colonic lesions

7/31/2019 Colonic Lesions

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Colonic lesions


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Colonic lesions


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Colonic lesions


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Colonic lesions

Midgut derivatives

1.small intestine distal to

the ampulla of Vater,

2.cecum and appendix, 3. ascending colon, right

half to two-thirds of the

transverse colon.

Blood supply -frombranches of the superior

mesenteric artery


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Colonic lesions

The hindgut -left one-

third to one-half of the

transverse colon,

the descending colon,

the sigmoid colon,

the rectum,

and the superiorportion of the anal

canal.

inferior mesentericarter


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Colonic lesions


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Colonic lesions


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Porto-systemic anastomosis


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Lymphatics of colon and rectum


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Para-aortic nodes


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Pelvic floor-diaphragm

The muscles

pubococcygeus,iliococcygeus,

puborectalis,

a group of muscles thattogether form the levator

ani.

The pelvic diaphragm

resides between thesacrum, obturator fascia,

ischial spines, and pubis.


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Physiology of the Colon

Right colon- fermentation chamber

Left colon- storage and dehydration of stool

Rectum- reservoir

Absorbs water, sodium, and chloride

Secretes mucus, potassium and bicarbonate

Sodium and chloride are absorbed actively in colon

Potassium secretion- passiveChloride and bicarbonate are exchanged in the lumen


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Approximately 1,500 mL of ileal effluent reachesthe cecum in a 24-hour period, of which 90% is

water. Of this amount, only 100 to 150 mL of water

remains in the stool Store intraluminal contents until elimination is

socially convenient

Salvage nutrients after bacterial metabolism ofcarbohydrates that have not been absorbed in the

small intestine.


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Feature Right Colon Left Colon

Embryological origin Midgut Hindgut

Blood supply SMV IMVParasympathetic Vagus Pelvic nerves from

sacral S24 segments

Sympathetic Sup. mes. Ganglion. Inf.mes. ganglion

Function Mixing and storage Conduit


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Physiology of the ColonColonic Flora

The bacterial flora of the colon is established soonafter birth and depends in large part on dietary andenvironmental factors. Approximately 400 differentspecies of bacteria

Anaerobic bacteria ( Bacteroides ) B. fragilis,Lactobacillus bifidus, Clostridium species, andEubacterium species.

Aerobic bacteria are mainly coliforms andenterococci. Escherichia coli ,Klebsiella, Proteus,and Enterobacter.

The principal enterococcus is Streptococcus faecali.


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Has a bacterial concentration of 10 to the power of

12 anerobes per gm of feces

In colonic surgery- contamination and infection

supervenes.

To avoid this, colonic preparation is needed before

surgery or on-table procedures- needed

Bacterial load is reduced both mechanically and

chemically.

3-days liquid low residue diet or 1-day

administration of electrolyte solution of

polyethylene glycol (Peglec or Golytely)


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Neomycin,Erythromycin- broad spectrum and act

intra luminally Metronidazole- for anerobes

In emergency situations- on table

Lavage is done with litres of saline


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Physiology of the Colon-Fns.of flora

Vitamin K -produced by many colonic bacteria.

The enterohepatic circulation of bilirubin and bileacids depends greatly on bacterial enzymes.

Degradation of bile pigments by colonic bacteria

gives stool its characteristic brown color. Influence colonic motility and absorption,

Generate intestinal gases,

Prevents infection by keeping the growth ofpathogenic bacteria such as C. difficile in check.


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VOLVULUS

COLON

DEFINITION

Is the folding,twisting or axial rotation of aportion of GI Tract about its mesentery

It may be

1.Partial

2. Complete


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VOLVULUS

COLON

If complete, it forms a closed loop

obstruction with resultant ischemiadue to vascular occlusion.


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VOLVULUS

COLON

1.Primary-due to congenital

malrotaion of the

gut(v.neonatorum),

Congenital bands

2.Secondary-aquired bands(post-op)

3. spontaneous


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VOLVULUS

COLON

. Sites of vol.

Sigmoid-90%

Caecum

Tr.colon

Splenic flexure

Descending colon

Small bowel


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Volvulus of caecum

Occurs when the right half of colon is lax

and mobile.

Terminal ileum is also involved in the

rotation.

l l f


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Volvulus of caecum


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Volvulus caecum-

folding(bascule),twisting


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Bascule bridges


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Volvulus of caecum

Symptoms

Features of distal small bowel obstr.

Severe intermittent colicky pain in the right

side abdomen.

Vomiting

Bulging tympanic mass.

May be recurrent.-caecal bascule


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Volvulus of caecum

Investigations

X-ray abdomen erect

Hugely dilated caecum in the left epi and

hypo-gastrium with fluid level.

This may mimic distended stomach.


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Volvulus of caecum

Treatment

If viable----caecopexy

If not-------right hemicolectomy with ileo-transverse anastomosis.


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Ileo-sigmoid knotting


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sigmoid volvulus Incidence

1.commonly seen in Russia,India,Pak,Africaand eastern Europe.

2.Age.-common in 60-70 yrs.

3.sex-Male preponderance

4.Economic condn.-rural poor strata

5.Diet-consumption of course grains in bulk

quantity and with poor quality makes thesigmoid&its mesentery elongate Cont.


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sigmoid volvulus

Factors that facilitate formation

of volvulus.

1.long loop

2.narrow base of mesentery

3.loaded colon

4.adhesion at the summit of the

loop

Volvulus is mostly counter clock-

wise


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sigmoid volvulus

Clinical features.

1.acute onset of int.obstrn

2.occasionally preceded by milder attcks with

spontaneous recovery

3.absolute constipation with tenesmus due to

traction of rectum

4.extreme distension of abd.

5.at late stage-faecal peritonitis.


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sigmoid volvulus

Investigation Plain x-ray abdomen erect view.

--huge dilated gas filled large bowel without

haustra mainly on the left side.Inverted U shape,bent inner tube,omega loop,

Frimann-Dahl sign.all may be seen

Barium enema- bird beak appearance


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sigmoid volvulus

Treatment

1.In the early stage.ie when no strangulation

or perforation.pass a flexible fibroptic

colonoscope gently-untwisting may occur

2.On suspecion of strang.,perf.,int.obstn.

only surgical treatment.


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sigmoid volvulus

Surgical management.

1.if the bowel is gangrenous.

resection without primary anastamosis-

Paul-Miculicz type of double barrel colostomywhich is closed after 4 weeks.

2.If,after untwisting,found viable

Fixation procedures.eg.sigmoidopexy to thetr.colon or parietes etc.


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Primary resection &

anastamosis


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Thank you

Congenital disorders of large bowel


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Congenital disorders of large bowel

Megacolon-is an abnormally large or dilated colon

Primary- Hirschprungs disease

Acquired- follows faulty bowel training

Hirschprungs disease or congenital megacolon-

absence of ganglion cells in both the submucosal(Meisseners plexus) and the intermuscular

(Auerbachs plexus) layers with a marked increase in

nerve fibers in the submucosa.This neurogenic abnormality is associated with

muscular spasm of the distal colon and internal

anal sphincter resulting in a functional obstruction.


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Hi h di


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Hirschsprungs disease

Etiology

Unknown

Seen in 1 out of 5000 newborns

70% to 80% -boys Familial-10%

Sporadic-90%

Associated anomalies- bowel atresia,

Anorectal-urogenital-cardiac malformations

Hi h di


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Hirschsprungs disease Pathology

Aganglionosis leads to lack of propagation ofpropulsive waves and

Absence of relaxation of internal sphincter.

In the region of Internal anal sphincter-no ganglionsnormally

In HD, this segment extends proximally for varying

distance

Upto rectosigmoid-(80%) short segment disease

Beyond that-(15%) long segment

Entire colon- total colonic a an lionosis


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chagas disease, or South American trypanosomiasis, is similar in that the oesophagus and colon are aganglionic, but the

whole bowel is affected

Hi h di


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Hirschsprungs disease(In achalasia cardia-idiopathic or infectious

neurogenic degeneration)As the child grows-proximal ganglionic normal bowel

dialates, hypertrophies

Taenia disappears-Transition zone-funnel shaped

Distal aganglionic (abnormal) bowerlooks normal

and collapsed- this is the segment where pathologylies.



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Hirschsprung s disease

progressive abdominal distention and bilious emesis.

Failure to pass meconium in the first 24 hours -cardinal feature

. diarrhea -enterocolitis.

The diagnosis - overlooked - poor feeding, chronicabdominal distention, and constipation

Enterocolitis -common cause of death - diarrhea

alternating with periods of obstipation, abdominaldistention, fever, hematochezia, and peritonitis.



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Hirschsprung s disease

Diagnosis

Barium enema-normal -rectum is wider than thesigmoid colon.

In HD -spasm of the distal rectum -smaller caliber

when compared with sigmoid colon.Identification of a transition zone may be quite

helpful


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Anorectal manometry - failure of the internal

sphincter to relax when the rectum is distended witha balloon.

A rectal biopsy is the gold standard

Absent ganglia, hypertrophied nerve trunks, and

robust immunostaining for acetylcholinesterase are

the pathologic criteria to make the diagnosis.


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Enzyme histochemistry

showing aberrant

acetylcholine esterase

(ACHE)-positive fibres

(brown) in the lamina

propria mucosae

Surgical management
http://upload.wikimedia.org/wikipedia/commons/f/fb/Hirschsprung_acetylcholine.jpg


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Surgical management

Laparotomy ,Biopsy- diverting colostomy in the

region of normal ganglionated bowel.

A definitive procedure is then performed later.

1. Swensons pullthrough

2. Duhamels pullthrough

3. Soaves pullthrough

Intestinal Atresia or Stenosis


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The midgut -a tubular structure that progressively

undergoes several predictable, developmentalstages:

(a) elongation;

(b) herniation from and reduction into thecoelomic cavity;

(c) rotation; and

(d) fixation of the mesentery to the posterior bodywall.

Any aberration at these stages results in intestinal

atresia



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Atresia is a congenital interruption or

discontinuity of the luminal organresulting in its obstruction due to failure

of vacuolization or failure of

channelization from its solid state.



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Type I, muscular

continuity with a

complete web.

Type II, mesenteryintact, fibrous cord.

Type IIIa, muscular

and mesentericdiscontinuous.


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Type IIIb, apple-peeldeformity.

Type IV, multiple

atresias. (After

Grosfeld JL.Jejunoileal atresia

and stenosis.

Clinical Presentation


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Clinical Presentation

Detection of maternal polyhydramnios on routine

prenatal ultrasound screening can be an indication ofproximal bowel obstruction caused by the

interruption of normal amniotic fluid absorption in

the fetal gut.Bilious emesis,

Abdominal distention, and

Failure to pass meconium



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1.Plain xray abd.-marked gaseous distention of the

proximal intestine with gasless distal small bowel andcolon

2. A contrast enema -. A diminutive, unused but

otherwise normal microcolon is typical of proximalintestinal obstruction.

The inability to reflux contrast into the proximal,

dilated small bowel segment is diagnostic forcongenital intestinal obstruction.



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Intestinal Atresia or Stenosis Surgical treatment-restore gastrointestinal tract

continuity while preserving as much intestinal

length as possible.

an end-to-end or end-to-oblique anastomosis is

typically performed .

Short segmental bowel resection and excision of an

intraluminal web or diaphragm are used when

necessary


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Meconium Ileus


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Meconium Ileus

Mi. -earliest clinical manifestation of CF inherited disease

the terminal ileum is dilated and filled with thick,

tarlike, inspissated meconium. Smaller pellets of meconium are found in the

more distal ileum, leading into a relatively small

colon.

Meconium Ileus


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Meconium Ileus

Meconium Ileus


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Meconium Ileus Diagnosis X ray abd

.-dilated, gas-filled loops of small bowel, absence of air-fluid levels,

mass of meconium within the right side of the

abdomen mixed with gas to give a ground-glass orsoap bubble appearance.


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Meconium Ileus


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contrast enema

-unused butfunctionally normal

microcolon

Reflux of contrastinto the terminal

ileum may confirm

the presence ofinspissated

meconium pellets

Treatment-Nonoperative


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p Useful in 60% to 70% of newborns

retrograde irrigation of the terminal ileum withnormal saline, hyperosmolar contrast agents, or

dilute N-acetylcysteine

designed to dissipate the obstructing meconium.

operative management

The goal of operative management in simple

uncomplicated meconium ileus is to evacuatemeconium from the intestine while preserving

maximal intestinal length

Meconium Ileus


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Indications for surgery

Persistent or worsening abdominal distension Persistent bowel obstruction

Enlarging abdominal mass

Intestinal atresia

Volvulus

Perforation

Meconium cyst formation with peritonitis

Bowel necrosis


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A distal chimney

enterostomy,( Bishop

and Koop) involves

resection with

anastomosis between

the end of the proximalsegment and the side of

the distal segment of

bowel, approximately 4

cm from the opening ofthe distal segment. The

open end is brought out

as the ileostomy


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Thankyou

Colon-polyps


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Colon polyps

The term polyp (from the Greek polypous, morbid

excrescence) refers to a macroscopic protrusion ofthe colonic mucosa into the bowel lumen.

This can result from abnormal growth of the

mucosa or from a submucosal process that causes the

mucosa to protrude into the lumen.

Mucosal polyps can be sessile, protruding directlyfrom the colonic wall, or

pedunculated, extending from the mucosa

through a fibrovascular stalk.

Colo-rectal polyps-classification


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Colo rectal polyps classification

MUCOSAL

NEOPLASTIC

Benign

Adenomatous polyps

Tubular adenomaTubulovillous adenoma

Villous adenoma

Serrated polyp

MalignantCarcinoma in situ

Invasive carcinoma

Polypoid carcinoma

NONNEOPLASTIC

Hyperplastic polyps

Juvenile polyps

Peutz-Jeghers polypsInflammatory polyps

Normal epithelium

Colo-rectal polyps-classification


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p yp

SUB-MUCOSAL

LipomasLeiomyomas

Colitis cystica profunda

Pneumatosis cystoides intestinalisLymphoid aggregates

Lymphoma (primary or secondary)

Carcinoids

Metastatic neoplasms


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Neoplastic Mucosal Polyps


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p yp

colorectal cancers arise in preexisting

adenomatous polyps. Neoplastic mucosal epithelium evolves through a

series of progressive, cumulative molecular and

cellular steps that lead to altered proliferation,

cellular accumulation, and

glandular disarray.

invade and metastasize through the adenoma-to-

carcinoma sequence

Histopathology and Malignant


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PotentialAdenomatous polyps are characterized according to

physical features, -sessile or pedunculated

size,-Malignant potential increases with polyp size

glandular structure, - Tubular, villous,tubulo-villous degree of dysplasia,-ca.insitu or invasive

-all have important implications for clinical

management

Pathology of polyps


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a left-sided predominance

mucosa to polyp--5 to 10 years

Polyp to invasive carcinoma 3 to 5 years

Associated conditions-acromegaly elevated

gastrin levels prior cholecystectomy,

atherosclerosis, acrochordons (skin tags)

Clinical Features-polyps


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Occult bleed, haematochezia

Alteration of bowel habits

Lower abdominal crampy pains

Secretory diarrhoea (hypokalemia and

hypochlorhydria )Diagnosis

Fecal Occult Blood Test

Sigmoidoscopy

air-contrast barium enema or colonoscopy

Computed tomographic (CT) colography

Management -polyps


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Excision of poylps to resectional surgery according

to the histological report and other risk factors.

Familial adenomatous polyposis (FAP) and

Gardner's syndrome.

autosomal dominant.

hundreds of colorectal polyps in the first three

decades of life.

Seen in the stomach and small intestine.

Familial adenomatous polyposis


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p yp

(FAP)

Gardner's syndrome is distinguished by

osteomas, fibromas, in addition to the

intestinal polyps..

Total proctocolectomy with an ileostomy or ananal sphincter-saving procedure is indicated if

the diagnosis of FAP is made

Familial adenomatous polyposis


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colonic lesions

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