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269 Cards in this Set

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What biochemical markers occur in chronic liver failure
1) high oestogen
2) high ammonia
3) low clotting factors
4) low albumin
5) impaired secretion of bile (jaundice)
What are specific signs of portal congestion
1) ascites
2) splenomegaly
3) oesophageal varices
What are the 3 stages of alcoholic liver disease
1) faty liver (reversible)
2) steatohepatitis
3) cirrhosis
What are teh non-alcohol causes of steatosis
1) obesity
2) diabetes
3) amiodarone
Which 4 viral groups cause hepatitis
1) Hep
2) EBV
3) Herpes
4) CMV
Which Hep's cause acutem fulminant and/or chronic hepatitis
Acute: ABCE
Fulminant: ABC
Chronic: BCD
Which Hep's can be varried asymptomatically
B and C
What are liver segments
Anatomical regions based on branches of the portal vein
Describe the features of cirrhosis
loss of normal architecture
fibrous bands with inflammation
compression and destruction of branches of the portal vein
Nodules of regeneration of parenchyma with steatosis
List 3 causes of cirrhosis
Alcoholic metabolic
Infection
Biliary obstruction
What are the bodies formed in alcoholic liver disease
Mallory's hyaline, precipitation of cytoskeleton from hepatocytes
What cause of hepatitis should be considered in immunosupressed patients
EBV
CMV
What are the likely outcomes of Hep C
Chronic hepatitis
cirrhosis
hepatocellular carcinoma
What are the features of hep B chronic
portal inflammation
interface hepatitis (portatract interface encroachment of lymphocytes into lobule causing necrosis)
lobular inflammation
portal fibrosis
linkage
cirrhosis
What are the primary biliary diseases
Primary biliary cirrhosis: antimictochondrial antibodies against intrahepatic bile ductules
Primary schlerosing cholengitis (autoimmune, IBD scarring around and occlusion of large bile ducts)
Congenital biliary atresia (common bile duct fails to form fully, can be bypassed surgically)
What does the liver look like with biliary cirrhosis
green, destruction of bile ducts and fibrosis around small and medium bile ducts.
Collections of granulomas and lymphocytes around bile ducts
What are the sites causing secondary biliary cirrhosis
Lumen: Gallstones, CF
Wall
Obstruction: Pancreatic carcinoma obstructing common bile duct
Hereditary haemachromatosis causes
Excessive absorption of iron from the GI, failure of regulatory mechanisms causing "rusted liver" and eventual cirrhosis
Alpha 1 antitrypsin ZZ phenotype causes
Liver parenchyma is destroyed causing cirrhosis. The abnormal alpha 1 antitrypsin precipitates as lobules
What does Wilson's disease cause. How is it diagnosed
Deposition of copper in liver causing cirrhosis. KF brown ring surrounding iris
What is absent in hepatocellular adenoma
Portatracts but hepatocytes are present
What are the major complications of hep B and C
Hepatocellular carcinoma
Cirrhosis
Why does lactic acid rise in liver failure
Glucose homeostasis unable to be maintained and muscle doesn't have G6p ase, but releases lactate into Cory cycle
How are LFTs indicative of liver v skeletal muscle injury
AST is present in skeletal muscle and can be elevated alone without liver damage
AST/ALT around 1 for viral hepatitis
AST/ALT is 2 for ALD
In acute hepatitis, what is the effect on bile metabolism and excretion
Conjugation preserved
Conjugated hyperbilirubinaemia
Liver oedema blocks biliary canniliculi, hence unable to excrete bile
Urine and blood has high levels of conjugated bilirubinaemia
In fulminant liver disease, what are the principal biochemical derangements
Hypoglycaemia and lactic acidosis
Ammonia encephalopathy
Bleeding due to reduced clotting factors
How is AFP used to indicate liver disease
Raised 10x if hepatocellular gegeneration, very high and increasing if cancer
What is the likely cause of high indirect bilirubin and low direct with normal LFTs
Gilbert's syndrome: congenital defective glucuronidase. Can worsen if blood glucose fall
What are the markers of long standing biliary obstruction
ALP, GGT produced by bile ducts
What is raised in end stage alcoholic liver disease
Biliary obstruction, ALP, GGT
Raised cholesterol
Normal ALT, AST due to prior damage to hepatocyted and destruction in prior waves
Hypercalcaemia
What are the two methods of talking about the liver functional units
lobule(pathology) v acinar (toxicolgists/pharmacists)
What are the two features of cirrhosis
Nodules of fibrosis surrounding a central core of regeneration
What is the pathogenesis of fibrosis
Insult, nflammation, kuppfer cells release cytokines, stelate cells causes fibrosis in spaces of disse, loss of fenestrations, migration of lymphocytes, activation of bibroblasts causing loss of architecture and resistance of blood flow in sinusoids
What are the consequences of portal hypertension
There are shunts between the portal and systemic veins, collaterals form around the oesophagus and abdomen forming varices, backward congestion to the spleen, ascites
How is steatohepatitis different to steatosis
Inflammation, necrosis, Mallory bodies
An alcoholic stops drinking, can he develop cirrhosis
Past the point of steatohepatitis, the liver may continue to degenerate to cirrhosis
What is the histological pattern of paracetamol toxicity
Paradoxically zone 3 is most likely because of low oxygen in zone 3
What are 3 metabolic liver disease
Wilson's disease
Haemochromatosis
G6P deficiency
Describe the classifications of haemochromatosis
Haemosiderosis (secondary, transfusion type with macrophage accumulation) - will not cause cirrhosis
HFE gene defect, primary disease with accumulation of iron in hepatocytes - cirrhosis
What is piecemeal hepatitis
Hepatitis around the interface of the portal triad
What histological sign is distinctive of hep B
Ground glass bodies caused by accumulation of surface antigen
What is the distinctive feature of autoimmune hepatitis
Plasma cell infiltrate
What is budkiari syndrome
Hepatic vein occlusion causing ascites, acute abdominal pain
What is the cause of nutmeg liver
Heart failure
What are the commonest nodules of the liver
Haemangioma (blood vessel neoplasms)
Focal nodular hyperplasia
Nodular regenerative hyperplasia (contraceptice pill)
Diffuse nodular regeneration with obliteration of architecture)
Bile duct adenoma
What are the neoplasms of the liver
Hepatocellular carcinoma
Haemangiosarcoma (endothelial origin)
Cholangiocarcinoma
Carcinoid
Metastases
What are the risk factors for cholangiocarcinoma
hep c
? ? ?
Describe primary biliary cirrhosis
autoimmune destruction of intrahepatic bile ducts by antimitochondrial antibodies. Bile ducts are obliterated and absent from portal triad
How is biliary schlerosis different from primary biliary cirrhosis
Onion skin rings of fibrosis surrounding bile ducts
Describe the pathology of reflux oesophagitis. What are 2 complications
oedema in epithelium, inflammatory cells, esp eosinophils
Complications are ulceration and Barretts oesophagus
Describe the pathogenesis of Barretts
Reflux and oesophagitis
glandular intestinal metaplasia with presence of goblet cells
dysplasia with risk of high grade dysplasia and risk of adenocarcinoma of the glandular epithelium
Describe early oesophageal cancer
Early microinvasive adenocarcinoma with glands invafing the submucosa
Multinucleated giant cells are found in an oesophageal biopsy. What is happening
Herpes virus infection
A child has difficulty swallowing bolus and an oespophageal biopsy shows many eosinophils. What gives?
Eosinophilic oesophagitis
What type of cancer is likely in the oesophagus of a heavy smoker/drinker. What is the course of the disease
SCC with likely invasion into the mediastinum
What are risk factors for acute gastritis
H.pylori, age, alcohol, caffeine, burns, steroids, NSAIDS
Describe autoimmune atrophic gastritis
Antibodies against crypt glandular cells with destruction of parietal cells and loss of intrinsic factor. Patient develops pernicious anaemia (glossitis, neuropathy, megaloblastic anaemia)
What are the layers of a peptic ulcer
Exudate (necrosis)
Granulation tissue
Fibrosis
AWhat are complications of a peptic ulcer
Perforation and possible adhesion with underlying pancreas or liver
Haemorrage
Fibrosis and obstruction
Carcinoma
List gastrointestinal tumours
GIST (gastrointestinal stromal tumours (metastatic) made up of spindle cells - can be malignant)
Adenocarcinoma derived from adenomous polyps (villous, serrated)
Lymphoma derived from MALT
Mucocoele, haemangioma
What are the two types of stomach adenocarcinoma and what are the risk factors
Intestinal and diffuse
Diet, nitrosamines
Tobacco
H.pylori
What cells morphology is typical of adenocarcinoma, why?
Signet ring cells. Cells are filled with mucin, pushing the nucleus to the extremity
What haematological malignancy can occur in the stomach
MALT lymphome forming very undifferentiated masses
How has the prevalence of hepatitis A changed in developed countries
Hygeine has shifted the burden to older age groups with more a serious disease response
How effective is the Hep B vaccine
Monovalent but does not cover against 20-30% escape mutants with weak binding of the surface antigen (may be in pre S region)
What is the marker present in Hep B patients infected perinatally. What is the mechanism of infection of the foetus?
HBeAg which has been passed on through the placenta and the foetus becomes immune tolerant
Why are combination antivirals more effective than monotherapy against Hep B
Cross resistance occurs where one antiviral results in a mutation that affects the target epitope of another. Combinations with different targets greatly reduce the probability that the right sequence of mutations will occur to decrease the inhibition caused by both vaccines.
Hoe does proglumide treat Zollinger-Ellison syndrome
Blocks gastrin receptors, effective because ZE involves neuroendocrine tumours secrting gastrin
What drug counters the GI effects of NSAIDS, explain
NSAIDS inhibit the conversion of arachadonic acid to prostaglandin (which normally inhibits H+ secretion and promotes mucin secretion). Misoprostol is a prostaglandin agonist.
A diabetic patient complains food is stuck in his oesophagus. What is happenning
Achalasia occurs because of vagal nerve lesions causing reduced oesophageal motility, increased LOS tone, decreased LOS relaxation
What is typical in the herpes infected oesophagus
Large multinucleated cells and numerous neutrophils
Where does eosinic oesophagitis occur
Throughout the entire length
How is Barretts diagnosed
Biopsy showing intestinal epithelium with goblet cells. Classification is short segment (<3cm) and long with shifting of the gastrooesophageal junction
What is evident in advancing dysplasia followed by neoplasia in Barretts
At the GE junction, adenocarcinoma forms with increase in glandular looking aggregations of abnormal cells
How do the cell types differ between the antrum and fundus
Antrum is absent of parietal cells and high in ECL cells
Fundus has high chief and parietal cell content
A bout of salmonella will cause what in the stomach
Acute gastritis with small flat erosions (muscularis isn't penetrated). There is no fibrosis and evidence of contractile puckering around the erosions
What does a PAS stain of H.pylori show
Flagellated rods on the mucosal surface
The diffuse type of adenocarcinoma shows what? What are signs on examination
It is linitus plastica with a stiff, thickened submucosa reducing the lumen size. Shows signet ring cells. Identified by Virchows node and Sister Mary Joseph nodule at the periumbilicar region
Do carcinoid tumours cause carcinoid syndrome
Not in the GI tract because it secretes into the portal system causing first pass breakdown of vasoactive amines
How do we grade GIST
Mitotic bodies
Size greater than 10cm
Who is at risk of gallstones
The F's: fair, fat, female, flatulant, family and resected or distal ileal disease eg Crohns wth decreased bile salt reabsorption
Gall bladder stasis
Haemoglobinopathies eg thallassemia, sickle-cell
Bile duct colonisation of SE Asians eg Ascaris lumbracoides
How likely are asymptomatic gallstones likely to cause symptoms. How likely that these will be serious
3% per year. 3-5% of these will develop complicated biliary disease eg cholestatic liver disease
Describe the pathogenesis of gallstones
Precipitation of bile constituents (mixed cholesterol) from a supersaturated solution. Small's triangle shows that stones form when the cholesterol content of bile rises or the lecithin or bile salt content falls.
What is the role of an xray in diagnosis of gallstones
None, cholesterol and mixed stones are not radio opaque
How are brown pigment stones formed
Deconjugation of bilirubin diglucuronidide, typically by pathogenic flukes and worms
Describe the pain from a gallstone
Epigastric, RUQ, infrascapular radiation (Boas sign), typically 1 hour after a fatty meal. Asociated with nausea.
What are the complications of gallstones
Fulminant necrotising pancreatitis due to choledocolythiasis
Septicaemia from cholangitis
Cholecystitis, ulceration, perforation, fistula, empyema, emphysematous gall bladder, carcinoma
What is the likely cause of painless jaundice
Pre-hepatic: haemolysis (thallasaemia, sickle cell, G6P dehydrogenase deficiency, hereditary spherocytosis)
Hepatic, pancreatic or biliary tract cancers as opposed to a biliary calculus, NASH, Primary biliary cirrhosis
How is the function of a gallbladder tester
HIDA scan pre and following a fatty meal. Expect 80% ejection fraction
An ultrasound shows a thickened gallbladder wall. What is likely
Gallstone causing inflammation of the gallbladder wall
What are complications of a gallbladder from a stone
choledocolythiasis: (Cholangitis, pancreatitis, biliary cholic disease)
acute and chronic cholesystitis
hydrops (mucus)
Infection: empyema
perforation
gangrene
emphysematous (gas filled wall - surgical emergency)
Carcinoma (porcelaine gallbladder)
What is Charcod's triad
Cholangitis: ruq pain, fever jaundice
What is Reynolds pentad
Sepsis due to infrcted biliary tree - shows sign of Charcods yriad plus confusion and other signs of sepsis (changes in vitals and urine output)
What are the prognostic criteria and imaging of acute pancreatitis
Ransons indices eg wcc > 15, AST, age > 55, raised glucose 11+, raised urea (declining renal function)
Need contrast CT of pancreas
What is a porcelain gallbladder indicative of
Cancer in up to 40% of cases
GB 5th commonest GI cancer
Cholesystectomy is compulsory
What are complications of a gallbladder from a stone
biliary colic
acute and chronic cholesystitis
hydrops (mucus)
Empyema
perforation
gangrene
emphysematous (gas filled wall - surgical emergency)
Cholangitis (inflammation of the bile duct)
Carcinoma
What is Charcod's triad
Cholangitis: ruq pain, fever jaundice
What is Reynolds pentad
Sepsis due to infected biliary tree - shows sign of Charcods triad (RUQ pain, jaundice, fever due to cholangitis) plus confusion and other signs of sepsis (changes in vitals and urine output)
What are the prognostic criteria and imaging of acute pancreatitis
Poor if 3 or more of Ransons indices eg wcc > 15, decreased renal function ie raised urea, age > 55, glucose 11+, raised LDH, raised AST
Need contrast CT of pancreas
What is a porcelain gallbladder indicative of
Cancer in up to 40% of cases
GB 5th commonest GI cancer
Cholesystectomy is compulsory
Where is located
rectum to splenic flexure
Where is Crohns located
From perineum to perianium
Colonic disease
How does Crohns present on colonoscopy
Transmural disease with pseudopolyps, dysplasia, exudate
What tissue does UC affect and what do blood tests show
mucosa and submucosa, less mucosal damage than Crohns, hence CRP, platelets and haemoglobin are normal. May be positive to HLA-B27, especially if ankylosing spondilitis is present
What does UC show on histology
Depletion of goblet cells
Crypt architecture distortion
What does Crohns show on histology
Granulomata with numerous mucin containing goblet cells (different to UC with absence of goblet cells)
Cobblestone mucosa
Deep ulcerated mucosa
Deep fissures and fistulas, sometimes to the abdominal wall
What are UC symptoms
Tenesmus causing trauma to anus, fissures
Urgency because of non compliant rectum
Colic due to obstruction
Infection of anal glands
Fistula in ano discharge
What are Crohns disease
Colic due to ileal obstruction
Diarrhoea
What other diseases are associated with Crohns
Primary schlerosing cholangitis
Ankyloding spondilitis
Eye conditions associated with UC
Uveitis, scleritis due to thinning, injection
What skin conditions are associated with UC
pyoderma gangrenosum
erythema nodosum
What types of arthritis are associated with UC
seronegative arthritis
ankylosing spondylitis
Type 1 arthritis is polyarthritis
What are the main serious complications of IBD
Fistulas and strictures in CD
Colorectal cancer
Iron deficiency anaemia and anaemia of chronic inflammation
B12 deficiency and bile dalt wasting due to ileal resection of CD
What is the pathophys of UC
Mucosal dysfunction causing inappropriate immune response possibly to benign bacteria but also associated with the HLA-B27 antigen. the inflammation begins towards the rectum and proceeds without break along the sigmoid colon, possibly affecting the entire mucosa and sub-mucosa of the large intestine while sparing the muscularis and serosa. erosions and pseudopolyps line the mucosa, causing bloody diarrhoea.
Wha are protective factors for UC
Smoking and appendicectomy are protective
What are triggers for UC
Stress
Infection
Smoking cessation
Constipation (causes more proximal flareups)
What is the association of UC and goblet cells
Improper unfolding of mucin causing apoptosis of goblet cells
What are the targets of treatments for IBDs
1) Modulate NK T cell function, hence, budesonide, hydrocortisone, prednisolone, cyclosporin
2) Aminsalicylates: released in different parts of the colon
3) Purine analogues, azathiopurine hijacking the purine salvage pathway causing abnormal ribonucleoside formation inhibiting
t cell production. Take 6 months to work so need to start on steroids
What is the Paed treatment for UC
Exclusive enteral treatment followed by biologics (azathioprine)
What surgical treatments are used for CD
Ileal resection
Stricturoplasty or resection
Colectomy
Temporary diversion ileostomy to allow healing on rectum, anus and perianum
What are the common viruses casing colitis
rota
norwalk, noro
astro
herpes (cmv, herpes simplex)
What are the types of enterotoxins
secretogogues (travellers)
Cytotoxins (shigella) with invasion
Staphylcoccal exotoxin
Describe the pathogenesis and complications of campylobacter
uncooked chicken, faecal oral route
neutrophil infiltrate exudes into lumen, severe inflammation and sloughing of mucosa
complications include reactive arthritis and Guillian-Barre
What are the complications of c.difficile
Watery diarrhoea, dehydration, fever
Ulcerations and volcano lesions
What gene is associated with IBD
NOD2
In UC, what is the pattern of colon involvement
Rectum to distal colon with no ulceration. Serosal surface is normal. Inflammation is continuous
A section of bowel shows a fissuring ulcer affecting the muscularis. What is the likely disease
CD
How does cancer risk increase with UC
10 years 2%
20 years 10%
30 years 20%
Higher risk with pan colitis
What type of cancer occurs with UC
Signet ring adenocarcinoma
What is the difference between collagenous colitis and lymphocytc colitis
Collagenos collitis is thickening of collafen of lamina propria with lymphocitic infiltate. Lymphocytic collitis is less severe with less thickening of the epithelium
What comon dysplatic lesions are present in UC
Villous adenoma. Can develop into adenocarcenoma when it penetrates the basement membrane
What is the pathophysiology of serrated polyps
Generally have either BRAF or KRAS mutations ihibiting apoptosis and forming serrated lesions. Sessile serrated polyps appear as innoculous raised lesions. Dysplasia can arise leading to adenoma.
What are the main pathways to colon cancer
1) Chromosomal instability pathway causing adenoma leading to adenocarcinoma.
Serrated neoplasia pathway where serated polyps undergo mutatios in BRAF and KRAS, dysplasia folliwed by gene methylation of DNA repair and gene (silencing) followed by rapid progression of adenocarcinoma
What is the prognosis of FAP
Colon is carpeted with polyps and 100% risk of cancer development, hence early colon resection
With rectal bleeding, what are the examination requirements
Anaemia (may not show as occult)
Jaundice for metastaces and lymphadenopathy
Abdo palpation of enlarged organs and masses or tenderness
Rectal blood, masses, fissures
DRE, look at any residual stool, blood, mucus
How can you interpret bloody faeces in a DRE
Blood mixed with stool Ca
Surface blood with pain: fissure
Blood with mucus IBD
What are the investigations for rectal bleeding
Colonoscopy
CT for identifying masses but not fine enough for polyps
Double contrast barium enema picks up gross changes but not subtle mucosal changes
What could be visualised by barium enema for lower GI bleed. Why is there risk involved with the procedure
Diverticular disease
Strictures
Masses
Baloon in anus and air inflation of abdomen can perfrate the bowel
What are red blood cell scans used for
RBC scintography to find a bleeding point
Describe anal fissures
Tear in rectal epithelium (may involve ischemia in acute fissures) exacerbated by constipation and bowrl motions. Rectogesic relaxes the sphincter and Proctosedyle reduces ischemia. High fibre diet recommended
Describe the aetiology and pathophys of diverticular disease
Normally fibre retains water in stools. In western low fibre diets, usually after 40yo, the bowel has to generate high pressures to move the dry stool. Points of weakness occur where blood vessels enter the bowel, diverticula (outpouching) form that can perforate, become infected. Pain may be present in LLQ. Bleeding points arise causing dark red stools.
What is angiodysplasia
Enlarged veins in right colon. Usually patients with valvular disease, renal failure. Can bleed at different rates.
Describe pancreatitis
Acute inflammation of pancreas with regional tissue involvement and remote organ systems. Can be fatal.
List the causes of pancreatitis
Alcohol 25%, gallstones 50%
Post ERCP
trauma
idiopathic 25%
Describe the clasification of acute pancreatitis
Mild w no organ failure
Moderate w transient organ failure
Severe persistent organ failure
Critical - persistent multi organ failure
Describe the pain and symptoms of acute pancreatitis
Severe epigastric pain with radiation through to back. Vomiting, fever
What is the score system used for acute pancreatitis
Ranson criteria
What investigations are used for acute pancreatits
Lipase and amylase
Ranson score tests (glucose, urea, AST, LDH, WCC)
Imaging: High def ultrasound to find cholesystitis, bile duct enlargement.
CT
ERCP if Ranson score >3 ie severe plus jaundice plus cholengitis
CRP
LFTs
Describe the phases of acute pancreatitis
Acute phase: inflammatory phase with minimal necrosis but organ failure, ischaemia, SIRS
Necrotic phase with deterioration of Ranson score, infection, sepsis, pseudocyst forming in lesser sac
What are the causes of chronic pancreatitis
Chronic alcohol abuse
Hereditary pancreatic disorder
Pancreas divisum with narrow accessory papilla formed by non fusion of dorsal and ventral buds.
What are the clinical features of chronic pancreatitis
Endocrine and exocrine insufficiency, steatorrhoea, diabetes, malabaorption of fat soluble vitamins with bruising & bleeding
Why is xray and ultrasound not an effective investigation of chronic pancreatitis
Colon gas obscures pancreas. Better to use ERCP (2% mortality), CT and MRI
What are the risk factors and predispositions of developing pancreatic cancer
tobacco
obesity
chronic pancreatitis
tooth or gum disease
hereditary pancreatitis
polyposis coli
What are the areas responsible for emesis
ctz (5ht3, dopamine D3)
Vestibular (Ach)
GI (H1)
Medullary vomiting centre
A patient post GI surgery requires a laxative. Which are used
Stool softeners to reduce peristaltic effort eg docusate
A patient reveals his diet is very high in fat and protein and low in vegetables. Is a stimulant or stool softener appropriate
Neither is appropriate, need bulking agent to increase size and water content of stool to decrease colonic forces and mucosal injury
What agents in addition to proton pump inhibitors are used in GORD, why?
Prokinetics increase tone of LOS and increase gastric emptying
What are the congenital gi abnormalities
Atresia of bowel or anus
Hirschprung with loss of ganglion cells of myenteric plexus, megacolon, dilation, ischemia
Duplication
Meckel's diverticulum and congenital diverticulitis
Dilation of colon is caused by.
Inflammation of submucosa due to toxic megacolon in UC
Chagas
Hirschprung
Protozoal causes of diarrhoea
Cryptosporidium
Entamoeba hystolitica
Giardia
Viral causrs of diarrhoea
rota
adeno
astro
calci
Enterotoxin bacteria
Vibrio
Clostridium perfringens
E.coli
What neoplasia causes diarrhoea
Villous adenoma (lots of excess goblet cells) producing mucin
Carcinoid (eg seratonin, prostaglandin, peptides)
What type of diarrhoea is caused by pancreatitis
Osmolar, cf intraluminal malabsorption eg lactose intolerance
What are the complications of pseudomembranous colitis
Diarrhoea due to epithelial destruction, bleeding, inflammation and sepsis
What causes large amoebic ulcers. What is the main presentation
Entamoeba hystolitica. Diarrhoea with blood
Small round structures (smaller than lymphocytes) are seen attached to the intestinal lumen. Who is likely to be infected by what
Cryptosporidium infecting immunosuppressed patients
Explain radiation colitis
Radiation therapy of uterine cancer causes damage to blood vessels causing ischemia plus damage to enterocytes
What is the classic inflammatory feature of Crohn's
Non caseating geanulomas made up of epitheloid macrophages and giant cells
Most common causes of ischemic bowel disease
Atheroma, Angiodysplasia, embolus, strangulated hernia, volvulus
Complications of diverticula
Fistulae
Infection, abcesses
Rupture
Hypertrophy of neck muscularis making the lumen smaller causing impaction
What clinical conditions cause haemorroids
Portal hypertension
Pregnancy compressing the IVC
What painful complication occurs with haemorroids
Infarct
What polyps are of most concern
Adenomatous polyps
What would a surgeon do with hyperplastic polyps
Nothing, benign
What types of bowel adenomas are there
tubular
villous (most prone to hyperplasia)
Tubulovillous
sessile serrated
What congenital condition predisposes to bowel anenocarcinoma
familial adenomatous polyposis
A mutation in DNA repair causes what bowel cancer
Hereditary non-polyposis colorectal cancer
Risk factors for colorectal carcinoma
Excessive calorie intake
low fibre
refined carbohydrates
hugh meat
What does a typical advanced colorectal cancer lesion look like
Inflamed raised irregular borders, central necrosis with either fibrotic repair or perforation of the ulcer. Prognosis is poor.
An alcoholic shows shadows on an xray in the peritoneum. What is this
Fat necrosis due to pancreatitis
What colon abnormality occurs with laxative abuse
Melanosis coli due to high turnover and prolferation of immature pigmented epithelial cells
What are the broad types of diarrhoea and give examples
Secretory (Cholera enterotoxin, rotavirus)
inflammatory (C.jejuni)
osmotic (lastase)
motility (diabetes)
What is the most common infective cause of diarhoea in adults and children
adults - norovirus
children - rotavirus (notifiable)
What are the most common causes of dyesntry
Campilobacter
Salmonella
Yersinia
Shigella
Commonest cause of acute bacterial in children and travellers
Enterotoxogenic E.coli
What are forgotten questions regarding diarrhoea in history taking
Abdo pain, vomiting, contacts, mucus in addition to the usual history of duration, volume, frequency, blood
A person returns with travellers diarrhoea. Are antibiotics and loperimide indicated
Resolves in days but no loperimide with blood, fever or children
An elderly person presents for the first time with chronic diarrhoea. Causes?
Microscopic colitis
Faecal impaction
Colon cancer
What are the broad causes of acute diarrhoea. What are the alarm signs
Infective
Blood, systemic illness, dehydration
What are entero invasive bacteria
Shigella
EIEC
Salmonella
What are the 3 classes of toxins
Neurotoxins
Secretory
Cytotoxins
Indicate the three classes of GI infection. Where does each occur and give examples
Non inflammatory infection of upper GI - watery eg cholera, rota, noro, staph, cerius, clostridium, giardia, EPEC
Inflammatory of colon causing dysentry, shigella, campylobacter, salmonella, entamoeba histolytica, EIEC
Imvasive of distal SI causing enteric fever, typhoid, yersinia
How does bacillus mediate GI clinical features
In starchy foods - ingestion releases emetotoxin
In other cooked foods the toxin causes diarrhoea
A patient's stool dample cultured ETEC, what do you advise the patient
Traveller's diarrhoea, self limiting in 3 days
Weenling diarrhoea is caused by. . .
Rota and ETEC
What are the complications of salmonella
If invasive then systemic illness invading joints causing arthralgias, endocarditis and aortitis
What is the mechanism of shigella infection
Shigella toxin: enterotoxin, cytotoxin, neurotoxin and can cause haemolytic uraemic syndrome
Why aren't antibiotics used to treat shigella
Attack of bacteria by antibiotic causes release of large amounts of the phage toxin
Why is Salmonella typhi a concern
Penetrating the bowel and colonises peyer's patches, causes bacteraemia resulting in fever, splenomegaly and features of sepsis. May not cause diarrhoea
What are the forms of irritable bowel
spastic
diarrhoea
constipation/diarrhoea
What are the ckinical signs of irritable bowel
Pain (lower left)
altered bowel habits
bloating (out of proportion)
upper GI symptoms (gerd, nausea, vomiting)
GU symptoms, viscera becomes irritated and presses on bladder: urgency, nocturea, frequency
What are the ROME criteria
3 months of continuous symptoms of pain or discomfort such that:
Relieved by bowel movement
Coupled with change in frequency (more than 3 per day)
Mucous
Bloating
Incomplete feeling of evacuation, urgency, straining
Extraintestinal symptoms include nausea, fatigue
Why is a gynae exam and xray indicated for irritable bowel syndrome suspect
xray indicates bowel distension
gynae hx and exam rules out pain from GU source (endometriosis)
What is the aetiology of haemorroids
Portal hypertension
Pregnancy
Chronic constipation
Straining
What are the causes of intestinal obstruction
hernia
volvulus
intersussception
adhesion
tumour
FAP
Familial adenomatous polyposis
Autosomal dominant
Mutations of APC gene
What is GIST
GI Stromal Tumour - carcinoid
What are the fluid compartments of the body and which is the most volume. What factors change these volumes
intracellular 60%
Extracellular is plasma plus interstitial
transcellular
age and obesity reduces the fluid to weight ratio
If 2L are lost through a NG tube, what is needed as a replacement
Basal 3 L plus 2L with high NaCl content
A patient following trauma has reduced bp but haemoglobin 95. Should you transfuse
If blood loss caused hypotension then transfuse. Use lower limit of 70 for anaemic patients
A diabetic admitted with diabetic acidosis with hyponatremia. What is the effect of administring insulin
Glucose is highly osmotic and shifts fluid from the extracellular space to the intravascular space, hence the decrease in sodium concentration is artifactual (dilutional). The fluid shift out of the intravascular space restores the sodium level
What are the main causes of small bowel pathologies. give one specific example of each
obstruction (incarcerated hernia, intersussception, adhesions, tumour, ileus from a stone or meiconium)
infection (Ghiardia, Shigella, EHEC, ETEC)
malabsorption (coeliac (gliaden hypersensitivity), ghiardia, Crohn's)
ischaemia (strangulated hernia, volvulus, blockage of superior mesenteric arrtery by thrombus, emboli, shock, LVF)
tumours (adenomas, adenocarcinoma, lymphomas, carcinoid
What is the most common small bowel congenital abnormality
Meckels diverticulitis
Remnant of vililline duct that can become inflamed causing umbilical pain
What are the 3 malabsorption syndromes
coeliac
tropical sprue
Whipples
What is the pathology of coeliac disease
Causes atrophy of villi with lymphocyte infiltration (plasma cells secreting anti gliaden IgA) of the lamina propria and epithelium. Partial or total villous atrophy is possible.
T cell mediated disease of gliaden sensitivity
Associated to hladq2 and dq8
Cure is gluten free diet
Describe the pathology of tropical sprue
Bacterial overgrowth of unknown pathogen causing B12 and folate depletion. Treated with broad spectrum antibiotics
Large numbers of macrophages in the lamina propria is associated with a form of sprue. What is it
Whipples disease caused by a bacteria that cannot be destroyrd by macrophages
A patient presents with steatorrhoea and malabsorption. What is likely and what investigations
Giardia - stool sample to identify cysts. If villous atrophy is present then it may be compounded by coeliac disease,vrequiring antibiotic treatment and gluten free diet
What dors dog hookworm cause
Eosinophilic enteritis causing intestinal wass thickening, abdo pain, rectal bleeding and obstruction. Eosinophils proliferate in the intestinal wall.
What are the two main complications of hernias
incarceration (not reducible by pressing or lying down) and strangulation. This causes venous blockage and ischemia
What are adhesions
Internal hernias formed by healing adhesions of the peritoneum resulting in obstruction or ischaemia
What is the cause of intersussception in adults and what is the complication
Tumour. If mesentary is caught then blood flow is obstructed
what are causes of small bowel obstruction
tumours
strictures
pseudo obstruction such as paralytic ilius or complication of Crohn's
What are the modes of occlusion of the superior mesentaric artery
Atheroschlerosis
Embolism
What is the most common cause of venous occlusion of the small bowel
External compression such as hernia, volvusus, adhesions causing haemorragic infarction due to continues inflow of arterial blood causing red boggy necrosed tissue
What are causes of non occlusive ischaemia of the small bowel
shock
chf
dehydration
Fibrosis and stricture can occur at the site of the iliocaecal junction. How
Chronic ischaemia
What are the complications of a haemangioma
Intersussception and obstruction
What is the most common cancer of the small bowel
Carcinoid tumours causing diffuse slow growing metastatic disease. Appendix carcinoids, most common, are benign.
What is the most common haematological neoplasm of the small intestine
Maltomas - B cell lymphoma resulting from untreated helicobacter.
T cell lymphomas are caused by coeliac.
Pathology of acute appendix
Faecal nodule blocks lumen allowing colonisation by microbes, inflammation, peritonitis and perforation
What are the common causes of appendic pathology
Acute appendicitis
Carcinoid
Parasites
Adrnoma or adenocarcinoma causing mucocoele which can infiltrate the peritonium (dissrminated mucinous tumours)
Why does meiconium iliem lodge in the ileum
Ileocoecal valve causes obstruction
What type of infarct occurs in the bowel and why
Red infarct because of dual blood supply
What is the typical gross appearance of Crohn's
Cobblestone mucosa
What infiltration is present in Coeliac
lymphocytes in mucosa and plasma cells in the submucosa
Cancers if the SI
carcinoid
metastatic lymphoma
adenocarcinoma
GIST
What features would be visible in small bowel cancer
Lymphomas are white, homogenous and invades mesentary
Melanoma
Metastices are irregular, polypoid and ulcerated
Carcinoid are well demarcated and yellow
What are the causes of chronic inflammation in the appendix
Crohn's
Yersinia
TB
What is the cause of an all white appendix
Mucocoele caused by adenoma or andenocarcinoma
Where can mucinous depositing tumours form
Mucinous myxoma in SI, pancreas and ovaries. Can develop a swiss cheese and concrete look
What does the histology of carcinoid look like
Nests of smal cells with lots of cytoplasm
What can happen with Meckel's
Ulceration
Dilatation
Perforation
Inflammation infection
Obstruction
An area of mucosa shows thickening, loss of normal mucosa and adhesions. What inflammatory process is likely to cause this
Crohn's
The intestine of a baby is obstructed with a green yellow mass. What is it
Meiconium ileus
What are the complications of intersusseption
Obstruction
Ischaemia
Infarct
An appendix has white regions. What are the ddx
Mucocoele
Acute appendicitis with puss and fibrin
Lymphoma
A small bowel has an irregular yellow mass post infection. What is it
Xanthogranuloma caused by foam cell macrophages accumulating lipid
What physical examinations indicate alcoholism
Dupytrens
Signs of Wernicke-Korsakoff (abnormal gait, nystagmus)
Decreased personal hygeine and grooming
Contrast different colicky pain
Biliary cholic is associated with meals and never completely is relieved
True colic is peristaltic and waxes and wanes every 8 minutes
What is the histological picture of chronic cholesystitis
fibrosis, lots of macrophages, wall thickening
Describe the pathology of an indirect inguinal hernia. What are the complications.
In males, the testes form adjacent to the kidneys through the internal ring via the inguinal canal. This is an anatomical defect of the posterior abdominal wall allowing the samall intestine to enter, become incarcerated or strangulated causing obstruction and ischaemia
Describe the location of a femoral hernia. Who is at risk and why
Femoral vein, inguinal ligament and lacunar ligament form the borders with bone beneath. The region is more open in females because of hip geometry. Common cause of strangulation, incarceration
List the common groin lumps
Inguinal hernia
Femoral hernia
Hydrocoele
Cysts
Lymph nodes (infection or malignancy)
Skin lesions (cancers)
Lipomas, seb cysts, abcess
What are 3 ways to determine the cause of an enlarged femoral node
Fine needle
Core biopsy
Gland excision
Femoral aneurism (pulsatile)
Varicocoele, saphino varynx (fills on standing)
What can ultrasound find in the GB
calculus (appears opaque)
polypoidal mucosal thickening (not a polyp but indicates carcinoma)
tumour (adenoma)
Whar can ultrasound and CT identify in pancreatic pathology
Hypodense areas of necrosis
Calcifications
Peripancreatic fluid shadowing
Bleeding into a cavity
What would ultrasound identify with a renal calculus
Dilated calices and the echogenic calculus itself
The ureteric junction is a likely spot for the calculus
Hydroureter
RIF pain ddx
mesenteric adenitis
appendicitis
ectopic pregnancy
What can ultrasound identify in appendicitis
faecolith
Thickened wall
Increased vascularity when using doppler
A CT shows a narrow lumen in an appendix with dark areas around it. Explain
Wall thickening and periappendicular effusions indicating acute appendix
A patient with acute llq pain shows a well defined anechoic sac adjacent to the uterus but within the abdo cacity. What's happening
Ectopic pregnancy
What are the ddx of RIF pain
appendicitis
acute appendix, ectopic preg, mesenteric adenitis
infection
carcinoid
lymphoma
What pathologies might be visible on CT with acute LIF pain
UC shows ulcerations
Diverticular disease
Diverticular abcess
Free air indicates perforated viscus
Small bowrl obstruction showing proximal dilation and distal collapse (adhesions, incarcerated hernia, intersussception, Crohn's, tumour, carcinoma)
What are the large bowel obstructions common in the elderly
Volvulus
Ischaemic cholitis (atheroschlerosis, embolus)
What can US show in obstructive jaundice
Dilated ducts (intrahepatic and common bile)
Calculi
What are the causes of ascites
Cirrhosis
RHF
Peritonitis
Pancreatitis
Cancer (peritoneal, intrahepatic)
List 5 GI causes of clubbing
Primary biliary schlerosis
liver cirrhosis
Inflammatory bowel disease
hepatopulmonary disorder
Malabsorption (Whipples, coeliac, tropical sprue, pancreatic insufficiency)