Gastrointestinal Flashcards
(137 cards)
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
What is Budd-Chiari syndrome
- 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
Which bacterial infection is associated with colon cancer and how does it present?
- 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
Patient presents with abdominal pain, heme-positive stool and noncaseating granuloma on colonoscopy biopsy, what is most likely cause?
Chrons Disease
28
Chrons Disease
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
Ulcerative Colitis
```
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
Primary Sclerosing Cholangitis
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
Secondary Biliary Cholangitis
- 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
Irritable Bowel Syndrome
- 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
Appendicitis
- 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
What is a diverticulum?
- 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
What is diverticulosis?
- 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
What is diverticulitis?
- 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
What is a meckel diverticulum?
- 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
Hirschsprung Disease
- 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
How does malrotation of midgut result and what are the complications?
- Improper positioning of bowel, formation and fibrous bands (Ladd bands)
- Leads to volvulus, duodenal obstruction
40
What is a volvulus?
- 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
What is intussusception?
- 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
Acute Mesenteric Ischemia
- 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
Colonic Ischemia
- 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
Right sided abdominal pain without evidence of bleeding may be a sign for?
- 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
What is angiodysplasia?
- Tortuous dilation of vessels most often in the right sided colon
- Typically affects the elderly
- Confirmed via angiography
- Presents with hematochezia
46
How do adhesions present and what are the complications?
- Fibrous bands of scar tissue
- Commonly form after surgery
- The most common cause of small bowel obstruction
- Can have well demarcated necrotic zones
47
What is an ileus?
- 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
What is meconium ileus?
- Seen in cystic fibrosis
- Meconium plug onbstructs the intestine
- Prevents stool passage at birth
49
What is necrotizing enterocolitis?
- 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
What are the three ways which polyps are grossly characterized?
Flat, sessile or pedunculated
51
Name the non-neoplastic polyps
- Hamartomatous polyps
- Mucosal polyps
- Inflammatory pseudopolyps
- Submucosal polyps
- Hyperplastic polyps
52
Hamartomatous Polyps
- Solitary lesions
- No significant risk of transformation
- Growths of normal colonic tissue with distorted architecture
- Associated with Peutz-Jeghers syndrome and Juvenile polyposis
53
Mucosal Polyps
- Small, usually < 5 mm
- Look similar to normal mucosa
- Clinically insignificant
54
Inflammatory pseudopolyps
- Result of mucosal erosion in inflammatory bowel diseases such as Ulcerative Colitis or Chrons
55
Submucosal Polyps
- May include lesions such as lipomas, leiomyomas, fibromas and others
56
Hyperplastic polyps
- Smaller and predominantly located in the rectosigmoid region
- May evolve into serrated polyps and more advanced lesions
57
Name the polyps that have malignant potential
1. Adenomatous polyps
| 2. Serrated polyps
58
Adenomatous Polyps
- Neoplastic, via chromosomal instability pathway in APC and KRAS
- Tubular histology has less malignant potential than villous
- Tubulovillous has intermediate malignant potential
- Usually asymptomatic
- May present with occult bleeding
59
Serrated Polyps
- Premalignant via CpG hypermethylation phenotype pathway with microsatellite instability and mutations in BRAF
- Sawtooth pattern of crypts on biopsy
- Up to 20% of cases of sporadic colorectal cancer
60
Name the 5 polyposis syndromes
1. Familial adenomatous polyposis
2. Gardner Syndrome
3. Turcot syndrome
4. Peutz Jeghers syndrome
5. Juvenile polyposis syndrome
61
Familial adenomatous polyposis
- Autosomal dominant
- Mutation of the APC tumor suppressor gene on chromosome 5q
- 2-hit hypothesis
- Thousands of polyps arise after puberty; pancolonic, always involves the rectum
- Prophylactic colectomy or else 100% progress to Colorectal Cancer
62
Gardner Syndrome
- Familial adenomatous polyposis + osseous and soft tissue tumors
- Congenital hypertrophy of retinal pigment epithelium
- Impacted/supernumerary teeth
63
Turcot Syndrome
- FAP/ Lynch syndrome + malignant CNS tumor
- Tumor can be medulloblastoma or glioma
- Think Turcot = Turbin
64
Peutz-Jeghers syndrome
- Autosomal dominant syndrome featuring numerous hamartomas throughout the GI tract
- Hyperpigmented mouth, lips, hands and genitalia
- Associated with increased risk of breast and GI cancers such as colorectal, stomach, bowel and pancreatic cancers
65
Juvenile polyposis syndrome
- Autosomal dominant syndrome in children (< 5 years old)
- Features numerous hamartomatous polyps in the colon stomach, small bowel
- Associated with increased risk of Colorectal Carcinoma
66
Lynch Syndrome
- Previously known as hereditary nonpolyposis colorectal cancer (HNPCC)
- Autosomal dominant
- Mutation of DNA mismatch repair genes with subsequent microsatellite instability
- MSH2, MLH1, MSH6 and PMS2
- 80% progress to Colorectal Carcinoma
- Proximal colon is always involved
- Associated with endometrial, ovarian and skin cancers
67
Colorectal Cancer
- Patients usually >50
- 25 % have family history
Risk Factors
- Adenomatous polyps
- Serrated Polyps
- Familial cancer syndromes
- Inflammatory Bowel Disease
- Tobacco Use
- Diet of processed meat with low fiber
Presentation
1. Rectosigmoid colon
2. Ascending colon
- Exophytic (ball-shaped) mass
- Iron deficiency anemia
- Weight loss
3. Descending colon
- Infiltrating mass
- Partial obstruction
- Colicky pain
- Hematochezia
4. Rarely presents with S. bovis
Diagnosis
- Iron deficiency anemia in males > 50 years old and postmenopausal females raises concern
- Screen patients at age 50 with colonoscopy
- Alternate tests include flexible sigmoidoscopy, fecal occult blood testing, fecal immunochemical testing and CT colonography
- Pts with first degree relative who has colon cancer should be screened at age 40 or 10 years prior to relatives presentation.
- Pts with IBD have distinct screening protocol
- Apple core lesion seen on barium enema x-ray
- CEA tumor marker for monitoring recurrence, should not be used for screening
68
Cirrhosis
- Diffuse bridging fibrosis (via stellate cells) and regenerative nodules disrupts normal architecture of liver
- Splenomegaly
- Increased risk for hepatocellular carcinoma
Etiologies
- Alcohol in 60-70% of cases
- Non-alcoholic steatohepatitis
- Chronic viral hepatitis
- Autoimmune hepatitis
- Biliary disease
- Genetic/metabolic disorders
69
Portal Hypertension
- Increased pressure in portal venous system
Etiologies
- Cirrhosis (most common in western world)
- Vascular obstruction (portal vein thrombosis, budd chiari syndrome)
- Schistosomiasis
70
What are the integumentary effects seen in cirrhosis and portal hypertension?
- Jaundice
- Spider angiomas
- Palmar erythema
- Purpura
- Petechiae
71
What are the neurologic effects seen in cirrhosis and portal hypertension?
- Hepatic encephalopathy
| - Asterixis ( flapping tremor)
72
What are the gastrointestinal effects seen in cirrhosis and portal hypertension?
- Anorexia
- Nausea, vomiting
- Dull abdominal pain
- Fetor hepaticus (breath of death, thiols)
73
What are the effects of portal hypertension?
- Esophageal varices, can lead to hematemisis
- Gastric varices, can lead to melena
- Caput medusae, due to recanalization of paraumbilical veins
- Ascites
- Anorectal varices
74
What are the reproductive effects seen in cirrhosis and portal hypertension?
- Testicular atrophy
- Gynecomastia
- Amenorrhea
75
What are the hematologic effects seen in cirrhosis and portal hypertension?
- Thrombocytopenia
- Anemia
- Coagulation disorders
- Splenomegaly
76
What are the renal effects seen in cirrhosis and portal hypertension?
Hepatorenal syndrome (functional renal failure)
- Leads to increase in RAAS
- Leads to increased NA+ and H2O retention
77
What are the metabolic effects seen in cirrhosis and portal hypertension?
- Hyperbilirubinemia
- Hyponatremia
- Metabolic acidosis
78
What are the cardiovascular effects seen in cirrhosis and portal hypertension?
- Cardiomyopathy
| - Peripheral edema
79
What causes spontaneous bacterial peritonitis?
- Commonly caused by aerobic gram negative organisms, especially E. coli
- Common and potentially fatal in patients with cirrhosis and ascites
- Can often be asymptomatic
- Fevers, chills, abdominal pain, ileus or worsening encephalopathy
Diagnosis
- Paracentesis with ascitic fluid absolute neutrophil count (ANC) > 250 cells/mm
80
When are the AST and ALT elevated?
They are increased in most liver diseases
- In alcoholic liver disease AST > ALT
- This indicates progression to advanced fibrosis or cirrhosis
81
When is the alkaline phosphatase elevated?
- In cholestasis, such as biliary obstruction, infiltrative disorders or bone disease
82
When is the gamma-glutamyl transpeptidase elevated?
- In various liver and biliary diseases just as ALP, but not in bone diseases
- Associated with alcohol use
83
What are the enzymes released in liver damage?
- AST, ALT
- ALP
- Gamma-Glutamyl Transpeptidase
84
What are the functional liver markers?
- Bilirubin
- Albumin
- Prothrombin Time
- Platelets
85
What does the bilirubin tell us?
- It is increased in various liver diseases such as biliary obstruction, alcoholic or viral hepatitis
- Tells us if there is hemolysis or break down of RBCs
86
What does the albumin tell us?
- It tells us wether the liver is producing proteins
- Measures biosynthetic function
- It is decreased in advanced liver disease
87
What does the prothrombin time tell us?
- There is decreased production of clotting factors from the liver
- Measures biosynthetic function
- It is increased in advanced liver disease
88
What does the platelet count tell us?
- In advanced liver disease, tells us if there is decreased thrombopoietin or liver sequestration
- In portal hypertension tells us if there might be splenomegaly or splenic sequestration
- It is decreased in advanced liver disease
89
What is Reye Syndrome?
- Rare, but often fatal child (age 4-12) hepatic encephalopathy
- Associated with viral infection (VZV and influenza B) that has been treated with aspirin
- Aspirin metabolites decrease Beta-oxidation by reversible inhibition of mitochondrial enzymes
- Decreased ATP production
- Leads to increased ammonia in blood due to liver unable to filter it out
- Ammonia targets astrocytes leading to encephalopathy
Findings
- Mitochondrial abnormalities, fatty liver (microvesicular fatty change) hypoglycemia, vomiting, hepatomegaly and coma
90
What are the three stages of alcoholic liver disease?
1. Hepatic Steatosis
2. Alcoholic hepatits
3. Alcoholic cirrhosis
91
What is hepatic steatosis?
- Initial changes seen in alcoholic liver disease
- Macrovesicular fatty change
- Shows fat cells in liver biopsy
- May be reversible with alcohol cessation
92
What is alcoholic hepatitis?
- Secondary stage due to sustained, long term consumption of alcohol
- Swollen and necrotic heptatocytes with neutrophils infiltrating
- Mallory bodies seen, which are intracytoplasmic eosinophilic inclusions of damaged keratin filaments
- AST > ALT (2:1)
93
Alcoholic Cirrhosis
- The final and irreversible form of alcoholic liver disease
- Regenerative nodules surrounded by fibrous bands in response to chronic liver injury
- Leads to portal hypertension and end stage liver disease
- Sclerosis around central vein may be seen in early disease
94
Nonalcoholic fatty liver disease
- Metabolic syndrome (insulin resistance); obesity
- Leads to fatty infiltration of hepatocytes
- Leads to cellular "ballooning" and eventual necrosis
- May cause cirrhosis and Hepatocellular carcinoma
- It is independent of alcohol use
- ALT > AST
95
Hepatic Encephalopathy
- Cirrhosis
- Leads to portosystemic shunts
- Causes decreased NH3 metabolism
- Leads to metabolic acidosis
- Leads to neuropsychiatrci dysfunction
- Disorientation/asterixis (mild) to difficult arousal or coma (severe)
- Triggered by:
- Increased NH3 production and absorption (due to dietary protein, GI bleed, constipation or infection)
- Decreased NH3 removal ( due to renal failure, diuretics, bypassed hepatic blood flow post TIPS)
Treatment is with lactulose which increases NH4+ generation and rifaximin or neomycin which decrease NH3 producing gut bacteria
96
What does the foregut, midgut and hindgut give rise to?
Foregut
- Esophagus to upper duodenum
Midgut
- Lower duodenum to proximal 2/3 of transverse colon
Hindgut
- Distal 1/3 of transverse colon to anal canal above pectinate line
97
Describe the midgut development, when does it form and rotate?
6th week of development
- Physiologic midgut herniates through the umbilical ring
10th week of development
- Returns to the abdominal cavity
- Rotates around the superior mesenteric artery
- Makes a complete 270 counterclockwise turn
98
Developmental defects due to:
1. Rostral fold closure
2. Lateral fold closure
3. Caudal fold closure
1. Sternal defects (ectopia cordis)
2. Omphalocele, gastrochisis
3. Bladder exstrophy
99
Gastrochisis
Contents come out of the G
- Extrusion of abdominal contents through abdominal folds
- Typically right of the umbilicus
- Not covered by peritoneum or amnion
100
Omphalocele
Contents stay in the O
- Persistent herniation of abdominal contents into umbilical cord
- Sealed by the peritoneum
101
Congenital umbilical hernia
- Incomplete closure of umbilical ring
- Bowel contents may prtrude through umbilicus
- May close spontaneously
102
What is esophageal atresia?
Which is the most common?
What are the signs and symptoms?
1. Esophageal Atresia with Tracheoesophageal Fistula: the most common (85%).
2. Pure Esophageal Atresia or Stenosis: shows gasless abdomen
3. H type: Fistula resembles letter H
- Result from polyhydramnios in utero, fetus unable to swallow and reduce the amount of amniotic fluid
- Neonates drool, choke and vomit with first feeding
- If tracheoesophageal fistula present, allows air into the stomach and can be visualized on x ray
- Cyanosis is secondary to laryngospasm (to avoid reflux-related aspiration)
- Clinical test, failure to pass nasogastric tube into stomach
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How does intestinal atresia present?
| What are the different types of intestinal atresia?
- Presents with bilious vomiting and abdominal distension within the first 1-2 days of life
1. Duodenal Atresia: Failure to recanalize
- Associated with double bubble on x ray (dilated stomach proximal to duodenum)
- Associated with down syndrome
2. Jejunal and ileal Atresia:
- Due to disruption of mesenteric vessels
- Leads to ischemic necrosis
- Leads to segmental reasorption or narrowing
- Looks like apple peel or bowel discontinuity
Treatment
- Gastric decompression to remove contents from stomach
- IV fluids
- Duodenoduodenostomy
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What is the most common cause of gastric outlet obstruction in infants?
Hypertrophic Pyloric Stenosis
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Hypertrophic Pyloric Stenosis
- Palpable olive shaped mass in epigastric region
- Visible peristaltic waves and nonbilous projectile vomiting at 2-6 weeks old
- More common in first borne males
- Associated with exposure to macrolides
- Hypokalemic hypochloremic metabolic alkalosis
- Due to vomiting of gastric acid and volume contraction
- Vomiting depletes HCL from stomach and leads to hyperchloremia
- Dehydration leads to Na+ reabsorption from kidneys and wastes K+ leading to hypokalemia
- Hypokalemia leads to K+ out of cells to blood, H+ into cells to try and rebalance, H+ secretion and HCO3+ reabsorption leading to metabolic alkalosis
- Treat with pyloromyotomy
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How does the pancreas develop?
The foregut (endoderm)
- The ventral pancreatic buds contribute to the uncinate process and main pancreatic duct
- Dorsal pancreatic bud becomes the body, tail, isthmus and accessory pancreatic duct
- The ventral and dorsal buds contribute to the pancreatic head
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What is annular pancreas?
- Ventral pancreatic bud abnormally encircles 2nd part of the duodenum
- Forms a ring of pancreatic tissue that may cause duodenal narrowing and vomiting
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What is pancreas divisum?
Ventral and dorsal parts fail to fuse at 8 weeks
| - Common anomaly, asymptomatic, may cause chronic abdominal pain and/or pancreatitis
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How does the spleen develop?
- From mesentery of the stomach (mesoderm)
| - However it has foregut supply (celiac trunk to the splenic artery)
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What are the retroperitoneal structures?
SAD PUCKER
- Suprarenal Adrenal Glands
- Aorta and Inferior Vena Cava
- Duodenum
- Pancreas (not the tail)
- Ureters
- Colon (ascending and descending)
- Kidneys
- Esophagus (thoracic portion)
- Rectum (partially)
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Retroperitoneal structures include?
| Injuries to the retroperitoneal structures can cause?
- GI structures that lack mesentary and non GI structures
| - Blood or gas accumulation in the retroperitoneal space
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Falciform Ligament
- Connects
- Structures
- Notes
- Liver to the anterior abdominal wall
- Contains the ligamentum teres hepatis or round ligament which divides the liver into left and right hemispheres (round ligament is remnant of the fetal umbilical vein)
- Derived from ventral mesentary, as liver grows, it splits the ventral mesentery into the lesser omentum and falciform ligament
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Hepatoduodenal Ligament
- Connects
- Structures
- Notes
- Connects the liver to the duodenum
- Contains the portal triad which consists of the proper hepatic artery, portal vein and common bile duct
- Pringle maneuver may be used to clamp the ligament during abdominal operations, placed through omental foramen
- It is part of the lesser omentum
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What is the omental foramen?
Connects the greater and lesser sacs
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Gastrohepatic Ligament
- Connects the liver to lesser curvature of the stomach
- Contains the gastric arteries
- Seperates the greater and lesser sacs on the right
- May be cut during surgery to access lesser sac
- Part of the lesser omentum
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Gastrocolic Ligament
- Connects the greater curvature of stomach and transverse colon
- Contains the gastropiploic arteries
- Part of the greater omentum
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Gastrosplenic Ligament
- Connects the greater curvature of stomach and spleen
- Contains short gastric and left gastroepiploic vessels
- Seperates the greater and lesser sacs on the left
- PArt of the greater omentum
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Splenorenal Ligament
- Connects the spleen to posterior abdominal wall
| - Contains the splenic artery, vein and tail of the pancreas
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What are the layers of the gut wall inner to outer?
| What do they contain?
1. Mucosa
- Epithelium
- Lamina propia
- Muscularis mucosa
2. Submucosa
- Submucosal nerve plexus (Meissner)
- Submucosal glands, secretes fluid
3. Muscularis Externa
- Inner circular layer
- Myenteric nerve plexus (Auerbach), motility
- Outer longitudinal
4. Serosa (Intraperitoneal) / Adventitia (Retroperitoneal)
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What cells is the esophagus consist of?
- Nonkeratinizing stratified squamous epithelium
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What cells does the stomach consist of?
- Gastric glands
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What cells does the duodenum consist of?
- Villi and Microvilli
- Brunner glands (secrete HCO3-)
- Crypts of Lieberkuhn (stem cells that replace enterocytes/goblet cells and paneth cells that secrete defensins, lysozyme and TNF)
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What cells does the jejunum consist of?
Plicae circulares and crypts of Lieberkuhn
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What cells does the ileum consist of?
Peyer patches (kymphoid aggregates in lamina propia and submucosa
Plicae circulares (proximal ileum)
Cryps of lieberkuhn
Contains the largest number of goblet cells in small bowel
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What cells does the colon contain?
- Crypts of Lieberkuhn but no villi
| - Abundant goblet cells
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Celiac Artery
- Suplies the embryonic foregut
- Supplies the pharynx and lower esophagus to proximal duodenum
- Supplies liver, gallbladder, pancreas and spleen
- Innervated by the vagus nerve
- Arises from aorta at level T12/L1
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Superior Mesenteric Artery
- Innervated by the Vagus nerve
- Arises from Aorta at L1
- Supplies the distal duodenum to the proxima 2/3 of transverse colon
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Inferior Mesenteric Artery
- Innervated by the pelvic nerve
- Arises from Aorta at L3
- Supplies the distal 1/3 of the transverse colon to the upper rectum
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What are the stages and prognosis of colorectal carcinoma?
```
Stage A
- Confined to the mucosa
- 5 year survival is 90% +
Stage B
- Involves the muscular layer
- 5 year survival is 70-80%
Stage C
- Lymph node involvement
- Poor prognosis
Stage D
- Distant metastasis
- Poor prognosis
```
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Chrons disease with ileal resection can cause what?
Bile acid malabsorption
- May lead to impaired absorption of the fat soluble vitamins ( A, D, E, K)
- Vitamin K deficiency may lead to impaired coagulation with easy bruising, large hematomas in deep tissues and joints (hemarthrosis) after minor trauma and prolonged bleeding after surgery
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Pernicious Anemia (Autoimmune gastritis)
- Autoimmune disease characterized by CD4+ T cell-mediated destruction of parietal cells
- Leads to decreased parietal cell mass and decreased hydrochloric acid secretion (achlorhydria)
- Causes increase in intraluminal pH, feedback leads to increased gastrin secretion
- Results in B12 deficiency due to decreased intrinsic factor secretion from parietal cells
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Direct Hernia
- Occurs in?
- Defect in?
- Travels?
- Typically Occurs in Older men
- Weakness of the transversalis fascia
- Contents protrude through Hesselbach triangle
- Travels media (inside) to the inferior epigastric vessels
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Indirect Hernia
- Occurs in?
- Defect in?
- Travels?
- Typically occurs in male infants
- Patent processus vaginalis
- Contents protrude through the deep inguinal ring
- Travels lateral (outside) to the inferior epigastric vessels
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Femoral Hernia
- Occurs in?
- Defect in?
- Travels
- Typically occurs in women
- Weakness of the proximal femoral canal
- Contents protrude through the femoral ring
- Travels inferior to the inguinal ligament
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Mallory-Weiss tear leads to which acid base disturbance and why?
Metabolic alkalosis due to repetitive vomiting that leads to net loss of gastric acid secretion.
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64 YO man presents with abdominal pain, nausea and vomiting. History of hypertension, myocardial infarction and systolic heart failure. Exam shows soft, mildly distended and tender abdomen. Labs show bicarb of 12 mEq/L, pH of 7.2, PCO2 26 mmHg and Lactic acid of 6.2 mmol/L. CT shows ileal wall thickening and lack of enhancement with contrast. What is most common diagnosis?
Acute Mesenteric Ischemia with inadequate delivery of oxygen to intestinal tissues.
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Why does meckel diverticulum usually occur?
What are the signs?
How is it diagnosed?
- Failed obliteration of the vitelline (omphalomesenteric) duct
- Painless lower GI bleed
- 99m TC-pertechnetate
