I.5 – Colon, Rectum, and Anus (Lecture)
Dr. Mata
June 9, 2013
EMBROYOLOGY
The embryonic gastrointestinal tract begins developing during the 4th week of gestation
The primitive gut is derived from the endoderm and divided into three segments
Foregut Midgut* Hindgut*
*contribute to the colon, rectum, and anus
MIDGUT
Develops into the small intestine, ascending colon,
and proximal transverse colon
Receives blood supply from the superior mesenteric
artery
During the 6th week of gestation, the midgut herniates out of the abdominal cavity, and then rotates
27ocounterclockwise around the superior mesenteric
artery to return to its final position inside the abdominal cavity during the 10th week of gestation
MIDGUT
Develops into the distal transverse colon descending colon rectum
and proximal anus
all of which receive their blood supply from the inferior
mesenteric artery
during the 6th week of gestation, the distal-most end of the hindgut, the cloaca, is divided by the urorectal septum into
urogenital sinus rectum
DISTAL ANAL CANAL
derived from ectoderm and receives its blood supply from the internal pudendal artery
the dentate line divides the endodermal hindgut from the ectodermal distal anal canal
ANATOMY
the large intestine extends from the ileocecal valve to the anus
it is divided anatomically and functionally into colon
rectum anal canal
the 1st 6 cm of the large intestine just below the ileocecal valve, the ascending colon, and the hepatic flexure form a surgical unit, the right colon
Figure 1. Colon anatomy and measurements
HEPATIC FLEXURE
located under the 9th and 10th costal cartilages in the vicinity of midaxillary line
gallbladder is located anteriorly
duodenum is located posteriorly
ASCENDING COLON
The ascending limb of the right colon is fused to the posterior body wall and covered by the peritoneum
Fused variations
Deep lateral paracolic groove to the persistence of an entire ascending mesocolon
TRANSVERSE COLON
The transverse colon hangs in a U or V-shaped curve
The transverse mesocolon is formed by a double peritoneal fold
The 2 are fused at “X” to form the transverse
mesocolon containing the middle colic artery and vein
DESCENDING COLON
Covered anteriorly and on its medial and lateral sides by peritoneum
Has no mesentery
Mobilization of the ascending colon is accomplished by incising the peritoneal reflection at the left gutter along the “white line of Told”
SIGMOID – S shaped
2 portions
Iliac portion – fixed and located at the left iliac fossa
Pelvic portion – mobile
Begins at the iliac crests and ends at the 3rd sacral vertebra
RECTUM
The junction between the sigmoid colon and the rectum has been variously described:
A point opposite the left sacroiliac joint Level of the 3rd sacral vertebra
Level at which sacculations and epiploic appendages disappear and taeniae broaden to form a complete muscle layer (long transition)
Level at which the superior rectal artery divides
into the right and left branches
Construction with anterior angulation (proctoscopy) Transition between rugose mucosa of the colon and
smooth mucosa of the rectum
Posteriorly, the presacral fascia separates the rectum from the presacral venous plexus and pelvic nerves
At S4, the retrosacral fascia (Waldeyer’s fascia) extends forward and downward and attaches to the fascia propria at the anorectal junction
Anteriorly, Denonvilliers’ fascia separates the rectum from the prostate and seminal vesicles in men and from the vagina in women. The lateral ligaments support the lower rectum
The entire upper 1/3rd of the rectum is covered by peritoneum
The mesorectum, which suspends the rectum from the posterior body wall, comes off more laterally, leaving bare progressively more of the posterior rectal wall
The peritoneum finally leaves the rectum and passes anteriorly and superiorly over the posterior vaginal fornix and the uterus in females or over he superior ends of the seminal vesicles and the bladder in males
This creates a depression, the rectouterine or
With infection, this may become filled with pus
SPACES OF THE ANUS AND RECTUM
Pelvirectal space
Ischioanal (ischiorectal) space
Intersphincteric spaces
Subcutaneous space
Central space
Submucousspace
PERITONEAL LOCATIONS
Figure 2. Peritoneal Locations ARTERIAL SUPPLY OF THE COLON
Figure 3. Arterial Supply of the colon SMA BRANCHES TO THE COLON
Middle colic artery
Right colic artery
Ileocolic artery
Meandering Artery of Riolan – communicating between Middle colic and IMA
MEANDERING ARTERY OF RIOLAN
*blue arrows
SMA
*blue arrows
IMA
If the inferior mesenteric artery is divided at “a” above, the last full anastomosis, collateral circulation toward the rectum is still possible
Division at “b” would interrupt the collateral circulation
SUDECK’S CRITICAL POINT
Sudeck described a point on the superior rectal artery at which ligation of the artery would not devascularize a long rectosigmoid stump
This point is just above the origin of the last sigmoid artery
“Ligation below the Sudeck’s point would devascularize the rectum”
Not critical as it was thought to be
The concept of Sudeck’s critical point fails to recognize 2 other sources of blood to the rectum
ALTERNATIVE BLOOD SUPPLY
One is the intramural network of arteries in the
submucosal layer of the wall and the other is from collaterals
Branches of the inferior vesical artery
Arteries supplying the levator ani muscle
The middle sacral artery
The posterior retroperitoneal arterial plexus uniting the parietal and visceral circulation
The inferior rectal artery is responsible for the arterial blood supply of the distal 2 cm of the anal canal
MARGINAL ARTERY OF DRUMMOND
Composed of a series of anastomosing arcades between branches of the ileocoloc, right colic, middle colic, left colic, and sigmoidal arteries
These form a single looping vessel
Runs parallel, 1-8 cm from the intestinal wall
MEANDERING ARTERY OF RIOLAN
The long vasa recta branches bifurcate and
anastomose at the antimesenteric border of the bowel after encircling it
The short ones, branches of the marginal artery, are responsible for the mesocolic 2/3rd of the colonic
circumference
The vasa recta brevia run subserosally in the wall and
penetrate the circular muscle and run in the
submucosa
Effect of too much traction on an epiploic
appendage resulting injury to one of the long
branches of vasa recta followed by antimesenteric
ischemia
ORIGIN AND ARTERIAL SUPPLY TO RECTUM
Unpaired superior rectal artery Right and left branches
Middle rectal artery Dosro-caudal area
Inferior rectal artery Ventral and medial
Medial sacral artery Posterior wall
VENOUS DRAINAGE OF THE RECTUM
Portal system
Superior rectal vein
Systemic system
Middle rectal vein
Inferior rectal vein
Mainly responsible for the venous return of the
distal 2 cm of the anal canal
Anastomoses occur between superior rectal vein (portal) and the middle and inferior rectal veins
(systemic). These constitute a potential portosystemic
shunt.
LYMPHATIC DRAINAGE
Epicolic
Under the serosa of the wall of the intestine
Paracolic
On the marginal artery
Intermediate
Along the large arteries (SMA and IMA)
Principal
At the root of SMA and IMA
Above the pectinate line, drainage is to inferior
mesenteric nodes
Below the line, drainage is to the inguinal nodes
INNERVATION
Intramural plexus or intestinal enteric nervous system
Myenteric plexus Auerbach
Submucosa plexus Meissner
Controls secretions
Table 1. Right vs Left Colon
RIGHT COLON LEFT COLON
Sympathetic: lower 6 thoracic segments of the spinal cord
Sympathetic: L1, 2, 3 lumbar splanchnic nerves to the aortic plexus and the inferior mesenteric plexus
Parasympathetic: vagal fibers from the posterior trunk
Parasympathetic – pelvic splanchnic nerves S2, 3, 4
PHYSIOLOGY
The colon is a major site for water absorption and electrolyte exchange
Approximately 90% of water contained in ileal fluid is absorbed in the colon (1000 to 2000 ml/d), and up to 5000 ml of fluid can be absorbed daily
Sodium is absorbed actively via a Na-K ATPase channel
Chloride is absorbed actively via a chloride-bicarbonate exchange
SHORT-CHAIN FATTY ACIDS
Short-chain fatty acids are important sources of energy for the colonic mucosa, and metabolism by
colonocytes provides energy for processes such as
active transport of sodium
Short-chain fatty acids (acetate, butyrate, and proprionate) are produced by bacterial
fermentation of dietary carbohydrates
Lack of a dietary source for production of short-chain fatty acids, or diversion of the fecal stream by an ileostomy or colostomy, may result in mucosal atrophy and “diversion colitis”
MOTILITY – Cholinergic Response
Unlike the small intestine, the large intestine does
NOT demonstrate migratory motor complex
Intermittent contractions of either low or high amplitude
Low-amplitude, short-duration contractions occur in bursts and appear to move the colonic
contents both antegrade and retrograde –
absorption of water/electrolytes
High amplitude contractions create“mass movements”
DEFECATION
a complex, coordinated mechanism involving colonic mass movement,
increased intra-abdominal and rectal pressure, and relaxation of the pelvic floor
distention of rectum causes a reflex relaxation of the internal anal sphincter (the rectoanal inhibitory
reflex)
this “sampling reflex” allows the sensory epithelium to distinguish solid stool from liquid stool and gas
if defecation does not occur, the rectum relaxes and the urge to defecated passes (the accommodation
response)
defecation proceeds by coordination of increasing intra-abdominal pressure via
the Valsalva Maneuver increased rectal contraction
relaxation of the puborectalis muscle opening of the anal canal
CLINICAL EVALUATION
a complete history and PE is the starting point for evaluating any patient with suspected disease of the colon and rectum
special attention should be paid to the patient’s past medical and surgical history to detect underlying conditions that might contribute to a gastrointestinal problem
if patients have had prior intestinal surgery, it is essential that one understands resultant
gastrointestinal anatomy
in addition, family history of colorectal disease especially inflammatory bowel disease, polyps, and colorectal cancer, is crucial
medication use must be detailed as many drugs cause GI symptoms
before recommending operative intervention, the adequacy of medical treatment must be ascertained
in addition to examining the abdomen, visual inspection of the anus and perineum and careful digital rectal exam are essential
ENDOSCOPY
Anoscopy
Useful instrument for examination of the anal canal Anoscopes are made in variety of sizes and measure
approximately 8cm in length
A larger anoscope provides better exposure for anal procedures such as rubber band ligation or
sclerotherapy of haemorrhoids
Proctoscopy
IMAGING STUDIES
Plain X-rays and Contrast Studies
Computed Tomography
Magnetic Resonance Imaging
Positron Emission Tomography
Angiography
Edorectal and Edoanal Ultrasound
PHYSIOLOGIC AND PELVIC FLOOR INVESTIGATIONS
Anorectal physiologic testing uses a variety of
techniques to investigate the function of the pelvic floor
These techniques are useful in the evaluation of patients with incontinence, constipation, rectal
prolapse, obstructed defecation, and other disorders of the pelvic floor
Manometry
Neurophysiology
Rectal Evacuation Studies
MANOMETRY
Performed by placing a pressure-sensitive catheter in the lower rectum
Catheter is then withdrawn through the anal canal and pressures recorded
A balloon attached to the tip of the catheter also can be used to test anorectal sensation
The resting pressure in the anal canal reflects the function of the internal anal sphincter (Normal: 40-80 mmHg)
SQUEEZE PRESSURE
Defined as the maximum voluntary contraction pressure minus the resting pressure
Reflects function of the external anal sphincter (Normal: 40-80 mmHg ABOVE resting pressure)
The high-pressure zone
Estimates the length of the anal canal (Normal: 2.0 – 4.0 cm)
The rectoanal inhibitory reflex
Can be detected by inflating a balloon in the distal rectum
Absence of this reflex is characteristic of
HIRSCHSPRUNG’S DISEASE
NEUROPHYSIOLOGIC TESTING
Assesses function of the pudendal nerves and recruitment of puborectalis muscle fibers
Pudendal nerve terminal motor latency measures the speed of transmission of a nerve impulse through the distal pudendal nerve fibers (Normal: 1.8 – 2.2 msec)
Needle EMG has been used to map both the pudendal nerves and the anatomy of the internal and external sphincters
However, this examination is painful and poorly tolerated by most patients
Needle EMG has largely been replaced by pudendal
nerve motor latency testing to assess pudendal
nerve function and endoanal ultrasound to map the sphincters
RECTAL EVACUATION STUDIES
Include the balloon expulsion test and video defecography
BALLOON EXPULSION
Assess a patient’s ability to expel an intrarectal balloon
VIDEO DEFECOGRAPHY
Provides a more detailed assessment of defecation Barium paste is placed in the rectum and defecation
is them recorded fluoroscopically
Used to differentiate nonrelaxation of the puborectalis, obstructed defecation, increased perineal descent, rectal prolapse and intussuception, rectocele, and enterocele
Addition of vaginal contrast and intraperitoneal contrast is useful in delineating complex disorders of the pelvic floor
LABORATORY STUDIES
Fecal Occult Blood Testing
Stool Studies
Serum Tests
Tumor Markers
Genetic Testing
FECAL OCCULT BLOOD TESTING
FOBT is used as a screening test for colonic neoplasms in asymptomatic, average-risk individuals
The efficacy of this test is based upon serial testing because the majority of the colorectal malignancies will bleed intermittently
Has been a nonspecific test for peroxidase contained in haemoglobin
STOOL STUDIES
Are often helpful in evaluating the etiology of diarrhea
Wet-mount examination reveals the presence of faecal leukocytes, which may suggest colonic inflammation or the presence of an invasive organism such as invasive E. coli or Shigella
Stool cultures can detect pathogenic bacteria, ova, and parasites
C. difficile colitis is diagnosed by detecting bacterial toxin in the stool
Steatorrhea may be diagnosed by adding Sudan red stain to a stool sample
SERUM TESTS
Specific laboratory tests that should be performed will be dictated by the clinical scenario
Preoperative studies generally include CBC and electrolyte panel
The addition of coagulation studies, liver function tests, and blood typing/cross-matching depends upon the patient’s medical condition and the proposed surgical procedure
TUMOR MARKERS
Carcinoembryonic antigen (CEA) may be elevated in 60-90% of patients with colorectal cancer
Despite this, CEA is NOT an effective screening tool for this malignancy
Many practitioners follow serial CEA levels after curative-intent surgery in order to detect early recurrence of colorectal cancer
However, this tumor marker is nonspecific and no survival benefit has yet been proven
Other biochemical markers (ornithine decarboxylase, urokinase) have been proposed, but none has yet proven sensitive or specific for detection, staging, or predicting prognosis of colorectal CA
GENETIC TESTING
Although familial colorectal CA syndromes such as FAP and HNPCC are rare, information about the specific genetic abnormalities underlying these disorders has led to significant interest in the role of genetic testing for colorectal CA
Tests for mutations in the APC gene responsible for FAP and in mismatch repair genes responsible for HNPCC, are commercially available and extremely accurate in families with known mutations
Although many of these mutations are also present in sporadic colorectal cancer, the accuracy of genetic testing in average individuals is considerably lower
These tests are not recommended for screening. Because of the potential psychosocial implications of genetic testing, it is strongly recommended that professional genetic counsellors be involved in the care of any patient considering these tests
NOTE: The following topics under Evaluation of Common Symptoms are not emphasized by Doc Mata but are still included in the ppt. Tinamad na ata siya gumawa ng ppt kasi sobrang copy-paste lang from Schwartz.
EVALUATION OF COMMON SYMPTOMS ABDOMINAL PAIN
Pain related to colon and rectum can result from obstruction (either inflammatory or neoplastic), inflammation, perforation or ischemia.
Plain X-rays and judicious use of contrast studies and/or a CT scan can often confirm the diagnosis
Gentle retrograde contrast studies (barium or
Gastrografin enema) may be useful in delineating the degree of colonic obstruction
PELVIC PAIN
Can originate from the distal colon and rectum or from adjacent urogenital structures
Tenesmus may result from proctitis or from a rectal or rectrorectal mass
Cyclical pain associated with menses, esp when
accompanied by rectal bleeding suggests a diagnosis of endometriosis
PID also can produce significant abdominal and pelvic pain
The extension of a peridiverticular abscess or
periappendiceal abscess into the pelvis may also cause pain
CT scan and/or MRI may be useful in differentiating these diseases
Proctoscopy (if tolerated) also can be helpful
Occasionally, laparoscopy will yield diagnosis
ANORECTAL PAIN
Most often secondary to an anal fissure or perirectal abscess and/or fistula
PE can usually differentiate these conditions
Other less common causes: Anal canal neoplasms Perianal skin infection Dermatologic conditions
Proctalgiafugax–results from levator spasm and may present without any other anorectal findings
PE is critical in evaluating patients with anorectal pain
If a patient is too tender to examine in the office, an examination under anesthesia is necessary
MRI may be helpful in select cases where the etiology of pain is elusive
LOWER GI BLEEDING
The first goal in evaluating and treating a patient with GI haemorrhage is adequate resuscitation
The principles of ensuring a patient airway, supporting ventilation, and optimizing hemodynamic parameters apply and coagulopathy and/or thrombocytopenia should be corrected
The second goal is to identify the source of haemorrhage
Because the most common source of GI haemorrhage is esophageal, gastric or duodenal, nasogastric aspiration should always be performed
Return of bile suggests that the source of bleeding is distal to the ligament of Treitz
If aspiration reveals blood or nonbile secretions, or if symptoms suggest an upper intestinal source, esophagogastroduodenoscopy is performed
Anoscopy and/or limited proctoscopy can identify hemorrhoidal bleeding
A technetium-99-tagged RBC scan is extremely sensitive and is able to detect as little as 0.1 ml/h of bleeding; however, localization is imprecise
If the technetium-99-tagged RBC scan is positive, angiography can then be employed to localised bleeding
Infusion of vasopressin or angioembolization may be therapeutic
Alternatively, a catheter can be left in the bleeding vessel to allow localization at the time of laparotomy
If the patient is hemodynamically stable, a rapid bowel perforation (over 4-6 hours) can be performed to allow colonoscopy
Colonoscopy may identify the cause of the bleeding, and cautery or injection of epinephrine into the bleeding site may be used to control haemorrhage
Colectomy may be required of bleeding persists despite these interventions
Intraoperative colonoscopy and/or enteroscopy may assist in localizing bleeding. If colectomy is required, a segmental resection is preferred if the bleeding source can be localized. "Blind" subtotal colectomy may very rarely be required in a patient who is hemodynamically unstable with ongoing colonic hemorrhage of an unknown source. In this setting, it is crucial to irrigate the rectum and examine the mucosa by proctoscopy to ensure that the source of bleeding is not distal to the resection margin
Occult blood loss from the GI tract may manifest as iron-deficiency anemia or may be detected with FOBT. Because colon neoplasms bleed intermittently and rarely present with rapid hemorrhage, the presence of occult fecal blood should always prompt a colonoscopy. Unexplained iron-deficiency anemia is also an indication for colonoscopy.
Hematochezia commonly is caused by hemorrhoids or fissure. Sharp, knife-like pain and bright-red rectal bleeding with bowel movements suggest the diagnosis of fissure.
CONSTIPATION AND OBSTRUCTED DEFECATION
Constipation has a myriad of causes: Underlying metabolic
Pharmacologic Endocrine Psychologic
Neurologic causes often contribute to the problem
A stricture or mass lesion should be excluded by colonoscopy or barium enema. After these causes have been excluded, evaluation focuses on differentiating
slow-transit constipation from outlet obstruction.
Transit studies, in which radiopaque markers are swallowed and then followed radiographically, are useful for diagnosing slow-transit constipation.
Anorectal manometry and EMG can detect
nonrelaxation of the puborectalis, which contributes to outlet obstruction. The absence of an anorectal inhibitory reflex suggests Hirschsprung's disease and may prompt a rectal mucosal biopsy.
Defecography can identify rectal prolapse, intussusception, rectocele, or enterocele.
Medical management is the mainstay of therapy for constipation and includes fiber, increased fluid intake, and laxatives. Outlet obstruction from nonrelaxation of the puborectalis often responds to biofeedback.Surgery to correct rectocele and rectal prolapse has a variable effect on symptoms of constipation, but can be successful in selected patients.
Subtotal colectomy is considered only for patients with severe slow-transit constipation (colonic inertia) refractory to maximal medical interventions. Although this operation almost always increases bowel
movement frequency, complaints of diarrhea, incontinence, and abdominal pain are not infrequent, and patients should be carefully selected
DIARRHEA AND IRRITABLE BOWEL SYNDROME
Diarrhea is also a common complaint and is usually a self-limited symptom of infectious gastroenteritis. If diarrhea is chronic or is accompanied by bleeding or abdominal pain, further investigation is warranted
Irritable bowel syndrome is a particularly troubling constellation of symptoms consisting OF
Crampy abdominal pain Bloating
Constipation Urgent diarrhea
GENERAL SURGICAL CONSIDERATIONS
Anterior Resection High Anterior resection Low Anterior Resection
Hartmann’s Procedure and Mucus Fistula Abdominoperineal Resection
Extent of resection for carcinoma of the colon. A.Cecal cancer. B. Hepatic flexure cancer. C. Transverse colon cancer. D. Splenic flexure
cancer. E. Descending colon cancer. F. Sigmoid colon cancer INFLAMMATORY BOWEL DISEASE
ULCERATIVE COLITIS
Rare in Filipinos
Common in Caucasians esp in Jews
Non-specific, idiopathic mucosal inflammation of the colon and rectum
Usually begins at the rectum moving proximally by direct extension (mucosa and submucosa)
Inflammation stops at the ileocolic junction
Bloody mucoid diarrhea, abdominal pain, tenesmus, fever
TREATMENT
Sulfasalazine – 4g/day relapse rate 9%/yr
Rowasa – topical enema of 5-ASA
Steroids, azathioprine, cyclosporine, mercaptopurine, tacrolimus
Total abdominal colectomy with end ileostomy
CROHN’S DISEASE
Nonspecific, transmural inflammation
Exacerbation/remission
Mouth to anus, bloody diarrhea
Extraintestinal manifestation
Skip lesion, rectal sparing (40%)
Terminal ileum and cecum (41%), SI (35%)
Fistula, abscess, obstruction, stricture
NEOPLASMS OF THE LARGE INTESTINE
POLYP
A grape-like protrusion of tissue into the bowel lumen Sessile
Pedunculated: flat on the mucosal surface Epithelial or submucosal: has a stalk Non-neoplastic Neoplastic NON-NEOPLASTIC POLYP Hyperplastic Juvenile Peutz-Jegher Syndrome NEOPLASTIC POLYP Tubular adenoma Villous adenoma Tubulovillous adenoma
FAMILIAL ADENOMATOUS POLYPOSIS
a general neoplastic disorder of the intestine
affected area: mainly large bowel
other: stomach, duodenum, small intestine
most important thing: colorectal CA develops before age 40 in nearly all untreated patients
inherited as a Mendelian dominant. The gene
responsible (APC gene) has now been identified on the short arm of chromosome 5
Males and Females equally affected
CLINICAL FEATURES SYMPTOMATIC PATIENTS ASYMPTOMATIC PATIENTS Loose stool
Lower abdominal pain
Weight loss
Diarrhea
Passage of blood and mucus
Usually are diagnose during screening or incidentally
Polyps are usually visible on sigmoidoscopy by the age of 15 years and will almost always be visible by age 30
Carcinoma of the large bowel occurs 10-20 years after the onset of polyposis
SOME EXTRA-INTESTINAL MANIFESTATIONS
BENIGN MALIGNANT Endocrine adenoma Osteoma Epidermoid cyst Hypertrophic retinal pigmentation Medulloblastoma Duodenal carcinoma Desmoid tumor
Bile duct, pancreatic CA
CA stomach
TREATMENT
Restorative proctocolectomy with an ileoanal anastomosis
Nowadays more frequently used
Indicated esp in cases:
With serious rectal involvement with polyps
Who are likely to be poor at attending for follow up With an established cancer of the rectum or sigmoid
Colectomy with ileorectal anastomosis
Was practiced in the past as usual operation because it avoids ileostomy in a young patient
CARCINOMA COLON INCIDENCE OF CANCER-Philippines MALE FEMALE 1. Lungs 2. Liver 3. Colon/Rectum 4. Stomach 5. Prostate 1. Breast 2. Cervix/Uterus 3. Colon/Rectum 4. Lungs 5. Thyroid 6. Ovary 7. Liver PREDISPOSING FACTORS
Low-fibre containing diet
Smoked fish
High content of refined carbohydrate in diet
Red meat
Less intake of micronutrients esp Selenium
PATHOLOGY
Microscopically
Columnar cell CA originating in the colonic epithelium
Macroscopically
Tumor may take one of four forms Type 1 – Annular
Type 2 – Tubular Type 3 – Acinar
Type 4 – Cauliflower (is the least malignant form)
Spreading Local Lymphatic Hematogenous
CLINICAL FEATURES
CA of the LEFT side of the colon: Pain
Alteration of bowel habit Palpable lump Distension CA of the SIGMOID Pain Tenesmus Bladder symptoms
CA of the CECUM and ASCENDING colon: Anemia
Lump in the right iliac fossa Acute appendicitis
Intermittent obstruction
May present with features of metastasis Palpable liver Jaundice Ascites INVESTIGATIONS Diagnostics Endoscopy Sigmoidoscopy Colonoscopy With tissue biopsy
Radiology
Double contrast barium enema - Shows irregular filling defect
Ultra-sonography - Liver metastasis CT Scan - Local invasion esp in Pelvis
TREATMENT
Preoperative preparation:
General:
Correction of anemia by blood Correction of nutritional imbalance Correction of electrolyte imbalance
Resuscitation if there is intestinal obstruction, perforation
Special preparation:
Dietary restriction to fluids for 2 days before operation Laxative Enema Prophylactic antibiotics Operation: Laparotomy is done
The tumor is assessed for resectibility by checking involvement in
o Liver o Peritoneum o Local lymph nodes o Tumor itself for Mobility
In cases of operable cases:
Operations are done to remove the primary tumor and the draining lymph nodes
Removal of the portion of colon surrounding the tumor depends on the side of the original tumor
CA PROCEDURE
1. CA of the
cecum/ascending colon
Right hemicolectomy 2. CA of the hepatic
flexure Resection will be extended correspondingly 3. CA of the transverse
colon
Excision of the transverse colon and the 2 flexures together with the
transverse mesocolon and the 2 flexures together with the transverse mesocolon and the
greater omentum followed by end to end
anastomosis
Alternative: extended right hemicolectomy 4. CA of the splenic flexure
or descending colon
Resection from right colon to descending colon
Sometimes removal of colon up to the ileum with an ileorectal anastomosis
In cases of INoperable cases: Palliative procedure is done
LOCATION OF GROWTH PROCEDURE
1. Upper part left colon Transverse colostomy 2. Pelvic colonic growth Left iliac fossa colostomy 3. Ascending colon growth By-pass ilio-colic
anastomosis ANORECTAL DISEASES Haemorrhoids Ischiorectal abscess Fistula in ano Fissure in ano Warts Fournier’s gangrene Foreign body HEMORRHOIDAL DISEASE Primary Locations 3-7-11 o’clock positions
Left Lateral – Right Anterior – Right Posterior
Submucosal cushion contains venules, arterioles, smooth muscle fibers
Part of continence mechanism
Excessive straining, increase abdominal pressure, hard stools
Bleeding, thrombosis, prolapse
External haemorrhoids distal to dentate line
Internal haemorrhoids proximal to dentate line
External Skin Tag
Redundant fibrotic skin at the anal verge due to previous thrombosed external haemorrhoid of past operation
GRADING
GRADE DESCRIPTION
1. FIRST DEGREE Bulge into anal canal, prolapse beyond dentate line
2. SECOND DEGREE Prolapse through anus, reduce spontaneously 3. THIRD DEGREE Require manual reduction 4. FOURTH DEGREE Cannot be reduced prone
to strangulation MANAGEMENT MEDICAL SURGICAL Diet Sitz bath Suppositories Excision: Milligan Morgan
Rubber Band Ligation
Harmonic Scalpel
ANAL FISSURE
Etiology:
Passage of large hard stool
Conditions (Crohn’s disease, ulcerative colitis, syphilis, TB, leukemia)
Manifestations
Burning pain during and after bowel movement Bright red blood on toilet paper
Rectal examination / proctosigmoidoscopy
TREATMENT
CONSERVATIVE SURGICAL
Anal hygience/bulk forming agents
Hot sitz bath
Local anesthetic jelly
Botolinum Lateral internal sphincterotomy (chronic stage) ANORECTAL ABSCESS 5 potential spaces Perianal space Ischiorectal space Intersphincteric space Deep posterior anal space
Etiology:
Infection or anal gland
Organism (fecal and cutaneous flora) 1. E. coli 2. Bacteroides fragilis 3. Staphylococcus 4. Stretptococcus 5. Clostridium sp. Manifestation
Pain in the anal region
Treatment
Drainage/antibiotic Hygiene
Hot sitz bath
TYPES OF ANORECTAL ABSCESS 1. Perianal abscess
2. Ischiorectal abscess
Diffuse swelling of ischio-rectal fossa
3. Intersphincteric abscess
No apparent sign of swelling or induration in the perianal area
CLUE: deep seated tenderness when circumanal pressure is applied above the dentate line
Drainage: through the anal canal lining or through internal sphincteric muscle
4. Supralevator abscess
Uncommon
Mimic acute intra-abdominal condition Etiology: extension of
o Intersphincteric abscess o Ischiorectal abscess o Intra-abdominal abscess
NECROTIZING PERI-ANAL & PERINEAL INFECTION
Etiology:
Neglected or delayed treatment of primary anorectal infection
Extension of UTI particularly the periurethral gland
Manifestation
Pain, tenderness, and swelling with crepitation of perianal and scrotum or labia
Black spot on the site (necrosis)
Treatment
Broad spectrum antibiotics Debridement
Hyperalimentation/diverting colostomy and/or cystostomy
FISTULA-IN-ANO
Inflammatory tract with secondary opening (external) and a primary opening (internal) in the anal canal
Etiology:
Complication of perianal abscess
Classification: Inter-sphincteric Trans-sphincteric Supra-sphincteric Extra-sphincteric
Salmon Goodsalls Rule
To locate the internal opening Anterior – straight tracts
Posterior – curved tracts Exception: >3 cm curved
Manifestation:
Previous history of perianal abscess
Rule out ulcerative colitis and Crohn’s disease (colonoscopy/barium enema)
Treatment:
Identify the primary opening (probing/methylene blue/fistulography)
Fistulotomy/fistulectomy (healing by secondary intention)
If fistula is high in relation to anorectal ring, do a 2 stage procedure:
1. Insert a seton wire or suture to the tract for several weeks to create fibrosis
2. Open the fibrous tract on the second stage after 6-8 weeks
