Gastroenterology Flashcards
Haemochromatosis - inheritance, what gene
Autosomal recessive
HFE gene - C282Y - most common
H63D mutation
Haemochromatosis - what features
Arthritis Diabetes Cardiomyopathy Bronzed skin Liver failure Hypogonadism
Haemochromatosis - reversible organ damage
Pigmented skin
Cardiomyopathy
Haemochromatosis - irreversible organ damage
Arthritis, Diabetes, Liver disease, Hypogonadism
You suspect a patient has haemochromatosis - what test would you do
Screening: Transferrin saturation >50%
A man has haemochromatosis - what test would you do
Known mutations: HFE (or other) gene testing = C282Y gene test
What test would you order on liver histology to look for iron accumulation?
Perl’s stain
What is the greatest risk factor for isoniazid induced hepatitis?
Increasing age (suggest not treating for latent TB unless reactivation risk is high)
UC bowel surveillance
high risk: annual stricture in past 5 years extensive mod /evere colitis dysplasia in past 5 years PSC or transplant for same FHx CRC < 50yo
Primary biliary cirrhosis
cholestatic liver disease raised ALP ALT / AST > 5 times ULN AMA +ve 95% pts ANA +ve elevated IgG normal USS
What are the contraindications to liver biopsy
anaemia < 100 INR > 1.4 plts < 100 hydatid cyst with ecchinococcus granulosus (anaphylaxis if punctured) bile duct obstruction
SE of Boceprevir
Anaemia
Direct antiviral against Hep C (esp Genotype 1)
Altered taste
SE of Telaprevir
Rash - bad, could be hospitalised
Direct antiviral against Hep C (esp Genotype 1)
Extra intestinal manifestations of IBD in ACTIVE disease
Erythema nodosum
Oral ulcers
Arthritis
Episcleritis
Extra intestinal manifestation of IBD independent of active disease (in INACTIVE disease)
PSC Ank spond Uveitis Pyoderma gangrenousum Kidney stones, gall stones
Rx of eosinophilic oesophagitis
Topical steroids
Elimination - 6 foods - milk, egg, wheat, soy, peanuts/treenuts, seafood
Consider dilation (may get mucosal tearing)
Components of blatchford score for GI bleeding
BUN
Hb
BP
Others: Cardiac failure, hepatic failure, syncope, malaena
Dx of pernicious anaemia
intrinsic factor antibodies 100% specific; 50-70% sensitive
elevated fasting serum gastrin level is sensitive but not specific
Hepatic vein pressure gradient HVPG
> 12 indicates cirrhosis, ascites devt
H Pylori
a/w ulcers, MALT, gastric cancer
not a/w GORD
Drug induced liver disease - hepatocellular
paracetamol sodium valproate, phenytoin MAOIs halothane anti-tuberculosis: isoniazid, rifampicin, pyrazinamide statins alcohol amiodarone methyldopa nitrofurantoin
Drug induced liver disease - cholestatic
oral contraceptive pill
antibiotics: flucloxacillin, co-amoxiclav, erythromycin*
anabolic steroids, testosterones
phenothiazines: chlorpromazine, prochlorperazine
sulphonylureas
fibrates
rare reported causes: nifedipine
Drug induced liver disease - cirrhosis
methotrexate
methyldopa
amiodarone
painful red eye
dilated pupil - glaucoma
small pupil - uveitis
alpha 1 antitrypsin
alleles classified by their electrophoretic mobility - M for normal, S for slow, and Z for very slow normal = PiMM homozygous PiSS (50% normal A1AT levels) homozygous PiZZ (10% normal A1AT levels)
autoimmune hepatitis
Features
may present with signs of chronic liver disease
acute hepatitis: fever, jaundice etc (only 25% present in this way)
amenorrhoea (common)
type 1: ANA/Smooth muscle antibodies, raised IgG levels; respond well to steroids
type 2: LKM (liver kidney microsomal) Abs severe course
liver biopsy: inflammation extending beyond limiting plate ‘piecemeal necrosis’, bridging necrosis
coeliac diagnosis
anti endomysial IgA near 100% sens, spec
anti gliadin IgG, IgA 70-90% sens, spec
HLA DQ2 DQ8 universal
SAAG
> 11 indicates portal HT
protein > 3g/dL is exudate - heart failure
< 3g/dL is transudate - cirrhosis
cryoglobulins
type 1: monoclonal a/w lymphoma, hyperviscosity, normal complement levels
type 2: mixed monoclonal; Ab to Fc of IgG (Rh F), HCV, lymphoproflierative disorders, rheumatic disease low complement
type 3: mixed polyclonal HCV, Rh D, low complement
2 + 3: purpura, GN, peripheral neuropathy
Rx; pred, cyclo
CAG PAI
Virulence factor for H. Pylori
PAI = pathogenicity island
H. Pylori
Rx: PPI, clarithromycin, amoxicillin (metro if allergy) 7/7
urease breath test 4/52 post treatment completion PPI may cause FN result
clarithro resistance: levofloxacin, bismuth
amoxycillin DILI
cholestasis
methotrexate DILI
transaminitis
CRC kras mutation
40% CRC
predicts lack of response to EGFR inhibitors (cetuximab)
Lynch Syndrome
BRAF mutation - only in sporadic tumours
anti TNF agents in IBD indications
fisulising crohns
active crohns: induction / maintenance
salvage therapy in UC: fulminant and other treatments failed; not for UC maintenance (ciclo just as good)
paracetamol overdose
activated charcoal only in first 2 hours
cimetidine inhibits 2E1 (protective); chronic alcohol induces 2E1 (worse)
coeliac disease HLA type
HLA DQ2 or DQ8
Whipples disease
Tropheryma whipplei
worm
eye, CNS, lungs, heart, joints
diarrhoea, LOW, fever, malaise, arthralgias, cognitive impairment, ataxia, eye signs
autoimmune enteropathy
looks like coeliac disease but does not respond to exclusion diet
UGI bleed
restart aspirin if for secondary prevention (use PPI cover)
HBV
treat if DNA load > 106IU/ml at any time during the pregnancy
Precore mutant: HBeAg negative but high viral load
HDV is lamivudine resistant
histamine - which cell
ECL (enterochromaffin like) cells
most important paracrine stimulator of acid release
gastrin
G cells
stimulates histamine secretion from ECL cells which stimulates acid secretion from parietal cells
somatostatin
D cells - inhibit gastric acid secretion
(direct action on parietal cells and decreases histamine and gastrin release too)
released in response to low pH
intrinsic factor
parietal cells
acetylcholine
directly stimulates parietal cells to secrete gastric acid
ALT: AST
AST > ALT - alcoholic liver disease, AI liver disease
ALT > AST - NAFLD
Maddreys discriminant function
BI (bili + PT above control) X 4.6
> 32 indicates need for pred for 4/52
PBC
anti mitochondrial Abs 90%
HCC surveillance
6 monthly USS, alpha fetoprotein cirrhotics HBsAg +ve Asian male > 40yo; female > 50yo African male > 20yo; female > 50yo FHx HCC
do not recur post liver transplant
wilsons disease
alpha 1 antitrypsin
abnormality in Wilsons disease
neuro / liver + haemolysis auto recessive ATP 7B mutation Rx: penicillamine, zinc, trientine tetrathiomolybdate for neuro sxs
crohns disease
NOD2 card variant predicts severe disease
ASCA anti saccharomyces ceresvisiae in 70%
azathioprine active metabolite
6TGN
neuroendocrine tumours
chromogranin A positive in 90%
octreoscan
PPI side effects
osteoporosis increased; incl hip # in women
decreased iron absorption
increased c diff
increased CAP
Zollinger Ellison
gastrinoma in pancreas / duodenum
Dx: secretin stimulation test
octreoscan
nutrient absorption
mostly jejunum
calcium - proximal duodenum
B12, bile - terminal ileum
Fe - duodenum
Bloody diarrhoea
E Coli 0157:H7, salmonella, shigella, campylobacter
diarrhoea < 6/24
staph aureus / bacillus cereus
HVPG
hepatic vein pressure gradient = WHVP - FHVP wedged hepativ vein pressure minus free hepatic vein pressure normal 1-5; clin sigt portal HT > 10 risk bleeds > 12
Gilbert
defect in bilirubin conjugation due to defect in UGT1A1
Wilsons
cannot put copper into caeruloplasmin
low caeruloplasmin, copper accumulates in bile
auto rec ATP7B
