Gastrointestinal

Question 1

4 layers in the typical structure of the GI tract

Answer 1

Serosa: outer layer, has epithelium of peritoneum and connective tissue
Muscularis: outer longitudinal layer, inner circular layer, and myenteric plexus, (causes peristalsis)
Submucosa: submucosal plexus, gland, blood vessels, (strength from here)
Mucosa: smooth muscle, loose connective tissue, epithelium, innermost layer

Question 2

Deglutition

Answer 2

Swallowing

Question 3

Cleft lip

Answer 3

Congenital abnormality with clefting of the lip, and palate in some cases
Due to failed fusion of nasal and maxillary processes in fetal development
More common in certain families (polygenic inheritance)
Repaired by modern orthodontic surgery

Question 4

Dental and periodontal diseases

Answer 4

Dental caries are very common
Due to the accumulation of bacterial plaques on surface of teeth that erode through dentin and penetrate into the tooth
Prevented through water fluoridation, brushing, and dental hygeine

Question 5

Stomatitis

Answer 5

Inflammation of the mouth

Can be caused by a herpes virus infection, or Candida albicans infection (thrush)

Question 6

Aphthous stomatitis

Answer 6

Canker sores

Painful, recurrent, spontaneously healing oral ulcers of unknown etiology

Question 7

Oral cancer

Answer 7

Tumors are usually squamous cell carcinomas (adenocarcinomas)
Often related to alcohol and tobacco smoking
Some bases related to HPV
Morphologically present as leukoplakia, erythroplakia, ulcer or nodule

Question 8

Dysphagia

Answer 8

Difficulty swallowing

Question 9

Odynophagia

Answer 9

Retrosternal chest pain during swallowing

Question 10

2 types of hiatal hernias

Answer 10

Sliding: common and not usually clinically significant, where the top part of your stomach slides up above your diaphragm
Paraesophageal: uncommon but can be life threatening, could get ischemic and necrotic and then perforate your stomach

Question 11

Esophageal varices

Answer 11

Dilated veins in the distal esophagus
Usually due to portal hypertension (high pressure) in patients with cirrhosis of the liver
Rupture can result in a lot of bleeding - need transfusion and endoscopy to try and band or cauterize them

Question 12

Esophagitis defintion

Answer 12

Inflammation of the esophagus

Commonly causes heartburn

Question 13

Causes of esophagitis

Answer 13

Reflux esophagitis (gastroesophageal reflux disease) - due to reflux of gastric juice into esphagus
Infectious esophagitis (often immunosuppresed) - caused by viruses or fungi - rare but worse
Chemical irritants: exogenous chemicals like lye, or from medications getting stuck and irritating esophagus

Question 14

Carcinoma of the esophagus

Answer 14

Accounts for 4% of all cancers
Higher incidence in Asia and Africa than in the US/Europe
Correlates with alcohol, tobacco abuse
More common in men than women, and blacks than whites
Poor prognosis: 2 years
Squamous cell carcinoma in upper or lower
Adenocarcinoma in lower, developing in Barrett’s esophagus

Question 15

Clinical presentations pointing to disease of the stomach

Answer 15

Pain in midline and upper abdomen
Vomiting
Bleeding (hematemeis = vomiting, or melena = black tarry stool)
Dyspepsia (abdominal discomfort)
Systemic consequences: iron deficiency anemia caused by chronic blood loss, vitamin B12 malabsorption

Question 16

Gastritis (2 types, and their causes)

Answer 16

Acute (erosive): stress, shock, food, exogenous chemicals, drugs (NSAIDs) - causes erosions and ulcerations
Chronic: H pylori related, or autoimmune (with pernicious anemia)

Question 17

Peptic Ulcer causes

Answer 17

Multifactorial

Include gastric acid, mucosal barrier defects (stress, shock, NSAIDs, smoking reduce resistance), H pylori infections)

Question 18

4 complications of peptic ulcer

Answer 18

1. Hemorrhage (most common): hematemesis, melena, iron deficiency anemia
2. Penetration into the pancreas: acute pancreatitis
3. Perforation: peritonitis
4. Cicatrization (scaring): stenosis

Question 19

Definitions of:

1. Hematemesis
2. Melena

Answer 19

Hematemeis = vomiting
Melena = black tarry stool

Question 20

Gastric tumors

Answer 20

Benign epithelial tumors: polyps (ex: hyperplastic, fungic gland, adenomatous)
Malignant tumors: adenocarcinoma (most common) or lymphoma (uncommon)

Question 21

Clinical presentations of diseases of the intestines

Answer 21

Diarrhea
Blood in stool
Abdominal pain
Obstruction
Weight loss

Question 22

GI infections

Answer 22

Often cause acute, self limited diarrheal illness (not giardia)
Can be caused by viruses (rotavirus, norwalk), bacteral (e coli, camplobacter, C diff), bacterial toxins (shigella), parasites (giardia)

Question 23

Malabsoprtion syndromes

Answer 23

Result from an inability of the intestine to absorb nutrients from food
Most common in Canada is celiac sprue

Question 24

Celiac sprue

Answer 24

Hypersensitivity to gliaden (breakdown product of gluten)
Injury to duodenal villi causes them to be flattened
Weight loss, diarrhea, nutritional deficiencies result

Question 25

Inflammatory Bowel Disease

Answer 25

Chronic inflammatory disease of the intestines
Causes chronic abdominal pain and diarrhea (often with blood and mucus)
Includes both Crohn’s and ulcerative colitis
Cause unknown, may be partly familial

Question 26

Ulcerative colits versus Crohn’s location

Answer 26

Ulcerative colitis: ONLY the colon, and diffuse (never patchy)
Crohn’s: patchy and transmural, includes the small intestine

Question 27

Crohn’s Disease

Answer 27

Can cause a thickened wall with a stricture (narrowing) of the intestine
There are deep (often transmural) linear ulcers with intervening areas of sparing that can give the bowel a cobblestone appearance

Question 28

Ulcerative colitis

Answer 28

Has continuous involvement of the colon from distal up

Limited to the mucosa, can have superficial ulcers and inflammatory pseudopolyps making the surface irregular

Question 29

Acute appendicitis

Answer 29

Most often caused by obstruction of the appendiceal orifice by a fecalith
Trapped fecal bacteria invade the wall of the appendix and cause transmural inflammation
Inflammation can progress to rupture of the appendiceal wall, with leakage of the contents into the abdominal cavity, causing peritonitis

Question 30

Hernia

Answer 30

Protrusion of the abdominal contents into the abdominal wall, usually due to weakness or a defect in the wall
Ingunial is most common
Usually just fat, but if bowel gets it in can get get strangulated and necrotis

Question 31

Volvulus

Answer 31

Twisting of the intestine around its mesenteric root, which cuts off the blood supply
Surgical emergency

Question 32

Diverticulosis of the colon

Answer 32

Outpouchings of the colon
Some are congenital anomalies, but most are acquired cases due to increased intraluminal pressure
Common
Complications include inflammation, strictures, fistulas, and rupture causing peritonitis

Question 33

3 Intestinal vascular diseases

Answer 33

Hemorrhoids
Angiodysplasia
Ischemic bowel disease

Question 34

Hemorrhoids

Answer 34

Dilated submucoal veins in the anal canal

Bleeding, pain

Question 35

Angiodysplasia

Answer 35

Abnormal submucosal vessels that can bleed in colon

Question 36

Ischemic bowel disease

Answer 36

Acute thrombosis of mesenteric arteries, veins
Vasculitis
Mechanical obstruction of vessels

Question 37

Mesenteric thrombosis

Answer 37

Can occur due to atherosclerosis

Causes infarction of the intestines, which is a catastrophic and often fatal event

Question 38

Colon cancer etiology

Answer 38

Genetic factors
Dietary factors (western diet): low fiber, high carbs and fat
Interaction of carcinogens, oncogenes, TSGs

Question 39

Intussusception

Answer 39

Invagination of one segment of the intestine into the following segment
In kids, usually there is lymphoid hyperplasia as a leadpoint
In adults, a tumor is often the leadpoint