git patho (incomplete, summarised version) Flashcards
what are GIT polyps?
fleshy protuberant growth on epithelial surface
what are the 2 growth patterns of git polyps?
pedunculated, sessile (no stalk)
removal of polyps reduces the likelihood of them developing into…
colon cancer
prognosis for gastric carcinoma depends on…
depth of invasion and extent of nodal and distant metastasis
3 macroscopic (gross) growth patterns of gastric carcinoma evident in both early and advanced stages are:
- exophytic
- flat or depressed (linitis plastica in advanced stages)
- excavated
appearance of a bleeding/chronic peptic ulcer
- flat ulcer edge, level with remaining stomach
- straight vertical edges
- haemorrhagic or flat and clean base
(smth like being hole punched by a hole puncher)
3 gross growth patterns of adenomas are:
- tubular adenoma
- tubulovillous adenoma
- villous adenoma
What are possible causes of upper GIT bleeding? (3 oesophagus, 2 stomach, 2 duodenum and 1 universal!!)
Oesophagitis
Oesophageal varices
Mallory-weiss tear
Gastric erosions
Gastric ulcers
Erosive duodenitis
Duodenal ulcer
Neoplasm
Name 2 kinds of polyps that can form in the stomach:
- Fundic gland polyps
- Hyperplastic polyps
What are the gross appearances of peptic ulcers?
- Round to oval, sharply demarcated, punch-out defect
- Musocal margin may overhang the base slightly
- Variable depth
- Base is smooth and clean
- Scarring and puckering of wall
What are the microscopic appearances of peptic ulcers?
- Surface zone of fibrinopurulent exudate
- Acidophilic layer of necrotic tissue
- Zone of granulation tissue
- Zone of dense scar tissue
- Interruption of muscularis propria
- Proximation of muscularis propria and mucosae
- Endarteritis obliterans
Complication of diverticular diseases?
- Acute inflammation (diverticulitis)
- Pericolic abscesses
- Pericolic fibrosis and adhesions
- Fistulas
- Strictures (can cause obstruction)
- Free perforation into peritoneal cavity - Erosion of blood vessels
- Rectal bleeding
- Anemia
These are rarely malignant.
Generally doesn’t cause diarrhoea
Normal investigations of diarrhoea are:
- Usual stool cultures
- Salmonella
- Campylobacter
- Shigella (requires antibiotics)
- Vibrio (requires antibiotics) - Viral pathogen testing
- Rotavirus antigen detection
- Norovirus PCR
Ischaemic bowel disease is a disease of the…
small intestine where the arterial supply (celiac, superior and inferior mesenteric arteries) are impaired
effects of ischaemic bowel disease
- diarrhoea
- abdominal pain
- bloody diarrhoea (mucosal necrosis»_space; sloughing off and haemorrhage into the lumen)
- less peristalsis (necrosis of muscle)
- peritonitis (transmural necrosis»_space; perforation)
- bacteraemia
Complications of intestinal obstruction
Obstruction of:
1. arterial -> ischaemia
2. venous -> congestion
3. lymphatic -> edema
4. intestinal lumen -> functional
Effects of luminal obstruction:
Vomiting
Distension
Constipation
Pain
Bacterial proliferation
Microscopic appearance of colon adenocarcinoma
- Well/Moderate (90%)/Poorly differentiated degree of tubule formation
- Prominent desmoplastic response
- Abundant intraluminal eosinophilic necrotic debris
- Extracellular mucin pools seen in mucinous subtype of carcinoma
Microscopic appearance of colon adenocarcinoma
- Well/Moderate (90%)/Poorly differentiated degree of tubule formation
- Prominent desmoplastic response
- Abundant intraluminal eosinophilic necrotic debris
- Extracellular mucin pools seen in mucinous subtype of carcinoma
How do people test for linitis plastica?
Pump air into the stomach, inelastic stomachs would denote “leatherbottle appearance”
Adenoma-carcinoma genetic change sequences:
- loss of APC
- DNA hypomethylation
- KRAS activation
- loss of p53
- loss of 18q
- PRL3 amplification
Differences between peptic ulcer and gastric cancer?
Peptic ulcer:
- round to oval, sharply demarcated, punch-out defect
- flat ulcer edge, level with remaining stomach
- haemorrhagic, flat and clean base
- variable depth
- vertical straight edges
- mucosal margin overhang the base slightly
- scarring and puckering of wall
Gastric cancer:
- irregular borders
- not oval, irregular shape
- no punch out defect
- not well demarcated
Site of stomach cancer
Pylorus and antrum > Cardia > Lesser curve > Greater curve
What is the first sign of stomach cancer?
Virchow’s node
TNM grading for stomach is…
T: depth of invasion
N: number of nodes involved
M: presence of metastasis
stomach cancer can seed into the ______, metastasis into _______
peritoneum; lung and liver
Contrast between tumours in the proximal colon vs distal colon.
tumours in the proximal colon:
- polypoid, exophytic tumour
- obstruction is uncommon
tumours in the distal colon:
- annular, encircling lesion
- napkin ring constriction
What symptom is common in both tumours in proximal and distal colons and should rouse one’s suspicion of cancer?
Unexplained anemia
In which part of the colon can tumours easily cause obstruction and pencil-thin stools?
Recto Sigmoid Junction
Carcinoid tumours are ______ and originate from _______
They resemble ______ but might ________.
Carcinoid tumours are slow-growing neuroendocrine tumour and originate from the cells of neuroendocrine system
They resemble low grade cancers but might infrequently spread to other parts of the body.
Hamartomatous polyps are found occurring in what syndromes?
Peutz-Jegher Syndrome or Juvenile Polyposis Syndrome
Clinical presentation of hamartomatous polyps involve increased _______ around lips, genitalia, buccal mucosa feet and hands
pigmentation
Chance of hamartomatous polyp developing into malignancy?
very low
Diagnosis of the Peutz-Jegher Syndrome is normally at age ____ and when there’s _____.
9; intussusception
Diagnosis of the Peutz-Jegher Syndrome is normally at age ____ and when there’s _____.
9; intussusception
Gastrointestinal stromal tumours (GIST)
It involves the mutation of _____ and is diagnosed by ______ markers.
It involves the mutation of KIT/PDGFRA and is diagnosed by CD117 markers.
Most common cancer of the GIT
colon adenocarcinoma
How does colon adenocarcinoma begin?
- cells of colon crypts
- through wall of colon
- into other organs, lymphatics
Prognosis of colon adenocarcinoma
good for early detection, better than gastric cancer
Treatment of colon adenocarcinoma
Prophylactic total colonostemy
What are the 10 clinical presentations of colorectal cancer?
AAAABFWWOE
Abdominal pain
Altered bowel habits
Anaemia
Asymptomatic
Bleeding PR
Fistulation
Weakness
Weight loss
Obstruction
Extra (mets, organ failure, thrombosis)
Stomach hyperplastic polyps (not neoplastic) are often preceeded by
chronic erosive gastritis
Do we do lab investigations for most patients with acute diarrhoea?
Diarrhoea stool samples should be sent to laboratory if…
No;
Diarrhoea stool samples should be sent to laboratory if:
- diarrhoea persists > 3 days
- bloody diarrhoea
- immunocompromised patients
What are the common pathogens responsible for GI infections in longterm care facilities?
Clostridium difficile
Norovirus
What are the common pathogens responsible for GI infections in immunocompromised patients?
CMV colitis
Parasites (cryptosporidia, microsporidia, isospora, cyclospora)
What is the principle modality of liver imaging?
ultrasound
For saggital viewing what’s the preferred modality?
CT scan
What are the benefits of using MRI?
- no radiation
- small changes can be seen
- better soft tissue visualisation
How do we do imaging for colorectal cancer?
Barium enema (100-200cc of barium into colon)
What lesions are we looking for in colorectal cancer imaging?
Apple core lesions
What are the preferred imaging modalities for the upper GIT?
Barium swallow or Gastrografin swallow
then CT
What is oral contrast media? Normally which metal is used unless there’s a leak and what should be used instead?
We follow the bolus of barium using ___.
dense, radio-opaque liquid ingested by patients
barium, if there’s a leak use gastrografin since its water-soluble
We follow the bolus of barium using real-time x-rays.
5 Imaging modalities used for GIT imaging:
- Plain x-rays
- Ultrasound
- Oral contrast examinations
- CT
- MRI
Acute appendicitis presents with ______.
When you do imaging you look for ______.
What modality do we use for children?
What modality do we use for adults?
Normal appendix calibre is __mm.
Acute appendicitis presents with acute abdominal pain.
When you do imaging you look for McBurnley’s point.
What modality do we use for children? US
What modality do we use for adults?
CT
Normal appendix calibre is 6mm.
Imaging techniques for hepatobiliary system:
Plain X-ray abdomen (X-ray)
Ultrasound (US)
Computed Tomography (CT)
Magnetic Resonance Imaging (MRI)
Angiography
ERCP
PTC
MRCP
What is the preferred imaging modality for the small intestine?
Barium follow through or Gastrografin follow through
then CT
