GI Flashcards
What causes GORD?
red. lower oesophageal sphincter tone
hiatus hernia
delayed gastric emptying
Complications of GORD?
bleeding
ulceration
stricturing
Barrett’s oesophagus
What is the single most important risk factor for oesophageal adenocarcinoma?
Barrett’s oesophagus
What is Barrett’s oesophagus?
replacement of distal oesophageal squamous epithelium with glandular epithelium in response to chronic injury
Metaplasia
How is Barrett’s oesophagus diagnosed?
Endoscopy Biopsy (histological features)
What causes oesophageal varices?
Portal hypertension, usually due to liver cirrhosis
Causes of oesophageal haemorrhage?
Reflux oesophagitis Varices Cancer Mallory-Weiss tears Foreign body injury Boerhaave Syndrome
What is Boerhaave syndrome?
spontaneous perforation of the oesophagus that results from sudden increase in intraoesophageal pressure combined with negative intrathoracic pressure
e.g., severe straining or vomiting
Most common oesophageal carcinoma worldwide?
SCC (>90%)
Most common oesophageal carcinoma in developed countries?
Adenocarcinoma (50%)
Clinical features of oesophageal carcinoma?
Dysphagia, Odynophagia, Weight loss, Vomiting
Generally presents late
Prognosis of oesophageal carcinoma?
Poor- 5yr survival rate 20%
Oesophageal SCC risk factors?
Smoking and Alcohol!!!!!!
Characteristics of SCC?
Production of keratin
Destruction of intracellular bridges
Risk factors for Oesophageal Adenocarcinoma?
Barrett’s Oesophagus
Smoking
Obesity
*****NOT alcohol
What is pyloric stenosis?
congenital hypertrophy of gastric pylorus
When and how does pyloric stenosis present?
3-6 weeks old
projectile vomiting, palpable lump in RUQ, always hungry and malnourished
Treatment of pyloric stenosis?
Ramstedt pyloromyotomy
Causes of acute gastritis?
NSAIDs Alcohol Smoking Chemo Uraemia Inc. ICP Severe burns
Chronic Gastritis Definition?
chronic mucosal inflammatory changes, leading to mucosal atrophy and intestinal metaplasia
Chronic Gastritis Causes?
Helicobacter Pylori Autoimmune Gastritis Toxicity (alcohol, smoking) Post-surgical Obstruction Radiation Granulomatous Diseases
H. pylori diagnosis?
Urea Breath test
Gastric biopsy
H. pylori consequences?
peptic ulcers
gastric adenocarcinoma
gastric lymphoma (MALT)
What percentage of gastritis is caused by autoimmune gastritis?
Less than 10%
Complications of autoimmune gastritis?
Pernicious anaemia
Gastric Adenocarcinoma
Gastric neuroendocrine tumours
Causes of peptic ulcers?
H. pylori Stress Smoking Zollinger-Ellison syndrome Hypercalcaemia
What is Zollinger-Ellison syndrome?
gastrin secreting tumour of pancreas- too much acid is secreted
Peptic Ulcer Complications?
Bleeding, perforation, obstruction Malignant transformation (not in duodenal ulcers, rarely in gastric ulcers)
Gastric carcinoma associations?
H. pylori Autoimmune Gastritis Diet (salty, cured foods) Gastric Adenoma **********NOT smoking or alcohol
Spread of Gastric Carcinoma?
Direct- through stomach wall
Transcoloemic
Lymphatic- left supraclavicular node
Blood- brain, bone, lung, liver
What triggers malabsorption in Coeliac disease?
alpha-gliadin component of gluten
Genetic associations of coeliac disease?
HLA-B8, DR3, Dqw2
Symptoms of coeliac disease?
asymptomatic
anaemia, weight loss, failure to thrive
steatorrhea
osteomalacia in older ages (Vit D malabsorption)
Histology of Coeliac Disease?
Decreased villous height/ flat atrophic mucosa
Serology of Coeliac Disease?
Anti-tTG
Anti-gliadin antibodies (non-specific)
Anti-endomysial antibodies
Complications of coeliac disease?
Refractory coeliac disease Anaemia Osteomalacia GI malignancy (T cell lymphoma) Dermatitis Hepetiformis
Types of gallstones?
Pigment (5-10%)
Cholesterol (10%)
Mixed (75-90%)
Gallstones Consequences?
80% asymptomatic
Biliary colic (pain in RUQ)
Calculous cholecystitis
Pancreatitis
Acute Cholecystitis Presentation?
unwell
RUQ pain, radiating to tip of right shoulder
nausea and vomiting
pyrexia
tenderness and guarding in right hypochondrium
Murphy’s sign
What is Murphy’s sign?
palpate right hypochondrium
get patient to take deep breath in
on inspiration, examiner’s hand comes into contact with inflamed gallbladder
intense pain
Chronic Cholecystitis symptoms and signs?
irregular attacks of RUQ pain, worse after eating fatty meals
tenderness in RUQ
What percentage of chronic cholecystitis is associated with cholelithiasis?
90%
What causes ‘strawberry gallbladder’?
Cholesterolosis
What is cholangitis?
inflammation of the bile ducts
What is Charcot’s triad?
fever + pain + jaundice
What is primary sclerosing cholangitis associated with?
destruction of extrahepatic biliary tree
What disease is associated with PSC?
IBD, especially ulcerative colitis
What is primary biliary cirrhosis associated with?
destruction of small intrahepatic bile ducts
What are raised in PBC?
anti-mitochondrial antibodies (95%)
What are raised anti-mitochondrial antibodies most associated with?
Primary Biliary Cirrhosis
What genders suffer more commonly from PSC and PBC?
PSC- M:F = 2:1
PBC- primarily women
What is the prognosis for carcinoma of the gallbladder?
dismal - 1% 5 yr survival rate
most have mets at diagnosis
Risk factors for carcinoma of the gallbladder?
gallstones
PSC (ulcerative colitis)
liver fluke
Main causes of pancreatitis?
alcohol, gallstones
Presentation of acute pancreatitis?
severe epigastric pain, radiating to back
tenderness and guarding in upper abdomen
Cullens and Grey Turners sign
raised serum amylase
What is Cullens sign?
discoloration around the umbilicus
What is Grey Turners sign?
bruising of the flank region
Presentation of carcinoma of the pancreas?
weight loss, jaundice
+/- epigastric pain
Sites of pancreatic Ca?
Head- 60%
Body- 15-20%
Tail- 5%
Diffuse- 20%
What is Whipple’s operation?
removes head of pancreas, duodenum, gallbladder and bile duct
Prognosis of Pancreatic Ca?
dismal
5yr survival rate <5%
What are 2 tumours of the pancreatic Islet cells?
Insulinoma (Beta Cells, 5% malignant)
Gastrinoma (Gastrin G-Cells, 60% malignant, Zollinger-Ellison syndrome)
What is Meckel’s diverticulum?
incomplete obliteration of the vitelline duct leading to the formation of a ‘true diverticulum’
most common congenital abnormality of the GI tract
What is Hirschsprung disease?
congenital aganglionic megacolon
leads to functional obstruction and dilatation of affected area
Differential diagnosis for Hirschsprung disease?
Acquired forms of megacolon (Chagas’s disease, toxic megacolon)
What genetic mutation is Hirschsprung disease associated with?
Trisomy 21
What micro-organisms cause dysentery?
Shigella, Salmonella, Entamoeba histolytica
What does C. Difficile cause?
Pseudomembranous Colitis
What causes pseudomembranous colitis?
Clostridium Difficile
Who does necrotising enterocolitis affect?
Premature babies after oral feeding is initiated
Aetiology of IBD?
Genetic susceptibility, role of intestinal flora, abnormal T-cell response
Which IBD skips lesions?
Crohn’s Disease
Which IBD has continuous involvement?
Ulcerative Colitis
What is the relationship between ulcerative colitis and smoking?
Ex-smokers > Never smokers > smokers
Smoking protects against UC
Microscopic Crohn’s Disease?
Non-caseating granulomas (50%)
Transmural inflammation
Crypt abscesses and distortion
Microscopic Ulcerative Colitis?
No granulomas
Diffuse, superficial inflammation (limited to mucosa)
Crypt abscesses and distortion
Extra-intestinal manifestations of IBD?
migratory polyarthritis sacroiliitis ankylosing spondylitis erythema nodosum clubbing uveitis pyoderma gangrenosum PSC (ulcerative colitis)
Examples of intestinal obstructions?
Hernia, Volvulus, Intussusception, Adhesions
What is diverticular disease?
acquired outpouching of the mucosa, typically in the sigmoid colon
Complications of diverticular disease?
Haemorrhage, inflammation (diverticulitis), Abscesses
Causes of intestinal ischaemia?
arterial thrombosis, arterial embolism, venous thrombosis, nonocclusive ischaemia
Where are hyperplastic polyps found?
Rectum (50%)- most common, serrated appearance, no dysplasia
Right-sided- less common, larger, KRAS mutation, may evolve to Ca
Who are juvenile polyps most common in?
Children aged between 2 and 10 but can occur at any age
What percentage of people over 40 have colorectal adenomas?
30%
What percentage of colorectal adenomas progress to malignancy?
5%
Risk factors for adenomas to progress to carcinoma?
Villous architecture
Size > 4cm
High grade dysplasia
Types of colorectal carcinomas?
Adenocarcinomas vast majority
Neuroendocrine tumours
Risk factors for colorectal carcinomas?
Diet- excess food, low fibre
Obesity
Physical inactivity
Aspirin may be protective
Clinical features of colorectal carcinoma?
asymptomatic for many years
right-sided- iron deficiency anaemia, fatigue, malaise
left-sided- PR bleeding, abdo pain, changes in bowel habits
Two most common molecular pathways for colorectal carcinomas?
Chromosomal Instability (CIN)- FAP Microsatellite Instability (MSI)- HNPCC- Lynch
What genes are involved in the Chromosomal Instability Pathway?
APC, KRAS, DCC, p53
What condition does mutation in the APC gene cause?
Familial Adenomatous Polyposis (FAP)
What gene is mutated in Familial Adenomatous Polyposis?
APC Gene
What causes HNPCC (Lynch Syndrome)?
mutations results in microsatellite instability, leading to rapid progression from adenomas to carcinomas
Distinct pathological features of HNPCC (Lynch syndrome)?
right-sided, poorly differentiated, mucinous, lymphocytic host response
Symptoms of acute appendicitis?
Pain- umbilicus -> right iliac fossa nausea and vomiting abdominal tenderness mild fever elevated WCC
Causative organisms of GI infections?
Viruses, Bacteria, Parasites (protozoa), Fungi (immunocompromised)
What does Helicobacter pylori very actively produce and what does this do?
Produces urease
Splits urea
What diseases are associated with H pylori?
Duodenal ulcer, gastric ulcer, gastritis, gastric lymphoma, gastric carcinoma, non-ulcer dyspepsia
Diagnosis of H pylori?
Urea Breath test
Serology IgG
Endoscopy with biopsy
Faecal antigen testing
Eradication of H pylori?
7 days of:
PPI
Antibiotics (Amoxicillin + Clarithromycin/Metronidazole)
Causes of diarrhoea in Ireland?
Rotavirus, Norovirus
Campylobacter, C Diff, E Coli, Salmonella, Shigella
Cryptosporidia, Giardia lamblia
Most common bacterial cause of diarrhoea in Ireland?
Campylobacter
What is ‘rice-water stool’ associated with?
Cholera
What is the source of Campylobacter?
Animals (poultry, cattle)
Which infection is associated with recent antibiotic use?
Clostridium Difficile
Spectrum of what C Diff can cause?
Diarrhoea
Pseudomembranous Colitis
Toxic megacolon
Diagnosis of C Diff?
molecular methods (most sensitive)
Toxins A + B in stool
stool culture
endoscopy and biopsy (with care)
C Diff treatment?
Stop antibiotics if possible
Oral metronidazole or vancomycin
Fidaxomicin (reduce recurrence)
Control measures for E Coli O157?
no pink hamburgers keep fresh and cooked meats separate pasteurize milk hand hygiene at petting zoos drinking water treatment
Severe consequence of E Coli O157 infection?
Haemolytic uremic syndrome
Where is shigellosis endemic?
Tropics
Subtropics
What is the name of the human-adapted salmonella?
Salmonella enterica (not carried by animals) Typhoid
Viral gastroenteritis can be severe in?
Elderly and children
What does salmonella enterica cause?
Typhoid (enteric fever)
What does shigella cause?
Dysentery
What bacteria causes food poisoning following cooked meat being stored warm?
Clostridium Perfringens
Diarrhoea- resolves 24-48hrs
What bacteria causes food poisoning following eating re-heated rice?
Bacillus cereus
Rapid-acting- vomiting
Slower-acting- diarrhoea
When does staph aureus cause food poisoning?
Usually introduced during preparation
Lesions on hands NB
What parasites cause GI infections?
Entamoeba histolytica- dysentery, not acquired in Ireland
Giardia lamblia- causes malabsorption
Cryptosporidium
How common is Traveller’s Diarrhoea?
Very common
20-50% of travellers to developing country
Most common cause of traveller’s diarrhoea?
E Coli serotype
local population immune
What part of the colon is most affected in ischaemic colitis?
Splenic flexure
