Essentials of Pathophysiology
CHAPTER 29
DISORDERS OF GASTROINTESTINAL
FUNCTION
PRE LECTURE QUIZ TRUE/FALSE
T

F

F

F

F

Two of the major causes of gastric irritation and
ulcer formation are aspirin or nonsteroidal antiinflammatory drugs (NSAIDs) and infection with
Helicobacter pylori.
A peptic ulcer affects only a single layer of the
stomach or duodenum.
Clostridium difficile and Escherichia coli are two
types of viral infections that affect the
gastrointestinal system.
Small-volume diarrhea is usually painless and
watery and without blood or pus in the stool.
Appendicitis, a condition in which the appendix
becomes inflamed, swollen, and gangrenous, is very
uncommon.
PRE LECTURE QUIZ
Celiac


Diarrhea
Diverticulosis

Dysphagia
inflammatory


__________ refers to difficulty in swallowing.
Crohn disease and ulcerative colitis are two
related intestinal disorders that fit under the
category of __________ bowel disease.
__________ is a condition that occurs
primarily in the sigmoid colon, in which the
mucosal layer of the colon herniates through
the muscular layer.
__________ disease is an immune-mediated
disorder triggered by ingestion of glutencontaining grains (including wheat, barley,
and rye).
__________ is a common characteristic of
both ulcerative colitis and Crohn disease.
THE JOB OF THE BOWEL

To digest food: involves a corrosive solution and
potentially pathogenic bacteria

To absorb the food into the blood while keeping
the corrosive substances and the bacteria
inside the gut

To keep the solution moving down the bowel at
the right rate for digestion and absorption
INFLAMMATION AND DAMAGE TO THE BOWEL
WALL
•
Hemorrhage  anemia
•
Perforation  peritonitis
•
Decreased mucosal function  malabsorption
•
Decreased bacterial containment  sepsis
HEMORRHAGE





Hemorrhage above the stomach: frank
hematemesis
Hemorrhage into the stomach with partial
digestion of blood: coffee-grounds vomitus
Hemorrhage in the intestine with blood mixing
into stools: occult blood
Hemorrhage into the intestine with large volumes
of blood: melena
Hemorrhage in the rectum: red blood coating
stools
THE VICIOUS CIRCLE: ONE KIND OF BOWEL
PROBLEM CAN CAUSE ANOTHER
Inflammation
and cell damage
Reflex paralysis
Obstruction
Distension, ischemia
Food does not
pass through
bowel at correct
rate
Decreased
bowel
function
Malabsorption
QUESTION
Which symptom accompanies hemorrhage into
the stomach?
a. Hematemesis- the vomiting of blood
b. Occult blood – blood in the stool
c. Coffee-grounds vomitus – blood mixed w/ chime
d. Melena - black, tarry, bloody stools, usually resulting
from a hemorrhage in the alimentary tract.
ANSWER
c. Coffee-grounds vomitus
Rationale: Coffee-grounds vomitus is a classic
symptom of blood in the stomach (it mixes with
chyme to give it the coffee-grounds color and
consistency). Hematemesis occurs in
hemorrhage above the stomach; occult blood
is the result of blood mixing with stool in the
small intestine; and melena occurs with largevolume hemorrhages in the intestine.
DISORDERS OF THE ESOPHAGUS

Dysphagia - difficulty in swallowing

Achalasia - inability of a circular muscle to relax, resulting in
widening of the structure above the muscular
constriction
 Esophageal diverticulum - mucosal layer herniated through
the muscularis layer

Gastroesophageal reflux disease
a chronic condition in which acid from the stomach flows
back into the lower esophagus, causing pain or tissue
damage
 Cancer of the esophagus - malignant neoplasm
DISORDERS OF THE STOMACH



Acute gastritis
inflammation of the stomach, especially of
Chronic gastritis the mucous membrane of the stomach
Ulcer disease
 Peptic ulcer erosion of the mucous membrane caused in
part by the corrosive action of the gastric juice
 Zollinger-Ellison
syndrome
a condition in which a gastrin-secreting tumor of the pancreas
or small intestine causes excessive secretion of gastric juice,
leading to intractable peptic ulcers
 Stress
ulcers Acute peptic ulcers occurring in association
with various other pathologic conditions

Cancer of the stomach
Stomach Ulcer
SCENARIO
Mrs. D. has pain in her stomach at night and
vomits up blood.
 She is pale and weak
 The doctor finds that her hematocrit is low
 Her blood contains large, pale erythrocytes
and some reticulocytes
 Bilirubin levels are normal
Question:
 Explain her symptoms
HELICOBACTER PYLORI
• The major
cause of ulcers
H.
pylori
• Second most
common cause
is NSAIDs
damages
stomach
lining
ULCER
repair and
healing
increased risk of
gastric cancer
HELICOBACTER PYLORI
Helicobacter Pylori
“In the US: The frequency of HP infection may
be linked to race. White persons account for
29% of cases, and Hispanic persons account for
60% of cases.”
“Internationally: … At least half of all people
are infected … HP may be detected in
approximately 90% of individuals with peptic
ulcer disease...”
(Santacroce, L., and Miragliotta, G. 2005. Helicobacter pylori infection. eMedicine.
Retrieved April 2005 from http://www.emedicine.com/med/topic962.htm#top.)
INFLAMMATIONS OF THE SMALL AND LARGE
INTESTINES

Infectious enterocolitis
 Viral
infections
 Bacterial

infections
Inflammatory bowel disease
 Crohn
disease
 Ulcerative
colitis

Diverticular disease

Appendicitis
Crohn’s disease – an
autoimmune conditiona chronic inflammatory
bowel disease that causes
scarring and thickening of
the intestinal walls and
frequently leads to
obstruction.
DISCUSSION
Think back to the last time you had
enterocolitis.
Questions:
 List the things that happened to you
 Which of them were systemic signs of
inflammation?
 Which of them were caused by your
sympathetic system?
 Which of them helped you get over the
disease?
 Which of them could have caused serious
complications?
 Why?
QUESTION
Which intestinal disorder is an autoimmune
disease?
a. Enterocolitis
b. Crohn disease
c. Ulcerative colitis
d. Diverticulitis
ANSWER
b. Crohn disease
Rationale: Crohn disease is an autoimmune
disorder that affects the mucous membrane
lining of the bowel (it gets thicker and doesn’t
function as it should), causing chronic
malabsorption.
ENTEROCOLITIS

The bowel attempts to get rid of the
infectious agent
 Exudate
to dilute toxins
 Hypermotility
 Vomiting

Decreased intestinal function
 Food
º
not absorbed
Osmosis draws water into the bowel
º
Osmotic (or explosive) diarrhea
INFLAMMATIONS THAT CANNOT BE EXPELLED

Pain and sympathetic nervous stimulation
cause the bowel to freeze in position
 Reflex

paralysis or paralytic ileus
Muscles of the abdominal wall tighten to
protect the inflamed bowel
 Board-like

abdomen
Diaphragm and accessory breathing
muscle movements decrease
 Shallow
breathing
ONE KIND OF BOWEL PROBLEM CAN CAUSE
ANOTHER
Inflammation
and cell damage
Reflex paralysis
Obstruction
Distension, ischemia
INTESTINAL OBSTRUCTION

Mechanical
 Severe,
colicky pain
 Borborygmus
 Audible, high-pitched peristalsis; peristaltic rushes
 Awareness of intestinal movements

Paralytic
 Continuous
pain
 Silent abdomen
INTESTINAL OBSTRUCTION
RESULTS OF OBSTRUCTION

Vomiting  fluid and
electrolyte loss

Fluids move into intestinal
contents

Gas accumulates

Distension of bowel

Compartment syndrome 
ischemia, necrosis

Anaerobic bacteria produce
endotoxin  toxemia
QUESTION
Tell whether the following statement is true or
false.
Paralytic intestinal obstruction causes audible
paralysis.
ANSWER
False
Rationale: Mechanical obstruction results in highpitched peristalsis (bowel sounds); in paralytic
obstruction, bowel sounds are inaudible (silent
abdomen).
BOWEL DISTENSION AND COMPARTMENT
SYNDROME

The blood vessels
on the surface of
the gut are covered
and held in place by
the inflexible
mesentery

When the gut lumen
distends, it crushes
the blood vessels
between the gut wall
and the mesentery
COMPARTMENT SYNDROME
• An organ expands inside a membrane
that will not expand
• The blood vessels feeding the organ
are crushed between the organ and
the membrane
• Blood supply is cut off
SCENARIO
Mrs. K. presents with acute abdominal pain.
• She has a distended, board-like abdomen with no
bowel sounds. Blood pressure is low and heart
rate elevated. Her skin is pale and cool with cold
sweat. She is very restless and complains of
acute abdominal pain.
• The pain came on over the last 8 hours. WBC
count is elevated. Now she complains of nausea
and begins throwing up, but there is no blood in
her vomitus. She has had no bowel movements
or urine production.
Question:
• What adaptive responses and counterattacks are
evident?
SCENARIO (CONT.)
• Mrs. K. has begun to run a fever
• Her skin is now flushed and warm, and her
abdomen is further distended
• Her blood pressure has decreased further
• The doctor has ordered nasogastric suction and
an isotonic IV
Question:
• Why are you taking fluids out of her GI tract
and putting them into her veins?
ALTERATIONS IN INTESTINAL ABSORPTION


Malabsorption syndrome
Celiac disease