week 3 Flashcards
coeliac disease
a gluten-sensitive enteropathy. Small intestinal atrophy which resolves when gluten is removed from the diet
where is iron primarily absorbed
duodenum and upper jejunum
z line
the line of transition from the oesophageal mucosa to gastric mucosa
location of pancreas
retroperitoneal. Epigastric and left hypochondrium
blood supply of the pancreas
pancreatic branches of the splenic artery. Head supplied by branches of the coeliac trunk and mesenteric arteries.
drainage of pancreas
head drained into superior mesenteric branches of hepatic portal vein.
Pancreatic veins drain rest of pancreas into splenic vein
how much iron is in the body
4g
how much iron is contained within the rbcs and bone marrow?
3g
would ferritin be increasedor decreased in IDA?
decreased
what is the effect of hepcidin
reduces level of iron in the plasma by binding ferroportin and degrading it
defects in hepcidin (its loss) cause
increased iron absorption in the gut, increased iron release and increased Transferrin saturation which leads to parenchymal iron overload
Hep a
Rna virus, self-limiting, 30 days incubation period, only acute illness, IgM + or RNA in serum if acute illness. No treatment
Vaccine exists
Hep a vaccine
inactivated virus vaccine, 95% efficacy, given pre-exposure to at risk groups. Generally given for travel-related reasons
Hep e
RNA virus, similar to hep a but has rare neuro effects. No vaccine, faeco orla and pork but not really person-person
4 genotypes
Hep B
DNA virus, infected bodily fluids, acute and chronic, age factor in whether it will progress to chronic,
Chronic - can leads to HHC and CLD. Patients in two groups, eAg+ or eAG-.
To treat chronic either give IFN or anti-viral drugs to suppress viral replication.
Hep d
ss RNA virus, have to have hep B. Either co-infect with Hep b Or acquire at a later date. Can only treat with ifn alpha
hep c
6-7 week incubation after which 25% of people will be asymptomatic. Of thoss infectefd 30% will clear and 70% will develop chronic. Of these 25% will develop cirrhosis and 1-5% HCC
Treated with either IFN alpha + riabavarin or DAAs
reducing sugars
those that contain an aldelhyde group
reducing power
the smaller the chain the greater the reducing power. Greater power = greater sweetness
unconjugated hyperbilirubinaemia
indirect bilirubin wil be >85% of total bili.
Increased bili production, defects in hepatic uptake or conjugation
conjugated hyperbilirubinaemia
direct bilirubin >50%. Occurs where defects in hepatic excretion are seen
Gilbert’s syndrome
benign autosomal dominant condition. Caused by deficiency of enzymes that conjugate bilirubin. High levels of uncojugated bilirubin with normal LFTs is what you would see
which bacteria produce a toxin prior to infection?
S. aureau and B. cereus.
patients become unwell rapidly
which bacteria produce a toxin after consumption?
C.diff and E.coli 157
which bacteria invade across the epithelial cell barrier
salmonella
3 elements of a syndromic approach to enteric infection
vomiting, diarrhoea, non-intestinal manifestations
campylobacter
from chicken normally. 9000 infecting dose which is high. Normal incubation of 3 days but can vary depending on infecting dose.
Vomiting is rare. Sensitive to stomach acid. Normally 7 day course. Can become resitant to anti-biotics during treatment.
Guillan barré and reactive arthritis
Salmonella
typhoidal and non-typhoidal serotypes. Spreads person to person. Infectious dose of 10,000 organisms. Treat if worried about bacteraemia. Risk increased if reduced stomach acidity or diminished intestinal flora
fall ill within 72 hours.
E.coli 0157
person to person, Very lowinfectious dose of 10. Attaches to the large bowel and secretes shiga toxin. Kills enterocytes and enters systemic circulation. CAn cause haemolytic uremia syndrome- microangiopathic uraemic syndrome- deposition of fibrin clots, renal failure and thrombocytopenia. Bloody diarrhoea and abdominal tenderness, fever is rare. Supportive treatment.
C. diff
Less diverse gut flora. Have a loose stool and colic, and fever. If bad can develop into pseudomembranous colitis. Toxin is important. Lab tests - tissue culture assay (takes ages). C. diff antigen and then C.diff toxin.
Treating - change to narrow spectrum anti-biotic e.g. metronidazole. Faecal transplant.
Norovirus
faecal-oral, 10-100 infectious dose. very stable. 24-28 hours acute explosive diarrhoea and vomiting. No lasting immunity
pancreatic enzymes secreted as zymogens
trypsin (proteins), chymotrypsin (proteins), carboxypeptidase (proteins),. elastase (proteins), phospholipase (phospholipids), co-lipase
pancreatic enzymes secreted in their active form
amylase (starches), lipase (triglycerides), ribonuclease (ribonucleic acids), deoxyribonuclease (deoxyribonucleic acids)
MMC
Migrating motor complex - 90-120 minutes between meals. Causes weak repetitive peristaltic waves
chronic pancreatitis
chronic inflammation of the pancreas, leading to destruction of the exocrine and endocrine components
surface marking of the liver
same level as costal margin
location of gall bladder (surface anatomy)
where the right edge of rectus abdominus reaches the costal margin
how saturated is transferrin generally?
30%
Where does GI absorption of iron mainly take place?
duodenum
gastro-ileal reflex
segmentation in the ileum begins due to gastrin secreted in response to the presence of chyme in the stomach
major form of propulsion in the small intestine
peristalsis
hepcidin
hormone that binds ferroportin and degrades it. It reduces the level of iron in the plasma, reduces GI iron absorption and reduces macrophages iron release from the RES system.
produced by the liver. Loss results in haemacromatosis
hereditary haemachromatosis
autosomal recessive disorder or iron metabolism causing iron overload. Abnormalities of the HFE gene are responsible for most cases. Thought to work mainly through reducing hepcidin production.
Can see transferrin concentrations of 100%
Normal transferrin saturation
30%
IDA - <15%
refractory coeliac disease
recurrent malabsorptive symptoms and villous atrophy despite strict adherence to GF diet for at least 6-12 months and i absence of any other causes or malignancy
Type I: villous atrophy with negative immuno-phenotype
Type Ii: villous atrophy with abnormal immunio-phenotype
length of the duodenum
25-38cm
blood supply of duodenum
proximal to major dueodenal papilla - gastroduodenal artery (coeliac trunk)
Distal to major duodenal papilla supplied by superior mesenteric artery
length of the jejunum
2.5m
what marks the division between the duodenum and jejunum?
suspensory muscle of duodenum
lenght of the ileum
about 3 m long
characteristic pathology in coeliac
loss of villous height due to atrophy and inflammatory infiltrate
dermatitis herpetiformis
intensely itchy rash on extensor surfaces, associated with coeliac disease
what would suggest a chronic hep B carrier had a low chance of progression to HCC and cirrhosis
eAg negative - suggestive of low viral load and that they are less infectious
treatment of chronic Hep B sufferers with liver inflmmtion (LFT and biopsy)
immunological - pegylated IFN-alpha. Year long treatment but with lots of side effects
anti-viral drugs - tenofovir. Need to be taken life long. Fewer side effects
treatment of hep D
requires Hep B to be there. Increases likelihood of progression to chronic liver disease
Can only be treated with pegylated IFN-alpha
treatment of Hep C
pegylated IFN-alpha and ribavrin - cure rate of 40-60% after 24-48 weeks of treatment which is hard to maintain.
Direct-acting anti-virals: attack viral replication cycle with a cure rate of 95%. 8-12 week tablet course.
