GASTROINTESTINAL 2 Flashcards
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
what is the role of portal vein?
carries blood from GI tract & spleen to liver, delivers blood to hepatic sinusoids
what are the common pathologies of liver?
primary tumour, metastatic tumour, trauma, vascular obstruction, infections/abscesses
how does normal imaging of CT/MRI show liver?
assess outline of capsule, liver should be uniformlu contrasts, portal vein should fill with contrast, dilation of bile ducts
what type of primary tumours appear in liver?
hepatocellular carcinoma is most common- increasing & occurs in patients with cirrhosis
what cause liver primary tumours?
hep C, alcohol use, nonalcoholic fatty liver disease
what is diagnosis based on for liver tumours?
ultrasound for screening & CT for determining surgical approach for treatment (usually see hypervascular pattern)
is liver a common site for metastasis?
yes- CT is modality of choice due to differential enhancemen of metastases compared with normal tissue
what is severe liver trauma?
most severe injuries associated with laceration & damage to major vessels- most common cause of death due to abdominal trauma- cause haemodynamic changes
how is liver trauma diagnosed?
plain radiographs may show skeletal damage, contrast enhanced CT scaning is modality of choice
what is portal vein obstruction due to?
primary thrombosis (occurs in cirrhosis & hepatic malignancy) & occlusion by neoplasm
what happens due to portal vein obstruction?
collateral circulation develops resulting in oesophageal varices
how is portal vein obstruction diagnosed?
ultrasound & CT (shows varuces & intrahepatic vascular abnormalities)
what are varices?
veins are enlarged or swollen- develop in 50% of pateint with cirrhosis (mostly in oesophagus)- cause significant haemorrhage
what is the function of the gallbladder?
storage, concentration & release of bile
what does the right & left hepatic duct drain into?
common hepatic duct
what does the common hepatic duct & cystic duct form?
common bile duct
what does the common bile duct join & drain to?
pancreatic duct joins & drains to duodenum
what are the common pathologies of gallbladder?
calculi, inflammation, tumour
what forms gallstones?
abnormal bile composition- mostly asymptomatic
what accounts for more than 90% of all gallstones?
cholesterol stone in western industrialised countries
what are pigment stones?
composed primarily of calcium bilirubinate- secondary to chronic billary infection
what are factors that form cholesterol stones?
amount of cholesterol secreted by liver cells, relative to bile salts, and gallbladder stasis
what does cholesterol secretion increase with?
obesity, metabolic syndrome, high calorie & cholesterol-rich diets or drugs- pregnancy & rapid weight loss
what is bilary sludge?
thick, mucous material that contains crystals- precursor of gallstone
when do black pigment stones occur?
in patients with chronic haemolysis, liver cirrhosis or cystic fibrosis
what are brown pigment stones associated with?
infection
what is an accurte way of identifying gallstones?
ultrasonography of gallbladder, plain radiographs (when they’re radiopaque enough e.g. 10 to 15% cholesterol & 50% pigment stone), CT
what is cholecystitis?
acute inflammation of gallbladder wall usually following obstruction of cystic duct by a stone
what does gas in gallbladder wall or lumen indicate?
emphysematous cholecysitis (usually bacterial)
what is diffuse calcification associated with in gallbladder?
carcinoma (cancer that starts in cells making skin or tissue lining organs)
how is cholecytitis diagnosed?
ultrasound first line, CT and MRI (show wall thickening when more that 4mm and oedema)
what are cholangiocarcinoma?
malignancies of bile duct system that can arise in liver or in extrahepatic duct- due to long stand inflammation
how is cholangiocarcinoma diagnosed?
ultrasound and/or CT which may demonstrate enlarged bile duct
what is the function of pancreas?
exocrine function are production and secretion of proteases, lipases and amylase and secretion of bicarbonate. Endocrine functions are insulin and glucagon secretion
what are common pathologies of pancreas?
inflammation & tumour
what does swelling and shrinking of pancreas indicate?
swelling= acute inflammation & shrinkage= chronic inflammation
what does non-uniform perfusion indicate?
inflammation or tumour
what results due to masses at head of pancreas?
obstruct the bile duct
what does masses at tail of pancreas indicate?
issue with spleen
what is pancreatitis?
acute or chronic inflammatory condition in which pancreatic enzyme autodigest tissue
what is acute pancreatitis and causes?
gland heals without any effect on function or morphological changes- caused by alcohol use, gallstones, drugs
what is chronic pancreatitis?
recurs intermittently causing functional or morphological changes
how is pancreatitis diagnosed?
ultrasonography initially, CT only in severe cases or tumour- plain radiographs of little value
how visible is calcifications in chronic pancreatitis?
visible in 30% of plain radiographs- CT is used to identitfy complication & plain surgical or endoscopic intervention
how is pancreatic cancer diagnosed?
CT is imaging chouce but difficult to diagnose in early stages & very high fatality rate
what does the right upper quadrant contain?
right portion of liver, gallbladder, right kidney, small portion of stomach + ascending & transverse colon, duodenum, small intestine, head of pancreas
what does the left upper quadrant contain?
left portion of the liver, part of the stomach, the pancreas, left kidney, spleen, portions of the transverse and descending colon, and parts of the small intestine.
what does the left lower quadrant contain?
the small intestine, some of the large intestine, the left half of the female reproductive system, and the left ureter.
what does the right lower quadrant contain?
cecum, appendix, part of the small intestines, the right half of the female reproductive system, and the right ureter.
what does the right hypochondriac region contain?
right portion of the liver, the gallbladder, the right kidney, and parts of the small intestine.
what does the left hypochondriac region contain?
part of the spleen, the left kidney, part of the stomach, the pancreas, and parts of the colon.
what does the epigastric region contain?
majority of the stomach, part of the liver, part of the pancreas, part of the duodenum, part of the spleen, and the adrenal glands.
what does right lumbar region contain?
consists of the gallbladder, the left kidney, part of the liver, and the ascending colon.
what does left lumbar region contain?
consists of the descending colon, the left kidney, and part of the spleen.
what does the umbilical region contain?
contains the umbilicus (navel), and many parts of the small intestine, such as part of the duodenum, the jejunum, and the illeum + transverse colon
what does right iliac region contain?
appendix, cecum, and the right iliac fossa.
what does left iliac region contain?
part of the descending colon, the sigmoid colon, and the left illiac fossa
what does hypogastric region contain?
contains the organs around the pubic bone. These include bladder, part of the sigmoid colon, the anus, and many organs of the reproductive system, such as the uterus and ovaries in females and the prostate in males.
how long is th duodenum?
25cm
how long is the first part of the duodenum?
5cm long and runs backwards, upwards & to the right
how long is the second part of the duodenum?
7.5cm & curves downwards to level of L3 (5cm to the right of the midline)
how long is the third part of the duodenum?
10 cm & crosses midline, lying just above the umbilicus to end just to the left of midline at L2-L3 disk level
how long is the 4th part of duodenum?
2.5cm long & crosses the duodenojejunal flexure, situated about 2.5cm to left of midline at level of L2 upper body
what is the cardia of stomach behind?
7th costal cartilage- 2.5 cm from midline
where does the pylorus lie?
2.5cm to right of midline of transpyloric plane
what is the highest point that the stomach body reaches?
level of 5th intercostal space
what is the lowest point that the stomach point reaches?
10th costal cartilage
where does the caecum being & lie?
ileiocaecal valce & lies in right lower quadrant on abdomen
what are the dimensions of the caecum?
6cm long & 9cm wide
what level does the ascending colon bend?
level of right kidney at hepatic flexure
how long is transverse colon and where does it bend?
45cm & bends at splenic flexure
how long is descending colon and where does it travel?
25cm & travels medially to pelvic cavity
what level is the rectum at?
s3 in pelvis
what are the dimensions of the gallbladder?
7 to 10cm in length & 2.5cm in breadth
what ligament seperates right & left lobe of liver?
falciform ligament
where is the gallbadder located?
intersection between rectus abdominus muscle & 6th costal cartilage
where is the spleen located & protected by?
in left upper quadrant (left hypochondrium & part epigastrium)- protected by left 9th to 11th ribs
