Alimentary Pathology Flashcards
What is the aetiology of Reflux Oesophagitis
- Frequent relaxations of the LOS
- Low LOS pressure
- Increased Abdominal Pressure (ie. during Pregnancy)
- Hiatus Hernia
What are the epithelial changes in Reflux Oesophagitis?
- Thickening of squamous epithelium
- Ulceration of oesophageal epithelium when severe reflux
What are the complications of Reflux Oesophagitis?
- Healing by Fibrosis– Stricture Formation– Impaired Oesophageal motility– Oesophageal Obstruction
- Barrett’s Oesophagus
What is Barrett’s Oesophagus?
- Type of metaplasia
- Response in some patients to Oesophageal reflux
- Pre-malignant condition
What type of metaplasia occurs in Barrett’s Oeseophagus?
Transformation from non-keratinised stratified squamous epithelium to simple columnar epithelium
(ie. looks like intestinal mucosa -> “intestinal metaplasia”)
What malignancy does Barrett’s Oesophagus cause?
Oesophageal Adenocarcinoma
What are the risk factors for Oesophageal Squamous cell carcinoma
- Smoking
- Alcohol
- Dietary Carcinogens
What are the risk factors for Oesophageal Adenocarcinoma
- Barrett’s Metaplasia
- Obesity (Hiatus Hernia -> effects on LOS)
What is the most common place for Oesophageal cancer metastasis?
Liver!
(Portal venous system!)
(need to assess Liver with CT scanning in pts with oesophageal cancer to assess for mets)
Does oesophageal cancer have a poor prognosis?
Yes!
<15% survival rate at 5 yrs
What are the 3 aetiological types of Gastritis?
(ABC!)
- Autoimmune (Type A)
- Bacterial (Type B)
- Chemical injury (Type C)
What is the pathophysiology of Type A (Autoimmune) Gastritis?
- Organ-specific autoimmune disease
- Autoantibodies to parietal cells -> causes loss of intrinsic factor and decreased gastric acid secretion
What is the commonest clinical presentation of patients with Type A (Autoimmune) Gastritis?
- Vitamin B12-deficiency (Pernicious anaemia)
due to damage to gastric parietal cells -> causes loss of intrinsic factor
What is the commonest type of Gastritis?
What is it caused by?
- Type B: Bacterial Gastritis
- H. Pylori
What are the most common causes of Type C (Chemical injury) Gastritis?
- Drugs: NSAIDs
(reduced gastric mucus production -> more harmful effects of gastric acid on gastric mucosa) - Alcohol
- Bile reflux
(from Duodenum into stomach -> due to problems with pyloric valve due to ie. surgery, or obstruction (DU, or scar tissue))
What is the usual cause of Peptic Ulceration?
Usually H. Pylori-related
increases gastric acid production
What are the complications of Peptic Ulceration?
- Bleeding
- Haemorrhage (= acute)
- Anaemia (= chronic)
- Perforation (peritonitis)
- Healing by Fibrosis (obstruction)
What is the most common cause of stomach cancer?
PREVIOUS H. Pylori infection
not current!
What is the most common type of stomach cancer?
Adenocarcinoma
Where does stomach cancer usually metastasise to
Liver
nb. portal venous system!
Does stomach cancer have a poor prognosis?
Yes!
<20% survival rate at 5 yrs
What are the main causes of Acute Liver Injury?
- Hepatitis
- Bile duct obstruction
What are the 3 main causes of Hepatitis?
- Viruses
- Alcohol
- Drugs (prescribed + recreational)
What are the 4 most common viruses causing viral hepatitis?
Hepatitis…
- A
- B
- C
- E
What type/s of viral hepatitis most commonly progress to chronic hepatitis and cirrhosis?
- Hepatitis B (most common)
- Hepatitis C
Which is the No. 1 cause of Chronic Liver disease (+ Cirrhosis) globally?
Chronic alcohol consumption
Which is the No. 1 cause of acute Hepatitis globally?
Hepatitis B
What causes Jaundice?
- Increased circulating Bilirubin
- Caused by altered metabolism of Bilirubin
What is the most common cause of Pre-Hepatic Jaundice?
- caused by excessive Hb breakdown in Spleen due to excessive RBC breakdown (haemolysis) -> causes excessive bilirubin conversion from haem *
- Haemolytic anaemia
What are the most common causes of Intra-hepatic Jaundice?
- damage to the liver -> cholestasis, intrahepatic bile duct obstruction *
- Alcoholic Liver disease
- Viral Hepatitis
- Iatrogenic, e.g. medication
- Hereditary Haemochromatosis
- Autoimmune Hepatitis
- Primary Biliary Cirrhosis or Primary Sclerosing Cholangitis
- Hepatocellular Carcinoma
What are the most common causes of Post-Hepatic Jaundice?
- Intra-luminal causes: ie. gallstones
- Mural causes: ie. cholangiocarcinoma, strictures (ie. PSC (NOT PBC)), or drug-induced cholestasis
- Extra-mural causes: ie. pancreatic cancer, abdominal masses (e.g. lymphomas)
How is PBC diagnosed?
- A persistent elevation of serum alkaline phosphatase (ALP)
- The presence of Anti-Mitochondrial auto-Antibodies (AMA)
- (mainly females)
What condition is PSC associated with?
- IBD
80% of PSC pts have IBD
How is PSC diagnosed?
- MRI of bile ducts
What are the main causes of Hepatic Cirrhosis?
- Alcohol
- Hepatitis B, C
- Immune-mediated Liver Disease: auto-immune hepatitis, PBC
- Metabolic Disorders: primary haemachromatosis, Wilson’s disease
- Obesity: DM
What types of Viral Hepatitis cause Hepatic Cirrhosis?
- Hepatitis B + C
What types of Viral Hepatitis have a vaccine?
- Hepatitis A + B
What is the most common type of Liver cancer?
- Metastatic tumour -> common site of metastasis! (esp. from GIT tumours)
(secondary liver cancer is more common than primary liver cancer!!)
What are the effects of CBD obstruction?
- Jaundice
- No bile excreted into Duodenum
- Ascending Cholangitis -> due to infection of bile proximal to the obstruction
- Secondary Biliary Cirrhosis (if obstruction is prolonged)
Where is Meissner’s Plexus?
Submucosa
Where is Auerbach’s (Myenteric) Plexus?
Muscularis Externa: between the inner circular and outer longitudinal layer
What are the common causes of Common Bile duct Obstruction?
- Gallstones
- Bile duct Tumours (ie. Cholangiocarcinoma)
- Benign Stricture (PSC, not PBC bc extra-hepatic!)
- External compression ie. Tumours (nb. head of the pancreas tumours!)
What parts of the Small Intestine are retroperitoneal?
- Most of the Duodenum !!
except from the Duodenal Cap! (Proximal D1)
Which parts of the Colon are intraperitoneal?
- Caecum
- Transverse Colon
- Sigmoid Colon
What are the different types of Inflammatory Bowel Diseases?
- UC
- Crohn’s
- Ischaemic Colitis
- Radiation Colitis
- Appendicitis
Which auto-antibody is positive in the majority (75%) of UC?
p- ANCA
Which gene mutation is associated with Crohn’s?
NOD2
What causes IBD?
Exaggerated immune response against normal flora with defects in the epithelial barrier function in genetically susceptible individuals
What is the typical age of diagnosis of UC and Crohn’s?
20-40yrs
Pathology of UC?
- Large bowel only
- Continuous pattern of inflammation
- Rectum to proximal
- Pseudopolyps
- Ulceration
- Limited to the Mucosa + Submucosa (not Transmural)
Pathology of Crohn’s?
- Affects any level of GIT from mouth to anus
- “Skip lesions” -> sharp demarcations of disease segments from adjacent normal tissue
- “Cobblestone” ulceration
Histology of UC?
- Inflammation limited to Mucosa + Submucosa
- Architectural disarray of Crypts
- Mucosal Atrophy
- Pseudopolyps - (ulceration into submucosa)
- NO GRANULOMAS
Histology of Crohn’s?
- Crypt abscesses (!!!)
- Deep ulceration
- Transmural inflammation (!!!) -> “chain of pearls”
- NON-CASEATING GRANULOMAS (!!!)
Complications of UC?
Acute:
- Haemorrhage
- Toxic dilatation
- Perforation
- Venous Thromboembolism
Chronic:
- Colon cancer -> risk if Pancolitis >10 yrs
Complications of Crohn’s?
- Malnutrition
- Strictures
- Fistulae
- Abscesses
- Colon cancer (5x inc. risk)
What part of the GIT is most susceptible to Ischaemic Enteritis?
Splenic Flexure (LUQ)
-> “Watershed” area
Where does Radiation Colitis typically occur?
- Usually Rectum
post-pelvic RT
Clinical Features of Radiation Colitis
- Anorexia
- Abdominal cramps
- Diarrhoea
- Malabsorption
- Chronic -> mimics IBD
What are the main causes of Appendicitis?
- Obstruction
ie. Faecolith or RTI causing LN enlargement
What is the most common type of CRC?
Adenocarcinoma (98%)
What are the main risk factors for development of Colorectal Adenocarcinoma?
• Lifestyle - diet, alcohol intake, insufficient fruit and veg
• FH
- genetics + lifestyle
• IBD
- UC & Crohn’s Disease
• Genetics:
- FAP
- HNPCC
- Peutz-Jeghers
Which inherited syndromes most commonly cause CRC?
o FAP → (defect in APC gene → tumour suppressor)
o HNPCC → (defect in MSH2 → mis-match repair (MMR) protein)
o Peutz-Jeghers → (defect in STK11/LKB1 → tumour suppressor)
