hemorrhoids is that they may produce painful thrombosis (Figure 8.48).
C linical D isorders and Management .................................................................................................. 303
TABLE 8.14. TNM Staging of Colorectal Cancer
Designation Involvement
Primary Tumor (T)
TX Primary tumor cannot be assessed
T0 No evidence of primary tumor
Tis Carcinoma in situ: intraepithelial or invasion
of lamina propria
T1 Tumor invades submucosa
T2 Tumor invades muscularis propria
T3 Tumor invades through muscularis propria
into subserosa or into non-peritonealized
pericolic or perirectal tissues
T4 Tumor directly invades other organs or
structures, and/or perforates visceral
peritoneum
Regional lymph nodes (N)
NX Regional lymph nodes cannot be assessed
N0 No regional lymph node metastasis
N1 Metastasis in 1 to 3 regional lymph nodes
N2 Metastasis in 4 or more regional lymph nodes
Distant metastasis
MX Distant metastasis cannot be assessed
M0 No distant metastasis
M1 Distant metastasis
Source: Reprinted with permission from the American Joint Committee on
Cancer (AJCC), Chicago, Illinois. The original source for this material is the
AJCC Cancer Staging Manual, 6th ed. (2002) published by Springer-Verlag
New York, www.springer-ny.com.
TABLE 8.15. Staging of Colorectal Cancer and Survival Rates
According to Dukes’ Classification and TNM
Stage
Dukes’
Classification Stage TNM Classification 5-Year Survival
A I T1 or T2, N0, M0 90%
B II T3 or T4, N0, M0 60%–80%
C III Any T, N1, N2, or N3, M0 20%–50%
D IV Any T, Any N, M1 5%
FIGURE 8.48. Surgical drainage of thrombosed hemorrhoid. Thrombosed hemorrhoids are treated
with excision of the thrombosed hemorrhoid and the clot. (Adapted from Sabiston DC, ed: Textbook
of Surgery: The Biological Basis of Modern Surgical Practice, 15th ed. Philadelphia: WB Saunders,
1997:1038.)
Internal Hemorrhoid
Internal hemorrhoids are caused by increased abdominal
pressure during straining or lifting, from chronic constipation, portal hypertension, or obstruction of the superior
hemorrhoidal vein by tumor. They occur at three primary
positions as seen in Figure 8.49.
LINICAL PRESENTATION Bleeding is the earliest and
C
most common symptom of internal hemorrhoids. Rectal
bleeding should never be ascribed to hemorrhoids until
carcinoma is ruled out. Typically, the bleeding is seen in the
surface of the stool or on toilet tissue. As the hemorrhoids
enlarge, they begin to prolapse. At the outset, prolapse
occurs with defecation and is followed by spontaneous
reduction (first-degree hemorrhoid). At a later stage,
spontaneous reduction does not occur and the patient
must manually replace the hemorrhoid (second-degree).
Eventually, the hemorrhoids may remain permanently
prolapsed, causing mucoid discharge and soiling (thirddegree). In the latter stage, acute thrombosis may occur,
causing edematous enlargement of the hemorrhoids
(fourth degree), which may be very acute and painful.
NVESTIGATION Physical examination and anoscopy
I
suffice to establish the diagnosis. Bleeding, when present,
requires sigmoidoscopic or colonoscopic examination to
FIGURE 8.49. Common location of internal hemorrhoids. The three primary sites of internal hemorrhoids are 3, 7, and 11 o’clock. (Adapted from Goligher JC. Surgery of the Anus, Rectum, and Colon,
3rd ed. London: Balliere Tindall, 1975:117.)
304 ................................................................................................................ Small and L arge Intestine
rule out neoplasm and chronic inflammatory bowel
disease. Examination of the perineum during straining
may lead to prolapse of the hemorrhoids. Anoscopy allows
visualization of enlarged and protruding hemorrhoid(s).
T
REATMENT
Conservative Treatment First- and second-degree
hemorrhoids can be treated successfully with local measures (e.g., suppositories, ointment) and with diet. The goal
is to prevent constipation by increased daily fluid intake,
high-fiber diet, and bulk-forming laxatives. When edema
and prolapse are present, bed rest, local astringent compresses (witch hazel), and warm sitz baths may help.
Rubber-band Ligation Rubber-band ligation can be an
effective way of treating second- and third-degree hemorrhoids. One hemorrhoid is banded at a time. The tissue
over the hemorrhoid is grasped and pulled into the barrel
of the rubber-band applicator, and the rubber band is
placed at the base of the hemorrhoid. Placement must be
well above the mucocutaneous junction or the patient will
experience severe pain, and the band will have to be
replaced. The ligated hemorrhoid undergoes ischemic
necrosis and sloughs off in several days. Ligation of
hemorrhoidal complexes is performed 2 to 3 weeks apart.
Injection Sclerosis of the hemorrhoid may be achieved
by injecting 5% phenol in almond oil into the submucosa
at the base of each hemorrhoid. The procedure must be
performed in a manner that does not cause sloughing of
the mucosa.
Cryosurgery A cryoprobe using carbon dioxide or
nitrous oxide can be applied to generate necrosis of the
hemorrhoid. However, it is difficult to control the depth of
necrosis, and mucosal sloughing tends to occur.
Direct Current Coagulation Each hemorrhoid cushion
is coagulated for 10 minutes.
Hemorrhoidectomy Large and refractive third- or
fourth-degree hemorrhoids are treated surgically. The procedure requires conservative excision of normal anoderm
and skin, dissection of the hemorrhoid cushion off the
internal sphincter, high suture ligation of the hemorrhoid
pedicle, and amputation of the hemorrhoid distal to the
ligature (Figure 8.50). The skin defects are packed open.
Several techniques have been described for hemorrhoidectomy. The Whitehead technique, which involves circumferential excision of the anoderm and dentate line, is prone
to cause anal stricture.
Thrombosed External Hemorrhoid
This is an acute, painful thrombosis of a subcutaneous
vein just outside the anal verge. The thrombosed vein pro-
duces a very tender and tense bluish tumor. A common
problem, few patients are as grateful as those with this
lesion, when, under local anesthesia, the tumor is incised
and the clot evacuated. Relief is instantaneous. Some
surgeons prefer excision of the hemorrhoid to avoid
recurrence.
Anorectal Abscesses
Anorectal abscesses are common and can occur in one of
several potential spaces shown in Figure 8.51. Most probably they begin as an infection of an anal crypt, from
which the infection spreads into one of the potential
spaces. The infection is due to mixed flora consisting
of E. coli, bacteroides, streptococci, Proteus vulgaris, and
staphylococci.
Anorectal abscesses include:
1. Perianal abscess, which occurs under the skin of the
anus within the anal canal.
2. Submucosal abscess, in the submucosa just superior to
the anal canal.
3. Intermuscular abscess, lying between layers of the
sphincter muscle.
4. Ischiorectal abscess, which develops in the ischiorectal
fossae.
5. Supralevator or pelvirectal abscess, which lies above
the levator but below the peritoneum and is often associated with supralevator rectal disease.
6. Retrorectal abscess, lying behind the rectum.
Tr e at m e n t
Prompt incision and adequate drainage is the proper treatment. Except for superficial abscesses, which may be
drained under local anesthesia, drainage under general
anesthesia is required in most patients. The abscesses are
larger than they appear, and all loculations must be
broken. The wound is left open. A fistular tract from the
primary site of origin may be found. This should be
excised without significantly damaging the internal
sphincter. Ischiorectal abscesses are drained through the
perineum and may require the placement of a catheter
drain. Supralevator abscesses are drained transrectally.
A high percentage of operated anorectal abscesses may
develop an anal fistula following surgery. Patients should
be informed of this possibility preoperatively. Inadequate
or delayed drainage can result in major necrotizing
anorectal infection. At times, this type of infection may
involve the entire perineum and the scrotum (Fournier’s
disease). This complication requires major debridement,
diverting colostomy, and skin grafting after infection has
been eradicated.
When anorectal abscesses recur, the possibility of
underlying inflammatory bowel disease should be investigated with colonoscopy and barium enema. The anorectal
abscess wall should be biopsied whenever possible to
C linical D isorders and Management .................................................................................................. 305
B
A
C
D
E
FIGURE 8.50. (A–F) Internal hemorrhoidectomy. Open internal hemorrhoidectomy involves dissection
of the hemorrhoid cushion off the internal sphincter, high-suture ligation, and amputation of the
hemorrhoid. (Adapted from Goligher JC. Surgery of the Anus, Rectum, and Colon. London: Baillière
Tindall, 1975;155–156.)
FIGURE 8.51. Anorectal abscess. The sites where anorectal
abscesses occur include: (1) perianal, (2) submucus, (3) intrasphincteric, (4) ischerorectal, and (5) supralevator (pelvirectal).
Anorectal abscesses can also occur retrorectally (not shown).
determine any possible unusual cause (e.g., tuberculosis,
Crohn’s disease, malignancy).
Anorectal Fistulas
Most anorectal fistulas originate as crypt infection at the
anorectal junction. The internal opening may not correspond to the external opening. The second opening in skin
can be in one of several sites in the perianal perineum. Fistulas are usually due to bacterial infection that starts in the
crypts. Approximately 40% to 50% of patients in whom a
perianal abscess has been drained have a residual fistula.
Crohn’s disease and tuberculosis can also cause anorectal
fistulas.
The Salmon–Goodsall rule predicts the location of the
secondary opening in the skin, depending on the location
of the primary opening in the crypt (Figure 8.52). A fistula
that has its external opening anterior to an imaginary
transverse line drawn through the center of the anal orifice
opens internally in a crypt radially opposite. When the
external opening is posterior to this transverse line,
however, the internal opening is always in a crypt in the
midline posteriorly.While this rule holds most of the time,
exceptions do exist.
comitant digital exam. Recurrent fistulas should raise the
possibility of Crohn’s disease or tuberculosis.
Investigation
Digital rectal examination may reveal the site of the internal opening with or without a probe in the fistula. Proctoscopic examination is essential to rule out inflammatory
bowel disease. If rectal inflammation is present or if the
fistula is recurrent, colonoscopy with or without barium
enema will be necessary.
Tr e at m e n t
The most successful treatment is fistulotomy, in which the
fistulous tract is laid open without damage to the sphincter. Curettage or cautery of the fistula is performed and the
wound allowed to heal by secondary intention.
Trans-sphincteric fistulas result from drained
ischiorectal abscess and cross both the internal and external sphincters. Fistulotomy divides the internal sphincter
and part of the external. The procedure may produce
incontinence in some patients. When the trans-sphincteric
fistula is high, a seton suture may be inserted through it
and the sphincter divided slowly over many days by progressively tightening the knot. This procedure is rarely
used now, and the use of the seton suture is no guarantee
against incontinence.
Fissure-in-ano
Fissure-in-ano, or anal fissure, is a painful crack or longitudinal ulcer in the anal canal overlying the internal
sphincter. The base of the fissure is the internal sphincter,
Clinical Picture
The presenting complaint in patients with anorectal fistulas is drainage, usually pus, issuing from the perianal
perineum. Inspection of the perineum reveals the site of
the external fistula, and a cord-like tract towards the anal
canal may be palpable. A lacrimal probe inserted into the
fistula may reveal its relation to the anal sphincter, and the
site of the internal opening may be determined with a con-
C linical D isorders and Management .................................................................................................. 307
FIGURE 8.52. Salmon–Goodsall rule. When the secondary
opening in the skin is located anterior to the transverse line
drawn through the center of the anal orifice, the internal
opening is radially opposite. When the external opening is
posterior to this transverse line, however, the internal opening
is in the midline.
which may go into spasm and aggravate the pain. Acute
fissures are common in conditions producing constipation
or following bouts of diarrhea. Most heal spontaneously
without treatment. It is the chronic fissure that requires
specific treatment.
Clinical Presentation
Severe anal pain on defecation is the primary symptom. A
small amount of bright red bleeding may be noted on the
toilet tissue. Fear of painful defecation leads to constipation. The patient often will not allow digital rectal examination because of pain, but a prominent localized swelling
of the skin at the distal end of the fissure—the sentinel
pile—may be observed externally. Digital rectal and
anoscopic examination may be possible after liberal use of
topical anesthetic.
Tr e at m e n t
A dietary regimen to soften the stools, use of topical anesthetic and hydrocortisone, and sitz bath are the mainstay
of medical therapy. If conservative treatment fails to heal
the fissure in 4 to 6 weeks or less and pain is severe, lateral
internal sphincterotomy should be performed. The sentinel pile is also excised. The fissure heals quickly after this
procedure.
Forceful anal dilatation under anesthesia, known as the
Lord maneuver, is not recommended because of the associated high incidence of incontinence.
Pilonidal Disease
Pilonidal disease consists of either a draining sinus or an
abscess in the intergluteal region. Controversy exists as to
its origin. Some believe it is congenital, while others
believe it is acquired and results from ingrown hair.
Indeed, deep in the sinus or abscess a tuft of hair is usually
found. It is common in soldiers who ride in Jeep®-type
vehicles.
Clinical Presentation
Patients usually present with acute pain due to an abscess.
Some patients present with a draining sinus, the abscess
having drained spontaneously. On examination, a midline
abscess or one or more draining sinuses in the sacrococcygeal region is noted.
Tr e at m e n t
The simplest surgical treatment is incision and drainage,
with curettage to remove all hair follicles. The wound is
then allowed to heal by secondary intention. Alternatively,
the entire pilonidal complex can be excised and the wound
allowed to heal secondarily. This procedure leaves a large
wound, which requires a long time to heal. The third alter-
native is excision and primary closure, suitable only when
pilonidal sinus is present without abscess. The procedure
is best reserved for recurrent disease after prior incision
and drainage.
Pruritis Ani
Severe perineal itching may be caused by a multitude of
conditions. In children, a common cause is pinworm
infestations (Enterobius vermicularis). The diagnosis can
be made by applying a piece of cellophane tape to the anus
at night to recover eggs, which are then examined under
the microscope. In adults the causes range from dermatological diseases, to fungal or bacterial infections, to
systemic diseases such as diabetes. Some causes are psychogenic, but most often no cause can be identified and
the condition is idiopathic.
Tr e at m e n t
The treatment is that of the underlying cause. The patient
is advised to keep the perianal region dry and to avoid
foods that exacerbate itching (e.g., coffee, tea, chocolate,
tomatoes, etc.). Water-soluble corticosteroid cream with
an acid pH applied three or four times a day may be
helpful.
Rectal Prolapse
Rectal prolapse (procidentia) is a protrusion of the full
thickness of the rectum through the anus. The proposed
causes are colonic intussusception or a sliding hernia.
Essential defects may be poor rectal support and increased
intra-abdominal pressure. The condition is seen more
commonly in the elderly, particularly those from nursing
homes or on psychotropic drugs. Anatomically, patients
with rectal prolapse have deep rectovesical space (Douglas
pouch); lax levator muscles; a weak puborectalis, with loss
of the acute angle it produces between the rectum and
anus by pulling anteriorly; poor fixation of the rectum to
the sacrum posteriorly; and poor support from the lateral
ligaments.
Clinical Presentation
The patient complains of the prolapse, rectal bleeding, or
discharge. Prolapse occurs on straining and, early in the
course of the disease, it reduces spontaneously. With time,
the patient has to reduce it manually. As the prolapse
increases, anal sphincter incompetence and incontinence
develop. A situation of full procidentia, where the prolapse
cannot be reduced, may occur.
Investigation
It is essential that the prolapse be demonstrated. Full
evaluation of the colon is necessary with colonoscopy and
barium enema.
308 ................................................................................................................ Small and L arge Intestine
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