GI: 349 - 353 Flashcards
Bilirubin is a product of the metabolism of what?
Heme
What is another name for unconjugated bilirubin?
Indirect
Direct vs. indirect bilirubin - which one is water soluble?
Conjugated - water soluble; Unconjugated - water insoluble
What is bilirubin conjugated with to make it water soluble?
Glucuronic acid
What organ removes bilirubin from the blood?
Liver
Where is heme broken down into bilirubin?
Macrophages
How does bilirubin get to the liver?
Travels in the bloodstream bound to albumin
Where does bilirubin get conjugated?
Liver
What enzyme conjugates bilirubin?
UDP-glucuronosyl-transferase
Where does conjugated bilirubin go and what does it become?
To the gut where it becomes urobilinogen
80% of urobilinogen does what?
Excreted into the feces as stercobilin which gives feces its brown color
20% of urobilinogen does what (2 possible fates)?
- 90% (of this 20%) reenters enterohepatic circulation and goes back to the liver.
- 10% (of this 20%) is excreted in urine which gives urine its yellow color
Are salivary gland tumors generallly benign or malignant?
Benign
Which salivary gland is most likely to have a tumor?
Parotid gland
What are 3 types of salivary gland tumors?
- Pleomorphic adenoma
- Warthrin tumor
- Mucoepidermoid carcinoma
Which is the most common salivary gland tumor?
Pleomorphic adenoma
What is a pleomorphic adenoma composed of?
Benign mixed tumor - made of chondromyxoid stroma and epithelium
How does pleomorphic adenoma present?
Painless mobile mass
When does pleomorphic adenoma recur?
Incomplete excision or intraoperative rupture
Describe a warthrin tumor.
Papillary cystadenoma lymphomatosum - a benign cystic tumor with germinal centers
What is the most common malignant salivary gland tumor?
Mucoepidermoid carcinoma
Describe a mucoepidermoid carcinoma
Has mucinous and squamous components that typically presents as a painless slow-growing mass
What is achalasia?
Failure of relaxation of LES due to loss of myenteric (Auerbach) plexus
What happens in achalasia?
High LES opening pressure and uncoordinated peristalsis leads to progressive dysphagia to solids and liquids
How is achalasia different from obstruction?
Achalasia is dysphagia of solids and liquids while obstruction is just dysphagia of solids
What test can we use to check for achalasia and what will it show?
Barium swallow shows dilated esophagus with an area of distal stenosis - “Bird’s beak”
Achalasia is associated with an increased risk of what cancer?
Esophageal squamous cell carcinoma
Achalasia maybe be secondary to what other disease?
Chagas
What is Boerhaave syndrome?
Transmural, usually distal esophageal rupture due to violent retching
How should Boerhaave syndrome be treated?
Surgical emergency
What is eosinophilic esophagitis?
Infiltration of eosinophils in the esophagus in atopic patients (food allergy)
What are 3 characteristics of eosinophilic esophagitis?
Dysphagia, heartburn, strictures
Can eosinophilic esophagitis be treated with GERD therapy?
No
Characterize esophageal varices.
Painless bleeding of dilated submucosal veins in the lower 1/3 of esophagus
What are esophageal varices secondary to?
Portal hypertension
What are 3 associations of esophagitis?
- Reflux
- Infection in immunocompromised
- Chemical ingestion
What are 3 infections that are associated with esophagitis and how do you differentiate between them?
- Candida - white pseudomembrane
- HSV-1 - punched out ulcers
- CMV - linear ulcers
How does GERD typically present?
Heartburn, regurgitation upon lying down, nocturnal cough and dyspnea, adult-onset asthma
GERD involves decreased tone of which sphincter?
LES
What is Mallory-Weiss syndrome?
Mucosal lacerations at the GE junction due to severe vomiting
What is a key presenting symptom of Mallory-Weiss syndrome?
Hematemesis
What 2 groups are especially prone to Mallory-Weiss syndrome?
Bulimics and alcoholics
What is the triad of Plummer-Vinson syndrome?
Mnemonic: DIG
Dysphagia (due to esophageal webs), Iron deficiency anemia, Glossitis
Describe the pathophysiology of sclerodermal esophageal dysmotility.
Esophageal smooth muscle atrophy leads to decreased LES pressure and dysmotility leads to acid reflux and dysphagia leads to stricture, Barrett esophagus, and aspiration
What syndrome is sclerodermal esophageal dysmotility a part of?
CREST
What is Barrett esophagus?
Glandular metaplasia - replacement of nonkeratinized (stratifeid) squamous epithelium with intestinal epithelium (nonciliated columnar with goblet cells) in the distal esophagus
What causes Barrett esophagus?
Chronic GERD
What are 3 things associated with Barrett esophagus?
Esophagitis, esophageal ulcers, and increased risk of esophageal adenocarcinoma
What are the 2 types of esophageal cancer?
Squamous cell and adenocarcinoma
How does esophageal cancer typically present?
Progressive dysphagia and weight loss
Does esophageal cancer have a good prognosis?
No
Contrast the incidence of the 2 types of esophageal cancer as well as where they tend to occur in the esophagus.
- Squamous cell - more common worldwide (makes sense since this is the one linked to EtOH and Asian flush), upper 2/3 of esophagus
- Adenocarcinoma - more common in the U.S., lower 1/3
What are the risk factors for esophageal cancer?
Mnemonic: AABCDEFFGH Achalasia Alcohol - squamous Barrett esophagus - adeno Cigarettes - both Diverticula (e.g. Zenker) - squamous Esophageal web - squamous Familial Fat (obesity) - adeno GERD - adeno Hot liquids - squamous
Gastritis can broadly be broken up into what 2 groups?
Acute (erosive) vs. chronic (nonerosive)
Describe what happens in acute gastritis.
Disruption of mucosal barrier leads to inflammation
What can cause acute gastritis?
Stress, NSAIDs, EtOH, uremia, burns, brain injury
Why do NSAIDs cause acute gastritis?
Decreased PGE2 leads to decreased gastric mucosa production
What’s the difference between a curling ulcer vs. cushing ulcer?
Mnemonic: Burned by the curling iron and always cushion the brain
- Curling ulcer is associated with burns - decreased plasma volume causes sloughing of gastric mucosa
- Cushing ulcer is associated with brain injury - increased vagal stimulation causes increased ACh causes increased H+ production
What are the 2 types of chronic gastritis?
Mnemonic: A before B
Type A - fundus/body vs. Type B - antrum
Which is more common Type A or Type B chronic gastritis?
Type B
What causes Type A chronic gastritis?
Autoimmune disorder characterized by autoantibodies to parietal cells, pernicious anemia, achlorhydia
What causes Type B chronic gastritis?
H. pylori infection
Type B chronic gastritis is associated with increased risk of?
MALT lymphoma and gastric adenocarcinoma
What is Menetrier disease?
Gastric hypertrophy with protein loss, parietal cell atrophy, and increased mucous cells
What does gross inspection of Menetrier disease reveal?
Rugae of stomach are so hypertrophied that they look like brain gyri
How does Menetrier disease relate to cancer?
It is a precancerous condition
Stomach cancer is almost always what type?
Adenocarcinoma
What paraneoplastic syndrome often presents with stomach cancer?
Acanthosis nigricans
Describe the course of stomach cancer.
Early aggressive local spread and node/liver metastases
How can you break down the different presentations of stomach cancer?
Intestinal vs. diffuse
Is intestinal or diffuse stomach cancer associated with H. pylori?
Intestinal
Aside from H. pylori what are other causes of intestinal stomach cancer?
Dietary nitrosamines, tobacco smoking, achlorhydia, chronic gastritis
Describe what you would see with intestinal stomach cancer.
Commonly on the lesser curvature - looks like ulcer with raised margins
Describe what you would see with diffuse stomach cancer.
Signet ring cells and the stomach wall is grossly thickened and leathery (linitis plastica)
What is Virchow node?
Involvement of left supraclavicular node by metastasis from the stomach
What is a Krukenberg tumor?
Bilateral metastases to ovaries of stomach cancer; marked by abundant mucus and signet ring cells
Subcutaneous periumbilical metastasis from stomach cancer is called what?
Sister Mary Joseph nodule
Pain decreasing with meals - gastric or duodenal ulcer?
Duodenal
Weight gain - gastric or duodenal ulcer?
Duodenal
Which one is more strongly associated with H. pylori infection - gastric or duodenal ulcer?
Duodenal (almost 100%) vs. gastric (70%)
Aside from H. pylori infection what are other causes of ulcers?
NSAIDs - gastric, Zollinger-Ellison - duodenal
Are gastric or duodenal ulcers associated with increased risk of carcinoma?
Gastric
Which ulcer often occurs in older patients?
Gastric
What do we see histologically for duodenal ulcers?
Hypertrophy of Brunner glands
What are 2 complications of ulcers?
Hemorrhage and perforation
Where do we tend to see hemorrhage as a complication of ulcer?
- Ruptured gastric ulcer on the lesser curvature of the stomach - bleeding from the left gastric artery
- Ulcer on the posterior wall of the duodenum - bleeding from gastroduodenal artery
Where do we tend to see perforation as a complication of ulcer?
Anterior wall of the duodenum
Chest radiograph shows what with perforation of an ulcer?
Free air under the diaphragm
A patient with a perforated ulcer may have referred pain to where?
Shoulder
Tropical sprue, whipple disease, celiac sprue, disaccharidase deficiency, abetalipoproteinemia, pancreatic insufficiency are all examples of what?
Malabsorption syndromes
Malabsorption syndromes can cause what symptoms?
Diarrhea, steatorrhea, weight loss, weakness, vitamin and mineral deficiencies
What is the difference between tropical and celiac sprue?
Tropical sprue responds to antibiotics - cause is unknown but tropical sprue is seen in residents of or recent visitors to the tropics
What causes Whipple disease?
Tropheryma whipplei infection
Is tropheryma whipplei gram positive or negative?
Gram positive
What do you see on histology with Whipple disease?
PAS + foamy macrophages in intestinal lamina propria, mesenteric nodes
What demographic tends to get Whipple disease more often?
Older men
What are 3 characteristic symptoms (aside from GI) of Whipple disease?
Mnemonic: Whipped cream in a CAN
Cardiac symptoms, Athralgia, Neurological symptoms
What is celiac sprue?
Autoimmune-mediated intolerance of gliadin (wheat) leading to malabsorption and steatorrhea
What are three things (2 genetic, 1 demographic) associated with celiac sprue?
- HLA-DQ2
- HLA-DQ8
- Northern European descent
Name 3 antibodies found in celiac sprue.
- Antiendomysial
- Anti-tissue transglutaminase
- Anti-gliadin
What happens to villi in celiac sprue?
Blunting
Where do you see lymphocytes in celiac sprue?
Lamina propria
Decreased mucosal absorption in celiac sprue primarily affects what parts of the GI tract?
Distal duodenum and/or proximal jejunum
What is used to diagnose celiac sprue?
Serum levels of tissue transglutaminase antibodies
What other condition is celiac sprue associated with?
Dermatitis herpetiformis
Does celiac sprue increase your risk of cancer?
Moderately (e.g. T cell lymphoma)
How is celiac sprue treated?
Gluten-free diet
What is the most common disaccharidase deficiency?
Lactase deficiency
What happens to the villi in disaccharidase deficiency?
Nothing - they look normal
What symptoms characterizes disaccharidase deficiency?
Osmotic diarrhea
When do you see self-limited lactase deficiency and why?
Following injury (e.g. virus) to the tips of the villi which is where lactase is located
What marks a positive lactose tolerance test for deficiency of lactase?
- Administration of lactose produces symptoms
2. Glucose rises < 20 mg/dL
Describe the pathophysiology in abetalipoproteinemia.
Decreased synthesis of apolipoprotein B leads to inability to generate chylomicrons leads to decreased secretion of cholesterol and VLDL into the bloodstream leads to fat accumulation in enterocytes
When does abetalipoproteinemia present?
Early childhood
What are 5 symptoms in abetalipoproteinemia?
- Failure to thrive
- Steatorrhea
- Acanthocytosis
- Ataxia
- Night blindness
What are 3 causes of pancreatic insufficiency?
- Cystic fibrosis
- Obstructing cancer
- Chronic pancreatitis
Pancreatic insufficiency causes malabsorption of what?
Fat and fat-soluble vitamins (A, D, E, K)
What happens to stool in pancreatic insufficiency?
Increase in neutral fat
Describe what we use a D-xylose absorption test for.
Normal urinary excretion in pancreatic insufficiency vs. decreased excretion with intestinal mucosa defects or bacterial overgrowth