GI Pathology Flashcards
What is the pathogenesis of Diverticular Disease? (protrusions of mucosa/ submucosa through bowel wall, commonly sigmoid colon)
- Increased intra-luminal pressure
- Irregular, uncoordinated peristalsis
- Points of relative weakness in bowel wall
- Age related changed in connective tissue
Colorectal Polyps…
a) features
b) cause
a) -‘mucosal protrusion’, pedunculated, sessile or ‘flat’
- Solitary or multiple (polyposis)
- neoplastic, hamartomatous, inflammatory or reactive
b) Due to mucosal/ submucosal pathology or a lesion deeper in bowel wall
What are 6 types of non-neoplastic polyps in the colo-rectum?
- Hyperplastic polyps
- Hamartomatous polyps (juvenile polyps)
- Polyps related to mucosal prolapse
- Post-inflammatory polyps (‘pseudopolyps’)
- Inflammatory fibroid polyps
- Benign lymphoid polyps
What are hyperplastic polyps?
Common, 1-5mm, located in rectum & sigmoid colon.
Small, distal HPs have no malignant potential
Some large right sided HPs may give rise to microsatellite unstable carcinoma
What are harmatomatous polyps?
(Juvenile polyps- commonest type in children) Spherical and pedunculated, 10-30mm, usually in distal colon & rectum.
No malignant potential but associated with increased risk of colorectal & gastric cancer.
What are adenomas and what relevance do they have to the colon?
Adenomas are benign epithelial tumours
Precursor of colorectal cancer (at least 80%)
Histological grade= high vs low grade dysplasia.
What are some risk factors for colorectal cancer?
Diet Obesity/ alcohol HRT & oral contraceptives Schistosomiasis UC & Crohn's
2 types of inheritance of colorectal cancer?
-FAP (familial adenomatous polyps) <1%
Autosomal dominant, due to a mutation in the APC tumour suppressor gene
-Lynch Syndrome 1-2%
Direct invasion of adjacent tissue, lymphatic & haematogenous metastasis
What is A-D of Duke’s Staging of Colorectal cancer?
Stage A: adenocarcinoma confined to bowel wall, no lymph node metastasis
Stage B: invading bowel wall, no lymph node metastasis
Stage C: adenocarcinoma with regional lymph node metastasis
Stage D: distant metastasis present
What is Angular Cheilitis caused by?
Excessive moisture & maceration from saliva, and secondary infection with C albicans or S aureus
What is Hairy Leucoplakia?
Seen in HIV patients, caused by Epstein Barr Virus
Well-demarcated white plaques visible on lateral aspects of the tongue.
What are some periodontal infections? (plaque between the gingival margin)
- Gingivitis (presents with red swollen bleeding gums)
- Periodontitis (progression of gingivitis & inflammation with loss of supportive connective tissues)
- Periodontal abscess
What is Vincent’s angina, or trench mouth?
Acute necrotising ulcerative gingivitis (superficial greyish pseudomembranes. Requires antibiotics)
What is a Peritonsillar abscess (quinsy)?
Unilateral swellings of the tonsil
Caused by Streprococcus pyogenes
Painful swallowing, unilateral deviation of uvula towards the unaffected side.
What is Ludwig’s angina?
Bilateral infection of the submandibular space.
An aggressive, rapidly spreading cellulitis with potential for airway obstruction.
What does Carotid Sheath involvement mean?
The carotid sheath abuts all three layers of the deep cervical fascia. It is a dreaded complication becuase of potential for carotid artery erosion & supportive jugular thrombophlebitis.
What are the 2 clinical manifestations of Thrush (oral & oesophageal candidiasis)?
1) The pseudomembranous form (most common, white plaques on buccal mucosa, palate, tongue)
2) The atrophic form (denture stomatitis) (more common in older adults, erythema without plaques.
What is mucositis? And what induces it?
Inflammation of the mucosa linking of the GI tract.
Chemotherapy induced
Increased risk of bacteraemia, principally viridans streptococci.
What is Boerhaave syndrome?
Oesophageal rupture.- spontaneous perforation of the oesophagus that results from a sudden increase in intraesophageal pressure combined with negative intrathoracic pressure.
Results in contamination of the mediastinal cavity with gastric contents
What is H. Pylori Infection, how is it diagnosed and what treats it?
Bacterial urease hydrolyses gastric urea to form ammomia that helps neutralise gastric acid- enabling organism to penetrate the gastric mucus layer.
Diagnosis: Urease breath test, faecal antigen test
Treatment: Triple antibiotic therapy plus PPI (for 7-14 days)
What is Charcot’s triad and what is it associated with?
Fever, abdominal pain & jaundice
Associated with Cholangitis
Whipple’s Disease… agent? 4 cardinal manifestations?
Agent= Tropheryma whepplei
Multi-systemic process characterised by joint symptoms, chronic diarrhoea, malabsorption and weight loss. (mainly affects white european males)
Should be considered in patients with the 4 cardinal manifestations: arthralgias, diarrhea, abdo pain and weight loss
What does Entamoeba histolytica cause?
Amebic liver abscesses
the parasite exists in 2 forms: a cyst stage (infective form) and a throphozoite stage (causes invasive disease
What bacteraemia is usually associated with colonic malignancy?
Streptococcus bovis (nor renamed S. gallolyticus). Also associated with endocarditis.
What is the pathology of Gastroenteritis?
Preformed toxins eg)Staphylococcal toxin
Toxins eg) Shiga toxin
What are the 2 types of Hiatus Hernia?
1- Sliding Hiatus Hernia = reflux symptoms
2- Para-oesophageal Hernia = strangulation (part of stomach above diaphragm)
What is Barrett’s oesophagus and what causes it?
A premalignant condition with increased risk of developing adenocarcinoma
Cause: longstanding gastro-oesophageal reflux
Macroscopy: Proximal extension of the squamo-columnar junction
Histology: Squamous mucosa replaced by columnar mucosa»_space; ‘glandular metaplasia’
What are the 2 main types of oesophageal carcinoma?
1) Adenocarcinoma (mainly lower oesophagus, higher incidence rate among men & Caucasians.
2) Squamous Cell Carcinoma (Middle & lower 1/3 oesophagus, preceded by squamous dysplasia. Risk factors include tobacco, alcohol, nutrition, HPV, male.
How do you stage oesophageal cancer?
Use TNM system (with pT = depth of invasion of primary tumour) (N= regional lymph nodes) (M= distant metastasis)
What is acute gastritis usually due to?
Usually due to chemical injury (Drugs eg. NSAIDS, Alcohol, H Pylori)
Generally heal quickly
What is chronic gastritis usually due to?
Autoimmune --> anti-parietal & anti-intrinsic factor antibodies. Bacterial infection (H pylori) Increased risk of gastric cancer and MALT lymphoma
What is H pylori?
Gram negative spiral bacterium.
Damaged the epithelium leading to chronic inflammation of the mucosa.
Results in glandular atrophy, replacement fibrosis and intestinal metaplasia
What are the main causes of peptic ulceration?
Hyperacidity H pylori infection Duedeno-gastric reflux Drugs (NSAIDs) Smoking
What are the features of acute gastric ulceration?
Full-thickness coagulative necrosis of mucosa.
Covered with ulcer slough (necrotic debris + fibrin + neutrophils)
Granulation tissue at ulcer floor
What are the features of chronic gastric ulceration?
Clear-cut edges overhanging the base
Extensive granulation & scar tissue on ulcer floor
Scarring through entire gastric wall with breaching of the muscularis propria?
Causes of gastric carcinoma?
Diet H Pylori infection (carcinoma of body/antrum) Bile reflux Hypochlorhydria ~1% hereditary
What is the pathogenesis behind coeliac disease?
Reaction to gliadin (alcohol soluble component of gluten) induces IL15 secretion by epithelium
Histology of Coeliac disease?
Villous atrophy
Crypt elongation
Increased IELs
Increased lamina propria inflammation
