GASTROINTESTINAL SYSTEM PATHOLOGY

GI: Overview: Organ systems

Gastrointestinal (GI) tract [Alimentary canal] a continuous muscular digestive tube Digests:

breaks food into smaller fragments Absorbs:

digested material is moved through mucosa into the blood

Eliminates: unabsorbed & secreted wastes.

Organ systems

Includes: Mouth, pharynx &

esophagus Stomach Small intestine Large intestine

Accessory digestive organs: teeth, tongue, gall bladder, salivary glands, liver & pancreas

esophagus

ANATOMY OF ESOPHAGUS Flattened muscular tube,

size 18 to 26cm beginning at lower border

of cricoid cartilage (opposite 6th cervical vertebra)

ending at cardiac orifice of stomach(opposite 11th cervical vertebra)

Divided into 3 anatomical segments i.e., cervical, thoracic & abdominal

Normal barium swallow showing normal esophageal caliber with no evidence of filling defects, ulcerations, strictures or diverticulae

Esophageal disorders

1. Filling defects: Intraluminal or extraluminal

2. Stricture: Corrosive, Achalasia, malignant

3. Diverticulum• Zenker ’s diverticulum• Traction diverticulum• Epi - phrenic diverticulum

Esophageal abnormalities

[1] Filling defect

[A] Intraluminal lesion

A lesion inside the bowel lumen

totally surrounded by Barium

[B]Extraluminal lesion

Arises from outside+ compresses

the bowel

Causes narrowing from one side only

Forms a shallow angle with the

bowel wall

[2] Stricture

A segment of luminal

narrowing

[3] Diverticulum

A saccular out pouching connected

to the bowel lumen usually fills

with barium

[A] Corrosive Stricture

Affect Long segment starts at the level of

the aortic arch

Accidentally in children or Suicide

attempts in adults

Radiographic appearance of the stricture:

long, with smooth outline

Upper end of which is funnel shaped and

tapers into normal oesophagus

Lost mucosal pattern

Corrosive stricture: Barium swallow showing a long segment of esophageal narrowing with mild proximal esophageal dilatation

[B] Achalasia of the cardia Achalasia is an esophageal motility

disorder that occurs due to the inability

of the lower esophageal sphincter (LES)

to relax.

As a result, the esophagus fills with

ingested food and fluids.

Barium swallow showing smooth

tapering "Bird's beak" of the distal

esophageal segment with marked

proximal esophageal destination

"megaesophagus

"Bird's beak" appearance and "megaesophagus," typical in achalasia.

[c] Malignant Stricture

Occur anywhere in the

oesophagus Commonly seen in

the middle third of esophagus

Post cricoid carcinoma affects

the upper third

Lower third lesions may simulate

achlasia

Radiographic appearance:

Barium swallow showing

esophageal stricture with

overhanging edges resulting in

the typical apple core

configuration

[2] Filling defect

Esophageal filling defects

may be due to benign lesion

as benign liomyoma or

malignant lesion like

esophageal carcinoma or

lymphoma.

In all cases endoscopic

evaluation is needed for

biopsy taking Esophageal carcinoma: Barium swallow showing a large midesophageal filling defect distending the esophageal lumen

[3] Esophageal diverticulae

Zenker ’s diverticulum: arise from the posterior wall of

the upper esophagus in the area of the pharynx.

Traction diverticulum: forms in the mid esophagus area ;

may form due to scarring from pulmonary tuberculosis or

an inflammatory process within the mediastinum.

Epi - phrenic diverticulum arises in the distal esophagus

just superior to the lower esophageal sphincter (LES).

They may form as a complication to achalasia.

Zenker ’s diverticulum Traction diverticulum Epi - phrenic diverticulum

Stomach and Duodenum

STOMACH

Muscular bag that forms the widest & most distensible part of digestive tube

Extened from Oesophagus to duodenum

Location – epigastric, umbilical & left hypochondriac• 25cm long• Capacity – 1.5 to 2L

Gastric disorders

1. Hiatus hernia2. Filling defect Gastric bezoar Benign lesions Malignant lesions 3. Peptic Ulcer Disease (PUD)

Hiatus hernia Herniation of the stomach through the esophageal hiatus above the diaphragmTypes:1. sliding hiatal hernia (commonest). 2. A rolling (paraesophageal

hiatal hernia) (rare)

Bezoars : This is a hard mass of entangled material

found within the stomach or intestines that cannot be digested.

They are often made of hair and food fibers.

The artifact (arrows) depicted on this radiograph consists of a hard ball of entangled materials called a bezoar.

Gastric carcinoma It is generally asymptomatic in the early stages and has generally metastasized to other areas of the body by the time it has been diagnosed.As a result, it has a poor prognosis.UGI studies present thick, irregular, and rigid (linitis plastica) folds.

Linitis plastic: Barium meal showing marked reduction of the gastric lumen with irregular outlines compared to the normal stomach seen in the right image

The arrows on this UGI radiograph are pointing to a gastric carcinoma. Note the classic “apple-core” appearance that is a characteristic of an adenocarcinoma.

Peptic Ulcer Disease (PUD)

Gastric Ulcers These are very rare and may be a

complication of gastric carcinoma.Peptic Ulcers These are located in the duodenum and

are much more common than gastric ulcers.

They are mostly located in the duodenal bulb and are usually not associated with cancer.

Peptic Ulcer Disease: normal vs acute

Normal duodenal cap: Spot view of barium meal showing the normal triangular shape of the duodenal cap which should be radiographed when it is filled with barium

Acute duodenal ulcer: Double Contrast barium meal study demonstrating an ulcer in the duodenal bulb with radiating mucosal folds.

Chronic duodenal ulcer

•Duodenal ulcer with scarring and marked

deformity of the base of the duodenal bulb after

healing of a duodenal ulcer.

•By Barium meal showing the classic trefoil

deformity of the duodenal cap due to fibrosis

resulting from healed ulcer

Bowel Obstruction:

The two types of bowel obstructions are as follows:

small bowel and large bowel obstruction.

Signs and symptoms of a bowel obstruction would

include the following:

Abdominal Pain

Abdominal Distention

Vomiting

Constipation

Causes of Bowel Obstruction:

Causes of mechanical bowel obstruction :

1. Hernia2. Adhesions3. Volvulus4. Intussusception5. Neoplasm (Adenoma/Polyp,

adenocarcinoma)6. Crohn’s Disease7. Constipation

Plain film1. colonic distension: gaseous

secondary to gas-producing organisms in faeces

2. collapsed distal colon3. small bowel dilatation, depends

on duration of obstruction incompetence of the ileocaecal

valve CT is the best diagnostic

modality used as: 1. confirm the diagnosis 2. localize the location of

obstruction 3. identify the cause. 

Large bowel obstruction

Radiographs reveal dilated small bowel loops with multiple air fluid levels

Small bowel obstruction

Radiographic features Plain film1. In most cases, the abdominal

radiograph will have the following features:

2. Dilated loops (over 3cm) of small bowel predominantly central proximal to the obstruction

3. fluid levels if the study is erect (non-standard technique)

CT is more sensitive than plain radiographs and will demonstrate the cause in ~80% of cases . 

Hernia:

It is a weakening of the

abdominal wall that allows a

portion of the intestine to

protrude through it.

A reducible hernia can be pushed

back into the abdominal cavity

while an incarcerated hernia

cannot leading to obstruction.

A common hernia in men is

called an inguinal hernia. inguinal hernia

Sub mucosal lymphoid tissue hyperplasia → thickening and rigidity of the affected segment → luminal narrowing = Stricture

Radiographic appearance: The characteristic of Crohn disease is the presence of

skip lesions. Barium small bowel follow-through mucosal ulcers

when severe leads to cobblestone appearance may lead to sinus tracts and fistulae

thickened folds due to oedema pseudodiverticula formation: due to contraction at the

site of ulcer with ballooning of the opposite site string sign: tubular narrowing due to spasm or

stricture depending on chronicity

Corhn’s disease

Corhn’s disease

This image demonstrates the classic radiograph appearance of the “string sign” that is a characteristic of Crohn’s disease.

cobblestone appearance

Edematous inflammatory infiltration of the mucosa which ulcerates

The colon is diffusely affected with involvement of the rectum

Radiographic features Plain film Non specific but may show evidence of mural thickening

(more common), with thumbprinting also seen in more severe cases.

Fluoroscopy - Barium enema Mucosal ulcers are undermined (button-shaped ulcers). When most of the mucosa has been lost, islands of mucosa

remain giving it a pseudo-polyp appearance. In chronic cases the bowel becomes featureless with loss of

normal haustral markings, luminal narrowing and bowel shortening (lead pipe sign).

Ulcerative Colitis

Ulcerative colitis: Double contrast barium enema shows a featureless descending and sigmoid colon, lacking normal haustral marking.

Diverticulosis

diverticulum can occur along the entire length of the GI tract.

In regards to the large intestine, they are commonly found in the area of the sigmoid colon.

Diverticulum often have no signs or symptoms and are often a serendipitous discover on a barium study or colonoscopy.