Gastrointestinal Flashcards
1
Q
Define Primary Biliary Cholangitis
A
- Chronic autoimmune reaction
- There is lymphocyte infiltrate and granulomas
- Leads to destruction of the small and mid-sized intrahepatic bile ducts
- Results in cholestasis
- Classically in middle aged females
- Associated with other autoimmune disorders like Sjogren Syndrome, Hashimotos Thyroiditis, CREST, Rheumatoid Arthritis and celiacs disease.
- Labs show Anti-mitochondrial antibodies and increased IgM
- Also increased conjugated billirubin, increased cholesterol and alkaline phosphatase
2
Q
What do patients typically present with in PBC and what do their labs show?
A
- Fatigue, pruritus, hepatomegaly
- Labs show increased alkaline phosphatase, and antimitochondrial antibody titers are positive
3
Q
What do biopsy findings in PBC show?
A
- Patchy lymphocytic inflammation with destruction of intrahepatic bile ducts and necrosis and micro nodular regeneration of periportal tissues.
- Can also see granulomas and bile staining of hepatocytes.
4
Q
Graft vs Host Disease
A
- Occurs in immunocompromised patients following transplant of allogenic bone marrow or other lymphocyte rich tissues (liver, non irradiated blood)
- Donor T cells migrate into host tissues, they recognize host major histocompatibility complex antigens as foreign.
- Skin, liver and GI tract are most common affected organs
- Liver involvement is heralded by rise in alkaline phosphatase and characterized histologically by lymphocytic infiltration and destruction of small intrahepatic bile ducts (Similar to PBC)
5
Q
What are the complications of chronic alcoholic pancreatitis?
A
- Leads to alcohol-induced secretion of protein rich fluid
- Proteinacious secretions can precipitate within the pancreatic ducts and form ductal plugs that calcify
- Ductal obstruction causes exocrine insufficiency due to atrophy of the pancreatic acing cells and pancreatic fibrosis
6
Q
What results from exocrine pancreatic insufficiency?
A
- Failure to secrete adequate amylases, proteases and lipase.
- Leads to malabsorption with diarrhea/steatorrhea.
- Weight loss, bulky frothy stools and abdominal pain
7
Q
Classical presentation of celiac disease?
A
- Malabsorption due to immune mediated enteropathy involving the proximal small intestine.
- Triggered by ingestion of gluten (Wheat)
8
Q
Presentation of gastrinoma?
A
- AKA duodenal/pancreatic gastrin secreting neuroendocrine tumor
- Hydrochloric acid hypersecretion results in multiple and/or refractory peptic ulcers
- Diarrhea/malabsorption results from digestive enzymes being deactivated by high gastric acid output.
9
Q
When does bile acid malabsorption result?
A
With conditions that affect the terminal ileum such as ileal resection and Chron ileitis
10
Q
What causes portal hypertension and what are the results?
A
- Due to liver cirrhosis
- Causes varices at sites of portocaval anastomoses
- Perianal varices, caput medusae over the abdomen and esophageal varices
- Bleeding of esophageal varices causes hematemesis and melena
11
Q
What is believed to be the pathophysiology of Chrons Disease?
A
- There is increased activity of TH-1 Helper cells
- They mediate a delayed hypersensitivity reaction and non-caseating granuloma formation.
- They also produce IL-2 and interferon-gamma which activate macrophages to produce TNF
12
Q
Zenker Diverticulum
A
- False diverticulum
- Results in early oropharyngeal dysphagia with a feeling of food obstruction at the level of the neck that causes coughing or choking.
- Increased oral pharyngeal intraluminal pressure results in herniation of pharyngeal mucosa through a zone of muscle weakness in the posterior hypopharynx (Killian triangle)
13
Q
How does Zener diverticulum present clinically and how is it diagnosed?
A
- Usually in the elderly
- Patients develop food retention (halitosis) with regurgitation.
- Pulmonary aspiration may lead to aspiration pneumonia
- When diverticulum enlarges, it may be palpable in the lateral neck
- Diagnosed with barium swallow study
14
Q
Describe the deglutition phase
A
- Voluntary oral phase
- Food bolus collected in the back of the mouth and raised towards the posterior wall of the pharynx - Pharyngeal phase
- Involuntary pharyngeal muscle contractions that propel food towards esophagus - Esophageal phase
- Bolus stretches the walls of the esophagus, stimulating peristalsis above the site of distension moving the food downward - Relaxation of the lower esophageal sphincter allows food to enter stomach
15
Q
What is the first phase in colon adenoma to carcinoma sequence?
A
- Progression from normal mucosa to small adenomatous polyp (adenoma)
- Due to mutation in APC tumor suppressor gene.
- There is Loss of APC gene
- Located on chromosome 5, its mutation leads to Beta-Catenin accumulation, decreased intercellular adhesion and uncontrolled cell proliferation
16
Q
What is the second phase in colon adenoma to carcinoma sequence?
A
- Adenoma increases in size.
- Due to mutation of the KRAS protooncogene
- Causes a protein to stimulated unregulated cell growth
17
Q
What is the third phase in colon adenoma to carcinoma sequence?
A
- Malignant transformation of adenoma to carcinoma
- Due to mutation in TP53
- TP53 is a antioncogene (tumor suppressor) that codes for p53, which triggers apoptosis of cells with damaged DNA.
- When mutated, TP53 allows damaged cells to enter cell cycle and proliferate
There is increased tumorigenesis
18
Q
Dubin-Johnson Syndrome
A
- Benign disorder
- Defective hepatic excretion of bilirubin glucoronides across the canalicular membrane
- Results in direct hyperbilirubinemia and jaundice
- Liver appears black
- Due to impaired excretion of epinephrine metabolites
- Appear as dense pigments within lysosomes
19
Q
Chronic Mesenteric Ischemia
A
- Pathogenesis is similar to angina pectoris
- Due to atherosclerosis of the celiac, superior or inferior mesenteric arteries
- Results in diminished blood flow to the intestines after meals (hypoperfusion)
- Causes postprandial epigastric pain known as intestinal angina
- Associated with food aversion or weight loss
20
Q
Wilsons Disease
A
- Autosomal recessive
- Mutation in copper-transporting ATPase
- ATP7B gene on chromosome 13
- Decreased copper excretion into bile and incorporated into apoceruloplasmin
- Decreased serum ceruloplasmin
- Copper is pro-oxidant, accumulates in liver then leaks to cornea and basal ganglia.
- Patients diagnosed between ages 5-40
- Liver disease (Hepatitis, acute liver failure, cirrhosis)
- Neurologic disease (dysarthria, dystonia, tremmor, parkinsonism, atrophy of basal ganglia)
- Psychiatric disease
- Keiser fleischer rings (deposits in Descemet membrane of the cornea)
- Hemolytic anemia
- Renal disease (Fanconi syndrome, icreased urine copper)
- Treatment is by chelation with penicillamine or trientine and zinc
21
Q
Hemochromatosis
A
- Autosomal Recessive
- Mutation in HFE gene
- C282Y > H63D, chromosome 6, associated with HLA-A3
- Leads to abnormal iron sensing, increased intestinal absorption
- Increased ferritin, increased iron, decreased TIBC lead to increased transferrin saturation
- Iron overload can also be secondary to chronic transfusion therapy such as Beta-thalassemia major
- Iron accumulates in liver, pancreas, skin, heart, pituitary, joints
- Hemosiderin (iron) can be identified on MRI or biopsy with Prussian blue stain
- Disease presents after age 40 when total body iron is > 20 g
- Iron loss through menstruation slows progression in women
- Classic triad of cirrhosis, diabetes mellitus and skin pigmentation.
- Causes restrictive cardiomyopathy (classic) or dilated cardiomyopathy (reversible)
- Hypogonadism
- Arthropathy due to calcium pyrophosphate deposition, especially metacarpophalangeal joints
- Hepatocellular Carcinoma is most common cause of death
- Treatment: repeated phlebotomy, chelation with deferasirox, deferoxamine, oral deferiprone
22
Q
Hepatocellular Carcinoma
A
- Most common malignant tumor of the liver
- Associated with Hepatitis B and all other causes of cirrhosis:
- Hepatitis C, alcoholic and nonalcoholic fatty liver disease, autoimmune disease, hemochromatosis, alpha1-antitrypsin deficiency
- Associated with Carcinogens (aflatoxin from Aspergillus)
- May lead to Bud-Chiari syndrome (obstruction of hepatic venous outflow)
Findings - Jaundice, tender hepatomegaly, ascites, polycythemia, anorexia
- Spreads hematogenously
Diagnosis: - Increased alphafetoprotein; ultrasound or contrast CT/MRI, biopsy
23
Q
Angiosarcoma of liver
A
Malignant liver tumor of endothelial origin
- Associated with exposure to arsenic or vinyl chloride (used in polymerization in plastics)
24
Q
Which cancers usually metastasize to the liver
A
GI malignancies
Breast Cancer
Lung cancer
25
Q
What is Budd-Chiari syndrome
A
- Thrombosis or compression of the hepatic veins with centrilobular congestion and necrosis
- Congestive liver disease (hepatomegaly, ascites, varices, abdominal pain and liver failure)
- No JVD
- Can lead to hypercoagulable state, polycythemia vera, postpartum state and HCC
- May cause nutmeg liver (mottled)
26
Q
Which bacterial infection is associated with colon cancer and how does it present?
A
- Streptococcus Gallolyticus (S. bovis) is the main human pathogen in the group D
- Causes subacute bacterial endocarditis similar to that of S. viridans
- However most cases occur in patients without preexisting valvular disease
- Every patient with S. gallolyticus should be evaluated for colonic cancer or vice versa
27
Q
Patient presents with abdominal pain, heme-positive stool and noncaseating granuloma on colonoscopy biopsy, what is most likely cause?
A
Chrons Disease
28
Q
Chrons Disease
A
Location
- Inflammatory bowel disease that causes patchy inflammation throughout the GI tract with skip lesions of normal bowel
- Usually in the ileum and colon, skips the rectum
Gross Morphology
- Transmural inflammation (all layers)
- May lead to fistulas
- Cobblestone mucosa, creeping fat, bowell wall thockening (string sign), linear ulcers and fissures.
Microscopy
- Noncaseating granulomas and lymphoid aggregates (Th1 mediated)
Complications
- Malabsorption, malnutrition, colorectal cancer
Fistulas, phlegmon/abcess, strictures leading to obstruction and perinanal disease
Manifestations
- Diarrhea may be bloody or not
- Rash (pyoderma gangrenosum, erythema nodosum)
- Eye inflammation (episcleritis, uveitis)
- Oral ulcers (aphthous stomatitis)
- Arthritis (peripheral, spondylitis)
- Kidney stones (calcium oxalate)
- Gallstones
- May show + ASCA
Treatment
- Corticosteroids
- Azathioprine
- Antibiotics (ciprofloxacin, metronidazole)
- Infliximab
- Adalimumab
29
Q
Ulcerative Colitis
A
Location - Colon inflammation - Continuous lesions always with rectal involvement Morphology - Mucosa and submucosa only - Friable mucosa with superfiial or deep ulcerations - Loss of haustra "lead pipe appearance" Microscopy - Crypt abscesses and ulcers, bleeding, no granulomas (Th2 mediated) Complications - Malabsorption, malnutrition, increased risk of colorectal cancer - Fulminant colitis - Toxic megacolon - Perforation Manifestations - Bloody diarrhea - Rash - Eye inflammation - Oral ulcerations - Arthritis - Primary sclerosing cholangitis - PANCA Treatment - 5-aminosalicylic preparations (mesalamine) - 6-mercaptopurine - Infliximab - Colectomy
30
Q
Primary Sclerosing Cholangitis
A
Unknown cause of onion skinning of the bile duct or fibrosis
- Alternating strictures and dilation with beading of intra and extrahepatic bile ducts on ERCP, MRCP
- Usually in middle aged men with IBD
- Associated with ulcerative cholitis
- p-ANCA +
- Increased IgM
- Can lead to secondary biliary cholangitis
- Increases risk of cholangiocarcinoma and gall bladder cancer
31
Q
Secondary Biliary Cholangitis
A
- Extrahepatic biliary obstruction
- Increased pressure in intrahepatic ducts
- Leads to injury, fibrosis and bile stasis
- Occurs in patients with known obstructive lesions (gallstones, biliary strictures, pancreatic carcinoma)
- May be complicated by ascending cholangitis
32
Q
Irritable Bowel Syndrome
A
- Recurrent abdominal pain associated with 2 of the following:
1. Related to defecation
2. Change in stool frequency
3. Change in form (consistency) of stool - No structural abnormalities
- Most common in middle aged women
- Chronic symptoms may be diarrhea-predominant, constipation-predominant or mixed
- Pathophysiology is multifaceted
33
Q
Appendicitis
A
- Acute inflammation of the appendix
- Can be due to obstruction by fecalith or lymphoid hyperplasia (in children)
- Initial diffuse periumbilical pain migrates to McBurney point
- Nausea, fever
- May perforate and lead to peritonitis
- May elicit psoas, obturator and Rovsing signs
- Gaurding and rebound tenderness on exam
- Differential diagnosis are diverticulitis in elderly and ectopic pregnancy in women (B-hcg to rule out)
- Treat with appendectomy
34
Q
What is a diverticulum?
A
- A blind pouch protruding from the alimentary tract that communicates with the lumen of the gut
- Most are acquired or “false diverticula” which means only the mucosa and submucosa outpouch, occurs where the vasa recta perforates the muscularis externa
- True diverticulum involve all 3 gut wall layers, such as a meckle diverticulum
35
Q
What is diverticulosis?
A
- Many false diverticula of the colon, commonly in sigmoid colon
- Caused by increased intraluminal pressure and focal weakness in colonic wall
- Associated with low fiber diets
- Usually asymptomatic or associated with vague discomfort
- Complications include diverticular bleeding (painless hematochezia) and diverticulitis
36
Q
What is diverticulitis?
A
- Inflammation of diverticula
- Classically causing LLQ pain, fever, leukocytosis
- Complications are abcess, fistula (colovesical fistula can lead to pneumaturia), obstruction (inflammatory stenosis) and perforation (peritonitis).
- Treat with antibiotics
37
Q
What is a meckel diverticulum?
A
- A true diverticulum
- Persistence of the vitelline duct
- May contain ectopic acid secreting gastric mucosa and/or pancreatic tissue
- Most common congenital anomaly of the GI tract
- Can cause hematochezia/melena, RLQ pain, intussusception, volvulus or obstruction near terminal ileum
- Contrast with omphalomesenteric cyst which is dilation of the vitelline duct
- Diagnosis: petechnetate study for uptake by ectopic gastric mucosa
- Rule of 2s
2 times as likely in males
2 inches long
2 feet from ileocecal valve
2% of the population
2 years of life or under
2 types of epithelium (gastric/mucosa)
38
Q
Hirschsprung Disease
A
- Congenital megacolon
- Lack of ganglion cells/enteric nervous plexuses (auerbach and meissner) in distal colon
- Neural crest cell migration failure
- Associated with RET mutations
Presentation - Bilious emesis, abdominal distension and failure to pass meconium within 48 hrs
- Leads to chronic constipation
- Normal portion of the colon proximal to aganglionic segment is dilated, results in transition zone
- Increased risk with down syndrome
- Explosive expulsion of feces (squirt sign)
- Empty rectum on digital exam
- Diagnosed by absence of ganglionic cells on rectal suction biopsy
- Treatment via resection
39
Q
How does malrotation of midgut result and what are the complications?
A
- Improper positioning of bowel, formation and fibrous bands (Ladd bands)
- Leads to volvulus, duodenal obstruction
40
Q
What is a volvulus?
A
- Twisting of a portion of bowel around its mesentery
- Can lead to obstruction and infarction
- Can occur anywhere in the GI tract
- Midgut volvulus is more common in infants and children
- Sigmoid volvulus more common in elderly
- Coffee bean sign on xray (giant coffee bean)
41
Q
What is intussusception?
A
- Telescoping of a proximal bowel segment into a distal bowel segment
- Commonly occurs at the ileocecal junction
- Blood supply becomes compromised
- Leads to abdominal pain with currant jelly stools
- If occurs in adults, due to mass or tumor that acts as lead point that is pulled into lumen
- Meckel diverticulum is most common pathologic lead point
- Most cases in children are idiopathic and may be associated with viral infection (adenovirus), leads to peyer patch hypertrophy which leads to lead point
- May be associated with rotavirus vaccines
42
Q
Acute Mesenteric Ischemia
A
- Critical blockage of intestinal bloodflow, often due to embolic occlusion of SMA
- Leads to small bowel necrosis
- Abdominal pain is out of proportion to physical findings
- May see red “currant jelly” stools
43
Q
Colonic Ischemia
A
- Reduction in intestinal bloodflow causes ischemia
- Crampy abdominal pain followed by hematochezia
- Occurs in watershed areas (splenic flexure, distal colon)
- Typically affects elderly
- Thumbprint sign on imaging due to mucosal edema/hemorrhage
44
Q
Right sided abdominal pain without evidence of bleeding may be a sign for?
A
- Isolated right colon ischemia
- May be the SMA since it supplies the entire small bowel, cecum, ascending colon and part of the transverse colon
- Associated with more severe disease
- CT scan with contrast is best diagnostic exam
45
Q
What is angiodysplasia?
A
- Tortuous dilation of vessels most often in the right sided colon
- Typically affects the elderly
- Confirmed via angiography
- Presents with hematochezia
46
Q
How do adhesions present and what are the complications?
A
- Fibrous bands of scar tissue
- Commonly form after surgery
- The most common cause of small bowel obstruction
- Can have well demarcated necrotic zones
47
Q
What is an ileus?
A
- Intestinal hypermotility without obstruction
- Leads to constipation and decreased flatus
- Distended tympanic abdomen with decreased bowel sounds
- Associated with abdominal surgeries, opiates, hypokalemia and sepsis
Treatment: bowel rest, electrolyte correction, cholinergic drugs (stimulate intestinal motility)
48
Q
What is meconium ileus?
A
- Seen in cystic fibrosis
- Meconium plug onbstructs the intestine
- Prevents stool passage at birth
49
Q
What is necrotizing enterocolitis?
A
- Seen in premature, formula fed infants with an immature immune system
- Necrosis of intestinal mucosa (primarily colonic) with possible perforation that can lead to pneumatosis intestinalis, free air in abdomen, portal venous gas
50
Q
What are the three ways which polyps are grossly characterized?
A
Flat, sessile or pedunculated
51
Q
Name the non-neoplastic polyps
A
- Hamartomatous polyps
- Mucosal polyps
- Inflammatory pseudopolyps
- Submucosal polyps
- Hyperplastic polyps
52
Q
Hamartomatous Polyps
A
- Solitary lesions
- No significant risk of transformation
- Growths of normal colonic tissue with distorted architecture
- Associated with Peutz-Jeghers syndrome and Juvenile polyposis
53
Q
Mucosal Polyps
A
- Small, usually < 5 mm
- Look similar to normal mucosa
- Clinically insignificant
54
Q
Inflammatory pseudopolyps
A
- Result of mucosal erosion in inflammatory bowel diseases such as Ulcerative Colitis or Chrons
