GI Path (Part I and II) Flashcards
Contains both Part I and II. Happy studying!
What is the esophagus?
Hollow, distensible muscular tube that extends from the epiglottis to the gastroesophageal junction.
Through which arteries are blood supplied to the esophagus?
- Cervical - inferior thyroid artery
- Thoracic - bronchial arteries and aorta
- Abdominal - left gastric and inferior phrenic arteries
What are the common causes of esophageal stenosis?
- GERD (chronic)
- Irradiation
- Ingestion of caustic agents
- Other severe injury
What is the timeline of dysphagia associated with esophageal stenosis?
Progressive
Difficulty eating solids followed by difficulty drinking liquids.
What are differences between primary and secondary esophageal dysmotility in regards to mechanism of disease?
1° - Achalasia, congenital esophageal dysfunction
2° - Secondary to stroke, myastenia gravis, ALS, polio.
What are the characteristics of the achalasia triad?
- Incomplete relaxation of lower esophageal sphincter
- Increased tone of lower esophageal sphincter
- Esophageal aperistalsis (lack of peristalsis)
What are the findings of esophageal varices? Identify the most significant risk!
Anatomical findings:
Tortuous dilated veins w/i submucosa of distal esophagus and proximal stomach.
(Overlying mucosa may be ulcerated and necrotic.)
Risk:
Rupture –> massive, fatal bleeding
What are the morphologic findings, cause and clinical presentation of Mallory-Weiss tears?
Morphologic findings:
Esophageal lacerations at the gastroesophageal junction.
Cause:
Severe retching or vomiting
(alcoholism, bulimia, pregnancy, food poisoning)
Clinical presentation:
Hematemesis, retching, abdominal pain, hx of severe vomiting, melenic stools
What are the common causes of esophagitis?
- Irritants (alcohol, acid/alkalis, hot fluids, smoking)
- Medications
- Iatrogenic (chemotherapy, radiation, GVHD)
- Infections (HSV, cytomegalovirus, candida)
- Immune-mediated (eosinophilic)
- Reflux (of gastric contents)
What is the mechanism, clinical features and complications of reflux esophagitis (GERD)?
Mechanism:
Reflux of gastric contents into lower esophagus causing mucosal injury
Clinical features:
+40-year-olds, heartburn, dysphagia, sour-taste
Complications:
Esophageal ulceration, hematemesis, melena, stricture development, Barrett esophagus
What is the epidemiology and clinical features of Barrett esophagus?
Epidemiology:
White males > 40 y/o
Clinical features:
Prompted by GERD symptoms but requires endoscopy and biopsy
What is the relationship between GERD, Barrett esophagus and esophageal adenocarcinoma?
Barrett esophagus:
- complication of GERD
- metaplasia of esophageal squamous mucosa
- increase risk of esophageal adenocarcinoma
What are the two forms of esophageal cancer?
- Adenocarcinoma
2. Squamous cell carcinoma
Compare the 2 forms of esophageal cancer in regards to:
1) precursor lesion
2) common anatomical location
3) epidemiology
Precursor lesion
1) Adeno: Barrett esophagus, flat, raised lesions in intact mucosa that can become exophytic nodules
1) SCC: gray-white, plaque-like mucosal thickening
Common anatomical location
2) Adeno: distal 3rd of esophagus
2) SCC: middle 3rd of esophagus
Epidemiology
3) Adeno: white males > females
3) SCC: adult male > 45 y/o, male > female, blacks > whites
What is the anatomy and physiology of the stomach?
1) Cardia:
- mucin-secreting foveolar cells
2) Fundus :
- HCl and intrinsic factor-producing parietal cells
- pepsinogen-producing chief cells
3) Antrum
- gastrin-releasing G-cells
- parietal cells stimulation by gastrin
What is the definition of gastritis v. gastropathy?
Gastritis:
- inflammation (neutrophils), irritation or erosion of lining of the stomach
Gastropathy:
- cell injury and regeneration is present but inflammatory cells are rare or absent
What are the common causative factors for gastritis v. gastropathy?
Gastritis:
- H. pylori
- NSAIDs
Gastropathy:
- NSAIDs
- Alcohol
- Bile
- Stress-induced injury
What is the disease mechanism for gastritis v. gastropathy?
Both results from the destruction of protective and defensive forces of the stomach.
(mucus secretion, bicarbonate secretion, mucosal blood flow, epithelial regeneration, prostaglandin synthesis)
What is the underlying mechanism of chronic gastritis and autoimmune gastritis?
Chronic gastritis:
H. pylori in gastric mucous create imbalance in defence and bacterial damage.
(flagella, urease, adhesions, toxins)
Autoimmune gastritis:
Immune-mediated loss of parietal cells and reduction in acid and intrinsic factor secretion
(low acid, low intrinsic factor, low serum pepsinogen)
What is epidemiology of chronic gastritis and autoimmune gastritis?
Chronic gastritis:
US - poverty, crowding, limited education, poor sanitation, birth outside US, rural
Autoimmune gastritis:
Patients with autoimmune disease, thyroiditis, DM, graves
What are the location of chronic gastritis and autoimmune gastritis and their clinical sequelae?
Chronic gastritis:
- Antrum
- peptic ulcer, adenocarcinoma, lymphoma
Autoimmune gastritis:
- Body
- atrophy, pernicious anemia, adenocarcinoma, carcinoid tumor
Describe the following for peptic ulcers:
- risk factors
- causative agents
- anatomical locations
- clinical features
Risk factors:
NSAID, smoking, corticosteroids use, previous hx of ulcers, cirrhosis, COPD, renal failure, hyperparathyroidsim
Causative agents:
Gastric acid, H. pylori, NSAID, imbalance of mucosal defenses
Anatomical location:
Gastric antrum and first portion of duodenum, esophagus 2° to GERD
Clinical features:
Recurring lesions, burning and aching pain 1-3 hours post-eating and at night, N/V, bloating, belching, relieved by alkali or food
Describe the following for gastric adenocarcinoma:
- epidemiology
- infectious risk factors
- clinical features
Most common stomach malignancy.
Epidemiology:
Low socioeconomics, mucosal atrophy, intestinal metaplasia, gastrectomies, male >55 y/o, males > females
Infectious risks:
H. pylori and EBV
Clinical features:
Early - dyspepsia, dysphagia, nausea
Late - weight loss, anorexia, altered bowel habits, anemia, hemorrhage
What is the anatomy and physiology of the small and large bowel?
Small: Duodenum (25cm) - mixing of food with bile and enzymes Jejunum (2.5cm) - absorb carbs and proteins, nutrients Ileum (3.5cm) - absorb Vit B12
Large:
Absorbs water and electrolytes and vitamins (K, B12, thiamine, riboflavin)