Gastrointestinal Flashcards
4 layers in the typical structure of the GI tract
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
Deglutition
Swallowing
Cleft lip
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
Dental and periodontal diseases
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
Stomatitis
Inflammation of the mouth
Can be caused by a herpes virus infection, or Candida albicans infection (thrush)
Aphthous stomatitis
Canker sores
Painful, recurrent, spontaneously healing oral ulcers of unknown etiology
Oral cancer
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
Dysphagia
Difficulty swallowing
Odynophagia
Retrosternal chest pain during swallowing
2 types of hiatal hernias
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
Esophageal varices
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
Esophagitis defintion
Inflammation of the esophagus
Commonly causes heartburn
Causes of esophagitis
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
Carcinoma of the esophagus
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
Clinical presentations pointing to disease of the stomach
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
Gastritis (2 types, and their causes)
Acute (erosive): stress, shock, food, exogenous chemicals, drugs (NSAIDs) - causes erosions and ulcerations
Chronic: H pylori related, or autoimmune (with pernicious anemia)
Peptic Ulcer causes
Multifactorial
Include gastric acid, mucosal barrier defects (stress, shock, NSAIDs, smoking reduce resistance), H pylori infections)
4 complications of peptic ulcer
- Hemorrhage (most common): hematemesis, melena, iron deficiency anemia
- Penetration into the pancreas: acute pancreatitis
- Perforation: peritonitis
- Cicatrization (scaring): stenosis
Definitions of:
- Hematemesis
- Melena
Hematemeis = vomiting Melena = black tarry stool
Gastric tumors
Benign epithelial tumors: polyps (ex: hyperplastic, fungic gland, adenomatous)
Malignant tumors: adenocarcinoma (most common) or lymphoma (uncommon)
Clinical presentations of diseases of the intestines
Diarrhea Blood in stool Abdominal pain Obstruction Weight loss
GI infections
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)
Malabsoprtion syndromes
Result from an inability of the intestine to absorb nutrients from food
Most common in Canada is celiac sprue
Celiac sprue
Hypersensitivity to gliaden (breakdown product of gluten)
Injury to duodenal villi causes them to be flattened
Weight loss, diarrhea, nutritional deficiencies result
Inflammatory Bowel Disease
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
Ulcerative colits versus Crohn’s location
Ulcerative colitis: ONLY the colon, and diffuse (never patchy)
Crohn’s: patchy and transmural, includes the small intestine
Crohn’s Disease
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
Ulcerative colitis
Has continuous involvement of the colon from distal up
Limited to the mucosa, can have superficial ulcers and inflammatory pseudopolyps making the surface irregular
Acute appendicitis
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
Hernia
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
Volvulus
Twisting of the intestine around its mesenteric root, which cuts off the blood supply
Surgical emergency
Diverticulosis of the colon
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
3 Intestinal vascular diseases
Hemorrhoids
Angiodysplasia
Ischemic bowel disease
Hemorrhoids
Dilated submucoal veins in the anal canal
Bleeding, pain
Angiodysplasia
Abnormal submucosal vessels that can bleed in colon
Ischemic bowel disease
Acute thrombosis of mesenteric arteries, veins
Vasculitis
Mechanical obstruction of vessels
Mesenteric thrombosis
Can occur due to atherosclerosis
Causes infarction of the intestines, which is a catastrophic and often fatal event
Colon cancer etiology
Genetic factors
Dietary factors (western diet): low fiber, high carbs and fat
Interaction of carcinogens, oncogenes, TSGs
Intussusception
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
