Disorders of the GI Tract

1
The Nature of DiseasePathology for the Health
Professions Thomas H. McConnell

• Chapter 11
• Disorders of the GI Tract
• Lecture 11

2
Overview of Todays Lecture

• Review of Digestive System
• General Signs and Symptoms of GI Disorders
• Oral Cavity Disease
• Esophageal Disease
• Stomach Disorders
• Vascular Diseases of the Small/Large Bowel
• Infectious Diseases of the Small/Large Bowel
• Malabsorption Syndromes
• IBD and IBS
• Neoplasms of the Small/Large Bowel
• Colonic Diverticulosis/Anorectal conditions
• Disease of the Appendix and Peritoneum

3
Review of the GI Tract Anatomy Function
Figures from McConnell, The Nature of Disease,
2nd ed., LWW, 2014
4
Hormonal and Neural Signals Involved in Digestion
Table from McConnell, The Nature of Disease, 2nd
ed., LWW, 2014
5
The Peritoneum and Mesenteries
Figure from McConnell, The Nature of Disease,
2nd ed., LWW, 2014
6
Signs and Symptoms of GI Disorders

• Some terms to know the definitions of
• Anorexia
• Nausea
• Vomiting (emesis)
• Character is important (yellow/green, brown,
  coffee grounds, bloody (hematemesis)
• Dysphagia
• Belching/flatulence
• Diarrhea (Thinner, more frequent bowel movements)
• Dysentery (low-volume, bloody, painful)
• Constipation and Impaction

See Exercise 11-5
7
Causes of gastrointestinal bleeding
Important terms associated with GI bleeding -
Hematemesis- Hematochezia- Melena- Occult
Bleeding (test?)
EVERY instance of GI bleeding should get
immediate attention and be considered as a
potential malignancy.
Figure from McConnell, The Nature of Disease,
2nd ed., LWW, 2014

• Two types of GI bleeding classified according to
  source
• Upper GI Everything from the 1st few cm of the
  duodenum to the esophagus
• Lower GI Below the 1st few cm of duodenum

8
Interruptions of Peristalsis

• Ileus
• Lack of peristalsis (intestinal paralysis)
• Associated with many conditions, e.g. post-op,
  intra-abdominal inflammation, intestinal
  ischemia, spinal cord injury, hypokalemia
• Mechanical Obstruction
• Adhesions (surgery, infection)
• Intussusception (telescoping)
• Volvulus (twisting)
• Hernia
• Incarcerated hernias
• Strangulated hernias

Figures from McConnell, The Nature of Disease,
2nd ed., LWW, 2014
9
Diseases of the Oral Cavity
Herpesvirus
Cleft Lip/Palate
Cadidiasis (oral thush)
Apthous ulcers
Squamous cell carcinoma
10
Diseases of the Oral Cavity

• Cleft Lip and Cleft Palate (Congenital)
• Genetic and environmental factors
• Mildest is split uvula
• More serious lip or soft palate
• Interferes with speech and feeding
• Associated with maternal smoking and alcohol use
• Folic acid before pregnancy may decrease risk

Figure from McConnell, The Nature of Disease,
2nd ed., LWW, 2014
11
Diseases of the Oral Cavity

• Apthous ulcers (canker sores)
• Small, painful, shallow
• Mainly in children and young adults
• Salt-water gargle is helpful
• May indicate more serious disease, e.g, Crohn
• Herpesvirus (multiple shallow ulcers)
• Cadidiasis (oral thrush) (Candida albicans)
• Overgrowth of fungus when normal protective
  mechanisms are impaired
• Squamous cell carcinoma
• On lip usually better prognosis
• Floor of mouth poorer prognosis
• Associated with poor oral hygiene, alcohol,
  tobacco

Figures from McConnell, The Nature of Disease,
2nd ed., LWW, 2014
12
Diseases of Oral Cavity Teeth/Gums
Figure from McConnell, The Nature of Disease,
2nd ed., LWW, 2014
13
Diseases of the Oral Cavity

• Tooth and Gum Disease
• Dental caries
• Erosion of tooth enamel (cannot be replaced!)
• Plaque (bacteria, dead cells, food debris,
  mucus)
• Tartar (calcified plaque)
• Gingivitis and Periodontitis
• Inflammation of superficial gums
• Untreated may lead to periodontitis deep
  inflammation of soft tissues around tooth root
• Infection of root periapical abscess

Figure from McConnell, The Nature of Disease,
2nd ed., LWW, 2014
14
Diseases of the Oral Cavity - Salivary Glands

• Inflammation (sialadenitis)
• Acute streptococcus or mumps
• Chronic typically autoimmune, e.g., Sjogrens
• Pleomorphic adenoma
• Usually benign
• Usually occur in major salivary glands, esp.
  parotid
• When occurring in minor salivary glands, more
  serious

15
Normal Esophagus
16
Diseases of the Esophagus

• Atresia
• Absence or narrowing, with or without obstruction
• Most common congenital defect
• May accompany tracheoesophageal fistula
• Achalasia
• Spasm of LES
• Disappearance of autonomic ganglion cells
• Autoimmune, immune reaction to viruses
• Slowly progressive dysphagia and esophageal pain

17
Diseases of the Esophagus

• Hiatal hernia
• Protrusion of part of stomach through esophageal
  hiatus
• May cause GERD especially lying down
• Mallory-Weiss Syndrome
• Tears or lacerations
• Due to frequent vomiting/retching, e.g., in
  bulimia
• Esophageal varices
• Dilated veins, varices (sing. Varix)
• Almost always from cirrhosis of liver

18
Diseases of the Esophagus

• Esophagitis
• Inflammation of esophagus
• Painful swallowing (odynophagia)
• Alcohol, smoking, reflux
• When infectious, usually opportunistic
• Gastroesophageal reflux disease (GERD)
• Incompetence of LES
• Many causes
• Heartburn (substernal pain) most common
• When chronic, may cause Barrett esophagus

19
Barretts Esophagus
From http//blogs.nejm.org/now/index.php/barretts
-esophagus-2-2/2014/08/29/
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Carcinoma of the Esophagus

• Squamous cell carcinoma (50)
• Arise from esophageal epithelium
• Usually mid-upper esophagus- Risk factors
• Male, African American
• Heavy tobacco use alcohol
• Low fiber, high fat diet (a.k.a. US)

• Esophageal Adenocarcinoma (50)
• Usually lower esophagus (at GE junction)
• Risk factors
• Male, Caucasian
• GE Reflux, e.g., Barretts
• Obesity

Figure from https//gi.jhsps.org/
21
Disorders of the Stomach
From Medline Plus
Acute nonerosive gastritis
Ulcers due to - Stress Curling- Brain trauma
Cushing
Autoimmune gastritis ab against parietal cells
(no IF -gt pernicious anemia Zollinger-Ellison
Syndrome Pancreatic tumor secreting gastrin -gt
ulcerogenic
Chronic stress ulcers (90 due to H. pylori some
autoimmune)
- Acute erosive gastritis
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Chronic peptic ulcer of stomach
23
Disorders of the Stomach

• Gastric adenocarcinoma (almost all)
• Arise from gastric epithelium
• Genetic Environmental- Risk factors
• H. pylori
• Smoked, pickled salt-preserved foods
• Nitrites (preserved meat)
• Low fiber, high fat diet (a.k.a. US)

• Primary Gastrointestinal Lymphomas
• Stomach most common site (60)
• B or T cell tumors
• Originate in MALT- Risk factors
• H. pylori
• Malabsorption syndromes
• Immunodeficiency

Figure from Marieb, Anatomy Physiology,
Pearson Education, 2016
24
Vascular Diseases of Small and Large Bowel

• Ischemic vascular disease
• Common in elderly with athersclerosis (celiac or
  mesenteric arteries)
• Causes
• Thrombosis and embolism
• Vasculitis
• Volvulus
• Angiodysplasia
• Small, twisted mass of blood vessels
• Usually in colon or cecum
• Prone to bleeding
• Hemorrhoids
• Varicies either within (internal) or outside
  (external) anal canal
• From straining when defecating or venous stasis
  (pregnancy)
• Blood will be bright red and ON stool (or toilet
  paper)

Figure from McConnell, The Nature of Disease,
2nd ed., LWW, 2014
25
Infectious Diseases of Small and Large Bowel

• Acute gastroenteritis
• Inflammation of the stomach (fewer), or
  small/large bowel (more)
• Viruses and bacteria
• More typical in developed countries
• usually produce only mild mucosal inflammation
• Protozoa and Parasites
• More typical in developing nations
• Associated with more severe, chronic disease
• Viral Gastroenteritis (main cause of acute
  gastroenteritis in US)
• Rotavirus leading cause of diarrhea in small
  children (daycare)
• Norovirus (Norwalk) older children/adults in
  close quarters where food is prepared for groups
  (think NORwegian CRUISELINE)

26
Infectious Disease of the Small and Large Bowel
Travellers diarrhea
Salmonellosis Typhoid fever
Pseudomembranous colitis
Shigellosis (bacillary dysentery)
Amebic dysentery
Figure from McConnell, The Nature of Disease,
2nd ed., LWW, 2014
27
Malabsorption Syndromes

• Malabsorption
• Poor digestion or absorption of dietary
  substances
• Excess fecal excretion of nutrients (along with
  minerals and water)
• Effect of syndrome depends on which phase of
  digestion/absorption is affected
• Luminal phase (within lumen of intestine)
• Lack of pancreatic enzymes (esp lipase), e.g.,
  cystic fibrosis
• Hepatobiliary disease (bile) -gt steatorrhea
• Change in acid/base balance or microflora
  ecosystem
• Epithelial phase
• disturbance of mucosal enzymes, e.g., lactase
• Inflammation
• Immune reaction to dietary content, e.g., gluten
• Lymphatic phase
• Blockage of lymphatic ducts (affects fat
  absorption, mainly)

28
Malabsorption Syndromes

• Major effects of malabsorption syndromes
• Hematopoietic (Vit B12, folic acid, vit K)
• Musculoskeletal
• Hormonal
• Skin
• Nerve
• Examples
• CHO Intolerance - Lactose intolerance
• Celiac sprue Immune sensitivity to gluten
  (barley, rye, oats, wheat)
• Bacterial overgrowth syndrome
• Short bowel syndrome
• Chronic diseases

29
Inflammatory Bowel Disease (IBD)

• Chronic inflammatory disease
• T-cell mediated
• Suspect normal bacteria in genetically
  predisposed individuals
• Two major varieties both immune-mediated
  inflammation
• Crohn Disease
• Ulcerative Colitis (UC)

30
Inflammatory Bowel Disease
Figures from McConnell, The Nature of Disease,
2nd ed., LWW, 2014
Mnemonic Cathy Rohn is skipping across the wall
on the way to grandmas before she goes fishing.
31
Irritable Bowel Syndrome (IBS)

• Difficult to define in terms of pathology
• Also called spastic colon, irritable colon,
  nervous colon
• No consistent anatomical/pathological lesions it
  is a functional disorder
• Typically teens or young adults
• Abdominal pain, bloating, diarrhea, altered bowel
  habits
• Psychological problems are common
• Unlike IBD, weight loss, bleeding and vomiting do
  NOT occur.

32
Neoplasms of the Large and Small Bowel

• Overview
• Far greater number of neoplasms occur in large
  intestine than small intestine
• Colon cancer is 2nd leading cause of cancer death
  in US
• Early detection is critical since
• Many benign lesions can be found early
• Most colon CA arise from pre-malignant lesions
  called adenomatous polyps at least 10-15 years
  before becoming malignant
• Iron deficiency in adult males and
  post-menopausal females should always lead to
  investigation for intestinal CA.

33
Neoplasms of the Large and Small Bowel

• Neoplasms of the intestine fall into several
  major groups
• 1. Non-neoplastic polyps (NOT pre-malignant)
• Hamartomatous hyperplastic
• 2. Adenomatous polyps (Pre-malignant)
• Tubular adenomas Villous adenomas Tubulovillous
• 3. Familial Adenomatous Polyposis (always leads
  to colon CA)
• 4. Colon cancer
• 5. Other tumors of the GI tract
• Carcinoid gastrointestinal stromal tumors (GIST)

34
Neoplasms of the Large and Small Bowel

• Non-neoplastic polyps (NOT pre-malignant)
• The term polyp refers to the shape of a growth
  which may or may not be a neoplasm
• They are classified as based on two major
  criteria
• Stalk (pedunculated) or no stalk (sessile)
• Non-neoplastic or Neoplastic (Benign or
  Malignant)
• Types
• Hamartomatous polyps
• Non-neoplastic, disorganized tissue (a hamartoma)
• Familial connection
• Usually in children (Peutz-Jeghers syndrome)
• Hyperplastic polyps
• Epithelial cell accumulation in mucosa (usually
  elderly)
• Common
• Not premalignant

35
Neoplasms of the Large and Small Bowel

• Adenomatous polyps (colonic adenomas)
• Premalignant neoplasms of colon epithelium
• High-fat, low-fiber diet has strong association
• Males affected more often over 65
• About half in rectosigmoid colon (detected
  easily)
• 10-15 years required for malignant transformation

Figures from McConnell, The Nature of Disease,
2nd ed., LWW, 2014
36
Neoplasms of the Large and Small Bowel

• Familial Adenomatous Polyposis (always leads to
  colon CA)
• Autosomal dominant defect in APC gene (a tumor
  suppressor gene)
• Left untreated 100 will develop into cancer,
  many before the age of 30
• Darkly pigmented retina, osteomas of mandible and
  long bones, extra teeth, benign skin tumors and
  cysts
• Total colectomy is Tx

Figure from McConnell, The Nature of Disease,
2nd ed., LWW, 2014
37
Neoplasms of the Large and Small Bowel

• Colon cancer
• 2nd leading cause of cancer death in US
• Almost all are adenocarcinomas (gland-forming)
• Early lesions are asymptomatic
• Like adenomatous polyps, about half found in
  rectosigmoid colon
• Invade colon wall directly and then metastasize
  (lymph nodes, liver (how?), lungs, and bones)
• Screening via FOBT (not very sensitive) and
  sigmoidoscopy

Figures from McConnell, The Nature of Disease,
2nd ed., LWW, 2014
38
Neoplasms of the Large and Small Bowel

• Colon cancer staging (American Joint Committee
  on Cancer)

Figure from McConnell, The Nature of Disease,
2nd ed., LWW, 2014
39
Colonic Diverticulosis
Figure from McConnell, The Nature of Disease,
2nd ed., LWW, 2014

• Diverticulum blind pouch with mouth opening
  onto the lumen of a space, e.g., colon
• Diverticulitis inflammation of a diverticulum
• Acquired diverticula are more common than
  congenital

40
Anorectal Conditions Are Common

• In addition to hemorrhoids (discussed earlier)
• Anal fissures
• Longitudinal tear in anal mucosa from straining
• Blood is bright red (where would this appear?)
• Anorectal Abscess
• Usually in crypts (folds) in anal canal
• Arise from bacterial invasion drainage required
• Anal fistula
• Tubular tract from anus to other surface
• Surgery usually required
• Pilonidal cyst (sinus)
• Cyst, pit, blind pouch in skin posterior to anus
• Almost exclusively in young, white males with a
  lot of hair in area
• Surgical drainage is usually performed
• Proctitis Inflammation of anal mucosa STI or IC

41
Diseases of the Appendix and Peritoneum

• Appendicitis
• Acute inflammation of the appendix
• Most common cause of acute abdominal pain
  teens/YA most often
• Several causes
• Obstruction of lumen (hyperplasia of MALT in
  mucosa)
• Fecalith, intestinal parasitic worms, foreign
  body
• Classic appendicitis
• Epigastric or periumbilical pain
• Nausea, vomiting, anorexia
• RLQ pain and low-grade fever common

Figure from McConnell, The Nature of Disease,
2nd ed., LWW, 2014
42
Diseases of the Appendix and Peritoneum

• Peritonitis
• Inflammation of the peritoneum (usually acute)
• May be infectious or sterile
• Can develop as extension of any inflammatory
  condition of abdominal organs
• Infectious direct spread of bacteria, e.g.,
  gastric ulcer or apendicular perforation
• Sterile chemical irritation, e.g, blood,
  pancreatic enzymes
• After healing my leave adhesions which can cause
  sequellae, e.g., intestinal obstruction
• Peritoneal carcinomatosis
• Spread of carcinoma from abdominal or pelvic
  viscera
• Common in px with ovarian or pancreatic CA