GASTROINTESTINAL 2 Flashcards
(101 cards)
what is the function of the large intestine?
absorbs water from indigestible material; expulsion of waste products; site of vitamin production by bacteria
what are common pathologies seen in large intestine?
obstruction/dilation, tumour, inflammation
what is a large intestinal obstruction?
less common than SBO- gastrointestinal obstruction- secondary to neoplasia (typically of colon, ovary, pancreas & lymphoma)
what causes large bowel obstruction?
may be due to volvulus, post-operative adhesions, strictures, hernia, intussusception, faecal impaction
how is large bowel obstruction radiographed?
site of obstruction can be easily visualised by transition from dilated to non-dilated- plain radiographs offer limited value in diagnoses- upright chest image helpful in diagnosing perforation- CT is optimal
what is ileus?
low gut motility in absence of obstruction- can occur after abdominal surgery & normal surgeries- resolves in 2 to 3 days
how does ileus appear in radiographs?
gets copious gas dilation of small intestine & colon- CT is modaility of choice
what is volvulus?
sigmoid colon twists on its mesentery, resulting in acute, subacute or chronic obstruction- usually impacts elderly, debilitated & bedridden
what is volvulus caused by?
over filling of sigmoid colon due to constipation & excessive fibre in colon
how does volvulus appear in radiographs?
massive dilation of sigmoud colon extending from pelvis to diaphragm & caecal volvulus produces large & intestinal obstructions
what are most colorectal cancers?
adenomatous polyps- present in 30 to 50% of people but less than 1% of polps become malignant
what population is colonic cancer incident increased?
patients with long-standing inflammatory bowel disease
what are symptoms of colonic cancer?
often associated with non-regenerative anaemia
how is screening for colon can done?
colonoscopy
what do tumours in tranverse & descending colon result in?
occasional obstruction & perforation
what do radiographs reveal on abdomen about colon cancer?
characteristic annular constricting lesions (apple core or napkin ring)
what is ulcerative colitis (UC)?
mucosal disease that usually involves the rectum & extends proximally to involve all or part- of colon - unknown aetilogy- occurs in continuous pattern (compared with chronic disease)
with UC, how many patients have disease limited to rectum & sigmoid colon?
40-50%
with UC, how many patients have disease extending beyond the sigmoid but not whole colon?
30-40%
with UC, how many patients have colitis?
20%
how is diagnoses made in UC?
endoscopy, plain radiographs show colonic dilation, contrast enema shows mucosal damage, CT shows complications of UC
what is the appendix?
blind ending tubular structure arising in the caecum- normally not visible only on US or CT in appendicitis- rarely tumours
what is the function of the liver?
filtration of blood draining digestive tract; metabolism of protein, carbs, lipid, chemicals; production of plasma proteins, bile salts; excretion of cholesterol & bilirubin
what is blood supply of the liver?
portal vein