1. Gastrointestinal System pathology

2. 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.

3. Organ systems Includes: Mouth, pharynx & esophagus Stomach
Small intestine
Large intestine
Accessory digestive organs: teeth, tongue, gall bladder, salivary glands, liver & pancreas

4. esophagus

5. 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

6. Esophageal disorders Filling defects: Intraluminal or extraluminal
Stricture: Corrosive, Achalasia, malignant
Diverticulum
Zenker ’s diverticulum
Traction diverticulum
Epi - phrenic diverticulum

7. 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

8. A segment of luminal narrowing
[2] Stricture
A segment of luminal narrowing
[3] Diverticulum
A saccular out pouching connected to the bowel lumen usually fills with barium

9. [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

10. [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.

11. [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

12. [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

13. [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.

14. Zenker ’s diverticulum
Traction diverticulum
Epi - phrenic diverticulum

15. Stomach and Duodenum

16. 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

17. Gastric disorders Hiatus hernia Filling defect Gastric bezoar
Benign lesions
Malignant lesions
Peptic Ulcer Disease (PUD)

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

19. They are often made of hair and food fibers.
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.

20. As a result, it has a poor prognosis.
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.
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.
Linitis plastic: Barium meal showing marked reduction of the gastric lumen with irregular outlines compared to the normal stomach seen in the right image

21. 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.

22. 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.

23. 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

24. 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

25. Causes of Bowel Obstruction:
Causes of mechanical bowel obstruction :
Hernia
Adhesions
Volvulus
Intussusception
Neoplasm (Adenoma/Polyp, adenocarcinoma)
Crohn’s Disease
Constipation

26. Large bowel obstruction
Plain film
colonic distension: gaseous secondary to gas-producing organisms in faeces
collapsed distal colon
small bowel dilatation, depends on
duration of obstruction
incompetence of the ileocaecal valve
CT is the best diagnostic modality used as:
confirm the diagnosis
localize the location of obstruction
identify the cause. 
Radiographs reveal dilated small bowel loops with multiple air fluid levels

27. Small bowel obstruction
Radiographic features
Plain film
In most cases, the abdominal radiograph will have the following features:
Dilated loops (over 3cm) of small bowel predominantly central proximal to the obstruction
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 . 

28. Hernia: inguinal 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

29. Corhn’s disease
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

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

31. Ulcerative Colitis
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).

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

33. 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.