GIT patho Flashcards
(145 cards)
1
Q
What is the pathogenesis of oesophageal varices
A
Portal HTN => Portosystemic shunt between L gastric V & Oesophageal V
=> Dilated submucosal V in lower 1/3 & prox stomach
2
Q
What are the consequences of esophageal varices
A
Rupture
Painless hematemesis
Painful melena
3
Q
What are the risk factors of GERD
A
Old age, BMI, Smoking
4
Q
What are the symptoms of GERD
A
Heartburn
Dysphagia
Acid regurgitation
Cough and sore throat
5
Q
What is the pathogenesis of GERD
A
LES relax => reflux of acid and bile into esophagus => squamous epithelial cells secrete cytokines
=> inflammation damages esophagus
6
Q
What are the complications of GERD
A
Barrett’s esophagus
Ulceration & strictures
Metaplasia/dysplasia => adenocarcinoma
7
Q
What is Barrett’s esophagus
A
Acid damages distal esophagus mucosa => stratified squamous -> nonciliated columnar epithelium w goblet cells
8
Q
What are the presentations of oesophageal cancers
A
Dysphagia, Odynophagia, Obstruction, Haemorrhage
9
Q
How are oesophageal cancers diagnosed
A
Endoscopy w biopsy
Barium swallowing => determine narrowing of lumen
10
Q
What are the different oesophageal cancers and compare their histology
A
Adenocarcinoma
- Glandular differentiation
- Mucin production
Squamous cell carcinoma
- Keratin pearls
- Intercellular bridges
11
Q
What are the risk factors for oesophageal adenocarcinoma
A
GERD
Obesity
Smoking
Male
12
Q
What are the risk factors for oesophageal squamous cell carcinoma
A
Low fibre
Alcohol
Smoking
Male
13
Q
What are the complications of oesophageal cancers
A
Tracheoesophageal fistula => Aspiration pneumonia
Aorta haemorrhage
Mediastinitis
Metastasis
14
Q
Which parts of the esophagus do oesophageal cancers affect
A
Adenocarcinoma = distal 1/3
Squamous cell carcinoma = prox 2/3
15
Q
How does the stomach protect itself from its own acid
A
Mucus
HCO3-
PGE2
16
Q
What are the effects of PGE2
A
Increase HCO3 and mucus
Increase mucosal growth and function
Decrease acid secretion
17
Q
What are some acute causes of gastritis
A
Alcohol
Smoking
Drugs = NSAIDS, steroids
Chemo
18
Q
What are the damages caused by acute gastritis
A
Ulcers
Erosion
Superficial inflammation
19
Q
What are the types of ulcers caused by gastritis
A
Stress ulcer (Shock, sepsis, trauma)
Curling ulcer (Burns/trauma)
Cushing ulcer (Intracranial diseases)
20
Q
What is the pathogenesis of H. pylori gastritis
A
Urease neutralises acid => increase pH => G cells increase gastrin => Parietal cells increase HCl => inflammation and mucosal damage
Endo/exotoxins cause direct mucosal damage and inflammation
21
Q
How is H pylori diagnosed
A
Histology (best)
Urea breath test (radio labelled urea => check radioactive CO2)
Serology for Ab
Culture => curved aerophilic bacili
22
Q
What are some diseases caused by H. pylori
A
Chronic gastritis
Peptic ulcer
Gastric carcinoma
MALT
23
Q
What is the treatment for H. pylori gastritis
A
Clarithromycin, Amoxicillin, Omeprazole for 7-14 days
24
Q
What is used for penicillin allergic patients for H pylori gastritis
A
Clarithromycin, Metronidazole, Omeprazole
25
How long after the antibiotics course should omeprazole be continued for
4 weeks for gastric ulcers
6 weeks for duodenal ulcers
26
Why should clarithromycin/ metronidazole never be prescribed alone for H. pylori infections
H. pylori gains resistance towards clarithromycin/ metronidazole
27
What can cause autoimmune gastritis
Type 1 Diabetes Mellitus
28
What is the pathogenesis of autoimmune gastritis
Type 4 hypersensitivity => Autoantibodies against parietal cells =>T cells kill parietal cells
- Decrease HCl => increase pH => increase HCl secretion by parietal cells => mucosal inflammation and damage
- Decrease IF => Decrease B12 absorption => B12 deficiency => megaloblastic anaemia
29
What are the presentations of autoimmune gastritis
Chief cell destruction
A/Hypochlorhydria
Megaloblastic Anaemia
G cell metaplasia
30
How is autoimmune gastritis diagnosed
Ab against parietal cells & IF in serum & gastric secretions
31
What is a complication of chronic gastritis
Intestinal metaplasia of the stomach
32
What can cause peptic ulcer disease
H. pylori
NSAIDs
33
What are the risk factors of peptic ulcer disease
Alcohol
Smoking
CVS disease
COPD
34
What are the presentations of peptic ulcer disease
Epigastric burning
- worse at night
- relieved by alkali/food
Coffee ground vomit
Melena
35
What are the complications of peptic ulcers
Haemorrhage
Perforation
Obstruction
Fistula
36
What are the types of gastric polyps
Fundic/Oxyntic gland polyp
Hyperplastic polyp
Adenoma
37
Where are the different gastric polyps most commonly found
Fundus = Fundic/Oxyntic gland polyp
Antrum = Hyperplastic polyp, Adenoma
38
What are the predisposing factors of different gastric polyps
Fundic/Oxyntic gland polyp = PPI use, Hypergastrinemia
Hyperplastic polyps = Chronic gastritis
Adenoma = Smoking, H. pylori, Salty, processed foods
39
Compare the malignancy risks of different gastric polyps
Fundic/ Oxyntic polyp = 0 risk
Hyperplastic polyps = Increase size, dysplasia => increase risk
Adenoma = Precancerous
40
What is the definition of gastric cancer
Invasive gastric cancer that invades no deeper than submucosa irrespective of lymph node metastasis
41
What are the presentations of gastric cancer
Weight loss
Abdominal pain
Anaemia and Melena
Vomit
Early satiety
42
What is the TNM staging for gastric cancer
T = Depth of invasion
N = Distant metastasis (Virchow's node)
M = Peritoneal spread => krukenburg tumours
43
What are the characteristics of intestinal type gastric cancer
Etiology = Chronic atrophic gastritis, Intestinal metaplasia, Dysplasia
Age group = Older, Male
Gross = Ulcerated, heaped-up margins
Histo = Glandular differentiation w goblet cells
Differentiation = Well differentiated, good prognosis
44
What are the characteristics of diffuse type gastric cancer
Etiology = CDH1 mutation, multifactorial
Age group = Younger, Female
Gross = Linitis plastica
Histo = Poorly differentiated, signet ring cells
Differentiation = Poorly differentiated, poor prognosis
45
What can cause appendicitis
Foreign matter, Faecolith (adults), Lymphoid hyperplasia (children)
46
What is the pathophysiology of appendicitis
Obstruction => Peristalsis => Colicky, poorly localised pain
Stasis of intestinal content
- Increase intraluminal P =>decrease venous outflow
- Bacterial overgrowth and neutrophilic infiltration
47
What are the presentations of appendicitis
Fever, n/v
Diffuse paraumbilical pain => localises @ McBurney's point
48
What are the complications of appendicitis
Venous outflow obstruction => Ischemia and gangrenous appendicitis
Rupture and perforation => bacteria spread to peritoneum => peritonitis
Local abscess => fibrinous adhesion of appendix to structures
Abscess spread => parabolic gutter => Subphrenic abscess
Septic emboli => mesenteric V => Liver abscess
49
Explain migratory pain in appendicitis
Visceral afferent pain fibres of midgut sup mesenteric plexus => enter spinal cord @ T10 => vague pain at paraumbilicus
Appendix more inflamed => irritates parietal peritoneum and abdominal wall => severe somatic pain at McBurney's point
50
Compare the types of diverticulosis
True diverticulum
- Involves all layers of bowel wall
- a/w congenital elastin abnormalities
False diverticulum
- Involves mucosa and submucosa
- Due to pulsion
51
What is the pathogenesis of diverticulosis
Low fibre diet/ Chronic constipation
=> increase intraluminal P => mucosal out pouching where neurovascular bundle penetrates muscular coat
52
What are the presentations of diverticulitis
LLQ pain, fever, leukocytosis
53
What is the pathophysiology of diverticulitis
Faecolith => obstruction & stasis => infection
54
What are the complications of diverticulitis
Pericolic abscess
Fibrosis, adhesions, stricture
Colovescial fistula
Perforation => Peritonitis
55
What are the different types of colonic polyps
Hamartomatous polyps
Serrated polyps
Adenomatous polyps
56
What are the characteristics of hamartomatous polyps
a/w Peutz-Jegher's syndrome
Low malignant potential
57
What are the characteristics of serrated polyps
Sawtooth pattern of crypt epithelium and dysplasia
Medium malignant potential
58
What are the characteristics of colon adenomatous polyps
Tubular/ Tubuvillous/ Villous adenoma
High malignant potential (Villous ~50%)
59
What are the risk factors of colorectal cancer
Hereditary
Colorectal adenomas and serrated polyps
IBD
Smoking/ alcohol
High fat diet
60
What is the molecular progression of colorectal cancer
APC mutation => inactivate TSG (p53) => evade growth suppression => Increase Wnt/B-catenin signalling
KRAS mutation => signalling molecules act without receptor => growth signal autonomy => polyp
p53 inactivation
- Increase angiogenesis => Increase COX => carcinoma
- LOF of SMAD2/4, p53
61
Compare the types of colorectal cancer (growth pattern, anaemia vs obstruction, clinical)
Right sided
- Exophytic growth
- Anaemia
- Melena => Fe deficiency
Left sided
- Circumferential, annular growth
- Obstruction
- Hematochezia and pencil thin stools
62
What are the presentations of colorectal cancer
Abdominal pain
Altered bowel habits (pencil thin stools and alternating diarrhoea/constipation)
Asymptomatic (early stage)
Anaemia and weakness
Obstruction => vomit, constipation
Fistula
Weight loss
Bleeding => hematochezia/ melena
63
What are the investigations done for colorectal cancer
Digital rectal examination
CT chest, abdomen, pelvis w contrast for staging
Colonoscopy and biopsy
64
What is the tumour marker for colorectal cancer
CEA
65
What are the microscopic features of colon adenocarcinoma
Moderate differentiated tubule formation
Abundant intraluminal eosinophilic necrotic debris
Prominent desmoplastic response
Extracellular mucin pools
66
What is the staging for colorectal cancer
Depth of invasion = no. of layers invaded
Beyond muscularis propria => stage 4
67
What are the complications of colorectal cancer
Ulcerated blood vessels => bleeding
Fistula => invade ureter, bladder, adj bowel
Obstruction => dehydration, sepsis
Perforation => peritonitis
68
Name 2 inflammatory bowel diseases
Crohn's disease (any part of GIT)
Ulcerative colitis (Colon only)
69
What are the gross morphology and microscopic features of Crohn's disease
Gross
- Cobblestone mucosa
- Creeping fat
- Thickened bowel wall
- Linear ulcers
Micro
- Transmural inflammation
- Deep, knifelike ulcers
- Non-caseating granulomas
70
What are the gross morphology and microscopic features of Ulcerative colitis
Gross
- Friable mucosa
- Superficial and deep ulcers
- Loss of haustra
Micro
- Mucosal/Submucosal inflammation
- Superficial, broad based ulcers
- Crypt abscess
71
What are the presentations of Crohn's disease
Diarrhoea
Kidney/Gall stones
Rash, Arthritis, Eye inflammation
72
What are the presentations of ulcerative colitis
Bloody diarrhoea
Toxic megacolon
Primary sclerosing cholangitis
Rash, Arthritis, Eye inflammation
73
What is the pathophysiology of amebiasis
Ingested cysts of entamoeba histolytica => Trophozoites invade colon eptihelium
74
What is the causative organism and treatment of diarrhoea a/w flasked shaped ulcers and liver abscess
Entamoeba histolytica
Metronidazole
75
What is a differential diagnosis for Crohn's disease
Intestinal Tb w caseating granulomas
76
What is the presentation of intestinal Tb
Regional lympahdenopathy => circumferential ulcers @ ileocecal region
77
What can cause diarrhoea a/w antibiotic use and what is the treatment
Clostridium difficile
Stop antibiotics and give vancomycin
78
What is a/w rice water stool and what is the treatment
Vibrio Cholerae
ORS + azithromycin
79
What are the causative organisms of acute bloody diarrhoea
Campylobacter
EHEC
Shigella
Salmonella
80
What is a/w mucus and blood in stool
Inflammatory/ Ischemic bowel disease
81
How is viral hepatitis transmitted
Hep A = contaminated water, raw shellfish, fecal-oral
Hep B, C, D = Vertical transmission, blood, sex
Hep E = fecal-oral
82
Classify viral hepatitis strains into acute or chronic
Acute = Hep A, D, E
Acute/ chronic = Hep B
Chronic = Hep C
83
Which viral hepatitis strains have a vaccine
Hep A, B
Hep D has an indirect vaccine through HBV vax
84
What are the antigens of HBV
HBsAg
HBcAg
85
What is the marker for high viremia and infectivity of HBV
HBeAg
86
What is required for diagnosis for HBV
Serum IgM anti-HBc and HBsAg
87
Which antibody is most protective against HBV
Anti-HBs
88
What is the window period of HBV infection
IgM anti-HBc present but no HBsAg
89
How long is the incubation period for HBV
120 days
90
Which hepatitis strain are pregnant women most at risk of getting
Hep E
91
What is the pathophysiology of drug induced liver damage
Drugs
- direct toxic effect
- metabolised to toxins => toxic effect
- activated by proteins/immune mechanisms => toxic effect
92
What are the risk factors of alcoholic liver disease cirrhosis
More than 6 beers every day for >10 years
Female
History of liver problems
93
What is the progression of alcoholic liver disease
Exposure => Steatosis => Continued exposure => Steatohepatitis/ Cirrhosis
Severe exposure => Steatohepatitis => cirrhosis
94
What are the characteristics of steatohepatitis
Mallory Denk bodies
Neutrophilic reaction
Pericellular fibrosis
Centrilobular steatosis
95
What is the pathophysiology of cirrhosis
Myofibroblast activation => bridging fibrosis => cirrhosis
Reversible if more degradation of collagen and elastin by metalloproteinases
96
What are the presentations of liver cirrhosis
Bruising
Melena
Testicular atrophy
Axillary hair loss
Itchy skin
97
What are the complications of cirrhosis
Degeneration
cell swelling => ischema, hypoxia => irreversible cell death => spotty necrosis => confluent necrosis
Regenerative parenchymal nodules
Increase resistance to sinusoid flow => increase Portal V pressure => Portosystemic shunting
98
List conditions caused by portal HTN
Ascites (increase peritoneal capillary P)
Hepatorenal syndrome (splanchnic vasodilation => decrease Bp and RAAS activation => renal vasoconstriction)
Portosystemic shunting
Congestive splenomegaly => anaemia, leukopenia, thrombocytopenia
99
What are the effects of portosystemic shunting
Paraumbilical V => ant. Abdm wall => Caput medusae
Sup. rectal V => Mid/Inf rectal V => anorectal varices
L gastric V => azygos system => oesophageal varices
100
What is non-alcoholic fatty liver disease a/w
Steatohepatitis w low alcohol consumption
Metabolic syndrome
101
What is metabolic syndrome
Insulin resistance
=> FFA liver influx =>. increase lipogenesis and fat accumulation => steatosis
Oxidative injury
=Oxidative stress => Reactive oxygen species => hepatocyte injury and necrosis => Kuffper cells release cytokines/chemokines => stellate cells increase collagen => fibrosis and mallory denk bodies
102
How does RHF affect the liver
Backpressure on systemic venous system => venous outflow obstruction => sinusoidal dilation and congestion => atrophy
Liver congestion => hypoperfusion => nutmeg liver
103
What are the acute events of pancreatitis
Acinar cell injury / Defective intracellular transport => proenzymes and lysosomal hydrolase release => enzyme activation and auto digestion
Duct obstruction
- Decrease blood flow and ischemia => interstitial oedema and proenzyme release
- Gallstones, ampulla obstruction, duct narrowing
104
What is the aetiology of pancreatitis
Acute = alcohol and biliary tract disease
Chronic = alcohol abuse
105
What are the presentations of pancreatitis
Acute = constant abdm pain, n/v, loss of appetite
Chronic = repeated/persistent abdm pain worsened by alcohol/overeating/drugs
106
What are the tests done for pancreatitis
Acute
- Increase amylase (24h), lipase (72h)
- Hypocalcemia (fat necrosis => Ca2+ ppt)
- Glycosuria
- Jaundice if gallstone
Chronic
CT scan => pancreatic calcification
107
What are the complications of pancreatitis
Acute = SIRS =>
- Organ failure
- ARDS
- DIVC
Chronic
- Chronic malabsorption (exocrine)
- DM (endocrine)
- Pancreatic pseudocysts
108
What are the presentations of cholelithiasis
RUQ/epigastric pain after fatty meal
109
What are the complications of cholelithiasis
GB = Cholecystitis, fistula, perforation, GB carcinoma
Cystic duct = Mirizzis syndrome
Bile duct = Cholendocolithiasis, Cholangitis
Hepatic duct = Intrahepatic stones
Pancreas = Pancreatitis
110
What are the different gall stones and their components
Yellow = Cholesterol
Brown = Cholesterol + Ca-bilirubin salts
Black = Ca-bilirubin salts
111
Which gallstones are radiolucent/opaque
Yellow and brown = radiolucent
Black = radiopaque
112
What are the risk factors of yellow gall stones
Fibrates
Fat
Female
Fertile
Middle aged
113
What is the pathophysiology of brown gall stones
Bile infections => hydrolysis of conj bilirubin, cholesterol and bile by microbes
114
What is the pathophysiology of black gall stones
a/w haemolytic anaemia
Increase bilirubin => hydrolysis
115
What are the types of cholecystitis
Calculous
- Stones => irritate mucosa, bile stasis & cause distension blocking blood supply
Acalculous
- Hypoperfusion => ischemia
- a/w sepsis, burns, trauma
116
What are the presentations of cholecystitis
Murphy's sign => inspiratory arrest upon deep palpation of RUQ w prior RUQ colicky pain
117
What is the pathogenesis of cholecystitis
Phospholipase => lethicins -> toxic products => disrupt mucus layer + inflammation => distension => compromise blood supply => possible infection
118
What are the gross features of chronic cholecystitis
Contracted, fibrotic wall and smooth mucosa
Porcelain GB = calcification
Rotikansy-Aschoff sinuses = small benign GB outpouchings
Hydrops = atrophic, obstructed, distended GB w clear secretions
119
What are the presentations of choledocholelithiasis
Jaundice and RUQ pain
120
What are the presentations of cholangitis
Charcot's triad
- Jaundice
- RUQ pain
- Fever
121
Which demographic is cholangitis common in
Primary biliary cholangitis = 50F
Primary sclerosis cholangitis = 30M
122
What are the different types of cholangitis a/w
Primary biliary cholangitis = Sjogren syndrome, Thyroid disease
Primary sclerosis cholangitis = IBD
123
Compare the pathologies of cholangitis
Primary biliary cholangitis = T-cells attack small intrahepatic bile ducts => jaundice
Primary sclerosis cholangitis = Progressive inflammation & fibrosis of intra/extrahepatic bile ducts => jaundice
124
Compare the histological features of cholangitis
Primary biliary cholangitis
- Florid duct lesions
- Loss of small/medium bile ducts
Primary sclerosis cholangitis
- Inflammatory destruction of extra/intrahepatic bile ducts
- Fibrotic obliberation of small/medium ducts
125
What are the serology and radiology findings of cholangitis
Serology
- PBC = AMA+, ANA+, ANCA+
- PSC = P-ANCA+
Radiology
- PSC = strictures and beading of large bile ducts, pruning of small bile ducts
126
What are predisposing factors of heptocellular carcinoma
B-catenin, p53 inactivation
Cirrhosis
HBV wo cirrhosis
127
What are the presentations of hepatocellular carcinoma
Asymptomatic until late stage
- Decrease liver function
- Abdominal mass
- Portal HTN bleed
- Hepatorenal syndrome
128
What are the complications of hepatocellular carcinoma
Weight loss
Variceal bleeding
Liver failure
Tumour rupture and bleed
129
What are the finding of hepatocellular carcinoma
Increase serum A-fetoprotein
130
What is the prognosis of hepatocellular carcinoma
Poor prognosis, death in 5 years due to bleeding/ cachexia
131
What is the gold standard for diagnosing heaptocellular carcinoma
Triphascic CT scan => cancer derives most blood supply from hepatic artery
132
What are the risk factors of cholangiocarcinoma
Chronic bile stasis eg NAFLD
HBV infection
133
What is the pathophysiology of cholangiocarcinoma
Risk factors => chronic inflammation => cholecystasis => sporadic mutations & gene alterations
134
Name a benign pancreatic cancer
Serous cystadenoma
135
What are some premalignant pancreatic cancer and their associated gene mutations
Mucinous cystic neoplasm (KRAS)
Intraductal papillary mucinous neoplasm (KRAS & GNAS)
136
What are some malignant pancreatic cancers
Pancreatic adenocarcinoma
Solid pseudo papillary neoplasm
Pancreatic neuroendocrine tumour
137
What are the risk factors of pancreatic adenocarcinoma
Chronic pancreatitis, DM, genetic, smoking, alcohol
138
What is pancreatic endocrine tumour a/w
MEN1
VHL syndrome
139
What are the presentations of head of pancreas tumours?
Bile duct compression
Jaundice
140
What are the causative organisms of food poisoning a/w raw meat
E coli
141
What are the causative organisms of food poisoning a/w fried rice
Bacillus cereus
142
What are the causative organisms of food poisoning a/w cream, mayo, custard
S. Aureus
143
What are the causative organisms of food poisoning a/w salad leaves
Listeria
144
What are the causative organisms of food poisoning a/w honey
Clostridium botulinum
145
What are the causative organisms of food poisoning a/w raw shellfish
Norovirus
Vibrio parahaemolyticus
