Alimentary disease Flashcards
Economics: summarise the financial burden of gastrointestinal disease Signs and symptoms: recall and explain common signs and symptoms of gastrointestinal and liver diseases Abdominal pain: list the important features describing abdominal pain, compare presentations of abdominal pain with common pathologies and explain the diagnostic approach Obesity: explain the aetiology, complications, and clinical management of obesity Jaundice: recall the features and aetiology of jaundice (pre-hepatic,
What are the three most common cancers of the GI tract?
Oesophageal, colonic (aka colorectal cancer – they ARE THE SAME) and pancreatic.
***For each cell type occurring in the GI tract, what are the names of the cancer?
This is actually really important.
Adenocarcinomas are most common.
What is another word for difficulty swallowing?
Dysphagia.
What is the anatomy of the oesophagus and therefore, what types of cancers occur along it?
Squamous epithelium found mainly at upper parts; columnar occurring more at the bottom. Therefore, chances of becoming an adenocarcinoma increases as you go down the oesophagus.
There’s also increased smooth and decreased skeletal muscle as you go down.
What are adenocarcinomas in the context of the oesophagus? Cause?
From metastatic columnar epithelium in the lower 1/3 of the oesophagus. Related to recurrent damage to the mucosa from acid reflux.
Epidemiology of oesophageal adenocarcinomas?
More frequent in the developed world – associated with increased weight which increases abdominal pressure and therefore forces acid up and into the oesophagus.
What are squamous cell carcinomas in the context of the oesophagus? Cause?
From normal oesophageal squamous epithelium (upper 2/3 of the oesophagus). Associated with the acetaldehyde pathway – various exposures including smoking and alcohol causes expression of acetaldehyde which can damage the squamous cells and cause malignant transformation.
Epidemiology of oesophageal squamous cell carcinomas?
More prevalent in the developing world, though incidence is going down.
What is the investigation for oesophageal cancer?
Endoscopy – tube with camera that allows us to see down the oesophagus. A biopsy is usually done at the same time.
What is the progression from reflux to oesophageal cancer?
OESOPHAGITIS: chronic exposure to acid.
BARRETT’S: caused by injury, ongoing inflammation and cytokine drive.
Paler tissue in the Barret’s oesophagus is healthy squamous; red is the columnar epithelium where there has been constant acid exposure.
What are the symptoms of oesophageal cancer?
Difficulty swallowing, weight loss.
For adenocarcinomas, history of heartburn, regurgitation and burping is a sign of acid reflux which could be an indication.
How is oesophageal cancer treated?
Surgery to remove the affected section of oesophagus (oesophagectomy).
Chemotherapy and sometimes radiotherapy.
These treatments are usually unsuitable for advanced stages of cancer.
What is the progression of colon/colorectal cancer?
- Small insult/raised area of epithelium from APC mutation, which results in hyperproliferation.
- There is COX-2 overexpression, and the lump grows into a small adenoma.
- K-ras mutation can cause progression into large adenoma.
- p53 mutation and loss of 18q (gene deletion) can lead to colon adenocarcinoma, and lots of necrotic tissue also.
OVERALL: sequence of genetic errors = APC, K-ras, p53 and 18q. It is NOT single gene process nor simple Mendelian inherited.
What are the symptoms of colon cancer?
· Asymptomatic.
· Early diagnosis from anaemia (slow, unnoticeable bleed into the GI tract).
· Change in bowel habit e.g. more often, diarrhoea.
· Blood in stool.
· Acute intestinal obstruction.
· Lower abdominal pain.
***What symptoms are not associated with colorectal cancer? (x3)
- · Rectal bleeding with anal symptoms (itch, soreness, external lump and prolapse).
- · Change in bowel habit to harder or less frequent stool (seems surprising that cancer doesn’t lead to constipation (from tumour obstruction). The reason why you don’t see constipation in colorectal cancers is because you see more frequent loose stools or periods of complete obstruction then loose stool instead). Patients with constipation have same incidence of colorectal cancer as those who do not have constipation!
- · Abdominal pain in the absence of obstruction.
Why is abdominal X-ray not useful for bowel cancer diagnosis?
Very hard to see.
What are the advantages and disadvantages of CT scan for bowel cancer diagnosis?
Quick and easy, but likely to miss small lesions.
What is a CT Virtual colonoscopy?
Give patient a label like barium which can be given orally. And it essentially labels the faeces, so they can be subtracted virtually in the colonoscopy, and a faecal-free image of your bowel can be given.
What are the components of energy expenditure and in what proportions are they? (x3)
ADAPTIVE THERMOGENESIS (responds to temperature and diet), PHYSICAL ACTIVITY, and OBLIGATORY ENERGY EXPENDITURE from normal cellular and organ functions.
What is the BMI scale in relation to obesity?
Over 30.
How does obesity change with age?
Generally, increases ad plateaus/decreases in elderly age.
What are the two types of obesity?
Android and gynoid respectively.
How can BMI be constant, but obesity complications risk differs? Why?
Look at the photo: left individual has lots of subcutaneous fat; right individual has lots of visceral fat.
The individual on the right has higher risk of CVS disease.
SO, WHERE YOU STORE FAT DETERMINES RISK.
WHY? It is because visceral adipose tissue gives rise to deterioration of lipid profile, impaired insulin sensitivity, increased susceptibility to thrombosis and impaired endothelial functions.
